| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply unit with built-in thereinto electric double- layer capacitors wherein the voltage applied across their terminals can be controlled independently of their temperatures or dependently on their temperatures so as not to charge them excessively. SOLUTION: When electric double-layer capacitors 1 are charged excessively, the voltage applied across their terminals is increased. An upper limit voltage which the voltage applied across the terminals of the capacitors 1 should not exceed at this time is preset in a reference voltage source 17. A voltage comparing portion 19 decides whether the sensed voltage by a voltage sensing portion 11 exceeds the upper limit voltage or not. When the sensed voltage by the voltage sensing portion 11 exceeds the upper limit voltage, the voltage comparing portion 19 outputs an on-signal to the base of a transistor 33. At this time, the transistor 33 is brought into a continuity to make an excess current flow through a resistor 31.
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