As shown in the figure below, it is a current-limiting protection circuit. The basic protection principle can be understood, but there are two positions that are not understood. One is the resistor R1 and C1 connected in parallel with the source and drain of Q1, and the other is Q2 connected in parallel. Capacitor C2, what is the role of these three resistances in the corresponding positions? What effect does the adjustment of resistance-capacitance parameters have on circuit characteristics?
Jay Lee Veröffentlicht am June 29, 2020
C2 and R6 form an RC charging circuit, which can delay the turn-on time of the MOS. The larger the capacity, the longer the delay. But the existence of R1 and C1 will destroy this delay effect to a certain extent, you can see the waveform by simulation. In addition, R1 and C1 are commonly connected across the MOS in the switching power supply circuit, which is mainly used to absorb the voltage spikes across the MOS. In your circuit, because you do not know the nature of the load, you cannot draw a conclusion.
