Patent ID: 7304871
Filing Date: 2007-12-04
Classification: H02M

Abstract:
1. A voltage generating apparatus comprising: a boost circuit which boosts an input voltage by a predetermined step-up ratio and outputs an output voltage accordingly; a regulator circuit which regulates the input voltage so that the output voltage matches a reference voltage; a control circuit which brings the regulator circuit to a power saving mode when the step-up ratio of 1.0 is designated; a first transistor provided between an input terminal and an output terminal of the regulator circuit; a pull up resistor provided between a control terminal of the first transistor and a first fixed potential; a constant current circuit provided between the control terminal of the first transistor and a second fixed potential; a second transistor provided between the control terminal of the first transistor and the second fixed potential; an operational amplifier having its output connected to a control terminal of the second transistor, its non-inverting input supplied with a predetermined reference voltage and its inverting input supplied with a feedback of the output voltage of the boost circuit; a first control switch which performs on and off control of the second transistor; and a second control switch which performs on and off control of the constant current circuit.