| 摘要 |
PURPOSE: To provide a power supply device which can supply driving power with a stable output voltage with a low power consumption and can rapidly recover the output voltage even though a voltage fluctuations occur in output voltage. CONSTITUTION: A power supply circuit 5 includes resistors R4, R6 and R8 that generate an intermediate voltage, for which a target voltage value is set, from an inputted voltage, an N type transistor which pulls in current from the external when the voltage value of the intermediate voltage becomes equal to or higher than the target voltage value, a P type transistor which outputs current to the external when the voltage value of the intermediate voltage becomes equal to or less than the target voltage value, and also, is provided with voltage follower constituted differential amplifier circuits AMP1 and AMP2 in which an allowable width of the fluctuation of the voltage value of the intermediate voltage with respect to the target voltage value is set as the difference of the respective operation starting voltage values of the N and the P type transistors and a resistor Ra which operates either the P type transistor or the N type transistor so that the voltage value of the intermediate voltage is pulled into the target voltage value and is made stationary.
|
