Circuit achieving multipath backlight driving through MCU (Micro Controller Unit) and driving method thereof

Abstract

The invention provides a circuit achieving multichannel backlight driving through an MCU (Micro Controller Unit) and a driving method thereof. A flyback topology constant pressure output unit and an MUC control unit are used, so that output voltage of the flyback topology constant pressure output unit is lower than driving voltage of LED (Light Emitting Diode) light strings when an MCU chip is not in operation; the MCP chip performs analogue voltage sampling processing on every path of current detection resistance when the MCU chip operates; the MCU chip adjusts a voltage output duty ratio output to the LED string if sampling voltage of one path of the LED string is higher than a preset value; the MCU chip reduces output voltage output to the flyback topology constant pressure output unit according to voltage of the LED light string which requires the highest voltage if the sampling voltage of one path of LED light string is smaller than a preset value. The circuit achieving multichannel backlight driving through the MCU and the driving method thereof have the advantages that the structure is simple, the configuration is flexible, manufacturing costs are low, and the safety is high.

Description

technical field [0001] The invention relates to the technical field of flat-panel televisions, in particular to a circuit and a driving method for realizing multi-channel backlight driving by using a single-chip microcomputer. Background technique [0002] In the prior art, there are generally two types of backlight driving for LED light strings in TV sets: multi-channel backlight driving completed by multi-channel DC-DC constant current driver ICs and multi-channel constant current backlight driving completed by linear dimming. drive. [0003] like figure 1 As shown, the circuit is the OZ9906 backlight drive scheme of O2 Technology Company. The AC-DC output constant voltage used in this scheme is slightly higher than the voltage of the LED light string, and then realized by 6 independently controlled BUCK step-down circuits. 6-way backlight constant current drive. This backlight driving solution requires a total of 6 sets of buck step-down architectures, which are costly...

AI Technical Summary

Problems solved by technology

This backlight driving scheme requires a total of 6 sets of BUCK step-down architectures, which are costly and complicated

[0004] like figure 2 As shown, the circuit is ON Semiconductor’s CAT4026 backlight driving solution. This solution uses a maximum of 6 LED strings to drive and external triodes for dimming. When there is a voltage difference between each LED string, the voltage difference will drop on the LED string. On the triode below, resulting in a higher temperature of the triode

Therefore, this backlight driving scheme has potential safety hazards caused by high temperature

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