Patent ID: 8884604

Claim:
A current mirror for generating a substantially identical current flow in two parallel current paths, each current path comprising a switching device and each switching device comprising first and second active terminals and a control terminal for controlling current flow between the first and second active terminals, the current mirror comprising: a first switching device arranged such that its first active terminal is arranged to receive a first voltage, its second active terminal is arranged to receive a variable voltage that varies independently of the first voltage and its control terminal is arranged to receive a control voltage; a second switching device connected such that its first active terminal is arranged to receive the first voltage and its control terminal is arranged to receive the control voltage; a voltage control device connected to the second switching device such that an input of the voltage control device is connected to the second active terminal of the second switching device, the voltage control device being arranged to receive a control signal indicative of the variable voltage and to alter the voltage at its input terminal in dependence on the control signal such that the difference between the voltage across the active terminals of the second switching device and the voltage across the active terminals of the first switching device remains substantially constant, and a control signal generation device comprising a third switching device arranged such that its second active terminal is arranged to receive the first voltage, its first active terminal is arranged to output the control signal to the voltage control device and its control terminal is arranged to receive the variable voltage, wherein the third switching device is a transistor.