POWER SUPPLY DEVICE, LED DRIVE DEVICE, LIGHTING DEVICE AND DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a power supply device capable of appropriately performing state control of a charge pump with a small-scale circuit structure. SOLUTION: The power supply device includes: a regulator 21 for controlling opening/closing of an output transistor Tr so that a feedback voltage Vfb (the minimum voltage Vc1 to Vcn in Fig. 1) corresponding to an output voltage Vout may meet a reference voltage Vref; the charge pump 22 for generating the output voltage Vout by raising an input voltage Vin' from the regulator 21; a detection portion 23 for detecting whether a control voltage Sa of the output transistor Tr reaches threshold voltage Vth; and a state control portion 24 for switching boosting magnification of the charge pump 22 based on a comparison result signal Sb of a detection portion 23. COPYRIGHT: (C)2008,JPO&INPIT