A control circuit of power supply with capacitance load capability

Abstract

This invention puts forward a control circuit of a supply with capacitive load ability including a short-circuit operating circuit and orderly connected compensated signal delay circuit and first signal comparison circuit, in which, said delay circuit delays the voltage compensation signal and outputs it to the first signal comparison circuit, which compares it with a preset threshold value, if it is greater, it sends a short-circuit control signal to the operating circuit, which generates a protection signal to control the switch entering into a protection state, when a load operates normally, the delay circuit outputs a threshold value with the voltage smaller than the set threshold value and the operating circuit does not work, when the load is over the preset sphere, the circuit outputs a threshold value with the voltage greater than the set one, the operatig circuit controls the switch to enter into a protection state.

Description

technical field [0001] The invention relates to a short-circuit protection device for a switching power supply, in particular to the field of switching power supplies that require relatively high capacitive load capacity and reliability. Background technique [0002] Due to its high efficiency, switching power supplies have been widely used. In the protection function of the switching power supply, an output short-circuit protection circuit is generally required to prevent the switching power supply from damaging the power supply and the load due to excessive operating current when it is short-circuited. The performance of the short-circuit protection circuit directly affects the reliability of the entire power supply. At present, most of the short-circuit protection circuits in switching power supplies use the current detection terminal of the current-mode pulse width modulation chip to detect the working current of the primary side of the transformer, and limit its peak v...

AI Technical Summary

Problems solved by technology

[0004] Another method uses a delay circuit to delay the action of the short-circuit protection circuit to improve the ability of the switching power supply to carry a capacitive load when it is turned on, but this method will increase the circuit loss during short-circuit protection and reduce the reliability of the switching power supply.

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