Circuit for preventing current backflow, chip, and electronic system

A chip, comprising:

• a signal pad;
• a power pad;
• a ground pad;
• an internal power supply terminal;
• an electrostatic protection circuit, coupled to the internal power supply terminal, the signal pad and the ground pad;
• a first switch element, coupled between the power pad and the internal power supply terminal;
• a cut-off control circuit, coupled to the signal pad, the power pad and the first switch element so as to control switching of the first switch element according to a voltage of the signal pad and a voltage of the power pad;
• a chip main circuit, coupled to the signal pad, the power pad and the ground pad;
• and
• a second switch element, coupled to the internal power supply terminal so as to provide a base voltage according to the voltage of the internal power supply terminal;
• wherein the cut-off control circuit is further coupled to the second switch element so as to control switching of the second switch element according to the voltage of the signal pad and the voltage of the power pad.

An electronic system, comprising:

• a first chip;
• and
• a second chip, coupled to the first chip, the second chip comprising:
• a signal pad, coupled to the first chip and configured to receive an input signal from the first chip;
• a power pad;
• a ground pad;
• an internal power supply terminal;
• an electrostatic protection circuit, coupled to the internal power supply terminal, the signal pad and the ground pad;
• a first switch element, coupled between the power pad and the internal power supply terminal so as to turn on or off electrical connection between the power pad and the internal power supply terminal;
• a cut-off control circuit, coupled to the signal pad, the power pad and the first switch element so as to control switching of the first switch element according to a voltage of the signal pad and a voltage of the power pad;
• a chip main circuit, coupled to the signal pad, the power pad and the ground pad;
• and
• a second switch element, coupled to the internal power supply terminal so as to provide a base voltage according to the voltage of the internal power supply terminal;
• wherein the cut-off control circuit is further coupled to the second switch element so as to control switching of the second switch element according to the voltage of the signal pad and the voltage of the power pad.