| 摘要 |
PURPOSE:To prevent erroneous functions by constituting an integrated circuit by a means for boosting the voltage of an external power source, a means for judging whether the value of voltage of the external power source is higher than a predetermined level, a load circuit and an output switching circuit. CONSTITUTION:When voltage is applied from the output 21 of an external power source 1 to a booster circuit 2, a boosted voltage is provided from the output 22 of the booster circuit 2. If a voltage judging circuit 5 judges that the voltage at the output 21 of the external power source 1 is higher than a reference voltage, a source switching circuit 4 provides the voltage at the output 21 as the source voltage for a load circuit 6. If the voltage judging circuit 5 judges that the voltage at the output 21 is lower than the reference voltage, the source switching circuit 4 provides the voltage at the output 22 as the source voltage for the load circuit 6. By such arrangement, erroneous functions due to fluctuation of the voltage at the output 21 of the external power source 1 can be prevented. |
