JP6990852B2 - Lighting device and lighting circuit - Google Patents

Description

The present invention relates to a lighting device and a lighting circuit provided in the lighting device.

Conventionally, a lighting circuit provided in a lighting device is a DC that supplies a constant current to a light source such as an LED (Light Emitting Diode) by switching a rectifier circuit that rectifies an AC voltage and a direct current voltage output from the rectifier circuit. It is composed of a / DC converter (for example, Patent Document 1). As a result, a lighting circuit for a lighting device that exhibits a high power factor is realized.

Japanese Unexamined Patent Publication No. 2016-21311

However, in the lighting circuit of Patent Document 1, since the number of parts is large, when applied to a small lighting device, for example, a light bulb-shaped LED lamp, the housing accommodating the lighting circuit occupies a large part of the lighting device. It ends up. In particular, in a small (that is, E17 base) LED bulb with a base diameter of 17 mm, the housing that houses the lighting circuit occupies more than half of the total volume of the light bulb, and the light distribution angle is a narrow value such as 120 degrees. There is a problem that it becomes.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a lighting device realized with a smaller number of parts than the conventional one and a lighting circuit provided in the lighting device.

In order to achieve the above object, the lighting device according to one embodiment of the present invention includes a light source and a lighting circuit that supplies a current to the light source, and the lighting circuit is a rectifying circuit that converts AC power into first DC power. A DC / DC converter that converts the first DC power supplied from the rectifying circuit into a second DC power and supplies a current to the light source, and the DC / DC converter is an inductor connected in series with the light source. The control IC comprises a diode for discharging the energy stored in the inductor and a control IC having a switching element connected in series with the inductor, and the control IC further has a capacitor for smoothing the first DC power.

In order to achieve the above object, the lighting circuit according to one embodiment of the present invention is a lighting circuit that supplies a current to a light source, and is supplied from a rectifying circuit that converts AC power into a first DC power and a rectifying circuit. The DC / DC converter includes a DC / DC converter that converts the first DC power into a second DC power and supplies a current to the light source. The DC / DC converter has an inductor connected in series with the light source and energy stored in the inductor. The control IC comprises a diode for discharging the current and a control IC having a switching element connected in series with the inductor, and the control IC further has a capacitor for smoothing the first DC power.

INDUSTRIAL APPLICABILITY According to the present invention, a lighting device realized with a smaller number of parts than before and a lighting circuit provided in the lighting device are realized.

FIG. 1 is a circuit diagram of a lighting device according to a reference example. FIG. 2 is a block diagram showing a detailed configuration of the control IC in FIG. FIG. 3 is a circuit diagram of the lighting device according to the embodiment. FIG. 4 is a block diagram showing a detailed configuration of the control IC in FIG. FIG. 5 is a schematic view showing the appearance of an application example of the lighting device according to the embodiment.

First, before explaining the lighting device according to the embodiment of the present invention, the lighting device according to the reference example will be described. The lighting device according to the reference example is an example of a lighting device that has not been improved in the lighting device according to the embodiment.

FIG. 1 is a circuit diagram of a lighting device 10 according to a reference example. The lighting device 10 is a device that emits light by receiving the supply of AC power, and is used, for example, in various lighting fixtures such as a light source for lighting such as a light bulb and a straight tube, a downlight, a ceiling light, a pendant, and a table stand. The lighting device 10 includes a lighting circuit 20 and a light source 15.

The light source 15 is an element that emits light by being supplied with an electric current, and is, for example, a solid-state light emitting element such as an LED or an EL (Electronic Luminescent).

The lighting circuit 20 is a circuit that supplies a constant current to the light source 15, and is composed of a rectifier circuit 21 and a DC / DC converter 22.

The rectifier circuit 21 is a circuit that converts the AC power supplied from the AC power supply 5 into the first DC power. In the present embodiment, the commercial AC power such as AC100V is full-wave rectified and converted into the DC power. It is a bridge diode composed of four diodes D1 to D4. The resistance element R1 is a protective resistance element connected in series with the bridge diode.

The DC / DC converter 22 is a power source that converts the first DC power supplied from the rectifier circuit 21 into the second DC power and supplies a predetermined current to the light source 15. The DC / DC converter 22 includes a control IC 23, diodes D5 to D6, resistance elements R2 to R15 and RP, capacitors C1 to C7, inductors L1 to L2, transistors Q1 to Q2, and a connector J1.

The inductor L1 and the capacitors C1 and C2 are circuits for smoothing the first DC power output from the rectifier circuit 21. Specifically, the inductor L1 and the capacitors C1 and C2 form a π-type filter. The resistance element RP connected between the capacitors C1 and C2 is a protection resistance element inserted in the current return path of the DC / DC converter 22.

The resistance elements R10 to R13 and the transistors Q1 to Q2 are bleeder circuits for passing a current between the two output terminals of the rectifier circuit 21. In the bleeder circuit, when a firefly switch (not shown) for turning on / off the supply of AC power from the AC power supply 5 is provided, a minute current is applied to the lamp (not shown) of the firefly switch when the firefly switch is turned off. It is a circuit that becomes a load for flowing.

The control IC 23 is a one-chip integrated circuit that has a built-in switching element and controls to supply a constant current to the light source 15. In the present embodiment, the control IC 23 has eight terminals (terminal ZCD, terminal GND, terminal VDD, and terminal). D, terminal CS, terminal COMP, terminal RS, terminal RTC).

The resistance elements R2 and R4 are current limiting resistors for supplying the DC voltage generated by smoothing the first DC power from the rectifying circuit 21 by the capacitors C1 and C2 and the inductor L1 to the terminal VDD of the control IC 23. It is an element.

The capacitor C3 is a bypass capacitor that smoothes the DC voltage supplied to the control IC 23. The resistance element R3 is a resistance element for discharging the electric charge accumulated in the capacitor C3.

The diode D5 and the resistance element R5 are circuits for supplying a current from the output terminal of the DC / DC converter 22 (terminal LED + of the connector J1) to the VDD terminal of the control IC 23.

The resistance element R6 is a resistance element that feeds back the voltage generated in the inductor L2 to the terminal ZCD of the control IC 23, and is used in the control IC 23 for detecting zero current that determines the on / off switching timing of the built-in switching element.

The resistance elements R7 and R8 are resistance elements that determine a resistance value (this resistance value is expressed as R7 // R8) connected to the terminal RTC involved in temperature control of the control IC 23. The resistance element R9 is a resistance element that determines the resistance value connected to the terminal RS involved in the temperature control of the control IC 23.

The capacitor C4 is connected to the terminal COMP of the control IC 23 and is a capacitor for stabilizing the output current to a predetermined value.

The resistance element R14 is connected between the terminal CS of the control IC 23 and the circuit ground SGND, and constitutes a resistance element for detecting the current flowing through the switching element of the control IC 23.

The inductor L2 is connected in series with the light source 15, stores energy when the switching element of the control IC 23 is turned on, releases the stored energy when the switching element is turned off, and reduces the ripple of the output current. It is a coil for.

The diode D6 is a diode for releasing the energy stored in the inductor L2.

The capacitor C5 is connected to both ends of a series circuit (terminal D of the control IC 23 and one end of the inductor L2) of the switching element of the control IC 23 and the inductor L2, and absorbs a transient high voltage generated when the inductor L2 is turned off. It constitutes a circuit.

The capacitors C6 and C7 are capacitors that smooth the output voltage and output current of the DC / DC converter 22.

The resistance element R15 is a dummy resistance element for passing a current between the output terminals of the DC / DC converter 22 (between the terminal LED + and the terminal LED − of the connector J1) even when the light source 15 is not connected.

The connector J1 is a connector for connecting the DC / DC converter 22 and the light source 15, and has a terminal LED + connected to the anode side of the LED which is the light source 15 and a terminal LED- connected to the cathode side.

FIG. 2 is a block diagram showing a detailed configuration of the control IC 23 in FIG. The control IC 23 includes a power supply circuit 30, a temperature control circuit 31, a switching control circuit 32, a driver 33, and a switching element 34.

The power supply circuit 30 distributes the DC voltage VDD supplied to the terminal VDD to each component of the control IC 23, or generates various reference voltages from the DC voltage VDD and supplies them to the temperature control circuit 31 and the switching control circuit 32. It is a circuit to do.

In the temperature control circuit 31, when the temperature of the control IC 23 exceeds the temperature control start temperature determined by the resistance value (referred to as the resistance value RTC) between the terminal RTC and the circuit ground (terminal GND), the switching element 34 Controls to suppress the current flowing through. At that time, as the temperature rises, a negative gradient (that is, a negative gradient) determined by the ratio between the resistance value (referred to as the resistance value RS) and the resistance value RTC between the terminal RS and the circuit ground (terminal GND) is determined. The current flowing through the switching element 34 is suppressed along the suppressed current / rising temperature). Therefore, the temperature control circuit 31 has a built-in thermistor, and the voltage Vadj for limiting the maximum current flowing through the switching element 34 based on the temperature, the resistance value RTC, and the resistance value RS of the control IC 23 obtained by the thermistor. Is generated and output to the switching control circuit 32.

The switching control circuit 32 outputs a control signal for turning on / off the switching element 34 to the driver 33 by PWM (Pulse Width Modulation) control. More specifically, the switching control circuit 32 detects the voltage of the terminal CS in order to detect the current flowing through the switching element 34, compensates the signal indicating the detected voltage with the capacitance connected to the terminal COMP, and after compensation. Compare the signal with the internal voltage. Then, when the compensated signal exceeds a predetermined voltage, a control signal for turning off the switching element 34 is output to the driver 33. Further, even when the voltage of the terminal CS exceeds the voltage Vadj sent from the temperature control circuit 31, a control signal for turning off the switching element 34 is output to the driver 33. On the other hand, the switching control circuit 32 outputs a control signal for turning on the switching element 34 to the driver 33 when the zero current is detected based on the voltage input to the terminal ZCD.

The driver 33 is a buffer amplifier that amplifies the control signal sent from the switching control circuit 32 and outputs it to the switching element 34 for driving.

The switching element 34 is a switching element that conducts or does not conduct between the terminal D and the terminal CS according to the control signal sent from the driver 33, and is, for example, a MOSFET.

The operation of the lighting device 10 according to the reference example configured as described above is as follows.

The AC power supplied from the AC power supply 5 is rectified by the rectifier circuit 21 to become the first DC power, the first DC power is converted to the second DC power by the DC / DC converter 22, and a constant current is supplied to the light source 15. Will be done.

In the front stage of the DC / DC converter 22, the DC voltage output from the rectifier circuit 21 is smoothed by the capacitor C1, the inductor L1 and the capacitor C2, and the smoothed DC voltage is sent to the control IC 23 via the resistance elements R2 and R4. Will be supplied.

The smoothed DC voltage is also supplied to the bleeder circuit composed of the resistance elements R10 to R13 and the transistors Q1 to Q2. In the bleeder circuit, when the firefly switch (not shown) connected to the AC power supply 5 is on, the DC / DC converter 22 outputs a DC voltage, so that the transistor Q2 is turned on through the resistance element R13 and the transistor Q1 is turned on. It is turned off and the function as a bleeder circuit is stopped. On the other hand, when the firefly switch (not shown) is off, the DC / DC converter 22 does not output a DC voltage, so that the transistor Q2 is turned off through the resistance element R13, the transistor Q1 is turned on, and the resistance element R10 and the transistor Q1 are turned on. A small amount of current flows. As a result, the lamp (not shown) of the firefly switch lights up.

Further, the DC voltage after smoothing is input to the terminal D of the control IC 23, and when the switching element 34 of the control IC 23 is turned on, a current is applied to the light source 15 via the resistance element R14 and the inductor L2. On the other hand, when the switching element 34 of the control IC 23 is turned off, the energy stored in the inductor L2 is released, and a current flows through the loop circuit formed by the light source 15, the diode D6, and the resistance element R14. The voltage and current applied to the light source 15 are smoothed by the capacitor C7.

Further, in the control IC 23, the on / off of the switching element 34 is controlled by PWM control by the switching control circuit 32. More specifically, the switching control circuit 32 detects the voltage of the terminal CS corresponding to the current flowing through the switching element 34, and the signal indicating the detected voltage is compensated by the capacitance connected to the terminal COMP, and the compensated signal. And the internal predetermined voltage are compared. Then, when the compensated signal exceeds a predetermined voltage, a control signal for turning off the switching element 34 is output from the switching control circuit 32 to the switching element 34 via the driver 33. Further, even when the voltage of the terminal CS exceeds the voltage Vadj sent from the temperature control circuit 31, a control signal for turning off the switching element 34 is output from the switching control circuit 32 to the switching element 34 via the driver 33. To. On the other hand, when the voltage input to the terminal ZCD is detected in the switching control circuit 32 and the voltage indicates zero current, a control signal for turning on the switching element 34 is output to the switching element 34 via the driver 33. ..

Further, the temperature control circuit 31 generates a voltage Vadj for suppressing the current flowing through the switching element 34 (that is, the current flowing through the light source 15) when the temperature of the control IC 23 is a constant condition, and outputs the voltage to the switching control circuit 32. Will be done. As a result, when the temperature control start temperature determined by the parallel resistance value RTC of the resistance elements R7 and R8 connected to the terminal RTC is exceeded, the current flowing through the switching element 34 is suppressed. In that case, as the temperature rises, a negative gradient (that is, suppressed current / rising temperature) that is determined depending on the ratio between the resistance value RS and the resistance value RTC of the resistance element R9 connected to the terminal RS. The current flowing through the switching element 34 is suppressed along the line.

Next, the lighting device according to the embodiment will be described. In addition, all of the embodiments described below show a specific example of the present invention. The numerical values, shapes, materials, circuit elements, positions and connection forms of circuit elements, signal waveforms, control methods, application examples, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components. In addition, each figure is not necessarily exactly illustrated. In each figure, substantially the same configuration is designated by the same reference numerals, and duplicate description may be omitted or simplified.

FIG. 3 is a circuit diagram of the lighting device 40 according to the embodiment. The lighting device 40 is a device that emits light by receiving the supply of AC power, and is used, for example, in various lighting fixtures such as a light source for lighting such as a light bulb and a straight tube, a downlight, a ceiling light, a pendant, and a table stand. The lighting device 40 includes a lighting circuit 50 and a light source 16.

The light source 16 is an element that emits light by receiving a current supply, and is, for example, a solid-state light emitting element such as an LED or EL.

The lighting circuit 50 is a circuit that supplies a constant current to the light source 16, and is composed of a rectifier circuit 51 and a DC / DC converter 52.

The rectifier circuit 51 is a circuit that converts the AC power supplied from the AC power supply 6 into the first DC power. In the present embodiment, the commercial AC power such as AC100V is full-wave rectified and converted into the DC power. It is a bridge diode composed of four diodes D21 to D24. The resistance element R21 is a protective resistance element connected in series with the bridge diode.

The DC / DC converter 52 is a switching power supply that converts the first DC power supplied from the rectifier circuit 51 into the second DC power and supplies a constant current to the light source 16. The DC / DC converter 52 includes a control IC 53, a diode D25, resistance elements R22 to R29 and RP1, capacitors C21 to C24, inductors L21 to L22, and a connector J2.

The inductor L21, the capacitors C21 and C22 are circuits for smoothing the first DC power output from the rectifier circuit 51. Specifically, the inductor L21, the capacitors C21 and C22 constitute a π-type filter. The resistance element RP1 connected between the capacitors C21 and C22 is a protection resistance element inserted in the current return path of the DC / DC converter 52.

The control IC 53 is a one-chip integrated circuit that has a built-in switching element and controls to supply a constant current to the light source 16. In the present embodiment, the control IC 53 has eight terminals (terminal VCS, terminal BL, terminal RC, and terminal). It has a GND, a terminal DRAIN, a terminal NC, a terminal SOURCE, and a terminal AUX).

The terminal VCC of the control IC 53 is a terminal corresponding to the terminal VDD of the control IC 23 of the reference example, and the first DC power from the rectifier circuit 51 is smoothed by the capacitors C21 and C22 and the inductor L21 to be generated in this terminal VCS. The DC voltage to be supplied is directly supplied. The resistance elements corresponding to the resistance elements R2 and R4 according to the reference example are omitted in this DC / DC converter 52 for the sake of simplification.

The resistance element R22 is connected between the terminal VCS of the control IC 53 and the terminal BL (terminal for the bleeder circuit), and corresponds to the resistance element R3 according to the reference example.

The resistance element R23 is a resistance element that determines the resistance value connected to the terminal RC involved in the temperature control of the control IC 53. The terminal RC corresponds to the terminal RTC of the control IC 23 according to the reference example.

The terminal GND of the control IC 53 is a terminal connected to the current return path (wiring path connecting the resistance elements R23 to R27) of the DC / DC converter 52.

The inductor L22 is connected in series with the light source 16 and stores energy when the switching element of the control IC 53 is turned on, releases the stored energy when the switching element is turned off, and reduces the ripple of the output current. It is a coil for.

The diode D25 is a diode for releasing the energy stored in the inductor L22.

The capacitors C23 and C24 are capacitors that smooth the output voltage and output current of the DC / DC converter 52.

The resistance element R28 is a dummy resistance element for passing a current between the output terminals of the DC / DC converter 52 (between the terminal LED + and the terminal LED − of the connector J2) even when the light source 16 is not connected.

The resistance elements R25 to R27 constitute a resistance element for detecting the current flowing through the switching element included in the control IC 53.

The resistance element R24 is connected between the terminal AUX of the control IC 53 and the current return path of the DC / DC converter 52. The resistance element R29 is connected between the terminal AUX and the terminal DRAIN of the control IC 53. In the control IC 53, the partial pressure determined by the resistance element R29 and the resistance element R24 is compared with the threshold value inside the control IC 53, and an abnormality in the load is detected.

The connector J2 is a connector for connecting the DC / DC converter 52 and the light source 16, and has a terminal LED + connected to the anode side of the LED which is the light source 16 and a terminal LED- connected to the cathode side.

FIG. 4 is a block diagram showing a detailed configuration of the control IC 53 in FIG. The control IC 53 includes a power supply circuit 30, a temperature control circuit 31a, a switching control circuit 32a, a driver 33, a switching element 34, a bleeder circuit 35, and a capacitor 36.

The power supply circuit 30 distributes the DC voltage VCS supplied to the terminal VCS to each component of the control IC 53, or generates various reference voltages from the DC voltage VCS and supplies them to the temperature control circuit 31a and the switching control circuit 32a. It is a circuit to do.

The bleeder circuit 35 is connected between the terminal BL and the terminal GND, and corresponds to the bleeder circuit (resistance elements R10 to R13 and transistors Q1 to Q2) included in the DC / DC converter 22 according to the reference example. As described above, in the present embodiment, the bleeder circuit 35 is built in the control IC 53, and the lighting circuit 50 is made compact.

The capacitor 36 is a bypass capacitor connected between the terminal VCS and the terminal GND, and corresponds to the capacitor C3 of the DC / DC converter 22 according to the reference example. As described above, in the present embodiment, the bypass capacitor 36 is built in the control IC 53, and the lighting circuit 50 is made compact.

In the temperature control circuit 31a, when the temperature of the control IC 53 exceeds the temperature control start temperature determined by the resistance value (referred to as the resistance value RC) between the terminal RC and the current return path, the current flowing through the switching element 34 Control to suppress. At that time, as the temperature rises, a negative gradient (that is, suppressed current / temperature change) that is determined depending on the ratio between the resistance value (referred to as the resistance value RS) of the built-in resistance element 37 and the resistance value RC is determined. ), The current flowing through the switching element 34 is suppressed. Therefore, the temperature control circuit 31a has a built-in thermistor, and the voltage Vadj for limiting the maximum current flowing through the switching element 34 based on the temperature, the resistance value RC, and the resistance value RS of the control IC 53 obtained by the thermistor. Is generated and output to the switching control circuit 32a. The built-in resistance element 37 is an example of at least one resistance element that determines the dependency relationship between the temperature of the control IC 53 and the current output to the light source 16, and functionally, the resistance element R9 according to the reference example. handle. As described above, in the present embodiment, the resistance element 37 for temperature control is built in the control IC 53, and the lighting circuit 50 is made compact.

The switching control circuit 32a outputs a control signal for turning on / off the switching element 34 to the driver 33 by PWM control. More specifically, the switching control circuit 32a detects the voltage of the terminal SOURCE in order to detect the current flowing through the switching element 34, and compares the signal indicating the detected voltage with the internal predetermined voltage. Then, when the signal indicating the detected voltage exceeds a predetermined voltage, a control signal for turning off the switching element 34 is output to the driver 33. Further, even when the voltage of the terminal SOURCE exceeds the voltage Vadj sent from the temperature control circuit 31a, a control signal for turning off the switching element 34 is output to the driver 33. On the other hand, the switching control circuit 32a detects a load abnormality by comparing the partial pressure determined by the resistance element R29 and the resistance element R24, which is input to the terminal AUX, with the internal threshold value.

The driver 33 is a buffer amplifier that amplifies the control signal sent from the switching control circuit 32a and outputs it to the switching element 34 for driving.

The switching element 34 is a switching element that conducts or does not conduct between the terminal DRAIN and the terminal SOURCE according to the control signal sent from the driver 33, and is, for example, a MOSFET.

The operation of the lighting device 40 according to the present embodiment configured as described above is as follows.

The AC power supplied from the AC power supply 6 is rectified by the rectifying circuit 51 to become the first DC power, the first DC power is converted into the second DC power by the DC / DC converter 52, and a constant current is supplied to the light source 16. Will be done.

In the front stage of the DC / DC converter 52, the DC voltage output from the rectifier circuit 51 is smoothed by the capacitor C21, the inductor L21 and the capacitor C22, and is directly supplied to the terminal VCS of the control IC 53 as the smoothed DC voltage VCS. Will be done.

Further, the DC voltage VCS is also supplied to the light source 16, and when the switching element 34 of the control IC 53 is turned on, a current flows through the light source 16, the inductor L22, and the switching element 34. On the other hand, when the switching element 34 of the control IC 53 is turned off, the energy stored in the inductor L22 is released, and a current flows through the light source 16 via the diode D25. The current flowing through the light source 16 and the voltage applied to the light source 16 are smoothed by the capacitor C23.

Further, in the control IC 53, the on / off of the switching element 34 is controlled by PWM control by the switching control circuit 32a. More specifically, the switching control circuit 32a detects the voltage of the terminal SOURCE corresponding to the current flowing through the switching element 34, and compares the signal indicating the detected voltage with the internal predetermined voltage. Then, when the signal indicating the detected voltage exceeds a predetermined voltage, a control signal for turning off the switching element 34 is output from the switching control circuit 32a to the switching element 34 via the driver 33. Further, even when the voltage of the terminal SOURCE exceeds the voltage Vadj sent from the temperature control circuit 31a, a control signal for turning off the switching element 34 is output from the switching control circuit 32a to the switching element 34 via the driver 33. To. On the other hand, in the switching control circuit 32a, the load abnormality is detected by comparing the partial pressure determined by the resistance element R29 and the resistance element R24 input to the terminal AUX with the internal threshold value.

Further, the temperature control circuit 31a generates a voltage Vadj for suppressing the current flowing through the switching element 34 (that is, the current flowing through the light source 16) when the temperature of the control IC 53 is a constant condition, and outputs the voltage to the switching control circuit 32a. Will be done. As a result, when the temperature control start temperature determined by the resistance value RC of the resistance element R23 connected to the terminal RC is exceeded, the current flowing through the switching element 34 is suppressed. In that case, as the temperature rises, along a negative slope (that is, suppressed current / temperature change) that depends on the ratio of the resistance value RS and the resistance value RC of the built-in resistance element 37. The current flowing through the switching element 34 is suppressed.

Further, when the firefly switch (not shown) connected to the AC power supply 6 is turned on by the bleeder circuit 35 built in the control IC 53, the space between the terminal BL and the terminal GND is opened. On the other hand, when the firefly switch (not shown) is off, a minute current flows between the terminal BL and the terminal GND, and the lamp (not shown) of the firefly switch lights up.

As described above, the lighting device 40 according to the present embodiment includes a light source 16 and a lighting circuit 50 that supplies a current to the light source 16, and the lighting circuit 50 is a rectification that converts AC power into first DC power. The circuit 51 includes a DC / DC converter 52 that converts the first DC power supplied from the rectifying circuit 51 into a second DC power and supplies a current to the light source 16, and the DC / DC converter 52 includes the light source 16. The control IC 53 further comprises an inductor L22 connected in series, a diode D25 for discharging the energy stored in the inductor L22, and a control IC 53 having a switching element 34 connected in series with the inductor L22. It has a capacitor 36 that smoothes the first DC power.

As a result, since the capacitor 36 for smoothing the first DC power is built in the control IC 53, the lighting circuit 50 has a smaller number of parts than the conventional lighting circuit in which such a capacitor is mounted outside the control IC. It will be realized. As a result, the lighting circuit 50 is made compact, structural restrictions on the lighting device 40 are reduced, and a structural design (for example, a high light distribution LED bulb) that sufficiently brings out the light emitting function of the lighting device 40 becomes possible.

Further, the control IC 53 further includes a bleeder circuit 35 for passing a current between the two output terminals of the rectifier circuit 51. As a result, a circuit corresponding to the firefly switch is built in the control IC 53, so that the lighting circuit 50 corresponding to the firefly switch has a smaller number of parts than the conventional lighting circuit in which such a circuit is mounted outside the control IC. Is realized. As a result, the lighting circuit 50 is further made compact.

Further, the control IC 53 further includes at least one resistance element 37 that determines the dependency relationship between the temperature of the control IC 53 and the current output to the light source 16. As a result, since the resistance element 37 that determines the dependency relationship between the temperature of the control IC 53 and the current output to the light source 16 is built in the control IC 53, the conventional lighting in which such a resistance element is mounted outside the control IC A lighting circuit 50 having a temperature control function is realized with a smaller number of parts than the circuit. As a result, the lighting circuit 50 is further made compact.

Next, an application example of the lighting device 40 according to the present embodiment will be described.

FIG. 5 is a schematic view showing the appearance of an application example of the lighting device 40 according to the embodiment. Here, for comparison, the appearance of the LED bulb of the E17 base as an application example of the lighting device 10 according to the reference example ((a) in FIG. 5) and the application example of the lighting device 40 according to the embodiment are shown. The appearance of the LED bulbs of the two types of E17 bases (the lighting device 40a in FIG. 5B and the lighting device 40b in FIG. 5C) is shown.

As shown in FIG. 5A, the lighting device 10 according to the application example of the reference example has a component as an LED bulb, that is, a glove 41, in addition to the lighting circuit 20 and the light source 15 shown in FIG. , The housing 42 and the base 43 are provided.

The glove 41 is a hemispherical cover member made of a resin or the like that covers the light source 15 made of LEDs and diffuses the light emitted from the light source 15. The housing 42 is a case that accommodates the lighting circuit 20 and is made of a cylindrical resin or metal that dissipates heat generated by the light source 15 and the lighting circuit 20. The base 43 is a cylindrical screw-in metal fitting that receives AC power from a commercial AC power source 5 and supplies it to the lighting circuit 20, and is an E17 base in the present embodiment.

In this figure, the circuit board 25 on which the lighting circuit 20 including the control IC 23 is mounted and the approximate mounting positions of the light source 15 housed in the housing 42 are shown by broken lines. As shown in this figure, the lighting device 10 according to the reference example has many electronic components mounted on the circuit board 25 without being built in the control IC 23. Therefore, the size of the circuit board 25 is larger than that of the lighting devices 40a and 40b according to the embodiment, the volume occupied by the housing 42 useful for the circuit board 25 in the LED bulb is large, and the light distribution angle is large (for example,). , It becomes difficult to realize a light distribution angle exceeding 180 degrees).

As shown in FIG. 5B, in the lighting device 40a according to the first application example of the embodiment, in addition to the lighting circuit 50 and the light source 16 shown in FIG. 3, a component as an LED bulb, That is, the glove 41a, the housing 42a, and the base 43a are provided.

The glove 41a is a spherical cover member made of a resin or the like that covers the light source 16a made of LEDs and diffuses the light emitted from the light source 16a. The housing 42a is a case that accommodates the lighting circuit 50 and is made of a cylindrical resin or metal that dissipates heat generated by the light source 16a and the lighting circuit 50. The base 43a is a cylindrical screw-in metal fitting that receives AC power from a commercial AC power source 6 and supplies it to the lighting circuit 50, and is an E17 base in the present embodiment.

As shown in this figure, in the lighting device 40a according to the first application example of the embodiment, the bleeder circuit 35 and the capacitor 36 are built in the control IC 53, and the circuit board 55 is compared with the lighting device 10 according to the reference example. There are few electronic components mounted on top. Therefore, the size of the circuit board 55 is smaller than that of the lighting device 10 according to the reference example, and the volume occupied by the housing 42a that uses the circuit board 55 in the LED bulb is small. As a result, the maximum dimension L1a of the glove 41a can be made larger than the maximum dimension L2a of the housing 42a in the cross-sectional view perpendicular to the cylindrical axis of the housing 42a. This makes it possible to scatter the light emitted from the light source 16a backward (that is, in the direction toward the base 43a), and realizes an LED bulb having a large light distribution angle (for example, a light distribution angle exceeding 180 degrees). can.

As shown in FIG. 5 (c), the lighting device 40b according to the second application example of the embodiment has components as LED bulbs in addition to the lighting circuit 50 and the light source 16 shown in FIG. That is, the glove 41b, the housing 42b, and the base 43b are provided.

The glove 41b is a spherical cover member made of a resin or the like that covers the light source 16b made of LEDs and diffuses the light emitted from the light source 16b. The housing 42b is a case that accommodates the lighting circuit 50 and is made of a cylindrical resin or metal that dissipates heat generated by the light source 16b and the lighting circuit 50. The base 43b is a cylindrical screw-in metal fitting that receives AC power from a commercial AC power source 6 and supplies it to the lighting circuit 50, and is an E17 base in the present embodiment.

As shown in this figure, in the lighting device 40b according to the second application example of the embodiment, the bleeder circuit 35 and the capacitor 36 are built in the control IC 53, and the circuit board 55 is compared with the lighting device 10 according to the reference example. There are few electronic components mounted on top. Therefore, the size of the circuit board 55 is smaller than that of the lighting device 10 according to the reference example. Further, in this application example, the circuit board 55 is arranged in the space covered by the base 43b, whereby the volume occupied by the housing 42b in the LED bulb is smaller than that of the lighting device 40a according to the first application example. .. As a result, the maximum dimension L1b of the glove 41b can be made larger than the maximum dimension L2b of the housing 42b in the cross-sectional view perpendicular to the cylindrical axis of the housing 42a. As a result, the light emitted from the light source 16b can be scattered further rearward (that is, in the direction toward the base 43b), and an LED bulb having a larger light distribution angle (for example, 260 degrees) can be realized. Further, the control IC 53 on the circuit board 55 is accommodated in the space covered by the base 43b, and the distance from the light source 16b is larger than that of the lighting device 40a according to the first application example, and the distance from the light source 16b is increased. The amount of heat received is suppressed.

In the LED bulbs shown in FIGS. 5 (b) and 5 (c), the light sources 16a and 16b are provided at positions covered by the upper ends of the housings 42a and 42b, respectively, but the light sources 16a and 16b are provided. The arrangement position of 16b is not limited to this. It may be placed in a space covered by gloves 41a and 41b. For example, a support column extending from the upper surfaces of the housings 42a and 42b to the vicinity of the center of the space covered by the gloves 41a and 41b may be provided, and the light sources 16a and 16b may be arranged at the tip of the support column. As a result, a high light distribution LED bulb is realized.

As described above, in the lighting device 40a (and 40b) according to the present embodiment, the glove 41a (and 41b) covering the light source 16 and the cylindrical housing 42a (and 42b) accommodating the lighting circuit 50 are provided. In a cross-sectional view perpendicular to the cylindrical axis of the housing 42a (and 42b), the maximum dimensions L1a (and L2b) of the gloves 41a (and 41b) are the maximum dimensions L2a (and L2b) of the housing 42a (and 42b). Greater than.

As a result, compared to the conventional lighting circuit in which a capacitor or the like is mounted outside the control IC, the light emitted from the light source 16a (and 16b) can be scattered in the rearward direction, and the light distribution angle is larger. It is possible to realize an LED bulb with.

Further, the lighting device 40a (and 40b) according to the present embodiment further has a base 43a (and 43b) for receiving AC power from the outside, and the control IC 53 is a space covered with the base 43a (and 43b). Is housed in. The base 43a (and 43b) is, for example, a cylindrical body having a diameter of 17 mm.

As a result, the control IC 53 on the circuit board 55 is separated from the light source 16a (and 16b) as compared with the conventional lighting circuit housed in the space covered by the housing, and the amount of heat received from the light source 16b is reduced. It is suppressed.

The lighting device and the lighting circuit according to the present invention have been described above based on the embodiments and application examples, but the present invention is not limited to these embodiments and application examples. As long as the gist of the present invention is not deviated, various modifications that can be conceived by those skilled in the art are applied to the embodiments and application examples, and other embodiments constructed by combining some components in the embodiments and application examples are also available. , Included within the scope of the present invention.

For example, in the above embodiment, the control IC 53 of the lighting circuit 50 incorporates a bleeder circuit 35, a capacitor 36, and a resistance element 37, but it is not always necessary to incorporate all of these circuits and electronic components, and at least one. It suffices to incorporate one. By incorporating at least one of these circuits and electronic components in the control IC 53, the lighting circuit 50 has a lighting circuit 50 as compared with the lighting circuit 20 according to the reference example in which all of these circuits and electronic components are mounted outside the control IC 23. , The number of parts is reduced and the size is reduced.

Further, in the application example in the above embodiment, the case where the lighting device 40 is applied to the LED bulb of the E17 base has been described, but the application of the lighting device 40 is not limited to this. The lighting device 40 can be applied to LED bulbs of other sizes or shapes, lighting light sources such as straight tubes, and various lighting fixtures such as downlights, ceiling lights, pendants, and table stands.

16, 16a, 16b Light source 40, 40a, 40b Lighting device 41a, 41b Gloves 42a, 42b Housing 43a, 43b Base 50 Lighting circuit 51 Rectifier circuit 52 DC / DC converter 53 Control IC
55 Circuit board D25 Diode L22 Inductor 35 Breeder circuit 36 Capacitor 37 Resistance element

Claims (7)

Light source and
It is equipped with a lighting circuit that supplies current to the light source.
The lighting circuit is
A rectifier circuit that converts AC power to first DC power,
A DC / DC converter that converts the first DC power supplied from the rectifier circuit into the second DC power and supplies a current to the light source is provided.
The DC / DC converter is
An inductor connected in series with the light source,
A diode for releasing the energy stored in the inductor and
A control IC having a switching element connected in series with the inductor is provided.
The control IC is a lighting device having a capacitor for smoothing the first DC power. The lighting device according to claim 1, wherein the control IC further includes a bleeder circuit for passing a current between two output terminals of the rectifier circuit. The lighting device according to claim 1 or 2, wherein the control IC further includes at least one resistance element that determines a dependency relationship between the temperature of the control IC and the current output to the light source. In addition, it has a base that receives AC power from the outside.
The lighting device according to any one of claims 1 to 3, wherein the control IC is housed in a space covered with the base. The lighting device according to claim 4, wherein the base is a cylindrical body having a diameter of 17 mm. Moreover,
The glove covering the light source and
It is provided with a cylindrical housing for accommodating the lighting circuit.
The lighting device according to claim 4 or 5, wherein the maximum dimension of the glove is larger than the maximum dimension of the housing in a cross-sectional view perpendicular to the cylindrical axis of the housing. A lighting circuit that supplies current to a light source.
A rectifier circuit that converts AC power to first DC power,
A DC / DC converter that converts the first DC power supplied from the rectifier circuit into the second DC power and supplies a current to the light source is provided.
The DC / DC converter is
An inductor connected in series with the light source,
A diode for releasing the energy stored in the inductor and
A control IC having a switching element connected in series with the inductor is provided.
The control IC is a lighting circuit having a capacitor for smoothing the first DC power.

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