LED driver with adjustable conduction time

A technology of LED driver and conduction time, which is applied in the field of LED driving, can solve the problems of low efficiency of linear LED driving circuit, low efficiency of driving circuit, affecting application reliability, etc., achieve high PF value, improve efficiency, and enhance reliability Effect

Active Publication Date: 2013-08-21
MAXIC TECHNOLOGY CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, if the voltage difference between Vin and LED is larger, the efficiency of the driving circuit will be lower
Especially in the case of using AC voltage to drive the LED, the AC voltage will be much higher than the LED voltage, resulting in low efficiency of the linear LED drive circuit in this case, and severe heat generation, which affects the reliability of the application

Method used

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  • LED driver with adjustable conduction time
  • LED driver with adjustable conduction time
  • LED driver with adjustable conduction time

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Embodiment Construction

[0021] The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0022] The present invention controls the conduction time of the LED current by comparing the power supply voltage Vin with the LED voltage drop, turns off the LED current when Vin is greater than a certain set value of the LED voltage, and turns on the LED current until Vin reaches the set value near the LED voltage again. LED current, and the on-time of the LED current is controlled by one or more voltages or currents. In this process, the LED current becomes a pulse waveform, and the average value of the LED current is kept constant through the constant current loop. In particular, when the LED is driven by the alternating current AC, the conduction time of the LED current is controlled by one or more voltages or currents, so as to achieve a compromise between the power factor PF and the efficiency. For application...

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Abstract

The invention relates to an LED driver with an adjustable conduction time. The LED driver with the adjustable conduction time comprises one way or multiple ways of LEDs, a conductive threshold value setting module and a controlling module, wherein the LEDs are conducted when power supply voltage rises to LED conduction voltage, the conductive threshold value setting module is used for setting the LED conductive time, and the controlling module is used for disconnecting the one way or the multiple ways of LEDs when the power supply voltage rises to exceed an LED conduction voltage setting threshold value, and connecting the one way or the multiple ways of LEDs when the power supply voltage reduces to exceed the LED conduction voltage setting threshold value according to the conduction time of the LEDs, wherein the setting threshold value is related to the LED conduction threshold value. Due to comparison of an input voltage and an LED voltage drop, conduction time of the LEDs is controlled, the problem that voltage differences of the input voltage and the LED voltage are too large is solved, efficiency of a linear LED driving circuit is improved, circuit heating value is reduced, and application reliability is enhanced. In addition, the LED driver with the adjustable conduction time flexibly achieves the compromising design of high efficiency of the linear controlling scheme and a PF value through controlling the LED conduction time.

Description

technical field [0001] The invention relates to the field of LED driving, in particular to an LED driver with adjustable conduction time. Background technique [0002] The LED drive adopts the linear drive mode, which has the advantages of simple structure and small EMI. The efficiency of linear LED drive is related to the input voltage. The input power is Pin=Vin*Iled, the output power is Pout=Vled*Iled, and the efficiency is Pout / Pin=Vled / Vin. Among them, Vin is the input voltage, and Vled is the voltage on the LED. The voltage drop, Iled is the current flowing through the LED. Obviously, the power consumed by the linear LED drive on the drive circuit is (Vin-Vled)*Iled. Therefore, if the voltage difference between Vin and LED is larger, the efficiency of the driving circuit is lower. Especially in the case of using an AC voltage to drive the LED, the AC voltage will be much greater than the LED voltage, resulting in low efficiency of the linear LED drive circuit in thi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02
CPCY02B20/40
Inventor 牟在鑫高峻刘柳胜程宝洪
Owner MAXIC TECHNOLOGY CORPORATION
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