Backlight open circuit protection circuit

Abstract

The utility model relates to a backlight open protection circuit, comprising at least two backlight open detection circuits, a pulse-width modulation integrated circuit, a control switch and an input circuit. The backlight open detection circuit comprises a detection output. The input circuit comprises at least two first diodes, at least two input resistances, at least two first filtering capacitors, a first biasing resistor, a transistor and a peak detection circuit. The peak detection circuit comprises a second diode, a second filtering capacitor and a second biasing resistor. The cathode of the first diode is connected with the cathode of the second diode, and a circuit pitch point between the first diode and the second diode is connected with a power supply through the biasing resistor. Each anode of the second diode is connected with a detection output after connecting in series with an input resistance. The anode of the second diode is connected with the grid of the transistor, and is respectively put to earth through the second filtering capacitor and the second biasing resistor. The source cathode of the transistor is put to earth. The drain of the transistor is connected with the pulse-width modulation integrated circuit through the control switch.

Description

technical field [0001] The invention relates to a backlight open-circuit protection circuit, in particular to a backlight open-circuit protection circuit for a liquid crystal display. Background technique [0002] Liquid crystal displays are widely used in fields such as portable DVDs, visual music players, mobile phones, and notebook computers due to their thinness, low power consumption, and low radiation. Since the liquid crystal molecules in the liquid crystal display do not emit light themselves, the liquid crystal display needs a backlight module to emit light to realize image display. Usually, the backlight module includes a plurality of backlight tubes and a pulse to adjust the working current of the multiple backlight tubes. For a width modulation integrated circuit, when a backlight lamp works accidentally, causing the output load of the pulse width modulation integrated circuit to open, the pulse width modulation integrated circuit needs a backlight open circuit p...

AI Technical Summary

Problems solved by technology

[0011] In order to solve the shortcomings of the complex structure of the backlight open circuit protection circuit in the prior art, it is necessary to provide a backlight open circuit protection circuit with a simple structure

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