Circuit for LED constant current power supply

A constant current power supply and circuit technology, which is applied in the direction of electric lamp circuit layout, electric light source, light source, etc., can solve the problems of many peripheral devices, high cost, complicated circuit, etc. Effect

CN102933005AInactive Publication Date: 2013-02-13SHANGHAI DANGOO ELECTRONICS TARDING
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-02-13
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a circuit for an LED constant current power supply. The circuit is characterized in that in the circuit, an alternating current voltage is subjected to rectification by a rectifier bridge, and then is subjected to a filter to enable the waveform of an input voltage to be smooth; the input voltage is converted into a direct voltage after passing an electrolytic capacitor filter; the direct voltage is loaded on an LED after passing a constant-current IC chip; current range of the LED is adjusted by resistors R2 and R3, which are connected with the constant-current IC chip; and a constant-current IC chip protection circuit formed by a Zener diode ZD1, a triode Q1 and a resistor R1 is arranged between the electrolytic capacitor filter and the constant-current IC chip. The circuit is simple in line, low in cost and high in current control accuracy.
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Description

technical field

[0001] The invention relates to an AC constant current power supply circuit applied to LEDs, in particular to an LED constant current power supply circuit. Background technique

[0002] As a substitute for fluorescent lamps, LED lights are widely used in commercial lighting and office lighting, bringing great convenience to people's daily work. A major feature of LED lamps is that they cannot be directly powered by mains electricity, so LED lamps need to be driven by a corresponding power supply if they are to be used as lighting lamps. Second, in order to ensure the constant current of LED lamps. Usually RC circuit or integrated IC control power supply is used as LED power supply. The advantages of the RC circuit are fewer peripheral components, simple wiring, and small PCB board size. Disadvantages The RC circuit is a regulated power supply rather than a constant current power supply. It needs to add a high-power resistor to control the output current. Th...

Examples

Embodiment Construction

[0008] LED constant current power supply circuit of the present invention consists of figure 1 As shown, the AC voltage is input to the rectifier bridge composed of four diodes BD1 through the fuse F1 and the parallel varistor RV for rectification, and is filtered by the filter composed of the electrolytic capacitor C1. The output end of the electrolytic capacitor C1 is respectively connected to the collector of the transistor Q1 and the base resistor R1 of the triode Q1, the other end of the output of the electrolytic capacitor C1 is grounded, the emitter of the triode Q1 is connected to the input terminal Vin of the constant current IC chip U1, and the base of the triode Q1 is connected to the constant current through the voltage regulator ZD1. The output terminal Vout of the current IC chip U1 is connected, and the output terminal Vout of the constant current IC chip U1 is respectively connected to terminal 1 of the constant current IC chip U1 and the anode of LED1, LED2, LE...