Power supply circuit and TV set

Abstract

The invention discloses a power supply circuit and a TV set. The power supply circuit comprises a transformer, a first secondary winding of the transformer is connected with a first rectifier, and a second secondary winding is connected with a second rectifier; a first output end of the first rectifier is connected with a positive electrode of a first capacitor, a connection node is a high voltage output end, and a second output end of the is connected with, a negative electrode of the first capacitor, a first end of a first sampling resistor and a first input end of an overcurrent protection circuit are connected with each other; a first output end of the second rectifier, the positive electrode of a second capacitor, a second end of the first sampling resistor and a reference input end of the overcurrent protection circuit are connected with each other, the connection node is a low voltage output end, the second output end of the second rectifier, the first end of a second sampling resistor and the second input end of the overcurrent protection circuit are connected with each other, and the second end of the second sampling resistor and the negative electrode of the second capacitor are grounded. The technical scheme provided by the invention can optimize the cross adjustment efficiency of voltages output from two paths of the power supply circuit and improve the reliability of the power supply circuit.

Description

technical field [0001] The invention relates to the technical field of televisions, in particular to a power supply circuit and a television. Background technique [0002] Such as figure 1 As shown, the TV set includes a backlight, a main board and a power supply, wherein the power supply has two outputs, one output is high voltage for supplying power to the backlight; the other output is low voltage and is used for supplying power to the main board. Connect the high-voltage output end of the power supply to the backlight, and the low-voltage output end to the main board, connect the input end of the power supply to the mains, and the TV can start to work. Generally, the difference between the two output voltages of the power supply is 10-20 times. For example, the output low voltage is 12V, and the output high voltage is 240V. [0003] In the prior art, the usual scheme of the power supply circuit is as follows figure 2 As shown, the output of the converter is connected...

AI Technical Summary

Problems solved by technology

[0004] (1) Since the output high voltage and output low voltage are independent, the voltage cross-regulation rate of the two outputs is relatively poor, which may cause the output characteristics to not meet the requirements;

[0005] (2) Overcurrent protection If the primary sampling of the converter is used, it will be inaccurate, because it cannot accurately detect which path is overcurrent or both are overcurrent

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