| 摘要 |
PROBLEM TO BE SOLVED: To interrupt the supply of supply voltage to a load when short-circuiting is detected in the load and normally supply voltage to the load when the supply of supply voltage is started. SOLUTION: During a predetermined period after start of the supply of supply voltage, in place of transistor Q4, transistor Q5 turns on transistor Q3. A control signal from a microcomputer 1 is supplied to transistor Q2 and the transistor Q2 is turned on. As a result, MOSFET Q1 is turned on. Therefore, supply voltage can be supplied to a load 2 also when the supply of supply voltage is started. When the predetermined period has passed, in place of the transistor Q5, the transistor Q4 turns on the transistor Q3 and supply voltage is supplied to the load 2. When the load is short-circuited, the transistor Q4 turns off the transistor Q3; therefore, the MOSFET Q1 is turned off and breakage in the MOSFET Q1 is prevented. COPYRIGHT: (C)2009,JPO&INPIT
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