CN104080247B - Integrated circuit, power supply device and illuminating device - Google Patents

Abstract

The present invention relates to an integrated circuit, a power supply device and a lighting device. The integrated circuit includes: a switch element with a pair of main terminals and a control element; a current control element with a pair of main terminals and a control element; a diode element with a pair of main terminals and a control element. For the main terminal; the integrated circuit includes a series connection body, the series connection body is connected in series with the main terminals of the switching element, the current control element and the diode element, and the series connection body includes : 1st external terminal; 2nd external terminal; 3rd external terminal; 4th external terminal; and 5th external terminal.

Description

Integrated circuit, power supply unit and lighting unit

This application is a divisional application of the application with application number 201010540958.1 and the title of the invention is "LED lighting device and lighting device". The filing date of the original parent application is November 8, 2010.

This application is based on Japanese Patent Application No. 2009-256363 filed on November 9, 2009, Japanese Patent Application No. 2010-027398 filed on February 10, 2010, and Japanese Patent Application No. 2010-027398 filed on March 19, 2010. Patent Application No. 2010-064436 and claims priority thereto, which are incorporated herein by reference in their entirety.

technical field

Embodiments of the present invention relate to an integrated circuit, a power supply device including the integrated circuit, and a lighting fixture including the power supply device.

Background technique

In recent years, devices using LED elements as light sources have been put into practical use as the optical properties of light-emitting diode (LED) elements have improved. As an LED lighting device for lighting an LED element, for example, a direct-current LED lighting device using a switching mechanism is widely used.

Conventionally, transistors (transistors) using Si (silicon) semiconductors and the like have been used for switching mechanisms (switching elements) of LED lighting devices. Furthermore, transistors using wide bandgap semiconductors such as SiC (silicon carbide), GaN (gallium nitride), and diamond are attracting attention.

Wide bandgap semiconductors generally have a normally on characteristic that allows current to flow when the gate voltage is zero. Semiconductor elements using wide bandgap semiconductors include Junction Field Effect Transistor (JFET), Static Induction Transistor (SIT), Metal-Semiconductor Field-Effect Transistor (Metal-Semiconductor-Field-Effect-Transistor), etc. , MESFET), heterojunction field effect transistor (Heterojunction Field Effect Transistor, HFET), high electron mobility transistor (High ElectronMobility Transistor, HEMT) and accumulation FET, etc.

In order to reliably turn off a semiconductor element having a normally-on characteristic (hereinafter referred to as a normally-on switch), the LED lighting device must include a control circuit for a negative gate voltage.

Furthermore, it is known to use a direct current-direct current (DC-DC) converter (DC-DC) to light an LED element to obtain an LED lighting device with high circuit efficiency. A DC-DC converter is capable of constant current control by driving switching elements using induced electromotive force.

However, the LED lighting device in the background art requires a current feedback type feedback circuit composed of an impedance mechanism such as a resistive element inserted in series with a switching element and convecting the current to the inductor ( inductor), the control circuit turns off the switching element when the voltage drop of the impedance mechanism reaches a preset threshold. Furthermore, in order to realize the constant current control of the light emitting diode, a secondary coil magnetically coupled to the inductor is provided, and a voltage induced in the secondary coil is used to obtain a conduction signal of the switching element. Therefore, there is a problem that the circuit structure is complicated, and the structure of the inductor is complicated, thereby hindering miniaturization or integrated circuits (Integrated Circuit, IC).

Contents of the invention

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an integrated circuit, a power supply device, and a lighting device using normally-on switching elements that have a simple circuit structure and can be made inexpensive.

An object of the present invention is to provide an integrated circuit, a power supply device, and a lighting device that can operate more efficiently.

In order to solve the above problems, the integrated circuit of the present invention includes: a switching element having a pair of main terminals and a control element; a current control element having a pair of main terminals and a control element; a diode element having a pair of main terminals; the integrated circuit It includes a series connection body, the series connection body is connected in series with the main terminals of the switching element, the current control element, and the diode element, and the series connection body includes: a first external terminal located at the One end side of the series connection body, and is a main terminal of at least one of the switching element, the current control element, and the diode element, the first external terminal and the main terminal not connected to other elements The main terminals connected are connected; the second external terminal is located at the other end side of the series connection body and is a main terminal of at least one of the switching element, the current control element, and the diode element, so The second external terminal is connected to the main terminal that is not connected to the main terminal of other components; the third external terminal is connected to at least two of the switching element, the current control element, and the diode element The main terminals are derived from the connection point; the fourth external terminal is derived from the control terminal of the switching element; and the fifth external terminal is derived from the control terminal of the current control element.

In addition, gallium nitride is used for at least any one of the switching element, the current steering element, and the diode element.

In addition, the switching element is a normally-on field effect transistor, the switching element has a source or a drain as the pair of main terminals, and the switching element has a gate as the control terminal.

In addition, the current control element is a normally-on type field effect transistor, the current control element has a source or a drain as the pair of main terminals, and the current control element has a gate as the control terminal .

In order to solve the above problems, the power supply device of the present invention includes the integrated circuit, and the power supply device includes: an inductor connected to the third external terminal of the integrated circuit; a drive coil magnetically coupled to the inductor And connected to the fourth external terminal of the integrated circuit.

In addition, when the switching element of the integrated circuit of the power supply unit has a current flowing through the current control element reaching a predetermined current value, the potential passing through the connection point between the switching element and the current control element becomes The potential of the control terminal of the switching element is higher than that of the switching element for turning off.

In order to solve the above problems, a lighting device according to the present invention includes: the power supply device; and a light emitting element supplied with power from the power supply device.

In addition, the current control element of the integrated circuit of the power supply unit utilizes the forward voltage generated in the light emitting element by applying the voltage between the control terminal and the main terminal of the switching element. The threshold voltage is set lower than the control terminal voltage, and the voltage between the control terminal and the main terminal of the switching element is set to a negative voltage, so that the switching element is turned off.

Furthermore, the current control element of the integrated circuit of the power supply device turns off the switching element when a forward voltage generated in the light emitting element is higher than a predetermined voltage.

In addition, the current control element of the integrated circuit of the power supply unit sets the voltage applied between the control terminal and the main terminal of the switching element to a threshold voltage higher than the control terminal voltage, so that The switching element performs a conduction operation.

According to the present invention, the entire chopper can be further miniaturized and high-speed switching can be easily performed by configuring the switching element, the constant current mechanism as the current control element, and the diode as an integrated circuit having five external terminals.

Furthermore, by using the forward voltage generated in the semiconductor light-emitting element to turn off the normally-on switching element, it is unnecessary to incorporate a special circuit, and the size and price of the device can be reduced.

According to the present invention, an appropriate negative potential can be obtained by the forward voltage generated in the semiconductor light-emitting element, and the normally-on field effect transistor can be reliably turned off, thereby reducing the self-inductance caused by the normally-on field effect transistor. Oscillation stops to realize circuit protection.

Description of drawings

FIG. 1 is a diagram showing an example of a lighting fixture according to an embodiment.

Fig. 2 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 3 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

FIG. 4 is a diagram showing a configuration example of a constant voltage power supply according to an embodiment.

Fig. 5 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 6 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 7 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 8 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

9( a ) to 9( e ) are diagrams showing examples of current and voltage waveforms in each part of the LED lighting device according to one embodiment.

Fig. 10 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 11 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 12 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

FIGS. 13( a ) to 13 ( f ) are diagrams showing examples of current and voltage waveforms in each part of the LED lighting device according to one embodiment.

Fig. 14 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 15 is a diagram showing a configuration example of an LED lighting device according to an embodiment.

Fig. 16 is a diagram showing an example of an integrated circuit module (module) of the LED lighting device according to the embodiment.

Fig. 17 is a diagram showing an example of an integrated circuit module of the LED lighting device according to the embodiment.

1: Instrument body 1a: Abutment

2, 3: LED lighting 4: Lampshade

10. AC: AC power supply 11: Full-wave rectification circuit

12, 20, 34, 36, 38, 41, 44, 48, 60, 75, 76: Capacitor

13, 32, 33, 43, 47, 51, 52, 53, 54, 61, 62, 71, 80: field effect transistors

14, 31, 55, 72: LED component group 15: Resistance component

16, 35, 65, 74, L1, L11: Inductor

17, 85: power supply

18: Normally off field effect transistor

19, 21, 24, 32a, 33a, 37, 40, 43a, 51a～54a, 56～59, 61a, 62a, 86, 87, D11: diode

22, 77: freewheeling diode 23, 81, 82: comparator

39: 1st driving source 42: 2nd driving source

46, DC, E3: DC power supply 49, ZD1, ZD2: Zener diode

63: Drive source 64: Switch drive unit

66, 73, 78, 83, 84: Resistance element 79: Oscillation stop part

100: Power supply unit 161: Auxiliary coil

A: 1st circuit B: 2nd circuit, substrate structure

C: Third circuit, planar capacitor structure C1: Smoothing capacitor

C2, C13: output capacitor C11: capacitor for high frequency bypass

C12: Coupling capacitor CC: Control circuit

CCM: Constant Current Mechanism CH: Chopper

CPh: Hysteresis comparator CS: Control switch

D: 4th circuit D1: Freewheeling diode

DB: rectifier circuit DW: drive coil

E: Reference potential E1: Adjustable potential source

E2: Reverse bias power supply G: Ground wire, GaN chip

h: through-hole IC, IC': integrated circuit module

ID: reduce current IO: output current

IU: Increased current L: Planar coil structure

LC: load circuit M: magnet layer

MC: Matching circuit P1: 1st external terminal

P2: 2nd external terminal P3: 3rd external terminal

P4: 4th external terminal P5: 5th external terminal

Q1: Normally-on switch Q2, Q3: Bipolar transistor

Q11: Switching elements Q12, Q13: Transistors

R1: Feedback resistor R2, R3, R4, R5, R6, R11: Resistors

T: Terminal forming body t: Terminal part

t1, t2: input terminals t3, t4: DC output terminals

TE: External terminal Vc: Constant voltage

VCCM: Voltage of constant current mechanism VD: Voltage divider

Vdd: Control power supply Vf: Reference signal

VGS: Voltage between gate and source VL1: Voltage

VZ1: Terminal voltage W: Wiring forming body

Z1: Impedance element for current detection

detailed description

Generally speaking, according to one embodiment of the present invention, an LED lighting device includes: an output generating mechanism having at least one normally-on switching element, which generates a DC output through the on/off operation of the switching element; The element is turned on by the DC output generated by the output generation means; and the drive control means is used to turn off the switching element by using the current flowing through the semiconductor light emitting element.

Embodiments are described below with reference to the drawings.

(first embodiment)

FIG. 1 is a perspective view showing a lighting fixture to which a power supply device (LED lighting device) according to a first embodiment is applied. First, a lighting fixture including a power supply device will be briefly described.

In Fig. 1, 1 is an appliance body. The tool body 1 has a disc-shaped base 1a. And, ring-shaped LED lighting lamps 2 and 3 , which are light sources and have different diameters, are arranged concentrically on the base 1a. A milky white shade 4 is attached to cover the LED lighting lamps 2 and 3 . Inside the appliance main body 1, a power supply unit 100 is arranged. In addition, although not shown, a reflector, terminals, wiring, and the like may be further provided on the appliance main body 1 .

FIG. 2 shows a schematic configuration of a power supply device 100 incorporated in the fixture body 1 of the lighting fixture shown in FIG. 1 .

In Fig. 2, 10 is an AC power supply. The AC power supply 10 includes a commercial power supply (not shown). An input terminal of a full-wave rectification circuit 11 is connected to the AC power supply 10 . The full-wave rectification circuit 11 generates an output of full-wave rectification of the AC power from the AC power supply 10 . A capacitor (condenser) 12 for smoothing a ripple current is connected between positive and negative output terminals of the full-wave rectifier circuit 11 .

A normally-on field effect transistor 13 made of, for example, GaN is connected to the capacitor 12 as a switching element constituting a step-down chopper.

The field effect transistor 13 is formed by joining different types of semiconductor materials having different band gaps. The field effect transistor 13 has a two-dimensional electron gas (gas) layer on the interface. The field effect transistor 13 can realize high-speed switching and sensitivity by utilizing the effect of the two-dimensional electron gas layer. The field effect transistor 13 is called a HEMT (High Electron Mobility Transistor).

In addition, in this field effect transistor 13 , the voltage between the gate and the source is Vgs, and the threshold value of the gate voltage is Vth (negative voltage). The field effect transistor 13 is turned off when Vth>Vgs, and turned on when Vth<Vgs.

The drain of the field effect transistor 13 is connected to the positive output terminal of the full-wave rectification circuit 11 . The source of the field effect transistor 13 is connected to the output terminal on the positive side of the full-wave rectification circuit 11 via a series circuit of an LED element group 14, a resistor element 15, and an inductor 16. The LED element group 14 has a plurality of LED elements connected in series. LED elements are semiconductor light emitting elements. Moreover, the gate of the field effect transistor 13 is connected to the connection point of the resistance element 15 and the inductor 16 via a field effect transistor 18 of normally off type, and the field effect transistor 18 of the normally off type serves as a driving control device. Mechanism switching element.

In addition, the field effect transistor 13 is connected between a source and a gate with a diode 19 of the illustrated polarity for gate protection.

The LED element group 14 corresponds to the LED lighting lamps 2 and 3 shown in FIG. 1 . When a current flows through the LED element group 14, a forward voltage with the polarity shown in the figure is generated at both ends. The field effect transistor 13 is turned off by applying the negative potential of the forward voltage between the source and the gate of the field effect transistor 13 . Furthermore, a capacitor 20 is connected in parallel to the LED element group 14 .

The inductor 16 has a coupled auxiliary coil 161 . One end of the auxiliary coil 161 is connected to a connection point between the resistance element 15 and the inductor 16 . The other end of the auxiliary coil 161 is connected to the gate of the field effect transistor 18 via a diode 21 of a polarity not shown. And, by accumulating and releasing electromagnetic energy (energy) in the inductor 16 according to the ON/OFF operation of the field effect transistor 13, an electromagnetic energy (energy) is generated at both ends of the capacitor 20 via a flywheel diode (flywheel diode) 22. buck DC output. Furthermore, a self-inductance circuit is configured for turning on/off the field effect transistor 18 by the output of the auxiliary coil 161 in synchronization with the accumulation and discharge of electromagnetic energy in the inductor 16 .

A comparator 23 constituting a constant current control mechanism is connected to the resistance element 15 . The comparator 23 is connected to the gate of the field effect transistor 18 via a diode 24 with the polarity shown in the figure. Furthermore, one input terminal of the comparator 23 is connected to a power supply 17 that generates a preset reference signal Vf. To the other terminal of the comparator 23 , a load current flowing through the resistance element 15 is input. The comparator 23 compares the input load current with the reference signal Vf. When the load current reaches the reference signal Vf as a result of the comparison, the comparator 23 forces the field effect transistor 18 to conduct an ON operation.

Next, the operation of the embodiment configured in this way will be described.

Now, when the power is turned on by a power switch not shown, a forward voltage of the illustrated polarity is generated across both ends of the LED element group 14 via the field effect transistor 13 in the on state. Moreover, when the current flowing in the LED element group 14 reaches the reference signal Vf of the comparator 23 due to the conduction of the field effect transistor 13, the field effect transistor 18 is turned on, and the negative potential of the forward voltage of the LED element group 14 is turned on. It is applied between the source and the gate of the field effect transistor 13 . At this time, Vth>Vgs is satisfied, and the field effect transistor 13 is turned off. In this state, a signal to keep the field effect transistor 18 turned on is generated from the auxiliary coil 161 of the inductor 16 . When the inductor 16 has finished discharging, the field effect transistor 18 is turned off. At this time, Vth<Vgs becomes Vth<Vgs, so the field effect transistor 13 is turned on again.

Hereinafter, the same operation is repeated, and the field effect transistor 13 is turned on/off by the switching operation of the field effect transistor 18 . Accumulation and discharge of electromagnetic energy in the inductor 16 generates a DC output with a reduced voltage across the capacitor 20 via the freewheel diode 22 . The LED element group 14 is turned on by this direct current output.

Moreover, when the load current flowing through the resistance element 15 reaches the preset reference signal Vf of the comparator 23, the field effect transistor 18 is turned on, and the field effect transistor 13 is turned off. Thus, the load current is limited, and the load current flowing through the LED element group 14 is controlled so as to always match the reference signal Vf, whereby constant current control is performed.

Therefore, in this way, the normally-on field effect transistor 13 can be used as a switching element constituting the step-down chopper, and the field effect transistor 13 can be turned off by the forward voltage generated on the LED element group 14 . Accordingly, it is no longer necessary to incorporate a special power supply circuit required to obtain a negative voltage for turning off the normally-on field effect transistor 13 , and the number of parts can be reduced. Furthermore, the circuit configuration can be simplified, the device can be downsized, and the price can also be reduced.

Furthermore, due to the forward voltage generated in the semiconductor light emitting element 14, an appropriate negative potential of Vth>Vgs (gate-source voltage) is obtained with respect to the threshold value Vth of the gate voltage of the field effect transistor 13, so that the normal The field effect transistor of the pass type is positively turned off.

Furthermore, a normally-on field effect transistor 13 made of GaN is used as a switching element. The field effect transistor 13 can be increased in frequency without lowering efficiency. Accordingly, the capacity of impedance elements such as inductors and capacitors constituting the circuit can be reduced, and modularization can be realized by further downsizing the device.

Furthermore, by changing the reference voltage Vf of the power supply 17 by an external operation or the like, dimming of the LED element group 14 can also be performed. At this time, for example, it is preferable to provide a receiving mechanism for receiving control signals through an insulating type input mechanism composed of a remote controller (remote controller) or a photocoupler (photocoupler) on the side of the substrate (not shown) on which the LED element group 14 is mounted. circuit.

In addition, in order to optimize the forward voltage generated at both ends of the LED element group 14, the number of LED elements connected in series is limited. Therefore, when more LED elements are needed as LED lighting lamps, as long as the appropriate More LED elements may be connected in series with the inductor 16 .

(second embodiment)

Next, a second embodiment will be described.

FIG. 3 shows a schematic configuration of the second embodiment, and the same parts as those in FIG. 2 are assigned the same reference numerals.

At this time, between the capacitor 12 connected between the positive and negative output terminals of the full-wave rectifier circuit 11, an LED element group 31 having a plurality of LED elements connected in series as semiconductor light emitting elements is connected in series, such as A series circuit of normally-on field effect transistors 32 and 33 made of GaN serves as a switching element. These field effect transistors 32 and 33 also have a negative threshold value Vth of the gate voltage, and are turned off when Vth>Vgs (gate-source voltage), and turned on when Vth<Vgs. Furthermore, these field effect transistors 32 and 33 are respectively connected between source and drain with diodes 32a and 33a of polarity shown in the figure.

A capacitor 34 is connected in parallel to the series circuit of field effect transistors 32 and 33 , and a series circuit of an inductor 35 and a capacitor 36 is connected in parallel to the field effect transistor 33 . A diode 37 with the polarity shown in the figure is connected between the gate and the source of the field effect transistor 32 , and a first drive source 39 is connected between the diodes 37 via a capacitor 38 . Furthermore, the field effect transistor 33 is also connected between the gate and the source with a diode 40 of the polarity shown in the figure, and between the diodes 40, a second drive source 42 is connected via a capacitor 41 . The first drive source 39 and the second drive source 42 output positive and negative pulse signals via the capacitors 38 and 41, and alternately input the negative voltage signals of the half-wave rectified by the diodes 37 and 40 to the field effect transistors. Between the gate and source of 32 and 33.

A normally-on field effect transistor 43 made of, for example, GaN is connected to a connection point between the capacitor 12 and the LED element group 31 as a switching element which is a drive control mechanism. The drain of the field effect transistor 43 is connected to the connection point between the capacitor 12 and the LED element group 31 , and the source is connected to the gate of the field effect transistor 33 via the capacitor 44 . Furthermore, the gate of the field effect transistor 43 is connected to the connection point between the capacitor 44 and the gate of the field effect transistor 33, the power is turned on, and the forward voltage of the LED element group 31 causes the capacitor 44 to generate a negative potential and input it to the field. The gate of the effect transistor 33. The field effect transistor 43 is connected between a source and a drain with a diode 43a having the polarity shown in the figure.

Next, the operation of the embodiment configured in this way will be described.

Now, when the power supply is turned on by a power switch not shown in the figure, and a forward voltage is generated in the LED element group 31, the charging current flows to the capacitor 44 through the field effect transistor 43 in the on state due to the forward voltage. Capacitor 44 is charged with the polarity shown. Then, the negative potential of the capacitor 44 is applied to the gate of the field effect transistor 33, and the field effect transistor 33 is turned off. This prevents a short circuit caused by the LED element group 31 and the on-state field effect transistors 32 and 33 when the power is turned on, and prevents accidents in which an overcurrent flows and damages the LED element group 31 . In addition, the charged charge of the capacitor 44 is discharged through the diode 43 a of the field effect transistor 43 .

Then, by the output from the first driving source 39 and the second driving source 42 , negative voltage signals are alternately input between the gates and sources of the field effect transistors 32 and 33 via the diodes 37 and 40 . First, when the field effect transistor 32 is turned on and a negative voltage signal is input from the second drive source 42 to the gate of the field effect transistor 33 to turn it off, the current flows from the positive side of the full-wave rectification circuit 11 to the LED element group. 31. A field effect transistor 32, an inductor 35, a capacitor 36, and the negative side of the full-wave rectification circuit 11. Electromagnetic energy is accumulated in the inductor 35. In this state, when a negative voltage signal is input from the first drive source 39 to the gate of the field effect transistor 32 to make it disconnected, the electromagnetic energy of the inductor 35 makes the charging current pass through the capacitor 36 and the gate of the field effect transistor 33. The diode 33a continues to flow to the capacitor 36 . So far, the operation of the step-down chopper using the capacitor 36 as an output capacitor has been described.

Secondly, when the field effect transistor 33 is turned on, and the gate of the field effect transistor 32 is input with a negative voltage signal from the first drive source 39 to make it disconnected, there is no charging current, and the discharging current passes from the capacitor 36 through the inductor 35, field The effect transistor 33 flows, and electromagnetic energy is accumulated in the inductor 35 . And, in this state, when a negative voltage signal is input from the second driving source 42 to the gate of the field effect transistor 33 to make it disconnected, the electromagnetic energy of the inductor 35 passes through the diode 32a of the field effect transistor 32, the capacitor 34 while flowing. Thereafter, when the same operation is repeated, the load current continues to flow to the LED element group 31 , and the LED element group 31 is turned on by this current.

Therefore, in this way, as the power supply rises, the forward voltage of the LED element group 31 can be used to cause the charging current to flow to the capacitor 44 through the normally-on field effect transistor 43 for charging, and the negative potential of the capacitor 44 can be charged. The normally-on field effect transistor 33 constituting the switch circuit is turned off. Also in this case, the same effect as that of the first embodiment can be obtained. Furthermore, the circuit short circuit at the time of power startup caused by the conduction of the field effect transistors 32 and 33 can be prevented, so the problem of overcurrent flowing through the LED element group 31 can be reliably eliminated, and accidents such as damage to the LED element group 31 can be prevented. Before it happens.

(Modification)

FIG. 4 is a diagram showing a schematic configuration of a constant voltage power supply applied to the second embodiment. In the second embodiment, a constant voltage power supply shown in FIG. 4 can be used as a power supply. At this time, the drain of a normally-on field effect transistor 47 is connected to the positive terminal of the DC power supply 46 , and the source of the field effect transistor 47 is connected to the negative terminal of the DC power supply 46 via a capacitor 48 . Furthermore, between the gate of the field effect transistor 47 and the negative side terminal of the DC power supply 46, a Zener diode (Zener diode) 49 of the polarity shown in the drawing is connected. The Zener diode 49 generates a fixed voltage by the Zener effect.

In this way, by turning on the field effect transistor 47, a constant voltage Vc of the Zener diode 49 can be generated between the capacitors 48, and this constant voltage can be used as a power source.

(third embodiment)

Next, a third embodiment will be described.

FIG. 5 shows a schematic configuration of the third embodiment, and the same reference numerals are assigned to the same parts as in FIG. 2 .

At this time, between the capacitors 12 connected to the positive and negative output terminals of the full-wave rectification circuit 11, a series circuit of a full bridge circuit and the LED element group 55 is connected. The full bridge circuit is made of, for example, GaN A series circuit of normally-on field effect transistors 51 and 52 is connected in parallel to a series circuit of normally-on field effect transistors 53 and 54 also made of GaN to serve as switching elements. The LED element group 55 has a plurality of LED elements connected in series serve as semiconductor light emitting elements. Furthermore, an inductor 65 is connected between the connection point of the field effect transistors 51 and 52 and the connection point of the field effect transistors 53 and 54 .

For the field effect transistors 51 to 54, the threshold value Vth of the gate voltage is also a negative voltage, and when Vth>Vgs (the voltage between the gate and the source), it is turned off and is turned on when Vth<Vgs. effect transistor. To these field effect transistors 51 to 54, diodes 51a to 54a with polarities shown in the drawings are connected between source and drain, respectively. Furthermore, the field effect transistors 51 to 54 are respectively connected with diodes 56 to 59 for gate protection between respective gates and sources. Furthermore, a capacitor 60 is connected in parallel to the bridge circuit of the field effect transistors 51 to 54 .

When a current flows in the LED element group 55 , a forward voltage of the polarity shown in the figure is generated at both ends, and the ground G side is brought to a negative potential by the forward voltage. At this time, the negative potential on the ground G side is set to be equal to or less than the threshold Vth of the gate voltages of the field effect transistors 51 to 54 .

The gates of the field effect transistors 51 and 54 are connected in common and are connected to the ground line G via a normally-on field effect transistor 61 made of GaN as a drive control mechanism. Similarly, the field effect transistors 52 and 53 are connected to the ground line G. The respective gates are connected in common and connected to the ground G via a normally-on field effect transistor 62 made of GaN as a drive control mechanism.

The field effect transistors 61 and 62 are respectively connected between source and drain with diodes 61a and 62a of polarity shown in the figure. These field effect transistors 61 and 62 and the drive source 63 constitute a switch drive unit 64 . The driving source 63 is connected to the gates of the field effect transistors 61 and 62 and alternately inputs negative voltage signals to the gates of the field effect transistors 61 and 62 .

In addition, 65 and 66 are resistive elements for accelerating recovery from the OFF state to ON of the field effect transistors 52 to 54 .

Next, the operation of the embodiment configured in this way will be described.

Now, when the power supply is turned on by a power switch not shown in the figure, due to the conduction of the field effect transistors 51 to 54, a forward voltage of the polarity shown in the figure is generated on the LED element group 55, so that the ground line G side is negative potential. In this state, a negative potential on the ground G side is applied to the respective gates of the field effect transistors 51 to 54 via the field effect transistors 61 and 62 in the on state, and the field effect transistors 51 to 54 are turned off. This prevents a circuit short circuit caused by the field effect transistors 51 to 54 and the LED element group 55 when the power is turned on.

Subsequently, a negative voltage signal is alternately input to the gates of the field effect transistors 61 and 62 by the output from the drive source 63 of the switch drive unit 64 . First, when the field effect transistors 51 and 54 are turned on, the field effect transistor 62 is turned on, and the gates of the field effect transistors 52 and 53 are turned off by applying a negative potential on the side of the ground line G, the current is from full-wave rectification The positive side of the circuit 11 flows to the field effect transistor 51 , the inductor 65 , the field effect transistor 54 , and the LED element group 55 , and electromagnetic energy is accumulated in the inductor 65 . In this state, when the field effect transistor 61 is turned on, and the gates of the field effect transistors 51 and 54 are turned off by applying a negative potential on the side of the ground line G, the electromagnetic energy of the inductor 65 causes the charging current to pass through the field. The diode 53 a of the effect transistor 53 , the capacitor 60 , and the diode 52 a of the field effect transistor 52 flow.

Secondly, when the field effect transistors 52 and 53 are turned on, the field effect transistor 61 is turned on, and the negative potential of the ground line G is applied to the gates of the field effect transistors 51 and 54 to make them disconnected, the charging current flows from the capacitor 60 through the field effect Transistor 53 , inductor 65 , and field effect transistor 52 flow, and electromagnetic energy is accumulated in inductor 65 . In this state, when the field effect transistor 62 is turned on, and the negative potential of the ground line G is applied to the gates of the field effect transistors 52 and 53 to turn them off, the electromagnetic energy of the inductor 65 passes through the diode of the field effect transistor 51 51a, the capacitor 60, and the diode 54a of the field effect transistor 54 flow as charging current. Thereafter, when the same operation is repeated, the load current continues to flow to the LED element group 55 , and the LED element group 55 is turned on by the load current.

Therefore, in this way, as the power supply rises, the forward voltage of the LED element group 31 can be used to set the ground line G side to a negative potential, and the negative potential on the ground line G side can be used to make the normally-on state of the switch circuit. Type field effect transistors 51 to 54 are turned off. Also in this case, the same effect as that of the first embodiment can be obtained. Furthermore, it is possible to prevent a short circuit during power startup caused by the conduction of the field effect transistors 51 to 54, so that the problem of overcurrent flowing through the LED element group 55 can be reliably eliminated, and accidents such as damage to the LED element group 31 can be prevented. Before it happens.

(fourth embodiment)

Next, a fourth embodiment will be described.

FIG. 6 shows a schematic configuration of the fourth embodiment, and the same parts as those in FIG. 2 are given the same reference numerals.

At this time, as described in the first embodiment, a normally-on field effect transistor 71 made of, for example, GaN is connected to the capacitor 12 as a switching element constituting a step-down chopper.

In this field effect transistor 71, the threshold value Vth of the gate voltage is a negative voltage. The field effect transistor 71 is turned off when Vth>Vgs (gate-source voltage), and turned on when Vth<Vgs. The field effect transistor 71 has its drain connected to the output terminal on the positive side of the full-wave rectifier circuit 11, and its source is connected via an LED element group 72 having a plurality of LED elements connected in series as semiconductor light emitting elements, a resistor element 73, and an inductor. A series circuit of 74 is connected to the positive-side output terminal of the full-wave rectification circuit 11 .

The LED element group 72 corresponds to the LED lighting lamps 2 and 3 shown in FIG. 1 in the same manner as above, and when a load current flows, a forward voltage of the illustrated polarity is generated across both ends. A capacitor 75 is connected in parallel to the LED element group 72 .

The inductor 74 has an auxiliary coil 741 coupled, one end of the auxiliary coil 741 is connected to the gate of the field effect transistor 71 via the capacitor 76 , and the other end is connected to the connection point between the field effect transistor 71 and the LED element group 72 . In addition, by accumulating and releasing electromagnetic energy in the inductor 74 according to the on/off operation of the field effect transistor 71 , a DC output of reduced voltage is generated at both ends of the capacitor 75 via the freewheel diode 77 .

Furthermore, a self-inductance circuit is formed, and the self-inductance circuit generates Vth>Vgs between the source and the gate of the field effect transistor 71 by the output of the auxiliary coil 741 synchronized with the accumulation and discharge of electromagnetic energy in the inductor 74. The negative potential of the field effect transistor 71 is turned off. In addition, as the freewheeling diode 77 here, a normally-on diode made of, for example, GaN is used.

The gate of the field effect transistor 71 is connected to a connection point between the resistance element 73 and the inductor 74 via a resistance element 78 serving as a current limiting resistor and a normally-off type field effect transistor 80 serving as a switching element.

The field effect transistor 80 constitutes an oscillation stop unit 79 as a drive control mechanism together with comparators 81 and 82 , resistive elements 83 and 84 , and a power supply 85 . At this time, one input terminal of the comparator 81 is connected to the connection point between the field effect transistor 71 and the LED element group 72, the other input terminal is connected to the power supply 85, and the output terminal is connected to the resistor through the resistor elements 83 and 84. The connection point of element 73 and inductor 74 .

Moreover, the comparator 81 operates as an operational amplifier (operational amplifier), and by setting the power supply 85, a reference signal Vf is generated at the connection point of the resistance elements 83 and 84, and the reference signal Vf is used to control the LED element group 72. A state in which the forward voltage (load voltage) is lower than the aforementioned Vth is detected as abnormal. One input terminal of the comparator 82 is connected to the connection point between the LED element group 72 and the resistance element 73 , the other input terminal is connected to the connection point between the resistance elements 83 and 84 , and the output terminal is connected to the gate of the field effect transistor 80 . The comparator 82 turns on the field effect transistor 80 according to the comparison result of the current flowing through the resistance element 73 and the reference signal Vf.

In addition, 86 and 87 are diodes constituting a gate voltage clamp circuit for clamping the gate voltage of the field effect transistor 71 . At this time, the gate voltage of the field effect transistor 71 is clamped using the forward voltage of the LED element group 72 .

Next, the operation of the embodiment configured in this way will be described.

Now, when the power is turned on by a power switch (not shown), a forward voltage of the illustrated polarity is generated across both ends of the LED element group 72 via the field effect transistor 71 in the on state. Furthermore, due to the conduction of the field effect transistor 71 , a current flows to the inductor 74 via the LED element group 72 . Accordingly, electromagnetic energy is accumulated in the inductor 72 , and at the same time, an output is generated from the auxiliary coil 721 and input to the gate of the field effect transistor 71 via the capacitor 76 . At this time, the output of the auxiliary coil 721 generates a negative potential of Vth>Vgs between the source and the gate of the field effect transistor 71, and the field effect transistor 71 is turned off.

In this state, the electromagnetic energy accumulated in the inductor 74 is released, and the field effect transistor 71 is turned on again with Vth<Vgs when there is no input from the auxiliary coil 721 .

Hereinafter, the same operation is repeated, and the field effect transistor 71 is turned on and off by the output of the auxiliary coil 741 in synchronization with the accumulation and discharge of electromagnetic energy in the inductor 74 . Simultaneously, the inductor 74 accumulates and discharges electromagnetic energy, and a DC output with a reduced voltage is generated at both ends of the capacitor 75 via the freewheel diode 77 , and the LED element group 72 is turned on by the DC output.

On the other hand, the comparator 81 operates as an operational amplifier, and generates a reference signal Vf at the connection point of the resistance elements 83 and 84 . In this state, a load current flowing through the resistance element 73 is input to the comparator 82 corresponding to the forward voltage (load voltage) of the LED element group 72 . In the comparator 82, the load current is compared with the reference signal Vf. Then, based on the comparison result, when it is judged that the load current at this time is lower than the reference signal Vf, that is, the forward voltage (load voltage) of the LED element group 72 corresponding to the load current is lower than Vth, an output is generated from the comparator 82. , so that the field effect transistor 80 is turned on. Then, the negative potential of the forward voltage of the LED element group 72 is applied between the source and the gate of the field effect transistor 71 to turn off the field effect transistor 71 and stop the self-inductance oscillation.

Therefore, also in this way, the same effect as that of the first embodiment can be obtained. Furthermore, when it is determined that the forward voltage (load voltage) of the LED element group 72 is lower than the Vth voltage, the field effect transistor 71 is forcibly turned off to stop the self-inductance oscillation. Thereby, it is possible to realize circuit protection capable of preventing the circuit from being out of control due to an abnormal drop in the forward voltage of the LED element group 72 .

Also, by changing the setting of the reference signal Vf, self-induction oscillation can also be stopped when the forward voltage (load voltage) of the LED element group 72 reaches a voltage higher than a predetermined forward voltage (load voltage).

The present invention is not limited to the above-described embodiments, and various modifications can be made without changing the gist in the implementation stage. For example, in the above-mentioned embodiments, an example in which a normally-on field effect transistor made of GaN is applied has been described, but other wide bandgap semiconductors such as SiC may also be applied. Furthermore, in the above-mentioned embodiments, an example of an LED element was described as a semiconductor light emitting element, but it can also be applied to a case where another semiconductor light emitting element such as a laser diode is used.

In addition, the power supply device (LED lighting device) according to one embodiment may also include: a switching element composed of a normally-on field effect transistor; The threshold value Vth of the gate voltage of the transistor is turned off by applying a negative potential of Vth>Vgs (voltage between gate and source).

Furthermore, the power supply device according to one embodiment may include a drive control mechanism for turning off the field effect transistor when the forward voltage generated on the semiconductor light emitting element is lower than the threshold value Vth or higher than a predetermined voltage. open.

Furthermore, the power supply device according to one embodiment may include a drive control mechanism including a normally-on field effect transistor.

According to the above-mentioned first to fourth embodiments, by using the forward voltage generated in the semiconductor light-emitting element to turn off the normally-on switching element, it is not necessary to incorporate a special circuit, and the device can be reduced in size and price.

Furthermore, according to the above-mentioned first to fourth embodiments, an appropriate negative potential can be obtained by the forward voltage generated on the semiconductor light emitting element, and the normally-on field effect transistor can be reliably turned off.

Furthermore, according to the above-mentioned first to fourth embodiments, the self-inductance oscillation caused by the normally-on field effect transistor can be stopped to realize circuit protection.

(fifth embodiment)

A fifth embodiment of the LED lighting device will be described with reference to FIG. 7 .

In this form, the LED lighting device is equipped with a direct-current power supply DC, a chopper CH, a load circuit LC, and a control circuit CC.

The direct current power supply DC may have any configuration, but for example, a rectifier circuit DB may be formed as a main body, and a smoothing circuit including a smoothing capacitor C1 and the like may be provided as necessary. In this aspect, the rectifier circuit DB is preferably constituted by a bridge rectifier circuit, and performs full-wave rectification on an AC power supply AC, for example, an AC voltage of a commercial AC power supply to obtain a DC voltage.

In this embodiment, the chopper CH is composed of a non-isolated step-down chopper. The power section of the chopper CH, that is, the circuit section through which the electric power supplied to the load passes, is configured including a normally-on switch Q1, an inductor L1, a freewheel diode D1, and a current detection impedance element Z1. Furthermore, the power unit can be divided into a first circuit A and a second circuit B in terms of circuit operation.

The first circuit A is a circuit for storing electromagnetic energy from the DC power supply DC in the inductor L1, and has a configuration in which a series circuit including the normally-on switch Q1, the load circuit LC, and the inductor L1 is connected to the DC power supply DC. Then, when the normally-on switch Q1 is turned on, an increased current flows from the direct current power supply DC to accumulate electromagnetic energy in the inductor L1.

The second circuit B is a circuit for releasing electromagnetic energy accumulated in the inductor L1. The second circuit B has a configuration in which a series circuit including a freewheeling diode D1 and a load circuit LC is connected to the inductor L1, and reduces the current flowing through the inductor L1 when the normally-on switch Q1 is turned off.

The normally-on switch Q1 allows the use of various wide bandgap semiconductors as described in the section on background art, but in this form, a HEMT using a GaN substrate is used. Therefore, the normally-on switch Q1 is a field-effect type wide-gap semiconductor including a drain, a source, and a gate. The normally-on switch Q1 has an extremely superior potential compared with widely used Si semiconductors, and can operate the chopper at, for example, an operating frequency of GHz order. Therefore, ultra-miniaturization of the inductor L1 can be realized. As a result, the overall size of the LED lighting device can be remarkably reduced.

The inductor L1 only needs to have the function of accumulating electromagnetic energy supplied from the direct current power supply DC and then releasing it, and therefore it is not necessary to arrange a secondary coil as in the background art. Therefore, the structure of the inductor L1 can be simplified to contribute to its miniaturization.

The freewheel diode D1 is a means for providing a second circuit B that is a current path for releasing and regenerating the electromagnetic energy accumulated in the inductor L1. As the freewheeling diode D1, a switching diode such as a Schottky barrier diode or a PIN diode can be used in accordance with the operating frequency of the chopper CH.

The impedance element Z1 for current detection is inserted in a position in the circuit through which both the increasing current and the decreasing current flow, that is, the line portion shared by the first circuit A and the second circuit B, to detect the above-mentioned respective currents. Also, for example, a resistor having a small resistance value is used.

Moreover, in the case of a step-up chopper, the chopper CH can be composed of a first circuit A that connects the series circuit of the inductor L1 and the normally-on switch Q1 to the direct current power supply DC, and the inductor L1, the freewheeling diode D1, and the first circuit A. The series circuit of the load circuit LC is connected to the second circuit B of the direct current power supply DC. In addition, in the case of a buck-boost chopper, it is as described above.

The load circuit LC is composed of a parallel circuit of a load light emitting diode LED and an output capacitor C2, and is connected to a position in the circuit where both the increasing current and the decreasing current flow. In addition, the light-emitting diode LED is composed of a single one or a plurality of them connected in series in the forward direction with respect to the above electric current.

The control circuit CC is provided with a control switch CS and a matching mechanism MC, and operates by receiving an appropriate control power supply to control the on and off of the normally-on switch Q1. In this form, control power is supplied to the control circuit CC from both ends of the load circuit LC.

The control switch CS is a mechanism for switching the normally-on switch Q1 on and off. That is, if the gate of the normally-on switch Q1 is connected to the connection point of the impedance element Z1 and the inductor L1 by controlling the switch CS to be turned on, a negative voltage is applied to the gate of the normally-on switch Q1 relative to the source. voltage, so the normally-on switch Q1 will turn off. Then, when the control switch CS is turned off and the gate of the normally-on switch Q1 is released from the connection to the connection point of the impedance element Z1 and the inductor L1 or becomes the same potential as the source, the normally-on switch Q1 is turned on.

The matching mechanism MC is interposed between the impedance element Z1 and the control switch CS, and when the increased current reaches the first specified value, the control switch CS is turned on. And, when the reduced current reaches the second predetermined value, the control switch CS is turned off.

Therefore, when the increasing current flows, when the terminal voltage of the impedance element Z1 reaches the first predetermined value, the matching mechanism MC turns on the control switch CS, so that the normally-on switch Q1 turns off. Furthermore, when the current flow is reduced, when the terminal voltage of the impedance element Z1 reaches the second predetermined value, the matching mechanism MC turns off the control switch CS, so that the normally-on switch Q1 is turned on.

Next, circuit operation will be described.

When the direct current power supply DC is turned on, the normally-on switch Q1 of the chopper CH is turned on, and the current flows from the direct current power supply DC in the first circuit A, and the current will increase linearly. This is to increase the current, thereby accumulating electromagnetic energy in the inductor L1. When the increased current flows out of the first circuit A, the terminal voltage of the impedance mechanism Z1 increases in proportion to the increased current. Then, when the terminal voltage reaches the first predetermined value, the matching mechanism MC turns on the control switch CS.

When the control switch CS is turned on, the gate of the normally-on switch Q1 becomes a negative voltage, so the normally-on switch Q1 is turned off, and the increased current is blocked. Thereby, the electromagnetic energy accumulated in the inductor L1 is released, and the current starts to flow in the first circuit B, and the current decreases linearly. This is to reduce the current. When the reduced current reaches the second predetermined value, the matching mechanism MC turns off the control switch CS.

When the control switch CS is turned off, the application of the negative voltage to the gate of the normally-on switch Q1 is released, so the normally-on switch Q1 is turned on, and the increasing current starts to flow again. Thereafter, by repeating the above circuit operations, the DC-DC conversion operation is continued.

(sixth embodiment)

A sixth embodiment of the LED lighting device will be described with reference to FIG. 8 .

In this form, control circuit CC is different from 5th form. In addition, in the figure, the same code|symbol is attached|subjected to the same part as FIG. 7, and description is abbreviate|omitted.

In this embodiment, the control circuit CC is composed of a P-type FET1 and an N-type FET2 connected in parallel to the control switch CS. In addition, the connection terminal between the drain of the P-type FET1 and the source of the N-type FET2 is connected to the gate of the normally-on switch Q1.

Furthermore, the matching circuit MC is composed of a hysteresis comparator CPh. In addition, in the hysteresis comparator CPh, the inverting input terminal is connected to one end of the load circuit LC side of the impedance mechanism Z1, the non-inverting input terminal is connected to the reference potential E, and the output terminal is connected to the gates of the P-type FET1 and the N-type FET2. pole. Furthermore, a feedback resistor R1 whose resistance value has been adjusted in advance is connected between the non-inverting input terminal and the output terminal. The above-mentioned reference potential E is formed at the connection point of the voltage divider VD composed of resistors R2 and R3 connected in parallel to the series part of the load circuit LC and the impedance mechanism Z1.

In this way, when the normally-on switch Q1 is turned on and the increased current IU flows to the impedance mechanism Z1, when the terminal voltage of the impedance mechanism Z1 reaches the first specified value, a positive first positive voltage is input to the inverting input terminal of the hysteresis comparator CPh. The specified value voltage outputs the negative maximum output voltage to the output terminal. The negative maximum output voltage is applied to the gate of the P-type FET1 controlling the switch CS, so the P-type FET1 is turned on. In addition, at this time, the N-type FET2 maintains the off state.

When the P-type FET1 is turned on, the gate of the normally-on switch Q1 becomes a negative potential, so the normally-on switch Q1 is turned off, and the increased current IU is blocked. Accompanying this, the current ID flowing from the inductor L1 is reduced. The terminal voltage of the impedance mechanism Z1 when the decreasing current ID flows is input to the inverting input terminal of the hysteresis comparator CPh immediately following the terminal voltage of the increasing current ID, so when this value reaches the second predetermined value, the current from the hysteresis comparator The output terminal of the device CPh outputs a positive maximum voltage. As a result, the P-type FET1 is turned off, and the N-type FET2 is turned on.

As a result of the P-type FET1 being turned off and the N-type FET2 being turned on, the normally-on switch Q1 is turned on, so the increased current flows to the load circuit LC again. Thereafter, the above operation is repeated to perform chopper operation.

Next, the relationship between the current and voltage waveforms of each part in the sixth embodiment will be described with reference to FIGS. 9( a ) to 9 ( e ). That is, Fig. 9(a) is the waveform of increasing current IU, Fig. 9(b) is the waveform of decreasing current ID, Fig. 9(c) is the waveform of the terminal voltage VZ1 of the impedance mechanism, and Fig. 9(d) is the waveform of the inductor The waveform of the voltage VL1 of FIG. 9(e) is the waveform of the gate voltage VGS of the normally-on switch, and the time axes are aligned. In addition, in the figure, increasing the peak value of the current IU corresponds to the time when the first predetermined value is reached. Furthermore, the zero value of the decreasing current ID corresponds to when the current ID reaches the second predetermined value.

The current waveform diagrams in Figure 9(a)-Figure 9(e) are ideal waveforms when there is no delay in control, but when the control of increasing current blocking produces a delay that cannot be ignored, the first specified value will exist at a ratio of the peak value Low corresponds to the value of the control delay. Furthermore, if there is a non-negligible delay in the control when the decreasing current reaches the second predetermined value, a current blocking time corresponding to the control delay occurs between the decreasing current and the next increasing current.

(seventh embodiment)

A seventh embodiment of the LED lighting device will be described with reference to FIG. 10 .

In this form, control circuit CC is different from 5th and 6th form. In addition, in FIG. 10, the same code|symbol is attached|subjected to the same part as FIG. 7, and description is abbreviate|omitted.

That is, the control switch CS is mainly composed of a bipolar transistor (bipolar transistor) Q2 . The bipolar transistor Q2 connects the collector to the gate of the normally-on switch Q1, and is connected to the source of the normally-on switch Q1 via a control power supply Vdd composed of a dropper, and the emitter ( emitter) is connected to the connection point of the inductor L1 and the impedance mechanism Z1.

Further, matching mechanism MC is mainly composed of bipolar transistor Q3, resistors R4 and R5. The collector of the bipolar transistor Q3 is connected to the base of the bipolar transistor Q2 controlling the switch CS through the resistor R4, the emitter is connected to the connection point of the inductor L1 and the impedance mechanism Z1, and the base is connected through the resistor R6 And connected to the collector of the bipolar transistor Q2. Furthermore, a series circuit of resistors R5 and R4 and the collector and emitter of the bipolar transistor Q3 is connected in parallel to the impedance mechanism Z1.

Thus, when the normally-on switch Q1 is turned on and the increased current flows, the bipolar transistor Q2 of the control switch CS is turned off, and the bipolar transistor Q3 of the matching mechanism MC is turned on. Therefore, the terminal voltage of the impedance mechanism Z1 is divided by the series circuit of the resistor R4 and the resistor R5, and the voltage across the resistor R4 is applied between the base and the emitter of the bipolar transistor Q2.

Therefore, by adjusting the values of the resistors R4 and R5 in advance to set the value of the resistor R4 to be relatively small, the bipolar transistor can be activated when the increasing current reaches a level before the first specified value. Q2 becomes off state. However, when the increasing current reaches the first predetermined value, the bipolar transistor Q2 is turned on and a negative voltage is applied to the gate of the normally-on switch Q1, so the normally-on switch Q1 is turned off and the increasing current is blocked.

When the bipolar transistor Q2 reaches the conductive state, the bipolar transistor Q3 is turned off, so when the normally-on switch Q1 is turned off to reduce the current flow, the terminal voltage of the impedance mechanism Z1 is not divided and applied to the bipolar transistor Q2 , and then, the bipolar transistor Q2 maintains the on state. However, when the terminal voltage of the impedance mechanism Z1 falls and reaches the second predetermined value, the bipolar transistor Q2 cannot maintain the on state and is turned off. As a result, the normally-on switch Q1 is turned on again. Then, the above-mentioned circuit operation is repeated, and the chopper operation is continued.

In addition, in the above-described embodiments, the chopper includes various choppers such as a buck chopper, a boost chopper, and a buck-boost chopper. In addition, the buck-boost chopper is formed by sequentially connecting the boost chopper and the buck chopper. The above-mentioned choppers have in common that the increased current flowing from the DC power supply into the inductor flows by turning on the normally-on switch, and the electromagnetic energy accumulated in the inductor is released by turning off to reduce the current. Current flows to perform chopper operation.

Furthermore, in the above-described embodiment, the control circuit includes a control switch and a matching mechanism.

The control switch includes at least a switch for switching from the on state to the off state of the normally-on switch. In addition, it is permissible to provide a second switch that switches from the off state of the normally-on switch to the on state as necessary. At this time, the switch for switching from the on state to the off state of the normally-on switch is the first switch.

The matching mechanism is interposed between the impedance mechanism and the control switch. When the increased current flows to the impedance mechanism, when the terminal voltage of the impedance mechanism reaches a first predetermined value, the control switch is activated to turn off the normally-on switch. Then, when the reduced current flows, when the terminal voltage of the impedance means reaches the second predetermined value, the control switch is controlled to turn on the normally-on switch. In addition, the second predetermined value is a value lower than the first predetermined value.

As long as the matching mechanism has the above-mentioned functions, other structures are not particularly limited. However, it is preferable to configure the matching mechanism with a hysteresis comparator. Moreover, the matching mechanism may also be configured to include a first detection mechanism that directly detects the terminal voltage of the impedance mechanism and a second detection mechanism that detects the voltage through the voltage divider, and the control switch is turned off when the normally-on switch is turned off. Switch from the second detection mechanism to the first detection mechanism in conjunction with each other.

In this way, when the normally-on switch is turned on, the increased current flows from the DC power supply to the inductor, but when the terminal voltage of the impedance mechanism reaches the first predetermined value, the control switch is turned on through the matching mechanism to apply a negative voltage to the normal The gate of the ON switch is thus turned off, blocking this increased current. Accompanying this, the electromagnetic energy accumulated in the inductor is released to reduce the current flowing from the inductor, and the control switch is turned off via the matching mechanism to release the application of the negative voltage to the gate of the normally-on switch. The normally-on switch is turned on. Then, the above-described circuit operation is repeated to perform chopper operation.

The load circuit is connected to the position on the circuit where both the increasing current and the decreasing current due to the operation of the chopper flow, so DC-DC voltage conversion is performed, and the light-emitting diode of the load connected to the output terminal is under the converted voltage. Lights up under constant current control. In addition, the output capacitor of the light-emitting diode connected in parallel to the load circuit functions to bypass the high-frequency components contained in the output of the chopper from the light-emitting diode. As a result, the light emitting diodes are turned on by the smoothed direct current.

In the above embodiment, the supply of control power to the control circuit is not particularly limited, but is preferably as follows. That is, control power is obtained from the load circuit or the high voltage side of a normally-on switch. In the scheme of obtaining the control power supply from the load circuit, a DC voltage smoothed by the output capacitor is generated on the load circuit, so a voltage higher than the gate threshold voltage of the normally-on switch is derived from the load circuit to obtain the control power supply, by This can simplify the circuit structure of the control power supply. Moreover, in the scheme of obtaining the control power supply from the high voltage side of the normally-on switch, for example, it may be configured to obtain a voltage higher than the gate threshold voltage of the normally-on switch from the drain side of the normally-on switch via a voltage reducer. Voltage.

In the above embodiments, the lighting device refers to all devices using light emitting diodes as light sources. Therefore, lighting fixtures, display devices, signage devices, etc. are allowed. The lighting device body refers to the remaining part after removing the LED lighting device from the lighting device.

According to the above-mentioned fifth to seventh embodiments, a normally-on switch is used as the main switching element of the chopper, and a control circuit is provided. The control circuit includes a switch that controls the gate of the normally-on switch at least when it is turned on. A negative voltage is applied to control the normally-on switch to an off state, and when it is off, the application of the negative voltage to the gate of the normally-on switch is released to control the normally-on switch to an on-state, and the control circuit is separated Between the impedance element and the control switch, when the increased current flows, the control switch is turned on when the terminal voltage of the impedance element reaches a first predetermined value, and when the reduced current flows, the control switch is turned on when the terminal voltage reaches a value lower than the first predetermined value. When the second predetermined value of , the control switch is turned off, thereby, it is possible to provide a chopper with a simple circuit structure, good characteristics and easy IC conversion without arranging a secondary coil in the inductor. And a lighting device including the chopper.

(eighth embodiment)

Fig. 11 shows an eighth form. The LED lighting device includes a direct current power supply DC, a chopper CH, and a load circuit LC.

The direct current power supply DC is means for inputting a direct current voltage before conversion to a chopper CH described later. Any configuration is possible as long as it can output a DC voltage, but for example, a rectifier circuit DB may be formed as a main body, and a smoothing circuit including a smoothing capacitor and the like may be provided as necessary. In this aspect, the rectifier circuit DB is preferably constituted by a bridge rectifier circuit, and performs full-wave rectification on an AC power supply AC, for example, an AC voltage of a commercial AC power supply to obtain a DC voltage.

In this form, the chopper CH has DC input terminals t1 and t2 and DC output terminals t3 and t4. The chopper CH internally includes any of various known choppers such as a buck chopper, a boost chopper, and a buck-boost chopper. In any of the above configurations, the chopper CH further includes a switching element Q11, a constant current mechanism CCM, an inductor L11, a diode D11, and a drive coil DW as a common configuration.

The switch element Q11 can be any one of a normally-off switch and a normally-on switch. The constant current mechanism CCM may be of a type whose constant current value is fixedly set in advance, or may be of a variable type. One end of the inductor L11 is connected to the drive coil DW. The drive coil DW is magnetically coupled to the inductor L11 to induce a voltage proportional to the terminal voltage of the inductor L11 and apply it to the control terminal of the switching element Q11 to drive the switching element Q11.

The chopper CH has a pair of input terminals t1, t2 and a pair of output terminals t3, t4, and its internal circuit can be divided into a third circuit and a fourth circuit in terms of its circuit operation. The third circuit is a circuit for accumulating electromagnetic energy in the inductor L11 by flowing an increased current from the direct current power supply DC. In the case of a step-down chopper, it includes a switching element Q11, a constant current mechanism, and an inductor L11. And the structure in which the series circuit of the load circuit LC is connected to the direct current power supply DC. Then, when the switching element Q11 is turned on, an increased current flows from the direct current power supply DC to accumulate electromagnetic energy in the inductor L11.

The fourth circuit is a circuit that releases the electromagnetic energy accumulated in the inductor L11 to make the reduced current flow. In the case of a step-down chopper, a series circuit including a diode D11 and a load circuit LC described later is connected to In the structure of the inductor L11, when the switching element Q11 is turned off, a reduced current flows from the inductor L11.

Furthermore, in the case of a step-up chopper, the chopper CH includes a third circuit in which the series circuit of the inductor L11, the switching element Q11, and the constant current mechanism CCM is connected to the direct current power supply DC, and the inductor L11 and the diode D11. And the series circuit of the load circuit LC is connected to the 4th circuit of the direct current power supply DC. In addition, the buck-boost chopper is as mentioned above.

The load circuit LC includes a light-emitting diode as a load, and is connected in parallel with an output capacitor that bypasses high-frequency components. In the case of a step-down chopper, it is connected to a circuit through which both increased current and decreased current flow. at the position above. In the case of a boost type, it is connected to a position on the circuit where a reduced current flows. In addition, the light emitting diode LED is composed of a single one or a plurality of them connected in series with respect to the current flowing to the output terminal of the chopper.

Hereinafter, ninth to twelfth forms will be described with reference to FIGS. 12 to 17 . In addition, in each figure, the same code|symbol is attached|subjected to the same part as FIG. 11, and description is abbreviate|omitted.

(ninth embodiment)

(9th form) is demonstrated.

Fig. 12 shows a ninth form. In this embodiment, a GaN-HEMT is used for the switching element Q11, a constant current diode is used for the constant current mechanism CCM, and an inductor L11 is connected between the constant current mechanism CCM and the load circuit LC. In addition, in the figure, the same code|symbol is attached|subjected to the same part as FIG. 11, and description is abbreviate|omitted. Symbol C11 is a high-frequency bypass capacitor connected between the input terminals t1 and t2 of the chopper CH. Symbol C12 is a coupling capacitor inserted between the drive coil DW and the control terminal of the switching element Q11. Symbol C is the third circuit, and symbol D is the fourth circuit. The symbol LED of the load circuit LC is a light-emitting diode, and C13 is an output capacitor.

Next, the circuit operation of the ninth embodiment will be described with reference to FIG. 12 and FIG. 13(a)-FIG. 13(f).

When the DC power supply DC is turned on, the switching element Q11 of the chopper CH is turned on, so the current flows from the DC power supply DC to the third circuit C through the switching element Q11 and the constant current mechanism CCM, and the current increases linearly. Accordingly, electromagnetic energy is accumulated in the inductor L11. In addition, while the switching element Q11 is on, the gate-source voltage VGS of the switching element Q11 is zero. When the increased current reaches the constant current value of the constant current mechanism CCM, the increasing trend of the current stops to maintain a constant current. In addition, while the increased current flows to the inductor L11, the terminal voltage of the inductor L11 has positive polarity as shown in (e) of FIG. 13 .

When the increased current reaches the constant current value of the constant current mechanism CCM, the current flowing to the inductor L11 tends to increase further, so the voltage VCCM of the constant current mechanism CCM increases in pulse form as shown in (a) of FIG. 13 . And, accompanying this, the source potential of the switching element Q11 becomes higher than the potential of the control terminal (gate), and as a result, the control terminal becomes relatively significantly negative potential, so the switching element Q11 is turned off. Therefore, the increased current IU flowing into the inductor L11 is blocked by turning off the switching element Q11 as shown in (b) of FIG. 13 .

Simultaneously with the switching element Q11 being turned off, the electromagnetic energy accumulated in the inductor L11 starts to be discharged, and the reduced current flows out through the fourth circuit D as shown in (c) of FIG. 13 . In addition, while the reduced current flows, the voltage polarity of the inductor L11 is inverted as shown in (e) of FIG. Potential voltage. At this time, as shown in (f) of FIG. 13 , a negative voltage is applied between the gate and the source of the switching element Q11 via the constant current mechanism CCM, and thus the switching element Q11 is maintained in an off state.

When the reduced current flowing through the third circuit C becomes 0, while the negative voltage applied to the control terminal of the switching element Q11 is no longer induced, a negative voltage is induced on the drive coil DW due to the counter electromotive force to generate a negative voltage applied to the control terminal of the switching element Q11. As shown in (e) of FIG. 13 , it becomes a positive voltage. As a result, switching element Q11 is turned on again, and thereafter, the same circuit operation as described above is repeated.

It can be clearly seen from the above circuit operation that the chopper CH performs a step-down chopper operation, and as shown in (d) of FIG. The output current IO of the load circuit LC between , and t4 uses these DC components to light the light-emitting diode LED, and the output capacitor C4 bypasses the high-frequency components.

(tenth embodiment)

The (tenth aspect) will be described.

Fig. 14 shows a tenth form. In this embodiment, the constant current mechanism CCM is a GaN-HEMT, and the inductor L11 is connected between the constant current mechanisms CCM at a position where the load circuit LC is interposed therebetween.

Furthermore, the constant current mechanism CCM makes the constant current value variable by using the adjustable potential source E to make the gate potential variable. In addition, symbol ZD1 in the figure is a diode for clamping so that the voltage VGS between the gate and the source of the switching element Q11 does not become 0.6V or more.

Furthermore, in this form, the switching element Q11, the constant current mechanism CCM, and the diode D11 which form a series connection body are comprised as an integrated circuit IC. This integrated circuit IC includes a first external terminal P1 to a fifth external terminal P5. The first external terminal P1 is derived from the drain of the switching element Q11. The second external terminal P2 is derived from the cathode of the diode D11. The third external terminal P3 is derived from a connection point between the source of the constant current mechanism CCM and the anode (anode) of the diode D11. The fourth external terminal P4 is derived from the gate of the switching element Q11. The fifth external terminal P5 is derived from the gate of the constant current mechanism CCM.

That is, the integrated circuit IC derives the first and second main terminals from the main terminals of the semiconductor elements located at both ends of the series connection body composed of the above-mentioned three power semiconductor elements of the chopper, and connects from the middle of the series connection body. The third external terminal is derived from the main terminal of the part, and the fourth and fifth external terminals are derived from the control terminal of the switching element Q11 and the constant current mechanism CCM. Therefore, the above-mentioned first to third external terminals are the power system, and the fourth and fifth external terminals are the control system.

In this way, in the tenth aspect, the constant current mechanism CCM is made of GaN-HEMT like the switching element Q11, so that the high-speed switching characteristics at high frequencies of 10 MHz or higher are further improved. However, if the diode D11 is also formed of a GaN-based substrate as required, an integrated integrated circuit can be formed using a GaN-based substrate, so that extremely high-speed switching can be performed, and an extremely miniaturized chopper can be easily constructed.

Furthermore, since the constant current value is variable by using the adjustable potential source E1, it is easy to set the required load current, and it is also possible to perform feedback control on the adjustable potential source E1 in response to fluctuations in the power supply voltage. Suppresses fluctuations in light output of light-emitting diodes with respect to fluctuations in power supply voltage. Furthermore, the negative voltage of the drive coil DW applied to the control terminal of the switching element Q11 is added to the voltage drop of the constant current mechanism CCM and the load circuit LC.

(the eleventh embodiment)

(Eleventh aspect) will be described.

Fig. 15 shows an eleventh form. In addition, the same code|symbol is attached|subjected to the same part as FIG. 12, and description is abbreviate|omitted. In this embodiment, the constant current mechanism CCM is constituted by a current mirror constant current circuit using transistors Q12 and Q13. In addition, in the current mirror constant current circuit, the series circuit of the transistor Q12 and the resistor R11 is inserted in series with the switching element Q11, the base of the transistor Q13 is connected to the base of the transistor Q12, and the emitter is reversed polarity The reverse bias power supply E2 is connected, and the DC power supply E3 is connected to the series circuit of the collector and the bias power supply E2. Furthermore, the collector and base of the transistor Q13 are directly connected by a conductor.

Furthermore, between the control terminal of the switching element Q11 and a position straddling the constant current mechanism CCM, a pair of zener diodes ZD1 and ZD2 are connected in parallel in reverse polarity to form a clamp circuit. The Zener voltage of the Zener diode ZD1 is -12V, and the Zener voltage of the Zener diode ZD2 is +0.7V, so as to protect against excessive VGS being applied to the switching element Q11.

Thus, according to the eleventh aspect, the constant current value flowing to the transistor Q12 can be controlled to a desired value by the DC voltage connected to the transistor Q13, and the voltage generated when the constant current value is reached becomes high. Therefore, it becomes unnecessary to use the voltage of the light-emitting diode LED of the load.

Furthermore, since the constant current value of the constant current mechanism CCM is controlled using the DC power supply E2, high-speed controllable transistors are no longer necessary. Furthermore, the switching element Q11 can be substantially normally off by turning off the constant current mechanism CCM synchronously with the switching element Q11 being turned off. Furthermore, the switching element Q11, the constant current mechanism CCM, and the semiconductor components of the diode D11 can be partially integrated on a GaN-based chip (chip) as required.

(12th embodiment)

(12th form) is demonstrated.

16 and 17 show a twelfth form. Fig. 16 is a schematic diagram of an integrated circuit module for implementing a fifth aspect of the LED lighting device. Fig. 17 is a schematic partially enlarged and partially cutaway perspective view of the planar coil structure.

In this aspect, in some or more of the eighth to eleventh aspects, the semiconductor components, coil components, capacitor components, and external terminals of the LED lighting device are integrated and integrated into an IC. That is, the remaining circuit parts of the LED lighting device except the light-emitting diode LED are divided and formed on a planar coil structure L, a planar capacitor structure C, a GaN chip G, a wiring forming body W, a terminal forming body T, and a substrate structure. On each planar structure composed of B. These planar structures are integrally stacked, and each structure is connected using a mechanism such as a through hole to form an integrated circuit module IC'. The integrated circuit module IC of the illustrated example is composed of planar structures outlined below.

As shown in FIG. 17 , the planar coil structure L is formed by winding the inductor L11 and the drive coil DW so that the respective flat coil bare wires are spirally formed on the plane. The inductor L11 and the drive coil DW are kept in a proper isolation state, and the inside and the periphery are covered with the magnetic layer M. Thereby, the planar coil structure L is comprised in planar shape as a whole.

In addition, one end of the inductor L11 and the drive coil DW is positioned at the center of the coil to form a terminal portion t. In addition, a through hole h is formed in the center of the terminal portion t, and a terminal conductor of a constant current mechanism part of the GaN chip G described later is inserted into the through hole h, and a conductor is injected into the inside to drive the inductor L11, drive The coil DW and the connecting conductor of the GaN chip G are connected together. In addition, the magnetic layer M is made of, for example, ceramics or plastic in which ferrite fine particles are dispersed, as shown in an enlarged cross section of a part of FIG. 17 on the right side of the figure.

The planar capacitor structure C is, for example, a planar structure obtained by aggregating a plurality of capacitors including a pair of electrode bodies each sandwiching a thin dielectric film.

The GaN chip G is a planar structure in which a switching element Q11 , a constant current mechanism CCM, and a diode D11 are formed on a GaN-based semiconductor substrate.

The wiring forming body W is a planar structure body that connects the planar coil structure L, the planar capacitor structure C, and the GaN chip G, and a terminal forming body T described later as necessary.

The terminal forming body T is interposed between the wiring forming body W and the substrate structure B described later, and connects both.

The substrate structure B includes external terminals TE and an external mounting mechanism (not shown), and integrally supports each of the planar structures described above to be modularized. In addition, the external terminal TE is an output terminal connecting the input terminal of the LED lighting device and the light emitting diode LED.

In this way, this form is suitable for an LED lighting device that operates at a high frequency of 10 MHz or higher. The external terminals TE arranged on the substrate structure B are all used for direct current, and only direct current is input and output, so the operation is stable and can Achieve remarkable miniaturization. Therefore, the LED lighting device can also be arranged between the light emitting diodes of the lighting device, thereby contributing to the remarkable miniaturization of the lighting device.

In addition, an LED lighting device according to one embodiment includes a series connection body of a switching element, a constant current mechanism, and a diode. The series connection body has an integrated circuit, and the integrated circuit has: first and second external terminals derived from a pair of main terminals located at both ends thereof; an external terminal; and fourth and fifth external terminals derived from the switching element and the control terminal of the constant current mechanism.

In addition, in the above-described embodiments, the term "chopper" refers to a concept including various choppers such as a buck chopper, a boost chopper, and a buck-boost chopper. In addition, the buck-boost chopper is formed by sequentially connecting a boost chopper and a buck chopper. The above-mentioned choppers have in common that the increasing current flows from the DC power supply to the inductor by turning on the switching element, and the reducing current flows through the inductor by using the electromagnetic energy accumulated in the inductor by turning off the switching element. The diode flows, and this operation is repeated to perform DC-DC conversion on the DC power supply voltage and output it to the output terminal.

The switching element may be any one of a normally-on switch and a normally-off switch. When a wide bandgap semiconductor is used for the switching element, such as GaN-HEMT, the switching characteristics at high frequencies above MHz, such as 10MHz or above, can be significantly improved to reduce switching losses, and the inductor can also be miniaturized, so it can Realize the substantial downsizing of the LED lighting device.

Furthermore, in the case of using a switching element of a wide bandgap semiconductor, it is easy to obtain a switching element having a normally-on characteristic at low cost, but a switching element having a normally-off characteristic is also possible, so a switch having the normally-off characteristic can also be used element. Furthermore, when a normally-on switch having a negative threshold value of the switch is used, off-control using a drive coil magnetically coupled to an inductor becomes easy, so it is suitable.

The constant current mechanism is a circuit mechanism having constant current characteristics, for example, various constant current circuits using constant current diodes, junction FETs, three-terminal regulators, and transistors can be used. In addition, as the constant current circuit using a transistor, a known constant current circuit using one or two transistors is allowed. Furthermore, GaN-HEMT, which is a type of junction FET, can be used as a constant current mechanism. This switching element has excellent switching characteristics at high frequencies of 10 MHz or higher, and thus is suitable for high-speed switching.

The constant current mechanism is connected in series with the switching element through a first circuit in which current flows to the inductor when the switching element is turned on. Furthermore, the constant current mechanism is also interposed in the driving circuit of the switching element including the driving coil for driving the switching element. With these configurations, when the increased current flowing through the constant current mechanism reaches the constant current value and is about to increase further, the voltage of the constant current mechanism rises sharply. Therefore, at this time, the voltage generated by the constant current mechanism rises to make the device The potential of the main terminal (for example, source) in the drive circuit of the input switching element is relatively high compared to the potential of the control terminal (for example, gate). As a result, since the potential of the control terminal is lower than the threshold value of the switching element, the switching element can be turned off. This circuit operation becomes easier and more reliable when the switching element is a normally-on switch and the threshold value is negative, but it is also effective for a normally-off switch.

Furthermore, it is allowed to directly connect the switching element and the constant current mechanism in series. In this case, it is easy to integrate the switching element and the constant current mechanism on a common semiconductor chip, for example, a GaN-based chip. In this case, the above-mentioned switching element and the constant current mechanism can be constituted by an IC module having a four-terminal structure, which can be further downsized as a single component (component). Two terminals of the power system, such as the drain and the main terminal on the other end side of the switching element of the constant current mechanism, and two control terminals of the switching element and the constant current mechanism, such as gates Terminals of the control system.

The inductor stores electromagnetic energy inside when an increased current flows from the DC power supply to the first circuit via the switching element and the constant current mechanism. Furthermore, since the inductor discharges the accumulated electromagnetic energy when the switching element is turned off, the reduced current at this time flows to the second circuit.

In addition, when the chopper is operated at a high frequency of 10 MHz or higher, the inductor and the drive coil magnetically coupled to the inductor have a planar coil structure, and the capacitor has a planar structure. The chopper is integrated into an integrated circuit, and a highly reliable operation can be obtained. That is, an inductor and drive coil with a planar coil structure, a capacitor with a planar structure, and a semiconductor chip integrating semiconductor components such as a switching element, a constant current mechanism, and a diode described later can be stacked to form an integrated integrated circuit. circuit module. As a result, remarkable miniaturization of the LED lighting device can be realized. Moreover, with this, the distance between the drive coil and the switch is minimized, and the generation of unnecessary and harmful parasitic inductance or parasitic capacitance can be suppressed to a minimum, so the operation of the chopper is stable and reliable. sexual enhancement.

The diode provides a path for the reduced current to flow from the inductor, that is, the second circuit. Further high-speed switching can be realized when a wide bandgap semiconductor, for example, a GaN-based diode is used as the diode. In this case, it is easy to configure the diode together with the switching element and the constant current mechanism as an integrated circuit of semiconductor elements. This integrated circuit has a structure in which a series connection body of a switching element, a constant current mechanism, and a diode is provided with a main terminal composed of a main terminal on one end side, a main terminal on the other end side, and a main terminal at an intermediate connection point. The five external terminals are three main terminals of the power system and two control terminals for controlling the switching element and the constant current mechanism respectively.

When the above-mentioned integrated circuit is used to constitute the chopper, the overall size can be further reduced, and high-speed switching can be easily performed.

The drive coil is a coil that is magnetically coupled to the inductor and controls the switching element. That is, when the switching element is turned on, when the increased current flowing to the inductor reaches the constant current value of the constant current mechanism and the switching element is turned off, a large voltage is generated, so the main terminal (source) of the switching element is higher than the control Terminal, on the other hand, the control terminal becomes negative potential and is lower than the threshold value, so the switching element is maintained in the OFF state.

According to the above eighth to twelfth embodiments, when the switching element is turned on, when the increased current flowing from the DC power supply to the inductor via the constant current mechanism reaches the constant current value of the constant current mechanism, a constant current mechanism generates Therefore, there is no need to provide an impedance mechanism such as a resistance element that detects the current flowing to the inductor, and control to turn off the switching element when the voltage drop reaches a preset threshold. The current feedback type feedback circuit composed of a circuit can use a simple structure to turn off the switching element and perform a chopper action when the increased current reaches a specified value, thus providing a circuit structure that is simple and has An LED lighting device for a chopper that is easy to realize integration and miniaturization.

Furthermore, by making the inductor and the driving coil a planar coil structure, and constituting an integrated circuit in which at least a switching element and a diode are stacked on at least one side of the planar coil structure, the distance between the driving coil and the switching element is minimized, Since generation of unnecessary and harmful parasitic inductance and parasitic capacitance can be suppressed to a minimum, the stability and reliability of the operation of the chopper are improved.

Furthermore, if the switching element, the constant current mechanism, and the diode are constituted as an integrated circuit having five external terminals, the entire chopper can be further miniaturized, and high-speed switching can be easily performed.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the structure and technical content disclosed above to make some changes or modifications to equivalent embodiments with equivalent changes, but any content that does not depart from the technical solution of the present invention, Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims (10)

1. it is a kind of to be used in the integrated circuit that DC-to-dc is changed, it is characterised in that to include：

Switch element, with a pair of main terminals and control element；

Current controling element, with a pair of main terminals and control element；

Diode element, with a pair of main terminals；

The integrated circuit includes series connection, in sequential series to be connected to the switch element, institute in the series connection The main terminals of current controling element and the diode element are stated,

And the series connection includes：

1st outside terminal, positioned at a side of the series connection, and in the switch element, the current controling element And in the main terminal of the diode element, the 1st outside terminal and the main terminal not being connected with other main terminals Connection；

2nd outside terminal, positioned at the another side of the series connection, and in the switch element, current control unit In the main terminal of part and the diode element, the 2nd outside terminal and the main side not being connected with other main terminals Son connection；

3rd outside terminal, leads from the tie point of the current controling element and the main terminals of the diode element Go out；

4th outside terminal, derives from the control terminal of the switch element；And

5th outside terminal, derives from the control terminal of the current controling element.

It is 2. according to claim 1 to be used in the integrated circuit that DC-to-dc is changed, it is characterised in that

Wantonly 1 of at least described switch element, the current controling element and the diode element is to use gallium nitride.

It is 3. according to claim 1 to be used in the integrated circuit that DC-to-dc is changed, it is characterised in that

The switch element is the field-effect transistor of normal open type,

The switch element has source electrode or drain electrode using as the pair of main terminal,

The switch element has gate pole using as the control terminal.

It is 4. according to claim 1 to be used in the integrated circuit that DC-to-dc is changed, it is characterised in that

The current controling element is the field-effect transistor of normal open type,

The current controling element has source electrode or drain electrode using as the pair of main terminal,

The current controling element has gate pole using as the control terminal.

5. a kind of supply unit, it is characterised in that

Comprising the integrated circuit for being used in DC-to-dc conversion described in any one of Claims 1-4, and

The supply unit includes：

Inductor, is connected with the 2nd outside terminal of the integrated circuit；

Driving coil, is connected with the inductor magnetic coupling and with the 4th outside terminal of the integrated circuit.

6. supply unit according to claim 5, it is characterised in that

The switch element of the integrated circuit of the supply unit reaches in the electric current for flowing through the current controling element During rated current value, the switch is become higher than by the current potential of the switch element and the tie point of the current controling element The current potential of the control terminal of element is turning off.

7. a kind of lighting device, it is characterised in that include：

Supply unit described in claim 5；And

Light-emitting component, from the supply unit electric power is supplied to.

8. lighting device according to claim 7, it is characterised in that

The current controling element of the integrated circuit of the supply unit is produced forward using in the light-emitting component Voltage, by the way that the voltage between the control terminal and the main terminal that put on the switch element is set below into control end The threshold voltage of sub- voltage, and the voltage between the control terminal and the main terminal of the switch element is set to into negative electricity Press to make the switch element turn off action.

9. lighting device according to claim 7, it is characterised in that

The forward electricity that the current controling element of the integrated circuit of the supply unit is produced in the light-emitting component When pressure is higher than assigned voltage, the switch element is set to turn off action.

10. lighting device according to claim 7, it is characterised in that

The current controling element of the integrated circuit of the supply unit will be by putting on the institute of the switch element State the voltage between control terminal and the main terminal to be set to be more than the threshold voltage of control terminal voltage, enter the switch element Row turn-on action.