| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter of simple circuit constitution small in parts count. SOLUTION: A resistor (Rs) for current detection, a load (RL), a choke coil (L1), and an NPN transistor (Q1) are connected in series, from the side of a power wire, between a plus power wire (5) and a grounding wire (6), and a diode (D1) is connected reversely between the mutual junction between the choke coil and the NPN transistor and the plus voltage power wire. A first PNP transistor (Q2) whose emitter is connected to the plus voltage power wire and whose base is connected to the mutual junction between the resistor for current detection and the load is connected in series to a first resistor (R1), and the other end of the first resistor is connected to the mutual junction between the load and the choke coil. The emitter of the second PNP transistor (Q3) is connected to the plus voltage power wire, and the base is connected to the collector of the first PNP transistor, and the collector is connected between the base of the NPN transistor, and a second resistor (R2) is connected between the base and the grounding wire, and a third resistor (R3) is connected between the collector and the grounding wire. COPYRIGHT: (C)2008,JPO&INPIT
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