Bidirectional power switch circuit

A bidirectional power switch (BPS) circuit comprising:

• first and second terminals;
• first and second MOSFETs connected in series between the first and second terminals and comprising respective first and second source to body diodes;
• first and second power supply rails;
• a first switchable current source connected between the first power supply rail and a body terminal of the first MOSFET;
• a second switchable current source connected between the first power supply rail and a common node connected to a source terminal of each of the first and second MOSFETs;
• a third switchable current source connected between one of the first and second power supply rails and a gate terminal of the first MOSFET;
• a fourth switchable current source connected between the second power supply rail and the body terminal of the first MOSFET;
• a fifth switchable current source connected between the second power supply rail and the common node;
• a first resistor connected between the body terminal of the first MOSFET and the common node;
• a second resistor connected between the gate terminal of the first MOSFET and the common node;
• and
• a BPS switching controller configured to control operation of the BPS circuit between a BPS ON state in which the first and second terminals are connected through the first and second MOSFETs and a BPS OFF state in which the first and second terminals are disconnected.

A method of operating a bidirectional power switch (BPS) circuit, the BPS circuit comprising:

• first and second terminals;
• first and second MOSFETs connected in series between the first and second terminals and comprising respective first and second source to body diodes;
• first and second power supply rails;
• switchable current sources comprising:
• a first switchable current source connected between the first power supply rail and a body terminal of the first MOSFET;
• a second switchable current source connected between the first power supply rail and a common node connected to a source terminal of each of the first and second MOSFETs;
• a third switchable current source connected between one of the first and second power supply rails and a gate terminal of the first MOSFET;
• a fourth switchable current source connected between the second power supply rail and the body terminal of the first MOSFET;
• and
• a fifth switchable current source connected between the second power supply rail and the common node;
• a first resistor connected between the body terminal of the first MOSFET and the common node;
• a second resistor connected between the gate terminal of the first MOSFET and the common node;
• and
• a BPS switching controller configured to control operation of the BPS circuit between a BPS ON state in which the first and second terminals are connected through the first and second MOSFETs and a BPS OFF state in which the first and second terminals are disconnected,
• the method comprising:
• in a BPS ON state, operating the switchable current sources to apply a forward bias voltage across the first and second source to body diodes;
• and
• in a BPS OFF state, operating the switchable current sources to apply a reverse bias voltage across the first and second source to body diodes.