A feedback drive circuit

A driving circuit and feedback voltage technology, which is applied in the field of step-up high-voltage LED current drive circuit design, can solve the problems of VREF_LED voltage changes greatly and affect power utilization efficiency, etc., so as to save voltage divider feedback resistors, maintain voltage stability, apply simple effects
CN105142293BActive Publication Date: 2017-12-26SICHUAN YICHONG TECH CO LTD
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Patents(China)
Current Assignee / Owner
SICHUAN YICHONG TECH CO LTD
Publication Date
2017-12-26

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Abstract

The present invention relates to a feedback driving circuit, which comprises a channel LED current driving circuit module (003) for outputting matching currents of at least two LED channels according to a received digital signal; at least two sampling and holding circuit modules (001) , used to collect and hold the node voltages at one end of at least two LED channels respectively; the channel feedback voltage selection and error amplifier module (002) is used to determine the minimum voltage from the voltages output by the at least two sample and hold circuit modules (001), Amplify the minimum voltage and output it; the boosting driver stage circuit module (006) is used to perform a voltage step on the node voltages at the other ends of the at least two LED channels according to the channel feedback voltage selection and the output voltage of the error amplifier module (002). Adaptive adjustment. The invention ensures that the external voltage divider feedback resistance is saved without increasing the chip area, the voltage stability of the external circuit is maintained, the output voltage is optimized, and the utilization efficiency of the power supply is improved at the same time.
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Description

technical field

[0001] The invention relates to the field of design of boost-type high-voltage LED current drive circuits, in particular to a feedback drive circuit. Background technique

[0002] LED backlights are used on small and cheap LCD panels; LED backlight structures are mainly divided into two types, series power supply and parallel power supply. The series power supply can use a lower constant current, but the input power needs to be raised to meet the series The total forward voltage level of the type power supply can drive the LED; the parallel type needs a higher constant current to drive, but reduces the demand for high voltage. Since the current of each LED in the same string is completely equal in the series power supply, there is no current matching problem; while in the parallel power supply, the current on each LED will have a certain deviation, and certain processing needs to be done on the current matching.

[0003] The Boost LED driver in the prior art...

Claims

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