Patent ID: 7548029
Filing Date: 2009-06-16
Classification: G01R,H02M

Abstract:
1. A gate driver for a bridge-connected switched transistor output circuit including a high-side and a low-side transistor switch, the gate driver comprising: a first input for receiving a high-side switch enable signal; a second input for receiving a low-side switch enable signal; a third input for connection to a common node between the high and low side switches; a first output for providing a gate drive signal for the high-side switch; a second output for providing a gate drive signal for the low-side switch; a third output for providing a measurement signal representative of the output current through the high and low side switches; an offset circuit electrically coupled to the third input which includes a reference current source, a level shifter, and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration; a measuring circuit electrically coupled to the offset circuit including a second current reference source having substantially the same electrical characteristics as the first current reference source, and a second plurality of transistors respectively matched to the input side circuit transistors, and connected in the same circuit configuration; a coupling element which connects the offset circuit to the measuring circuit in response to a gating signal, wherein the offset circuit is operative to offset the voltage of a signal at the first input terminal in a predetermined manner and to pass the offset signal to the coupling circuit; the coupling element is responsive to the gating signal to pass the offset signal to the measuring circuit; and the measuring circuit is operative to generate the measurement signal.