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Led drive circuit

An LED drive and circuit technology, applied in circuit layout, lamp circuit layout, electric light source, etc., can solve the problems of low rated power, low rated voltage, application limitations, etc.

Inactive Publication Date: 2012-10-31
SHARP KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these devices all have lower rated voltage and lower rated power, and their applications are not applicable when a constant DC voltage is generated, but instead, a commercial power supply is directly connected to the LED driving circuit and the LED is driven with a pulsating current. restricted

Method used

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Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0050] figure 1 The configuration of the LED driving circuit according to the first embodiment of the present invention is shown in . figure 1 The LED driving circuit of this embodiment shown includes: a bridge diode 2; constant current circuits A1 and B1; a PNP transistor Q1; a resistor R1; and a negative temperature coefficient resistor RN1 such as an NTC thermistor (hereinafter referred to as "NTC resistor RN1").

[0051] The input end of the bridge diode 2 is connected to the commercial AC100V power supply 1 , and one output end of the bridge diode 2 is connected to the anode of the LED module 3 . The constant current terminal T1 of the constant current circuit A1 is connected to the cathode of the LED module 3 , and the constant current terminal T2 of the constant current circuit A1 is connected to the other output end of the bridge diode 2 . The emitter of the PNP transistor Q1 is connected to the cathode of the LED module 3 , and the collector of the PNP transistor ...

no. 2 example

[0058] figure 2 The configuration of the LED driving circuit according to the second embodiment of the present invention is shown in . figure 2 The LED driving circuit of this embodiment shown is provided with: a bridge diode 2; constant current circuits A2 and B2; a PNP transistor Q2; a resistor R2; and a negative temperature coefficient resistor (hereinafter referred to as "NTC resistor") RN2.

[0059]The input end of the bridge diode 2 is connected to the commercial AC100V power supply 1 , and one output end of the bridge diode 2 is connected to the anode of the LED module 3 . The cathode of the LED module 3 is connected to the emitter of the PNP transistor Q2. The constant current terminal T1 of the constant current circuit A2 is connected to the collector of the PNP transistor Q2 , and the constant current terminal T2 of the constant current circuit A2 is connected to the other output terminal of the bridge diode 2 . Also, the collector of the PNP transistor Q2 is con...

no. 3 example

[0065] image 3 The configuration of the LED driving circuit according to the third embodiment of the present invention is shown in . image 3 The LED driving circuit shown in this embodiment includes: a bridge diode 2; a constant current circuit A3; a PNP transistor Q3; resistors R3_1 and R3_2; and a negative temperature coefficient resistor (hereinafter referred to as "NTC resistor") RN3.

[0066] The input end of the bridge diode 2 is connected to the commercial AC100V power supply 1 , and one output end of the bridge diode 2 is connected to the anode of the LED module 3 . The constant current terminal T1 of the constant current circuit A3 is connected to the cathode of the LED module 3 , and the constant current terminal T2 of the constant current circuit A3 is connected to the other output end of the bridge diode 2 . Moreover, the emitter of the PNP transistor Q3 is connected to the cathode of the LED module 3 , and the collector of the PNP transistor Q3 is connected to ...

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Abstract

An LED drive circuit that drives an LED is provided with: a rectifying circuit that converts an alternating voltage into a pulsating current; a constant current circuit; and an over-temperature protection portion that limits an output of the constant current circuit, wherein the LED and the constant current circuit are connected in series on an output side of the rectifying circuit.

Description

technical field [0001] The present invention relates to an LED drive circuit for driving LEDs (Light Emitting Diodes). Background technique [0002] Due to the characteristics of low power consumption and long life, LEDs are being used in a wide range of fields not only display devices but also lighting equipment and the like. In lighting fixtures, multiple LEDs are used to obtain the desired illumination. [0003] If the LED receives a current exceeding the rated current value, its life will be shortened. Therefore, the LED needs to be driven with a constant current, or a current limit is set so that no current exceeding a predetermined magnitude flows therethrough. [0004] General lighting equipment mostly uses commercial AC100V power supply. Therefore, if an LED lighting device is used instead of an incandescent lamp or the like, it should preferably be arranged to also use a commercial AC100V power supply like a general lighting device. [0005] Figure 20 An exampl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B37/02H02M7/08F21V23/00F21Y101/02
Inventor 丸山康弘小路弘之
Owner SHARP KK
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