| 摘要 |
PROBLEM TO BE SOLVED: To provide an excess current protection circuit where a switching (SW) element is off-controlled by a significant state of an excess current detection signal at the time of detecting excess current, and current flowing in a load can be reduced at the time of protecting excess current by connecting an excess current protection state with a simple circuit structure. SOLUTION: A power supply 1, the load 2, an SW element 3 controlling load current, and an excess current detection resistor DR4, are connected in series and the circuit is constituted. Excess current of the circuit is detected by both end voltages of DR and the SW element is off-controlled. The circuit is provided with an error amplifier 10 generating output when reference voltage Vth and both end voltages are inputted and both end voltages exceed Vth; a first SW element 11 which is conducted by output of the error amplifier, drops gate voltage of the SW element, and controls current limiting so as to suppress load current; and a second SW element 12 which is conducted by output of the error amplifier, drops Vth, and continues the excess current detection state. COPYRIGHT: (C)2007,JPO&INPIT
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