| 摘要 |
<p>PURPOSE:To provide a power circuit of a simple constitution by obtaining an operating voltage for an EP-ROM, etc., by utilizing the high smoothing point voltage on the side of a power transformer at the stop time of a heavy load circuit. CONSTITUTION:A DC stabilized power unit S has a voltage detecting circuit 1-5 in addition to a full-wave rectifying circuit 1-2, a smoothing capacitor 1-3, and a +5V constant voltage circuit 1-4. A voltage detecting circuit 1-5 detects a smoothing point voltage accompanying variation in load current at the stop time of the heavy load and outputs a write voltage detection signal SU1 and a check operation detection signal SU2. A CPU 2-1 once inputting the detection signal SU1 writes the smoothing point voltage in the EP-ROM as a driving voltage on condition that the smoothing point voltage maintains a specific high voltage range, but when the detection signal SU2 is inputted, the smoothing point voltage is used as the driving voltage on condition that the specific voltage range is maintained even if the voltage drops, thereby checking the EP-ROM.</p> |
