Load switch and power system

A load switch comprising:

• a power input terminal, a power output terminal, a voltage-current conversion circuit, a capacitor and a comparator,
• wherein the power input terminal is configured to receive an input voltage;
• wherein the power output terminal is configured to provide an output voltage;
• wherein the voltage-current conversion circuit comprises a first input terminal, a second input terminal and a current difference output terminal, wherein the first input terminal and the second input terminal are connected to the power output terminal and the power input terminal, respectively, and configured to receive the output voltage and the input voltage, respectively;
• and wherein a current difference corresponding to a voltage difference between the output voltage and the input voltage is output at the current difference output terminal;
• a first terminal of the capacitor is connected to the current difference output terminal, to integrate the current difference to obtain an average voltage difference corresponding to the voltage difference between the output voltage and the input voltage during an integration period for the capacitor, and a second terminal of the capacitor is connected to a ground line;
• and
• wherein the first terminal of the capacitor is further connected to a first input terminal of the comparator, a second input terminal of the comparator is applied with at least one reference voltage, and an output terminal of the comparator is a reverse current protection terminal to determine whether to send a signal to prevent current from flowing from the power output terminal to the power input terminal according to a value at the output terminal of the comparator.