Patent ID: 7560977
Filing Date: 2009-07-14
Classification: G11C,H02M

Abstract:
1. A step-up booster circuit comprising: a plurality of pump circuits connected in series; a pump control circuit that outputs a pump control signal, the pump control signal causing, in each of the pump circuits, a voltage of a signal inputted to each of the pump circuits to be stepped up so as to generate a required boost voltage in the step-up booster circuit; and an activation control circuit that generates a pump activation signal in accordance with a signal that instructs operation of the step-up booster circuit, wherein the pump control circuit controls output of the pump control signal in accordance with a voltage level of the pump activation signal, and wherein each of the pump circuits operates such that when the pump activation signal is at a first logical level outputs of the pump circuits are fixed to a predetermined low voltage level which is lower than the boost voltage, and when the pump activation signal is at a second logical level voltage signals input to the pump circuits are stepped-up in accordance with the pump control signal and the stepped-up voltage signals are output from the pump circuits.