Portable terminal using the same, and step-up DC-DC converter

摘要

PROBLEM TO BE SOLVED: To provide a step-up DC-DC converter which improves operating fault at start. ;SOLUTION: A power inductor L outputs a voltage of a secondary cell V1, connected to an input side to an external output terminal Vo via a rectifier diode D connected to the output side. A power transistor Q is connected to the output side of the inductor L to switch, in response to a control voltage. A capacitor C is connected to the output side of the diode D to filter the voltage outputted from the diode D. A step-up DC-DC controller U1a connects the N- channel terminal to a control terminal of the transistor Q, and outputs a control voltage. An electric connection line Lp connects the output side of the diode D to a power terminal of the step-up DC-DC controller U1a. A pass-through diode D1 connects a secondary cell B1 to the output side of the diode D.;COPYRIGHT: (C)2003,JPO