| 摘要 |
The present invention is to provide a power down circuit, which can configure a wide range of the voltage of the control signal regardless of the fluctuation of the power supply voltage. In the power down circuit 1 , the drain of the first N channel MOS transistor M 1 , into which the control signal PD is input, is connected to the power supply VDD via the resistor R, and at the same time, connected to the gate of the second N channel MOS transistor M 2 , the source of the second N channel MOS transistor M 2 being connected to the gate of the N channel MOS transistor M 4 , to which the bias voltage VB is supplied, the drain of the N channel MOS transistor M 4 being connected to the power supply VDD via the drain of the P channel MOS transistor M 3 , when the first N channel MOS transistor M 1 is turned on/off by the control signal PD, the second N channel MOS transistor M 2 is turned off/on, and the bias circuit 2 is operated under a normal condition when it is off, and comes into a power down state when it is on.
|
