Power supply circuit for suppressing startup instantaneous impulse current

Abstract

The invention discloses a power supply circuit for suppressing a startup instantaneous impact current. The power supply circuit comprises an input protection module, a rectification filtering module,a starting module and an output module; the input protection module is connected with the rectification filtering module and the starting module. The output module is connected with the rectificationfiltering module and the starting module, wherein the rectification filtering module is connected with a first thermistor in series; two ends of the first thermistor are connected with a self-lockingcircuit in parallel, the self-locking circuit is connected with the starting module, and after the output module outputs normally, the starting module controls the self-locking circuit to be conducted, so the first thermistor is short-circuited. The arrangement of the first thermistor can suppress the starting-up instantaneous impact current; through the arrangement of the self-locking circuit, after the first thermistor is short-circuited, the loss caused by the existence of the first thermistor can be avoided, so the power supply efficiency is improved; meanwhile, the problem that the impactcurrent is increased during startup due to the fact that the resistance value of the first thermistor is decreased is avoided, and product damage is prevented.

Description

technical field [0001] The invention belongs to the technical field of power supply circuits, and in particular relates to a switching power supply circuit that suppresses the instantaneous surge current when starting up. Background technique [0002] The power supply circuit refers to the circuit design of the power supply part of the power supply to the electrical equipment, which can be divided into switching power supply circuit, regulated power supply circuit, steady current power supply circuit, power power supply circuit, inverter power supply circuit, DC-DC power supply circuit, Protect power circuits, etc. [0003] With the continuous development of science and technology, electronic products are becoming more and more popular, and more and more devices are powered by switching power supplies. However, in order to smooth the input voltage and ripple after rectification, large-capacity high-voltage capacitors are generally used in the power supply. The role of smoot...

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Problems solved by technology

[0006] However, although the thermistor used in the suppressing circuit of the instant start-up current disclosed above suppresses the inrush current when starting up, it still has serious losses because it always exists in operation, and because the thermistor, The higher the temperature, the lower the resistance value. If the power is turned off and on again when the temperature rises, the inrush current will become larger and cause damage to the power supply product.

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