JP2020177847A - Driver and light emitting diode device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of a problem even if the type of a power source connected at the start of operation is erroneously determined.
SOLUTION: A controller for controlling a converter that converts a voltage from a power source and applies it to a light emitting diode has an on mode for operating the converter and an off mode for stopping the converter, and operates in the off mode. Start (S10).
[Selection diagram] Fig. 1

Description

The present invention relates to a driver for driving a light emitting diode and a light emitting diode device.

In a lighting device using an LED (light emitting diode), a driver drives the LED to emit light by electric power from a power source. As the power source, a constant current or constant voltage power source is used. When the power supply and the driver are separate bodies, it is desirable that the driver can handle any power source of the constant current and the constant voltage.

Patent Document 1 discloses a dimmer that dimmers an LED and can be connected to a current source or a voltage source. The dimmer measures the voltage of a resistor connected in series with the LED. When the voltage exceeds the maximum threshold value, it is determined that a high voltage and constant voltage power supply is connected. If the voltage exceeds the minimum value and falls below the maximum threshold value, it is determined that a constant current power supply is connected. Then, when the voltage is lower than the minimum value, it is determined that a low voltage and constant voltage power supply is connected. In this case, a boosting converter that boosts the voltage from the power supply operates.

Special Table 2017-534139

In the above dimmer, for example, chattering at the electrical contact with the power supply, reconnection with the power supply, connection with the power supply in a state where power can be supplied, noise in the circuit, noise from the outside, etc. There is a risk of judgment. In particular, if it is erroneously determined at the start of operation or during operation that a low-voltage and constant-voltage power supply is connected even though a constant-current power supply is connected, the boost converter fails and the LED There is a risk of problems such as non-lighting and blinking.

One aspect of the present invention is to realize a driver or the like that can suppress the occurrence of a defect even if the type of the connected power supply is erroneously determined.

In order to solve the above problems, the driver according to one aspect of the present invention is a driver that drives a light emitting diode, and controls a converter that converts a voltage from a power source and applies it to the light emitting diode, and the converter. The controller has an on mode for operating the converter and an off mode for stopping the converter, and is characterized in that the off mode is set at the start of operation.

According to one aspect of the present invention, even if the type of the connected power supply is erroneously determined, the occurrence of a defect can be suppressed.

It is a flowchart which shows the process flow in the controller of the lighting apparatus which concerns on one Embodiment of this invention. It is a circuit diagram which shows the schematic structure of the said lighting apparatus. It is a circuit diagram which shows the schematic structure of the lighting apparatus which concerns on another Embodiment of this invention. It is a circuit diagram which shows the schematic structure of the lighting apparatus which concerns on still another Embodiment of this invention. It is a circuit diagram which shows the schematic structure of the lighting apparatus which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail. For convenience of explanation, the members having the same functions as the members shown in each embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

[Embodiment 1]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 2 is a circuit diagram showing a schematic configuration of the lighting device according to the present embodiment. As shown in FIG. 2, the lighting device 1 includes a power supply 10, an LED 11 (light emitting diode), and a driver 12. An LED device (light emitting diode device) is configured by the LED 11 and the driver 12.

The power supply 10 is a constant current or constant voltage power supply. A driver 12 is provided between the power supply 10 and the LED 11. The number of LEDs 11 may be one or a plurality. Further, the plurality of LEDs 11 may be connected in series, may be connected in parallel, or may be connected in series and parallel. Further, the LED 11 may be formed of an inorganic compound or an organic compound. Since known power sources 10 and LEDs can be used, the details thereof will be omitted.

The driver 12 drives the LED 11, and includes a boosting converter 20 (converter), a smoothing capacitor 21, a sensor resistor 22 (sensor), and a controller 23.

The boosting converter 20 is a chopper-type boosting converter including a switching element 24, a choke coil 25, and a diode 26. The boost converter 20 operates by repeatedly turning on and off the switching element 24. The smoothing capacitor 21 is for smoothing the voltage and current from the boosting converter 20. The sensor resistor 22 is for detecting the value of the current flowing through the LED 11 as a voltage value, and is connected in series with the LED 11.

The controller 23 operates by the voltage from the power supply 10 and controls the boosting converter 20. In the present embodiment, the controller 23 determines which of the constant voltage and constant current power supplies 10 is connected based on the voltage of the sensor resistor 22.

When the constant voltage power supply 10 is connected, the controller 23 goes into the on mode and operates the boosting converter 20. As a result, a predetermined voltage from the power supply 10 is boosted (converted), smoothed by the smoothing capacitor 21, and applied to the LED 11 and the sensor resistor 22. As a result, a desired current can flow through the LED 11 to cause it to emit light.

On the other hand, when the constant current power supply 10 is connected, the controller 23 goes into the off mode, and the switching element 24 is always turned off to stop the boosting converter 20. In this case, a predetermined current from the power supply 10 can flow through the LED 11 to emit light.

The controller 23 can realize the above operation by including an AD (Analog to Digital) converter, a microcomputer, and a driver for a switching element.

In the present embodiment, the controller 23 is in the off mode at the start of operation. As a result, the driver 12 starts operating in the off mode even if it is erroneously determined that the constant voltage power supply is connected at the start of operation, and the boosting converter 20 is stopped. Therefore, it is possible to suppress the occurrence of malfunctions such as failure of the boosting converter 20 due to the above erroneous determination, non-lighting of the LED 11, and blinking.

FIG. 1 is a flowchart showing a processing flow in the controller 23 having the above configuration. As shown in FIG. 1, the controller 23 first starts operation in the off mode (S10). Next, the voltage Vr of the sensor resistor 22 is measured at a predetermined timing (S11).

By the way, when the constant voltage power supply 10 is connected and the boosting converter 20 is operating (on mode), the range of the current that causes the LED 11 to emit light and the constant current power supply 10 are connected to the boosting converter 20. It is different from the range of the current that causes the LED 11 to emit light when is stopped (off mode). Specifically, when emitting light in the off mode, the voltage Vr is at least the minimum value Vmin. Further, when the light is emitted in the on mode, the voltage Vr is equal to or higher than the threshold value Vth. Since the boosting converter 20 is operating in the on mode, Vmin <Vth.

Therefore, it is determined whether or not the voltage Vr is smaller than the minimum value Vmin (threshold value for turning on) (S12). When the voltage Vr is equal to or greater than the minimum value Vmin, it is determined that the constant current power supply 10 is connected, and the process returns to step S10 to repeat the above operation.

On the other hand, when the voltage Vr is smaller than the minimum value Vmin, it is determined that the constant voltage power supply 10 is connected, and the operation is performed in the on mode (S13). Next, the voltage Vr of the sensor resistor 22 is measured at a predetermined timing (S14), and it is determined whether or not the voltage Vr is smaller than the threshold value Vth (off threshold value) (S15). When the voltage Vr is equal to or higher than the threshold value Vth, it is determined that the constant voltage power supply 10 is connected, and the process returns to step S13 to repeat the above operation. On the other hand, when the voltage Vr is smaller than the threshold value Vth, the process returns to step S10 and the above operation is repeated.

Therefore, since it is possible to transition to an appropriate mode based on the minimum value Vmin and the threshold value Vth of the voltage Vr in each mode, the above-mentioned problem occurs even if the type of the connected power supply is erroneously determined during operation. Can be suppressed.

[Embodiment 2]
Another embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a circuit diagram showing a schematic configuration of the lighting device according to the present embodiment. The lighting device 1 of the present embodiment is different from the lighting device 1 shown in FIGS. 1 and 2 in that the function of the controller 23 is realized by a circuit, and other configurations are the same.

As shown in FIG. 3, the controller 23 includes comparators Ca and Cb, transistors Q1 to Q3, resistors R1 to R3, and a PWM (Pulse Width Modulation) controller 40. The controller 23 is provided with resistors and other circuit elements at appropriate positions.

In the comparator Ca, the input terminal on the positive side is connected between the resistors R1 and R2 connected in series, and the input terminal on the negative side is connected to one end of the sensor resistor 22 on the LED11 side. The output terminal is connected to the PWM controller 40 and is connected to the base of the transistor Q1 via a resistor.

In the resistors R1 and R2 connected in series, the end on the resistor R1 side is connected to the collector of the transistors Q1 and Q2 via the resistor, and the end on the resistor R2 side is connected to the other end of the sensor resistor 22. To. A power supply voltage Vcc is applied to the resistors R1 and R2 connected in series.

A resistor R3 is connected between the output terminal of the comparator Ca and the input terminal on the positive side. The resistors R1 to R3 make the comparator Ca a hysteresis comparator having two threshold values Vmin · Vmax with respect to the voltage Vr of the sensor resistor 22. Vmax is the upper limit of the voltage Vr of the sensor resistor 22.

The emitters of the transistors Q1 and Q2 are connected to the other end of the sensor resistor 22. The collector of the transistor Q2 is connected to the base of the transistor Q3 and is connected to the output terminal of the comparator Cb via a resistor.

A voltage having a threshold value of Vth is applied to the input terminal on the positive side of the comparator Cb, and the input terminal on the negative side is connected to one end of the sensor resistor 22 on the LED11 side. Therefore, the comparator Cb is a comparator having a threshold value Vth with respect to the voltage Vr of the sensor resistor 22. In the transistor Q3, the emitter is connected to the other end of the sensor resistor 22, and the collector is connected to the input terminal on the positive side of the comparator Ca.

The PWM controller 40 adjusts the pulse signal applied to the switching element 24 of the boosting converter 20. In the present embodiment, the PWM controller 40 generates the pulse signal when the output of the comparator Ca is at the H (high) level, and operates the boosting converter 20. On the other hand, when the output of the comparator Ca is at the L (low) level, a signal is generated so that the switching element 24 is turned off, and the boost converter 20 is stopped. That is, when the output of the comparator Ca is H level, the on mode is set, and when the output is L level, the off mode is set.

For the controller 23 having the above configuration, when the output of the comparator Ca is at the L level, that is, in the off mode, the transistor Q1 is turned off and the transistor Q2 is turned on, so that the transistor Q3 is turned off. As a result, the operation of the comparator Ca becomes irrelevant to the output of the comparator Cb. Then, when the voltage Vr of the sensor resistor 22 becomes smaller than the threshold value Vmin, the output of the comparator Ca becomes the H level and the on mode is set.

When the output of the comparator Ca is H level, the transistor Q1 is turned on and the transistor Q2 is turned off. Therefore, when the voltage Vr of the sensor resistor 22 becomes smaller than the threshold value Vth, the output of the comparator Cb becomes the H level and the transistor Q3 is turned on. As a result, the output of the comparator Ca becomes L level, and the off mode is set. On the other hand, when the voltage Vr of the sensor resistor 22 becomes larger than the threshold value Vmax, the output of the comparator Ca becomes L level and the off mode is set. As a result, when the voltage Vr of the sensor resistor 22 becomes larger than the upper limit value Vmax, the boosting converter 20 is stopped and the voltage Vr is lowered, so that a circuit failure can be prevented.

[Embodiment 3]
Yet another embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a circuit diagram showing a schematic configuration of the lighting device according to the present embodiment. The lighting device 1 of the present embodiment is different from the lighting device 1 shown in FIGS. 1 and 2 in that a protection circuit 50 is provided on the power supply side of the controller 23, and other configurations are the same.

The protection circuit 50 includes a fuse 51, a reverse voltage protection diode 52, and an overvoltage protection circuit 53. The fuse 51 is connected in series with the driver 12, and the reverse voltage protection diode 52 and the overvoltage protection circuit 53 are connected in parallel with the driver 12. The overvoltage protection circuit 53 clamps the voltage when an overvoltage is applied. As the fuse 51, the reverse voltage protection diode 52, and the overvoltage protection circuit 53, known ones can be used, and the details thereof will be omitted. Further, the fuse 51 may be a resettable fuse.

By the way, when the lighting device 1 shown in FIGS. 1 and 2 is connected to the driver 12 and the LED 11 while the constant voltage power supply 10 is operating, the current flowing through the choke coil 25 of the booster converter 20 at the time of connection is Since it is zero, an overvoltage may be applied to the controller 23 and the controller 23 may fail.

On the other hand, in the lighting device 1 of the present embodiment, since the protection circuit 50 is provided on the power supply side of the controller 23, it is possible to prevent an overvoltage from being applied to the controller 23, and as a result, the controller 23 is affected by the overvoltage. Can be protected. Further, even when the power supply 10 is reversely connected, the protection circuit 50 can prevent the reverse voltage from being applied to the driver 12 and the LED 11, and as a result, the driver 12 and the LED 11 can be prevented from failing.

In the present embodiment, when the power supply 10 is a constant current power supply, a constant voltage is applied to the driver 12 and the LED 11 by the protection circuit 50 at the start of operation, and there is a risk that the power supply 10 is erroneously determined to be a constant voltage power supply. There is. However, in the present embodiment, since the controller 23 is in the off mode at the start of operation, it is possible to suppress the occurrence of the above-mentioned trouble due to the above-mentioned erroneous determination.

[Embodiment 4]
Other embodiments of the present invention will be described with reference to FIG.

FIG. 5 is a circuit diagram showing a schematic configuration of the lighting device according to the present embodiment. The lighting device 1 of the present embodiment is different from the lighting device 1 shown in FIGS. 1 and 2 in that the controller 23 operates according to the output voltage of the boosting converter 20, and the other configurations are the same.

According to the above configuration, even if the overvoltage occurs, the constant voltage characteristic of the LED 11 makes the output voltage a predetermined voltage, and it is possible to prevent the overvoltage from being applied to the controller 23. Therefore, the controller 23 can be protected from the overvoltage.

[Example of realization by software]
The control block of the controller 23 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

In the latter case, the controller 23 includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, at least one processor (control device) and at least one computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, in addition to a "non-temporary tangible medium" such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

[Summary]
The driver according to the first aspect of the present invention is a driver for driving a light emitting diode, and includes a converter that converts a voltage from a power source and applies the voltage to the light emitting diode, and a controller that controls the converter. The controller has an on mode for operating the converter and an off mode for stopping the converter, and the off mode is set at the start of operation.

According to the above configuration, even if the driver erroneously determines that a constant voltage power supply is connected at the start of operation, the driver is in the off mode at the start of operation and the converter is stopped. Therefore, it is possible to suppress the occurrence of defects such as converter failure, LED non-lighting and blinking due to the above erroneous determination.

By the way, the range of the current that causes the light emitting element to emit light when a constant voltage power supply is connected and the converter is operating, and the above when the constant current power supply is connected and the converter is stopped. It is different from the range of current that causes the light emitting element to emit light. Specifically, the lower limit of the current when the converter is operating is larger than the lower limit of the current when the converter is stopped.

Therefore, the driver according to the second aspect of the present invention further includes a sensor for detecting the current flowing through the light emitting diode in the first aspect, and the controller turns on the value detected by the sensor in the off mode. When it is smaller than the on-threshold value, it transitions to the on-mode, while in the on-mode, when the value detected by the sensor is smaller than the off-threshold value which is larger than the on-threshold value, it transitions to the off-mode. You may. In this case, since it is possible to transition to an appropriate mode based on the current range in each mode, even if the type of the connected power supply is erroneously determined during operation, the occurrence of the above-mentioned problem can be suppressed. Can be done.

By the way, when the driver is connected to the driver in a state where the constant current power supply can be output, an overvoltage may be applied to the controller by the choke coil provided in the converter.

Therefore, in the driver according to the third aspect of the present invention, in the first or second aspect, the controller operates by applying a voltage from the power source, and may further include a protection circuit for protecting the controller. Good. In this case, the protection circuit can protect the controller from overvoltage.

Further, in the driver according to the fourth aspect of the present invention, in the above aspect 1 or 2, the controller may operate by applying a voltage from the converter. In this case, the diode provided in the converter can prevent an overvoltage from being applied to the controller.

The light emitting diode device according to the fifth aspect of the present invention is a light emitting diode device including a light emitting diode and a driver for driving the light emitting diode, and the driver is the driver of the above aspects 1 to 4. In this case, the above-mentioned effect is obtained.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

1 Lighting device 10 Power supply 11 LED (light emitting diode)
12 Driver 20 Boost converter (converter)
21 Smoothing capacitor 22 Sensor resistor (sensor)
23 Controller 24 Switching element 25 Choke coil 26 Diode 40 PWM controller 50 Protection circuit

Claims (5)

A driver that drives a light emitting diode
A converter that converts the voltage from the power supply and applies it to the light emitting diode,
It is equipped with a controller that controls the converter.
The controller
On-mode to operate the converter and
It has an off mode to stop the converter.
A driver characterized in that the off mode is set at the start of operation. It is further equipped with a sensor that detects the current flowing through the light emitting diode.
The controller
In the off mode, when the value detected by the sensor is smaller than the on threshold value, the transition to the on mode is performed.
The driver according to claim 1, wherein the driver transitions to the off mode when the value detected by the sensor in the on mode is smaller than the off threshold value larger than the on threshold value. The controller is operated by applying a voltage from the power supply.
The driver according to claim 1 or 2, further comprising a protection circuit for protecting the controller. The driver according to claim 1 or 2, wherein the controller operates by applying a voltage from the converter. A light emitting diode device including a light emitting diode and a driver for driving the light emitting diode.
The light emitting diode device, wherein the driver is the driver according to any one of claims 1 to 4.

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