Switchable current source circuitry having a current mirror and a switching transistor coupled in parallel

摘要

A switchable current source circuit having a current mirror and a switch, such switch including a current source coupled to the current mirror, such switch enabling or disabling current from the current source to pass to the input of the current mirror selectively in accordance with a control signal fed to such switch. In one embodiment, the switch includes a differential amplifier and the current source is part of the differential amplifier. One of a plurality of control signals is fed to control the differential amplifier with the differential amplifier serving as both a logic circuit and current source, therefore, reducing the number of circuit comparators required to provide a switchable current source circuit.