JP2007036167A - Light-emitting diode driving control circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a light-emitting diode drive control circuit that uses a microcomputer. <P>SOLUTION: A light-emitting diode drive control circuit comprises a DC power supply 2, such as a chopper power and a switching power to drive a plurality of light-emitting diodes 1 connected in series; a detecting means 3 by series resistance for detecting the current running through the light-emitting diodes 1; and a comparing means 4 such as an error amplifier to compare a voltage (or current) obtained, based on this detecting means 3 and a reference voltage V (or reference current), whereby the DC current power 2 is controlled to approximately stably control the current flowing to the light-emitting diodes 1. Then, the reference voltage V (or reference current) is obtained by converting a digital control signal obtained by a microcomputer 5 into an analog voltage V (or analog current) by a D/A converting means 6. In addition, a command signal from a remote control signal receiving part 7 is inputted in the microcomputer 5, and based on this command signal, the digital control signal is generated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit capable of driving and controlling a light emitting diode using a microcomputer.

In Patent Document 1, a DC power source using a chopper circuit (switching circuit) for driving a light emitting diode, a detecting means using a series resistor for detecting a current flowing through the light emitting diode, and a voltage obtained based on the detecting means are disclosed. And a reference voltage (reference potential source) is compared by a comparison means (error amplifier) to control the DC power supply, and a light emitting diode drive control circuit that controls the current to be supplied to the light emitting diode almost stably. It is disclosed. Further, it is described that dimming control can be performed from the outside if the reference voltage (reference potential source) is variable.
JP 2001-313423 A

  However, specific means for making the reference voltage (reference potential source) variable is not disclosed. Not limited to the above-mentioned Patent Document 1, consideration is not given when applying a light-emitting diode to a lighting fixture used in a general living room such as a home. Specifically, a specific configuration in the case of using a microcomputer is not realized. In view of such a problem to be solved, the present invention intends to realize a light emitting diode drive control circuit using a microcomputer.

  To summarize the first invention, a direct current power source for driving a light emitting diode, detection means for detecting a current flowing through the light emitting diode, a voltage (or current) and a reference voltage (or reference current) obtained based on the detection means. ) With a comparison means to control the DC power supply, and to control the current to be passed through the light emitting diode in a substantially stable manner, the light emitting diode drive control circuit, wherein the reference voltage (or reference current) Is a light emitting diode drive control circuit obtained by converting a digital control signal obtained by a microcomputer into an analog voltage (or analog current) by a D / A conversion means. To summarize the second invention, a DC power source for driving the light emitting diode, a detecting means for detecting a current flowing through the light emitting diode, and an A / D converter for A / D conversion of a voltage (or current) obtained based on the detecting means. / D conversion means and a microcomputer for controlling the direct current power source by comparing the output signal of the A / D conversion means with a reference digital signal to control the current to flow through the light emitting diode substantially stably. Is a light emitting diode drive control circuit. In any of the inventions, it is more preferable that a command signal from the remote control signal receiver is input to the microcomputer and a digital control signal (or reference digital signal) is generated based on the command signal.

  According to the first invention, the reference voltage (or reference current) is obtained by converting a digital control signal obtained by the microcomputer into an analog voltage (or analog current) by the D / A conversion means. A light-emitting diode drive control circuit was realized. According to the second invention, the voltage (or current) obtained based on the detection means for detecting the current flowing in the light emitting diode is input to the microcomputer via the A / D conversion means, so that the A / D conversion means The output signal and the reference digital signal can be compared by a microcomputer, and a light emitting diode drive control circuit using the microcomputer can be realized. These inventions can be adapted to lighting fixtures used in general living rooms such as homes. In particular, the circuit configuration is preferable for a lighting fixture controlled by a remote controller.

  Next, an embodiment of the present invention will be described. However, this is merely an exemplary embodiment adopted based on the present invention, and the present invention should not be limitedly interpreted based on matters specific to the embodiment. The technical scope of the present invention should be determined based on the matters shown in the claims of the claims and matters substantially equivalent to the matters.

  The first embodiment shown in FIG. 1 is detected by a DC power source 2 such as a chopper power source or a switching power source that drives a plurality of light-emitting diodes 1 connected in series, and a series resistor that detects a current flowing through the light-emitting diodes 1. The DC power supply 2 is controlled by comparing the means 3 and the voltage (or current) obtained based on the detection means 3 with the reference voltage V (or reference current) by the comparison means 4 such as an error amplifier. , A light emitting diode drive control circuit for controlling the current to be passed through the light emitting diodes 1. The reference voltage V (or reference current) is obtained by converting a digital control signal obtained by the microcomputer 5 into an analog voltage V (or analog current) by the D / A conversion means 6.

  In the illustrated example, the current flowing through the light-emitting diodes 1 is replaced with voltage by the detection means 3 using a series resistance. However, for example, a current flows around the electric wire through which the current flows through the light-emitting diodes 1 without using such a resistor. A detection coil may be mounted. According to such a detecting means, the current is directly detected, and this current may be compared with the reference current by the current input type comparing means. The output of the D / A conversion means 6 is also preferably an analog current output type and a reference current is output. The description in parentheses in the previous paragraph refers to such a specific example, for example.

  The microcomputer 5 usually includes a CPU, a ROM, a RAM, a peripheral circuit, and the like. In addition, it is preferable to provide a nonvolatile memory such as an EEPROM or a flash memory for holding data in the event of a power failure. An example of the characteristics of the D / A conversion means 6 is shown in FIG. 1B, in which the reference voltage V is determined corresponding to the digital control signal (8 bits) obtained by the microcomputer 5, and the D / A The term “conversion table” is also synonymous. Of course, the microcomputer 5 itself may have such a D / A conversion means 6.

  According to the present embodiment, the reference voltage V (or reference current) is obtained by converting the digital control signal obtained by the microcomputer 5 into the analog voltage V (or analog current) by the D / A converter 6. A light emitting diode drive control circuit using the microcomputer 5 was realized. In this way, it can be adapted to a lighting apparatus used in a general living room such as a home. In particular, the circuit configuration is preferable for a luminaire provided with a remote control signal receiving unit 7 for receiving a remote control signal transmitted from a remote control transmitter (not shown). That is, a command signal from the remote control signal receiving unit 7 is input to the microcomputer 5, and the digital control signal is generated based on the command signal.

  Further, according to the D / A conversion means 6 having the characteristics shown in FIG. 1B, the current of the light-emitting diodes 1... From the allowable maximum value to around the minimum value that can function as a night-light at night, and of course. It can be set stepwise or substantially continuously up to the zero value that turns off. Then, by inputting a command signal from the remote control signal receiving unit 7 to the microcomputer 5, it becomes possible to easily perform light to dark remote control of the light-emitting diodes 1 by a remote control transmitter (not shown). As preferred.

  Further, the other configuration will be supplementarily explained. The AC power supply 8 is rectified by a bridge type rectifier 9 and then supplied to the DC power supply 2. The DC power source 2 exemplifies a well-known step-up type chopper power source, and includes a choke coil 10, a semiconductor switching element 11 such as a MOS-FET, a diode 12, a smoothing capacitor 13, and switching control for controlling opening and closing of the semiconductor switching element 11. The circuit unit 14 and the comparison means 4 are used as components.

  Next, the second embodiment shown in FIG. 2 has the same technical significance as the first embodiment in that the microcomputer 5 is used in the light emitting diode drive control circuit, and has a circuit configuration that matches the solution problem. Yes. This second embodiment includes a DC power source 2 such as a chopper power source or a switching power source for driving a plurality of light-emitting diodes 1 connected in series, and a detecting means 3 using a series resistor for detecting a current flowing through the light-emitting diodes 1. A / D conversion means 15 for A / D converting the voltage (or current) obtained based on the detection means 3 and an output signal of the A / D conversion means 15 are inputted and compared with a reference digital signal. This is a light-emitting diode drive control circuit comprising a microcomputer 5 that controls the DC power supply 2 to control the current to flow through the light-emitting diodes 1. Further, when a command signal from the remote control signal receiver 7 is input to the microcomputer 5, the reference digital signal is generated based on the command signal.

  In addition to the illustrated example in which the current flowing through the light emitting diodes 1... Is replaced with a voltage by a series resistor, the detection means 3 may directly detect the current with the above-described current detection coil. Therefore, the A / D conversion means 15 may be a current input type in addition to the voltage input type. Of course, such an A / D conversion means 15 may be integrated with the microcomputer 5 itself, and claim 2 of the scope of claims includes such a case.

  According to the second embodiment, by inputting the voltage (or current) obtained based on the detection means 3 for detecting the current flowing through the light emitting diodes 1 to the microcomputer 5 via the A / D conversion means 15, The microcomputer 5 can compare the output signal of the A / D conversion means 15 and the reference digital signal, and the light emitting diode drive control circuit using the microcomputer 5 can be realized. Further, the output signal of the A / D conversion means 15 and the reference digital signal are, for example, 8 bits, and the current of the light emitting diodes 1... It is preferable that the value can be set stepwise or substantially continuously up to a zero value.

  (A) Circuit block diagram showing the first embodiment of the present invention, (B) Graph showing the input / output relationship of the D / A conversion means   Circuit block diagram showing a second embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting diode 2 DC power supply 3 Detection means 4 Comparison means 5 Microcomputer 6 D / A conversion means 7 Remote control signal receiving part 15 A / D conversion means

Claims (3)

  The comparison means compares the DC power source for driving the light emitting diode, the detecting means for detecting the current flowing through the light emitting diode, and the voltage (or current) obtained based on the detecting means and the reference voltage (or reference current). A light emitting diode drive control circuit for controlling the direct current power source to control the current to be supplied to the light emitting diode in a substantially stable manner, wherein the reference voltage (or reference current) is obtained by a microcomputer A light emitting diode drive control circuit obtained by converting a digital control signal into an analog voltage (or analog current) by a D / A conversion means.   A direct current power source for driving the light emitting diode, a detecting means for detecting a current flowing through the light emitting diode, an A / D converting means for A / D converting a voltage (or current) obtained based on the detecting means, and A light emitting diode drive comprising: a microcomputer for controlling the direct current power source by controlling the direct current power supply by comparing the output signal of the A / D conversion means with a reference digital signal, and controlling the current to flow through the light emitting diode substantially stably. Control circuit.   3. The light emitting diode drive control circuit according to claim 1, wherein a command signal from a remote control signal receiver is input to the microcomputer, and a digital control signal (or reference digital signal) is generated based on the command signal.

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