Patent attributes
A power MOSFET, comprising main and current mirror MOSFETs, has a current sense resistance coupled between its mirror and source terminals and a monitoring circuit responsive to a first voltage dependent upon current through the current sense resistance. The circuit arrangement includes a circuit that determines a second voltage, different from the first voltage, of a terminal of the current mirror MOSFET, and a circuit arranged to determine current of the power MOSFET in dependence upon the first and second voltages. The second voltage can be the voltage at the drain terminal, or the voltage at the mirror terminal with switching of the current sense resistance or a current that it passes. It can alternatively be determined by a control circuit to be a desired fraction of the drain voltage.
