Title:
SWITCHING POWER SUPPLY APPARATUS
Document Type and Number:
Japanese Patent JP3013597
Kind Code:
B2
Abstract:
PURPOSE: To perform the overheat protection of a switching element without using a photocoupler used exclusively for overheat protection.
CONSTITUTION: An overheat protection circuit 50 of the following constitution is provided in place of a conventional overheat protection circuit including photocoupler: The overheat protection circuit 50 is equipped with a positive characteristic thermistor 34 thermally coupled to a switching transistor 4 and resistance 32 serially connected with the thermistor for dividing the output voltage V2 on the secondary side, with a transistor 41 and Zener diode 36 to be turned ON when the voltage across the ends of the positive characteristic thermistor 34 reaches a predetermined value or higher, and with a transistor 46 and resistor 48 serially connected with each other and parallel-connected with a resistor 25 constituting the voltage-divider resistor 24 of an output voltage detector circuit 20.
Inventors:
Masashi Ikenari
Tsukasa Nagatsuma
Tsukasa Nagatsuma
Application Number:
JP12014992A
Publication Date:
February 28, 2000
Filing Date:
April 14, 1992
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
G05F1/10; H02H7/12; H02M3/28; (IPC1-7): H02M3/28; G05F1/10; H02H7/12
Domestic Patent References:
| JP5146147A | ||||
| JP5260735A | ||||
| JP61159888U |
Attorney, Agent or Firm:
Keiji Yamamoto