Title:
SWITCHING POWER SUPPLY UNIT
Document Type and Number:
Japanese Patent JP3426570
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce electric power consumption for positively high power efficiency by reducing switching loss under light load, using a simple structure.
SOLUTION: A control circuit 15 includes an error amplifier 22 of generating an error voltage signal VEAO, formed out of a difference between a auxiliary power supply voltage Vcc and a reference voltage, a current-detecting circuit 23 of detecting drain current ID flowing through a switching element 14 and outputting an element current detecting signal VCL, and a drain current detecting comparator 24 for comparing the error voltage signal VEAO with the element current detecting signal VCL and outputting a comparison signal. The control circuit 15 involves a light load detecting circuit 40 for stopping the output of a switching signal to a switching element 14 for a switching signal control circuit 25, if the error voltage signal VEAO is lower than a lower limit voltage value, and starting the output of the switching signal for the switching signal control circuit 25, if the error voltage signal VEAO is higher than an upper voltage value.
More Like This:
| WO/1997/020378 | POWER-SUPPLY CIRCUIT |
Inventors:
Osamu Takahashi
Yoshihiro Mori
Yoshiaki Hachiya
Naohiko Morota
You Shiomi
Yuji Yamanishi
Yoshihiro Mori
Yoshiaki Hachiya
Naohiko Morota
You Shiomi
Yuji Yamanishi
Application Number:
JP2000232612A
Publication Date:
July 14, 2003
Filing Date:
August 01, 2000
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
H02M3/28; (IPC1-7): H02M3/28
Domestic Patent References:
| JP10304658A | ||||
| JP62178167A | ||||
| JP410589U |
Attorney, Agent or Firm:
Hiroshi Maeda (7 outside)