Switching power supply protection circuit and power supply system

A switching power supply protection circuit, comprising:

• a protection circuit, a switching circuit, a voltage feedback circuit, and a control circuit;
• wherein the protection circuit is respectively connected to the switching circuit, the voltage feedback circuit, and the control circuit, and is used to obtain a corresponding supply voltage according to a control voltage of the control circuit, control output switch-on or output switch-off based on the supply voltage, correspondingly control switch-on or switch-off of the switching circuit according to the output switch-on or the output switch-off, and control the supply voltage according to a feedback voltage of the voltage feedback circuit;
• the switching circuit is connected to the control circuit and is used to control a working state of the control circuit, wherein the working state comprises working and stop-working;
• the voltage feedback circuit is connected to the control circuit and is used to adjust the control voltage and transmit the feedback voltage to the protection circuit;
• and
• the control circuit is connected to a power supply and is used to receive a voltage of the power supply for charging, provide a starting voltage for the protection circuit and control the supply voltage according to the control voltage.