Electronic fuse circuit and circuit system using the same

An electronic fuse circuit used in a circuit system with a switching power supply, the switching power supply being for supplying power to a load, wherein the electronic fuse circuit comprises:

• an electronic switch, coupled to a transmission terminal of an input power supply and an input terminal of the switching power supply, respectively through a corresponding wire, the electronic switch being configured to connect or disconnect the transmission terminal of the input power supply with the input terminal of the switching power supply according to a switch control signal;
• a first protection circuit, configured to obtain a first protection signal according to a first threshold signal and a current sense signal representing a current of a path where the electronic switch is located;
• a second protection circuit, configured to obtain a second protection signal according to a second threshold signal and a voltage sense signal representing a load voltage, wherein the second protection circuit is connected to an output terminal of the switching power supply or an input terminal of the load to obtain the voltage sense signal representing the load voltage,
• a logic circuit, configured to generate the switch control signal for controlling the electronic switch to be turned on and off according to the first protection signal and the second protection signal,
• wherein
• the logic circuit is configured to:
• during a startup operation state of the circuit system when the electronic switch is in an off state,
• if the first protection signal indicates that the current sense signal reaches the first threshold signal, and/or the second protection signal indicates that the voltage sense signal reaches the second threshold signal, control the switch control signal to keep the electronic switch in the off state, thereby preventing the input power supply from supplying power to the switching power supply, until the current sense signal is below the first threshold signal and the voltage sense signal is below the second threshold signal, and then after a delay, control the electronic switch to be turned on;
• and
• during a normal operation state of the circuit system after startup, if the first protection signal indicates that the current sense signal reaches the first threshold signal, and/or the second protection signal indicates that the voltage sense signal reaches the second threshold signal, control the switch control signal to switch the electronic switch from an on state to the off state.