Patent ID: 7525320

Claim:
A voltage control circuit, comprising: a voltage step-up device that steps up an applied voltage to a stepped-up voltage; an electronic device to which said stepped-up voltage is applied; a current monitor that monitors a supplied current that is supplied to said electronic device, based on said stepped-up voltage; a step-up controller that controls said stepped-up voltage to be a predetermined target voltage, based on said supplied current; and a warning provider that provides a warning when said current monitor can not monitor said supplied current, wherein said step-up controller controls said stepped-up voltage not to be larger than said target voltage, when said current monitor can not monitor said supplied current, and wherein said step-up controller comprises a current drawer that is connected to an output side of said voltage step-up device and draws additional current from said output side of said voltage step-up device when said stepped-up voltage is larger than a predetermined voltage, so that said stepped-up voltage is controlled not to be larger than said target voltage.