Circuit and method for open circuit and short circuit to ground protection

Abstract

The invention discloses a ground short-circuit protection circuit and a method for an N-channel LED lamp string control circuit. The short-to-ground protection circuit receives N open-circuit fault signals one-to-one corresponding to N LED light strings, and when any open-circuit fault signal is valid, charges the feedback terminal of the LED light string corresponding to the open-circuit fault signal, and charges After a preset period of time, compare the voltage at the feedback terminal of the LED light string with the short-circuit threshold and generate a short-circuit fault signal according to the voltage at the feedback terminal of the LED light string and the short-circuit threshold to represent the short-circuit condition of the LED light string. The voltage at the feedback terminal is less than the short-circuit threshold, the short-circuit fault signal is valid, and the LED light string control circuit stops working until it is restarted. The short-to-ground protection circuit and method disclosed in the present invention can prevent the short-to-ground fault from being recognized as an open-circuit fault, thereby effectively protecting the LED lamp string.

Description

technical field [0001] The present invention relates to an LED circuit, in particular to a circuit and a control method for open circuit and ground short circuit protection in the LED circuit. Background technique [0002] Light-emitting diodes (LEDs) play an important role in the field of displays because of their small size, low power consumption, high luminous efficiency, and high reliability. In backlight applications, LEDs usually provide backlight in the form of an array of multiple light strings. In these applications, system fault detection and fault protection are very important, especially for one or more LED light strings that are shorted to ground. Or when there is an open circuit fault, it is necessary to take corresponding measures to deal with it. [0003] However, when the existing LED light string control circuit handles open-circuit faults and short-circuit faults to ground, it often misjudges short-circuit faults to ground as open-circuit faults. An open...

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Problems solved by technology

[0003] However, when the existing LED light string control circuit handles open-circuit faults and short-circuit faults to ground, it often misjudges short-circuit faults to ground as open-circuit faults. LED light string open circuit fault and short circuit fault to ground

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