| 摘要 |
PURPOSE:To reduce current consumption during a standby period of a power supply voltage discriminating circuit which transmits a discrimination signal to an internal power supply voltage generating circuit (an internal voltage reduction circuit) indicating whether an external power supply voltage is within a recommended power supply voltage range or it is a voltage to enter into an accelerated test mode. CONSTITUTION:A power supply voltage detecting circuit 10 is provided to output an activating signal VACT to a power supply voltage discriminating circuit 20. The signal VACT becomes an L level when an external power supply voltage is below a prescribed value and when the voltage exceeds the value, the signal VACT becomes an H level. When the signal VACT becomes an L level, a comparator circuit 21 and a voltage dividing circuit 22 in the circuit 20 are made inactive. When the signal VACT becomes an H level, the circuits 21 and 22 in the circuit 20 are activated and the discriminating circuit is put into a condition in which a discriminating signal VDC is outputted. |
