Load switch circuit and control method

An electronic device, comprising:

• an inductive load;
• and
• a load switch circuit, the load switch circuit including:
• a power transistor, a first terminal of the power transistor configured to receive a power supply voltage, and a second terminal of the power transistor configured to be an output terminal of the load switch circuit and configured to be coupled to an external inductive load;
• and
• a clamping module including a clamping unit and a driving unit coupled together, wherein the clamping unit includes a voltage-current converter and a first resistor, the first resistor coupled between an output terminal of the voltage-current converter and the second terminal of the power transistor, a positive input terminal of the voltage-current converter coupled to receive the power supply voltage, a negative input terminal of the voltage-current converter coupled to the second terminal of the power transistor, a current output of the voltage-current converter generating a reference voltage drop on the first resistor;
• and an output terminal of the driving unit is coupled to a control electrode of the power transistor.

A control method of a switch circuit, including:

• generating a reference current through a voltage-current converter, the voltage-current converter having an equivalent resistance;
• generating a clamping threshold based on at least a reference voltage generated by the reference current on a reference resistor;
• and
• in response to a difference between a power supply voltage and an output voltage at an output node of the switching circuit is greater than or equal to the clamping threshold, turning on a power transistor that provides the output voltage.