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PWM light modulation control method and control circuit, and LED driving circuit applying same

A control circuit and dimming control technology, applied in the electronic field, can solve the problems of inaccurate average current, LED current distortion, short effective width time, etc., and achieve the effect of easy control circuit, simple control circuit and good effect

Active Publication Date: 2014-04-23
SILERGY SEMICON TECH (HANGZHOU) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if the effective width of the PWM dimming signal is very short, such as Figure 1B Another PWM dimming waveform diagram in the prior art, because the effective width time of the PWM dimming signal is very short, the LED current is distorted, resulting in inaccurate average current

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  • PWM light modulation control method and control circuit, and LED driving circuit applying same
  • PWM light modulation control method and control circuit, and LED driving circuit applying same
  • PWM light modulation control method and control circuit, and LED driving circuit applying same

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Embodiment Construction

[0030] Several preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any alternatives, modifications, equivalent methods and schemes made on the spirit and scope of the present invention. In order to provide the public with a thorough understanding of the present invention, specific details are set forth in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details.

[0031] refer to figure 2 , is shown as a circuit block diagram of an embodiment of the PWM dimming control circuit according to the present invention, as figure 2 As shown, the input power drives the LED load through the power stage circuit 205, and the power stage circuit includes a power switch tube (not shown) for controlling energy...

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Abstract

The invention discloses a PWM light modulation control method and control circuit, and an LED driving circuit applying the same. The effective width of a PWM light modulation signal is adjusted through a minimum conduction time determination circuit so that the effective width during a working process maintains greater than a minimum value and it can be ensured that LED load currents are not distorted. At the same time, the size of the driving currents of an LED load is adjusted so that it is ensured that the average currents of the LED load maintain unchanged, and the LED luminescence brightness is not affected. The control circuit is simple and can be easily realized, and the effects are good.

Description

technical field [0001] The present invention relates to the field of electronic technology, and more specifically, relates to a novel PWM dimming control method and a control circuit. Background technique [0002] LED backlights are widely used due to their energy saving, environmental protection, light and thin size, etc., but LEDs need a driving circuit that can provide a constant current and a dimming circuit that can adjust their brightness during use. At present, LED dimming technology mainly includes analog dimming and PWM dimming. Among them, PWM dimming has more accurate precision and is widely used in switching power supplies. PWM dimming adjusts the average value of LED current by setting the period and duty cycle. [0003] As we all know, when the LED load is powered on, a large inrush current is often generated, and the magnitude of the inrush current is greater than the driving current value of the LED load, such as Figure 1A In the PWM dimming waveform diagram...

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Application Information

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IPC IPC(8): H05B37/02H05B44/00
CPCY02B20/42H05B45/3725H05B45/10Y02B20/40
Inventor 张凌栋
Owner SILERGY SEMICON TECH (HANGZHOU) CO LTD