A current sensing circuit has an output NMOS transistor, connected between an output node and a power supply terminal, for passing a load current of an output load, a pair of sensing NMOS and PMOS transistors connected, in series at a first node, between the output node and the power supply terminal,...http://www.google.ca/patents/US5670867?utm_source=gb-gplus-sharePatent US5670867 - Current sensing circuit
