Constant-voltage constant-current switching power supply and television

Abstract

The invention discloses a constant-current and constant-voltage switching power supply and a television. The constant-current and constant-voltage switching power supply comprises a switch control module, a PFC control module, an overvoltage adjustment module, a constant-voltage control module and a constant-current control module. The switch control module respectively outputs power supply voltage to the first light bar group and the mainboard after filtering the power supply voltage; the overvoltage adjustment module outputs a first sampling voltage to the constant voltage control module according to the output voltage of the first light bar group; the constant voltage control module samples the power supply voltage to obtain a second sampling voltage, and outputs a feedback signal to the PFC control module according to the first sampling voltage or the second sampling voltage; the PFC control module controls the switch control module to output a constant power supply voltage according to the feedback signal; the constant-current control module controls the input current of the second light bar group according to the output current of the first light bar group, and controls the output current to be constant, thereby achieving the constant-voltage and constant-current synchronous power supply, improving the power efficiency, and reducing the standby power consumption.

Description

technical field [0001] The invention relates to the technical field of power supplies, in particular to a constant voltage and constant current switching power supply and a television. Background technique [0002] With the massive promotion of AIOT (Artificial Intelligence Internet of Things) products, most flyback switching power supplies in the past required high-voltage electrolytic capacitors to filter the rectified voltage, and the cost of this device was the highest, occupying the largest PCB area, and high-voltage electrolytic capacitors mainly The service life of the power supply is affected, the reliability is low, and problems such as large electrolytic capacitor bulging, explosion, and burning are prone to occur. In addition, the use of high-voltage electrolytic capacitors affects the machine-mounted rate of the power supply. Production requires pin molding and other processes, which increases the difficulty of the production process. Maintenance personnel are ea...

AI Technical Summary

Problems solved by technology

[0005] However, the output of the single-stage PFC control circuit in the current power supply is consistent with the voltage of the two light bars, and two constant current circuits are required to control the respective LED light bars, which increases the cost, the constant current loss is large, and the temperature rise is high. The matching range of the light bar is narrow; or the output of the single-stage PFC control circuit only has a constant current control circuit, which cannot output a high-power constant voltage source to supply power to the core board, and the PFC control circuit needs to be turned off during standby, which is only suitable for constant current and high-power output demand, another constant voltage source is required

Images