STABILIZED DC POWER SOURCE DEVICE

摘要

Disclosed is an inexpensive power source device with which a stable power source required for low-voltage measurement equipment is supplied from a high voltage solar battery power source which is subject to severe variations. A stabilized DC power source device which steps down DC input voltage obtained from a solar battery and outputs the stepped-down voltage to a load such as measurement equipment, wherein the stabilized DC power source device comprises: a series-type first constant-voltage power source circuit that performs voltage step-down and is connected to the solar battery and provided with a constant-current control circuit; a switching circuit that is connected to the first constant-voltage power source circuit; a switchable second constant-voltage power source circuit that is connected to the switching circuit; and a voltage detection circuit that detects the output voltage of the first constant-voltage power source circuit. The output voltage of the first constant-voltage power source circuit is detected and, if the detected voltage is greater than or equal to a first determination voltage, the switching circuit is closed and power is supplied to the load from the second constant-voltage power source circuit. If the detected voltage is less than or equal to a second determination voltage, which is lower than the first determination voltage, the switching circuit is opened and the power supplied to the load from the second constant-voltage power source circuit is stopped.