| 摘要 |
PURPOSE:To give a delay for a required time to the rise of an output voltage, by connecting an FET in parallel with a resistor for voltage set and controlling the said FET with the time constant by a resistor and a capacitor, in a constant voltae power supply circuit used for audio equipment or the like. CONSTITUTION:A resistor (R)2 is connected between an output terminal OUT having an input terminal IN and a voltage set terminal REF, and a R3 is connected between the terminal REF and ground. An FET6 is connected in parallel with the R2, the drain is connected to the terminal OUT, the source is to the terminal REF and a R7 is connected to the gate. Another end of the R7 is connected to the terminal IN via a capacitor (C)8 and grounded via a R9. With this constitution, just after an input voltage is applied to the terminal IN, the FET6 is conductive via the C8 to obtain a verty low on-resistance. Thus, the rise of the output voltage can be kept as a reference voltage Vref without using a large capacity of capacitor through the selection of the time constant of the R9, C8. |
