Voltage drop protection circuit, backlight driving power supply and television

Abstract

The invention discloses a voltage drop protection circuit, a backlight driving power supply and a television. The voltage drop protection circuit is connected with a flyback circuit in the backlight driving power supply; the voltage drop protection circuit comprises an AC sampling module and a switching module; the AC sampling module is used for sampling and detecting AC input voltage and outputting sampled voltage to the switching module; and the switching module is used for outputting a corresponding control signal to the flyback circuit to control the working state of the flyback circuit according to the sampled voltage, thereby controlling the flyback circuit to stop working when detecting a voltage drop and controlling the flyback circuit to return to work when detecting voltage dropreduction. The flyback circuit can be protected when a power grid unstably works and the voltage drop occurs, and automatic recovery is achieved, so that the equipment exception phenomenon is avoidedand the anti-jamming capability of the driving power supply is improved.

Description

technical field [0001] The invention relates to the technical field of electrical power supplies, in particular to a voltage drop protection circuit, a backlight driving power supply and a television set. Background technique [0002] With the development of technology, the safety protection of the circuit has attracted more and more attention. At present, when large-size LED TVs are working, they use high-efficiency power supply direct drive power supply circuits, but there is no perfect protection circuit at present, especially for power supply. The voltage drop protection circuit of the system, without these protections, when the mains power grid has a cycle drop, causing the input voltage of the TV to be unstable, which in turn makes the flyback circuit and the power supply system of the LLC direct drive LED backlight unstable, which will cause the LLC to drive The circuit is protected, but the flyback circuit still works normally, causing abnormal phenomena of the equip...

AI Technical Summary

Problems solved by technology

[0002] With the development of technology, the safety protection of the circuit has attracted more and more attention. At present, when large-size LED TVs are working, they use high-efficiency power supply direct drive power supply circuits, but there is no perfect protection circuit at present, especially for power supply. The voltage drop protection circuit of the system, without these protections, when the mains power grid has a cycle drop, causing the input voltage of the TV to be unstable, which in turn makes the flyback circuit and the power supply system of the LLC direct drive LED backlight unstable, which will cause the LLC to drive The circuit is protected, but the flyback circuit still works normally, causing abnormal phenomena of the equipment, such as black screen, sound, and no image phenomenon

resulting in customer complaints

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