LED (Light Emitting Diode) constant-current driving circuit

A constant-current drive and circuit technology, applied in electric lamp circuit arrangement, electric light source, lighting device, etc., can solve the problems of many peripheral components, unstable circuit, inconvenient use, etc., to simplify peripheral circuits, reduce application costs, overcome the The effect of decay

Inactive Publication Date: 2012-09-19
SUZHOU POWERLINK MICROELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of circuit has a good voltage stabilization effect, but the current transfer ratio (CTR) of the optocoupler will decay with time and high temperature, making the circuit unstable, and there are many peripheral components, inconvenient to use, and high cost

Method used

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  • LED (Light Emitting Diode) constant-current driving circuit
  • LED (Light Emitting Diode) constant-current driving circuit
  • LED (Light Emitting Diode) constant-current driving circuit

Examples

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Embodiment Construction

[0015] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0016] Such as figure 1 As shown, the LED constant current driving circuit includes: a transformer, a voltage reference unit 1, a peak current detection and holding unit 2, an error amplifier unit 3, a current comparator unit 4, a switching signal generation unit 5, a driving unit 6, and an adaptive unit 7 And the demagnetization detection unit 8, the voltage reference unit 1 is used to generate the reference voltage VREF.

[0017] The transformer includes a primary winding Np, a secondary winding Ns and an auxiliary winding NA, and the auxiliary winding NA is in phase with the secondary winding Ns. The primary winding Np is connected to a grounded sampling resistor Rcs through a power switch P, and the switch signal generation unit 5 controls the power switch P to be turned on and off through the drive unit 6 . The primary winding Np is co...

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PUM

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Abstract

The invention discloses an LED (Light Emitting Diode) constant-current driving circuit. The LED constant-current driving circuit comprises a voltage reference unit which is used for generating the reference voltage, a peak current detection keeping unit, an error amplifier unit, a current comparator unit, a demagnetization detection unit and a self-adaptive unit. According to the LED constant-current driving circuit disclosed by the invention, the LED constant-current control can be realized, the service life of an LED can be prolonged, the problem of CTR (Current Transmission Rate) attenuation of an optical coupler is overcome as the circuit is free from an optical coupler device, the stability of the circuit is increased, the EMI (Electro Magnetic Interference) and the harmonic distortion can be greatly improved as the switching frequency of a power switching tube of the circuit is a variable frequency, an external circuit can be greatly simplified by adopting the circuit, and the using cost can be greatly reduced.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a constant current circuit suitable for driving a light emitting diode (LED). Background technique [0002] At present, the use of light-emitting diodes (LEDs) is becoming more and more popular, and users have put forward higher and higher requirements for them. Among them, electrical isolation and constant current control technology are getting more and more attention because they involve safety and LED service life. [0003] The traditional method of realizing electrical isolation and constant current control is realized by conventional magnetic energy induction feedback or optocoupler feedback. The conventional magnetic energy induction feedback method usually consists of an auxiliary winding and a sampling filter circuit. The voltage on the auxiliary winding will increase with the increase of the output voltage. By sampling this voltage, it will become a DC voltage after ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02
Inventor 张永良
Owner SUZHOU POWERLINK MICROELECTRONICS
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