Power device and motor control apparatus provided with said power device

A power device that supplies internal power to a load, the power device comprising:

• a DC voltage output circuit that generates a DC internal power voltage from an external power supply;
• a capacitor that is connected to the DC internal power voltage;
• a voltage supply control circuit that monitors a voltage level of the DC internal power voltage and, when detecting a drop in the DC internal power voltage, cuts off supply of the internal power voltage;
• and
• a booster circuit that generates a boosted voltage by boosting the DC internal power voltage, wherein
• the voltage supply control circuit includes a selection switch that selects one of the DC internal power voltage and the boosted voltage and supplies the selected voltage to a first load that is a part of the load, a first terminal of the selection switch being connected to an output of the DC internal power voltage and a second terminal of the selection switch being connected to an output of the booster circuit, and
• the voltage supply control circuit is configured to cut off the supply of the DC internal power voltage to a second load that is a load other than the first load, when it detects a drop in the DC internal power voltage, and is configured to supply, to the first load, by controlling the selection switch, by switching from the supply of the DC internal power voltage to the supply of the boosted voltage.

A power device that supplies internal power to a load, the power device comprising:

• a DC voltage output circuit that generates a DC internal power voltage from an external supply power;
• a capacitor that is connected to the DC internal power voltage;
• a booster circuit that generates a boosted voltage by boosting the DC internal power voltage;
• and
• a selection switch that selects and outputs one of the internal power voltage and the boosted voltage, a first terminal of the selection switch being connected to an output of the DC internal power voltage and a second terminal of the selection switch being connected to an output of the booster circuit, and
• a voltage supply control circuit that monitors a voltage level of the DC internal power voltage and that, when detecting a drop in the DC internal power voltage, supplies the internal power by switching from supply of the DC internal power voltage to supply of the boosted voltage by controlling the selection switch, wherein
• the power device is configured to supply, to a part of the load, the internal power via the voltage supply control circuit.