A comparator (12) and method compare first and second signals (V.sub.IN+, V.sub.IN-) to provide an output signal (V.sub.O, V.sub.OB). A transistor (43) couples a supply terminal (64, 66) of the comparator to a power supply (V.sub.DD) to enable the comparator for comparing the first and second signals. When the output signal is valid, it turns off the transistor to isolates the supply terminal from the power supply. As a result, power is reduced and a change in the first and second signals is prevented from changing the output signal. When the transistor turns off, a charge is trapped on the supply terminal that unbalances the comparator and causes a comparison error. A balanced condition is restored with a discharge circuit (31-33) coupled to the supply terminal to alter the charge when a control signal (RESET) is applied.