Load driving circuit and driving method

Abstract

The invention provides a load driving circuit and a driving method. The load driving circuit comprises a voltage conversion circuit and a cascaded linear constant current circuit, the voltage conversion circuit is used for converting an input voltage into a first working voltage based on a feedback signal of the linear constant current circuit, and the linear constant current circuit is used as a post-stage circuit to be coupled with the voltage conversion circuit. The circuit is used for providing a driving voltage and a driving current for a load and generating a feedback signal based on a load voltage signal to control the voltage conversion circuit. According to the invention, the pre-stage boost circuit is combined with the feedback of the post-stage linear constant-current circuit so that the self-adaptive adjustment of the output voltage is realized, the overall efficiency of the system is improved, and a stable dimming and color modulation function of an LED can be realized.

Description

technical field [0001] The present invention relates to the field of electronics, specifically but not limited to a load driving circuit and a driving method. Background technique [0002] At present, LED driver chips can be divided into: constant voltage driver chips, constant current driver chips, and pulse driver chips. Among them, the constant voltage driver chips are mostly DC / DC boost chips. The advantage of this solution is that the chip cost is cheap and there is no complicated peripheral circuit. However, the constant voltage drive cannot control the drive current of the load, and cannot guarantee the consistency of LED brightness. The constant current drive chip controls the switching circuit based on the output current, which solves the problem of uncontrollable current in the previous constant voltage drive, and can flexibly set the required output current. However, the price of such chips is much higher than that of constant voltage chips and the peripheral ci...

AI Technical Summary

Problems solved by technology

However, there is strobe in this way, and the drive capability is more suitable for low-power applications

[0003] Most of the existing LED driver dimming and color matching systems adopt the method of front stage constant current + rear stage switch cut color temperature, the front stage adopts PSR buck architecture, and the rear stage adopts switch cut color temperature. As a result, there is a flickering problem in the color temperature switch, and the color temperature switch is driven by floating ground, which has high cost. At the same time, the buck structure determines that the output lamp voltage will not be too high, resulting in a large current and low overall efficiency.

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