| 摘要 |
PROBLEM TO BE SOLVED: To automatically set an output voltage by means of instructions from a load side. SOLUTION: The system comprises a load 2 provided with a resistor 21 that designates a required power source voltage and a switching power source unit 1 that reads the resistance value of the resistor 21 as a voltage-instructing signal and automatically outputs a corresponding output voltage VO. The switching power source unit 1 comprises: a voltage conversion section 11 that switches an input voltage VIN by a control pulse 101 and outputs the voltage- converted output voltage VO; an output voltage control circuit 12 that compares a standard voltage VS and the output voltage VO and outputs the control pulse 101 that changes a pulse width or frequency so that a voltage difference approaches 0; and an output voltage setting circuit 13 that reads the value of the resistor 21 in the load 2 and outputs the corresponding standard voltage VS. COPYRIGHT: (C)2003,JPO
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