Current sensing system and dc-dc converter comprising the same

A system, comprising:

• a transistor module, comprising:
• a primary transistor electrically connected between a first terminal and a second terminal, the primary transistor having a control terminal;
• and
• a secondary transistor electrically connected between the first terminal and a third terminal, wherein the secondary transistor has a control terminal that is electrically connected to a control terminal of the primary transistor;
• and
• a current sensing module is electrically connected to the transistor module and has an output terminal,
• wherein the system is configured to be operable in a first mode in which the current sensing module is configured to:
• present an impedance between the second terminal and the third terminal so that a voltage at the third terminal is substantially equal to the voltage at the first terminal;
• and
• output a first output signal at the output terminal that is indicative of a current through the primary transistor in a first current direction based on a voltage difference between the third terminal and the second terminal, wherein the first current direction is from the first terminal to the second terminal.