Title:
SELF-OSCILLATED SWITCHING POWER DEVICE
Document Type and Number:
Japanese Patent JP3470693
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent deterioration of the response property of a power device when RCC operation is performed, and to improve its efficiency when the device stands by, by slowly controlling oscillation frequency so as to be constant or lower when the device is lightly loaded, and making it possible to lower the oscillation frequency, largely by a changeover signal when the device stands by.
SOLUTION: A switching transistor Q1 is connected to the primary winding N1 of a transformer T, and an oscillation frequency control circuit 1 is connected to its feedback winding NB. By this control circuit 1, a first control transistor Q3 is controlled, and the turn-on delay time of the switching transistor Q1 is controlled. The control circuit 1 is set to a first operation mode, in which the above delay is not performed on the occasion of a rated load, to a second operation mode in which control is performed, so as to make the oscillation frequency constant or lower slowly on the occasion of a light load, and to a third operation mode in which the oscillation frequency is lowered further, when a switch Q5 is turned on.
Inventors:
Teruo Nishida
Ryuta Tani
Koji Nakahira
Ryuta Tani
Koji Nakahira
Application Number:
JP2000325621A
Publication Date:
November 25, 2003
Filing Date:
October 25, 2000
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
H02M3/28; H02M3/338; H03L7/00; (IPC1-7): H02M3/28; H02M3/338
Domestic Patent References:
| JP11235036A | ||||
| JP2000228873A | ||||
| JP2000278946A |
Attorney, Agent or Firm:
Hisao Komori