START CONTROL CIRCUIT OF POWER SUPPLY DEVICE

摘要

PURPOSE:To reduce the no-control time by using a circuit which increases rapidly the output voltage of a variable reference voltage acquiring circuit that is applied to an error amplifier as a positive input. CONSTITUTION:The voltage VO proportional to the output voltage of a power supply device S is compared with the variable reference voltage VR through an error amplifier 1 for control of the output voltage so as to satisfy VO=VR. In addition to such amplifier 1, a reference voltage acquiring circuit 4 is provided together with a vatiable voltage acquiring circuit (Miller integrator) 3 and a rapid raising circuit 5 for voltage VR. The circuit 5 contains an error amplifier 6 to which the voltage VR and a bias power supply VB are supplied and applies the error voltage obtained by the amplifier 6 as a positive input of the amplifier 1 via a reverse current preventing diode D and a resistance R4. Thus VR>VB is satisfied immediately after a start mode and therefore a capacitor C1 of the integrator 3 is charged suddenly. Then the output voltage VR of the C1 has a rapid rise.