Patent ID: 7312616

Claim:
A capacitance measurement circuit, comprising: a variable current source coupled to drive a selectable current through a circuit node; a switch coupled to the circuit node to switch the selectable current into a device under test (“DUT”) capacitor; a comparator including first and second input ports, the comparator coupled to compare a first voltage to be received on the first input port against a reference voltage to be received on the second input port and generate an output signal in response, wherein the first voltage is related to the selectable current driven through the circuit node, a switching frequency at which the switch is switched, and a capacitance of the DUT capacitor, wherein the switch is coupled between the first input port of the comparator and the DUT capacitor; and capacitance measurement logic coupled to receive the output signal from the comparator and coupled to adjust at least one of the switching frequency or a magnitude of the selectable current dependent upon the output signal.