PURPOSE: To provide a mirror amplifier with less current consumption, improving a bump margin and suitable for acceleration and a method for activating it in a semiconductor memory, etc.
CONSTITUTION: A capacitor part 6 for re-distributing charge is connected in parallel to an NMOS transistor 5 activating the mirror amplifier consisting of PMOS transistors 1, 2 and the NMOS transistors 3, 4. At this time, for a fixed interval before the mirror amplifier is activated at required timing, the NMOS transistor in the capacitor part 6 is turned on, and the charge of the Vth fall node α of the mirror amplifier is pulled out by the re-distribution of charge by a capacitor, and the mirror amplifier is activated minutely. Thus, the mirror amplifier is made to be activated rapidly at required timing, and the interval when the operation is unstable at the time of activating is eliminated, and the acceleration is attained.
KOGA SHINICHI