Patent ID: 7135891
Filing Date: 2006-11-14
Classification: G01R

Abstract:
1. A current sense circuit, comprising: a shunt resistor in a wire for measuring current through the wire, the shunt resistor having first and second ends; a sense resistor having a first end and a second end, which is in connection with the second end of the shunt resistor; a transistor intended to be coupled to a supply and having a drain coupled to the first end of the sense resistor and having a gate; an amplifier having an output coupled to the gate of the transistor and an input in connection with the first end of the shunt resistor; a biasing voltage coupled to the input of the amplifier, the biasing voltage causing a reference current to continuously flow through the sense resistor; a switch coupled between the first end of the shunt resistor and the biasing voltage for coupling and decoupling a voltage across the shunt resistor to and from the input of the amplifier; and wherein when the switch is operated to couple the shunt resistor voltage to the amplifier, an increased current, beyond the reference current, flows through the sense resistor.