Power supply undervoltage protection circuit with hysteresis window wide range input

The invention relates to a power supply undervoltage protection circuit with hysteresis window wide range input. The power supply undervoltage protection circuit comprises a comparator N3, a reference source N1, a voltage divider circuit, a voltage stabilizing circuit, and a switching circuit. The inverting input end of the comparator N3 is connected to a node between a resistor R2 and a resistor R3 connected in series. The other end of the resistor R3 is grounded, and the other end of the resistor R2 is used as a voltage input end. The noninverting input end of the comparator N3 is connected to the cathode of the reference source N1 through a resistor R4, the anode of the reference source N1 is grounded, and the reference end is grounded through a capacitor C1. The output end of the comparator N3 is connected to the input end of the switch circuit, and the noninverting input end of the comparator N3 is connected to the output end through a resistor R5. The input end of the voltage stabilizing circuit is grou