High-voltage differential amplifier and method using low voltage amplifier and dynamic voltage selection

摘要

A differential amplifier (1D) includes circuitry (5,R1,R2,52) coupling a common mode component of an input voltage (Vin+-Vin-) to a maximum voltage selector circuit (53) that produces an internal voltage (VRAIL-TOP) equal to the larger of a first supply voltage (VREG) and the common mode component. An input amplifier circuit (46) of the differential amplifier is powered by the internal voltage. The input voltage (Vin+-Vin-) is coupled to inputs (41A,B) of the input amplifier circuit (46). Outputs (64A,B) of the input amplifier circuit (46) are amplified by an output amplifier (50).