Multi-segment linear LED drive circuit, device and driving method

Abstract

The invention discloses a multi-segment linear LED drive circuit, device and method. The multi-segment linear LED drive circuit comprises a reference voltage input module, a current source module, a voltage control module, a current adjusting module, at least two LED lamp strings connected in series and at least two drive modules corresponding to the LED lamp strings. The reference voltage input module is used for providing reference voltage for each path of drive module; the current source module provides direct current for the voltage control module; the voltage control module controls the input voltage of the drive module according to the direct current; the drive module drives the corresponding LED lamp string to be turned on or turned off according to the reference voltage, the inputvoltage and the line voltage constant current; the current adjusting module adjusts the constant current; the constant current of the rear drive module is greater than the constant current of the front drive module, and when the current passes through the rear drive module, the front drive module stops driving, so that the harmonic influence is reduced, and meanwhile, the circuit implementation cost is reduced.

Description

technical field [0001] The invention relates to the technical field of LEDs, in particular to a multi-segment linear LED driving circuit, device and driving method. Background technique [0002] In the traditional single-segment linear constant current LED drive, the voltage of the LED light string must reach at least 2 / 3 of the output voltage of the rectifier bridge. High LED light string voltage will cause severe distortion of the current waveform flowing through the rectifier bridge, resulting in poor power factor and harmonics. High distortion and low efficiency. [0003] The traditional multi-segment linear constant current drive needs to generate multiple reference voltages to control the current of each constant current source. Compared with the single-segment linear constant current LED drive, its efficiency, power factor value and total harmonic distortion are all improved, but Sub-harmonic distortion still cannot meet the specification requirements, and generating...

AI Technical Summary

Problems solved by technology

[0002] In the traditional single-segment linear constant current LED drive, the voltage of the LED light string must reach at least 2 / 3 of the output voltage of the rectifier bridge. High LED light string voltage will cause severe distortion of the current waveform flowing through the rectifier bridge, resulting in poor power factor and harmonics. Large distortion and low efficiency

[0003] The traditional multi-segment linear constant current drive needs to generate multiple reference voltages to control the current of each constant current source. Compared with the single-segment linear constant current LED drive, its efficiency, power factor value and total harmonic distortion are all improved, but Sub-harmonic distortion still cannot meet specification requirements, and generating multiple reference voltages will complicate circuit implementation

Increasing the number of LED light string segments can partially solve the problem of sub-harmonics, but for each additional segment of LED light string, a corresponding constant current source is added, and the cost of circuit implementation increases

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