| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching regulator of a current mode control system which allows a higher switching frequency. SOLUTION: A sense amplifier 11 formed of an operational amplifier circuit operates so that a voltage of an inversion input end becomes smaller than an input voltage Vin by an amount of offset Vof. Thus, a PMOS transistor M5 is not turned off, and a current corresponding to an offset Vof is made to flow to a resistor R3, the PMOS transistor M5 and a resistor R4, which are connected in series between the input voltage Vin and the ground voltage. A switching transistor M1 is turned on from such a state. When a current sensing circuit 4 starts current detection, an output voltage Vi of the current sensing circuit 4 is made to rise by following a rise of the current i1 flowing in the switching transistor M1 since the PMOS transistor M5 is already turned on. COPYRIGHT: (C)2010,JPO&INPIT
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