Abstract: A circuit includes a current source providing an input current; first and second transistors having common control terminals and forming a current mirror generating a mirror current at the output of the second transistor. A control element having a first and second input and a first and second output is also provided; the first input being connected to the current source, the second input being connected to the output of the second transistor, the first output being connected to the common control terminals, and the second output being connected to the input of the first transistor of the current mirror. The control element is adapted to control the input to the first device and the voltage applied to the common control terminals in response to the inputs to the control device thereby maintaining the defined relationship between the input and output currents of the mirror. A method for implementing a current mirror in low headroom environments is also described.

Abstract: A voltage source circuit adapted to provide a regulated output voltage independent of variations in an input voltage and having an input node adapted to receive an input reference current and an output node adapted to provide a definable voltage output. The circuit comprises a control element adapted to provide an output signal to the output node, an impedance being driven by the output signal of the control element, and a sensing element having a current mirror adapted to sense the current flowing through the impedance, and to provide a feedback signal. The control element is responsive to the difference between the feedback signal and the input reference current, thereby providing a regulated voltage output.