Patent ID: 6573783
Filing Date: 2003-06-03
Classification: H03F

Abstract:
A circuit for adjusting input offset in a differential amplifier having a differential pair circuit having a plurality of input transistors and a plurality of current paths associated with the plurality of input transistors, circuit method comprising:a reference generator coupled to the differential amplifier; a trim circuit selectively coupled to the differential amplifier, wherein the trim amplifier in response to a trim control signal during an offset adjustment mode, the trim circuit being decoupled from the differential amplifier when the differential amplifier is in a mode that is different from the offset adjustment mode; and an open loop offset detector coupled to the trim circuit and selectively coupled to the differential amplifier, the open loop offset detector being configured to provide the trim control signal responsive to an input offset in the differential amplifier, the open loop offset detector being coupled to the differential amplifier during the offset adjustment mode, the open loop offset detector being decoupled from the differential amplifier when the differential amplifier in a mode that is different from the offset adjustment mode.