| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit for power supply control that can control currents with high precision with less power loss, that makes a layout design easy, and that can make an occupying area small. SOLUTION: In the semiconductor integrated circuit (100) for power supply control that incorporates a power transistor (Q1) and constitutes a switching regulator that generates a DC voltage of a desired level by switching a current flowing in a coil (L1) with the power transistor, the circuit is constituted of a sense transistor (Q2) provided in parallel with the power transistor, that is smaller than the transistor, and that makes a current flow that is proportional to an output current by receiving an identical control voltage at control terminals, and of a current detecting resistor (R1) connected in series to the sense transistor. This structure makes it possible to reduce power loss in the current detecting resistor of the switching regulator. Also, the resistor comprising a dispersed resistor or a polysilicon resistor whose resistance is less affected by quality fluctuation in manufacture or temperature change can be used as the current detecting resistor, and thereby makes it possible to control currents with high precision. COPYRIGHT: (C)2005,JPO&NCIPI
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