| 摘要 |
PROBLEM TO BE SOLVED: To avoid resetting of CPU and malfunction immediately after a switching regulator is started. SOLUTION: A device switches between voltage from the switching regulator 1 and voltage from VR2 and supplies the voltage to an output terminal. In the switching regulator 1 of this device, a first switching element 11 and an inductor L1 are connected in series between Vdd and the output terminal, and a second switching element 12 for synchronous rectification is connected between the junction of the first switching element 11 and the inductor L1, and ground. The switching regulator 1 comprises a drive circuit 13 that drives the first switching element 11, a drive circuit 14 that drives the second switching element 12, and a control circuit 20 that controls the two drive circuits. When the control circuit 20 outputs control signals to the drive circuits, and the switching regulator 1 is started according to a control signal; the control circuit keeps off the second switching element 12 until the first switching element 11 is turned on. COPYRIGHT: (C)2005,JPO&NCIPI
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