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Controller, chip and method for eliminating current ripple in led drive system

A technology of LED drive and system current, applied in the direction of electric light source, electrical components, circuit layout, etc., can solve the problems of eliminating ripple and inability to achieve, and achieve the effect of eliminating current ripple

Active Publication Date: 2018-12-25
SHANGHAI BRIGHT POWER SEMICONDUCTOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a controller, chip and method for eliminating current ripple in the LED drive system, which are used to solve the problem of LED dimming in the prior art. It is impossible to eliminate the ripple in the whole process, and the problem of overvoltage protection of the drain of the MOS tube

Method used

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  • Controller, chip and method for eliminating current ripple in led drive system
  • Controller, chip and method for eliminating current ripple in led drive system
  • Controller, chip and method for eliminating current ripple in led drive system

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Embodiment 1

[0048] This embodiment discloses a controller 100 for eliminating the current ripple of the LED driving system. The following uses a MOS transistor as the first power transistor as an example for illustration. In other implementations, the first power transistor can also be a triode or Other types of power tubes. Such as image 3 As shown, the controller 100 is electrically connected to the output terminal of the LED load 200, the first sampling resistor R0 and the first power transistor M1. The controller 100 is used to sample the voltage V at the output terminal of the LED load 200 DRAIN , the voltage V across the first sampling resistor R0 CS and the drain voltage of the first power transistor M1, and the drain voltage of the first power transistor M1 is the same as the voltage at the output terminal of the LED load 200, that is, the drain voltage of the first power transistor M1 is V DRAIN . Further, the controller 100 according to the voltage V of the output terminal ...

Embodiment 2

[0077] This embodiment discloses a method for eliminating current ripple in an LED drive system, which uses the controller disclosed in Embodiment 1:

[0078] First, use the controller to sample the voltage V at the output terminal of the LED load 200 DRAIN , the voltage V across the first sampling resistor R0 CS and the drain voltage V of the first power transistor M1 DRAIN , and according to the voltage V at the output of the LED load 200 DRAIN and the voltage V across the first sampling resistor R0 CS generate the first voltage signal V DV1 ; According to the drain voltage V of the first power transistor M1 DRAIN generate the second voltage signal V DV2 ; Then, the controller again according to the first voltage signal V DV1 and the voltage across the first sampling resistor V CS Generate control signal V GATE , so as to control the conduction state of the first power transistor M1 connected to the LED load 200, so that the first voltage signal V DV1 The magnitude ...

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Abstract

The present invention provides a controller, chip and method for eliminating current ripple in an LED drive system. The controller is electrically connected to the cathode of the LED load, the first sampling resistor and the first power tube, and the controller is configured to sample the current of the LED load. The voltage at the cathode, the voltage at both ends of the first sampling resistor and the drain voltage of the first power tube, and generate a first voltage signal and a second voltage signal; the controller generates a control signal based on the first voltage signal and the voltage at both ends of the first sampling resistor The signal is used to control the conduction state of the first power tube, so that the voltage of the first voltage signal is equal to the reference voltage, eliminating the current ripple of the LED load; when the drain voltage exceeds the voltage threshold, the controller, according to the second voltage The signal conditions the control signal so that the drain voltage remains stable. The present invention eliminates LED current ripple in the whole process of dimming, avoids LED flicker caused by low-frequency jitter, and realizes overvoltage protection of the first power tube.

Description

technical field [0001] The invention relates to the field of constant current drive control, in particular to a controller, chip and method for eliminating current ripple in an LED drive system. Background technique [0002] With the full application of LEDs in the field of lighting, high-efficiency APFC (Active Power Factor Correction, active power factor correction) drivers, thyristor dimming or high PF (Power Factor, power factor) linear drivers have been widely used . The front stage uses APFC driver, thyristor dimming or high PF linear driver, and its output current will contain 100hz / 120hz power frequency ripple components. Due to the existence of these ripple components, the brightness of the LED light source also fluctuates accordingly. With the development of the lighting industry, people have put forward higher requirements for the quality of LED light sources. No flicker and no jitter have become new requirements for high-performance LED lighting drivers. Theref...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B33/08F21V23/00H05B44/00
CPCF21V23/003H05B45/00Y02B20/30
Inventor 朱伟巨杭中健
Owner SHANGHAI BRIGHT POWER SEMICONDUCTOR CO LTD
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