Method and apparatus for sensing current in a back-to-back configuration

A method of sensing current in a back-to-back MOSFET configuration, the method comprising:

• generating, by a gate driver circuit, a gate drive signal to drive a gate terminal of a first MOSFET and a gate terminal of a second MOSFET;
• forming a gate drive signal return path from a source terminal of the second MOSFET through a shunt resistor coupled between the source terminal of the second MOSFET and a source terminal of the first MOSFET, to a return terminal of the gate driver circuit;
• and
• sensing current through the shunt resistor.

An apparatus for sensing current in a back-to-back MOSFET configuration, the apparatus comprising:

• a first MOSFET having a gate terminal, a drain terminal, and a source terminal;
• a second MOSFET having a source terminal coupled to the source terminal of the first MOSFET, a gate terminal, and a drain terminal;
• a gate driver circuit including an input terminal to receive a control signal, and at least one gate drive output terminal to output a gate drive signal to the gate terminals of the first and second MOSFETs based on the control signal;
• a shunt resistor coupled between the source terminals of the first and second MOSFETS;
• a first gate resistor coupled between the gate terminal of the first MOSFET and the at least one gate drive output terminal;
• and
• a second gate resistor coupled between the gate terminal of the second MOSFET and the at least one gate drive output terminal;
• wherein the gate driver circuit includes a return terminal coupled to the source terminal of the first MOSFET;
• and
• wherein gate drive return current from the gate terminal of the second MOSFET flows through the shunt resistor to the return terminal of the gate driver circuit.