Impulse current inhibiting circuit and supply circuit

Abstract

The invention discloses an impulse current inhibiting circuit and a supply circuit; when a constant current source is transformed into loaded state from unloaded state, a first control unit detects the output current of a main circuit of the constant current source and controls a first output switch to turn off and the main circuit of the constant current source to shutdown when the output current is no less than a predetermined current threshold value; a first discharge unit detects the predetermined parameter of the circuit and discharges an output capacitor when the predetermined parameter satisfies the discharge condition, namely the first discharge unit discharges the output capacitor when the impulse current exists in the supply circuit; the constant current source re-starts again at loaded state when the charge on the output capacitor is discharged to a certain degree, the voltage on the output capacitor slowly increases from a lower set value without occurring the impulse current. According to the technical scheme, the impulse current problem caused by the voltage instantaneous discharge on the output capacitor in the transformation process of the constant current source from unloaded state to loaded state is solved.

Description

technical field [0001] The present application relates to the field of circuits, in particular to a circuit for suppressing surge current and a power supply circuit. Background technique [0002] A switching power supply with constant current output is also called a constant current source. The constant current source can work in the no-load state or in the load state. [0003] The circuit structure when the constant current source is loaded is as follows: figure 1 As shown, a main circuit 110 including a constant current source, an output capacitor Co connected in series between the two output terminals of the main circuit, and a load 120; [0004] In general, the output voltage of the constant current source when it is working with no load is higher than the voltage of the load carried by the constant current source. exist figure 1 In the circuit shown, when the constant current source switches from the no-load state to the load state, since the voltage on the output c...

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Problems solved by technology

[0005] In view of this, the technical problem to be solved in this application is to provide a circuit and power supply circuit for suppressing inrush current, which can solve the problem of instantaneous discharge of the voltage on the output capacitor during the process of switching the constant current source from the no-load state to the load state. The inrush current problem

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