Title:
DC-DC CONVERTER
Document Type and Number:
Japanese Patent JPH01148065
Kind Code:
A
Abstract:
PURPOSE:To perform a good starting at the time of switching a power ON and to make it unnecessary to use elements having characteristic more excellent than required by turning OFF a Zener diode and preventing a protection circuit from operating for a specified period at the time of switching the power ON. CONSTITUTION:When a power switch 2 is turned ON, a transistor 16 is turned ON for a specified period of time determined by resistors 18, 19 and a capacitor 20. During the period of time, a parallel circuit of resistors 14 and 17 is connected between both ends of a load current sensing capacitor 13, and accordingly the resistance value of the resistor 14 is reduced by half. Therefore, voltage at a node of the resistor 14 and a Zener diode during that period of time becomes smaller than a set voltage under the influence of an internal impedance of a power source viewed from the capacitor 13. Further the Zener diode 15 is not turned ON, and the protection circuit does not operate. Therefore, even if a load current increases during the starting, the protection circuit does not operate and it is possible to start a DC-DC converter.
Inventors:
TSUCHIYA KEIJI
Application Number:
JP30643587A
Publication Date:
June 09, 1989
Filing Date:
December 03, 1987
Export Citation:
Assignee:
SONY CORP
International Classes:
H02M3/28; (IPC1-7): H02M3/28
Domestic Patent References:
| JPS62107675A | 1987-05-19 |
Attorney, Agent or Firm:
Sada Ito (1 person outside)