X capacitor discharge control device applied to flyback power source

Abstract

The invention provides an X capacitor discharge control device applied to a flyback power source. The X capacitor discharge control device comprises a high voltage starting circuit, an alternating current voltage detecting circuit and an X capacitor discharge circuit. After two ends of an X capacitor of the flyback power source are switched on by an alternating current power source, the high voltage starting circuit charges for a power source stabilivolt capacitor of a control chip of the flyback power source with a constant current, and when the voltage at two ends of the power source stabilivolt capacitor reaches working voltage of the control chip, the high voltage starting circuit is turned off. The alternating current voltage detecting circuit enters an alternating current voltage detecting model after the high voltage starting circuit is turned off, and the alternating current voltage detecting circuit detects whether alternating voltage exists at the two ends of the X capacitor or not. When the alternating current voltage at the two ends of the X capacitor is not detected, the alternating current voltage detecting circuit controls the X capacitor discharge circuit to discharge for the X capacitor. According to the X capacitor discharge control device applied to the flyback power source, X capacitor discharge can be accelerated, and stand-by power consumption on an X resistor can be removed.

Description

technical field [0001] The invention relates to a discharge control device, in particular to an X capacitor discharge control device applied to a flyback power supply. Background technique [0002] With the continuous progress and development of human society, the consumption of energy is increasing, and energy has gradually become a scarce resource. In order to achieve the maximum utilization rate under the condition of limited resources, it is necessary to reduce the standby power consumption of the power system. ,Improve efficiency. In order to reduce the standby power consumption of the power system, it is necessary to start from the design of the power system to reduce the current and multiplex the circuit. [0003] figure 1 It is a typical application circuit diagram of a traditional flyback power supply. Such as figure 1 Shown is a typical application circuit diagram of a traditional flyback power supply, where X-cap is the X capacitor used to suppress the differe...

AI Technical Summary

Problems solved by technology

However, in order to meet the safety regulations on the X-capacitor discharge time limit, the bleeder resistor cannot be too large, so the value of the bleeder resistor is a compromise choice

Moreover, for medium and high-power power supply systems, it is very difficult to reduce the standby power consumption to below 30mW due to the power consumption on the bleeder resistor. Therefore, a single chip for discharging the X capacitor has appeared, but such a power supply system. High cost, not conducive to cost reduction

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