Title:
DCCDC CONVERTER
Document Type and Number:
Japanese Patent JPS55109171
Kind Code:
A
Abstract:
PURPOSE:To stably control the output voltage of the secondary winding of a transformer by controlling the discharge of a capacitor controlling the on-off time of a switching circuit at the primary side of the transformer according to the output voltage at the secondary side of the transformer. CONSTITUTION:When a transistor TR1 is conducted, the voltage of a capacitor C4 charged through a resistor R4 and a diode D5 connected to the windings N2 and N3 of a transformer T1 is gradually raised. When the sum of the above voltage and the forward voltage of the diode D5 becomes higher than the sum of the voltage produced from the winding N3 of the transformer T1 and the voltage VBE of a transistor TR2, the transistor TR2 is conducted and the transistor TR1 is turned off. Thus, an energy stored at the transformer T1 through the diode D1 and capacitor C2 from the winding N4 of the transformer T1 is supplied to a load L. The output voltage from the transformer is detected by resistors R7, R6, Vref and an amplifier AMP1, and a photo coupler PC1 is conducted. Thus, the charge stored in the capacitor C4 is discharged in predetermined amount to determine the on time of the transistor TR1.
Inventors:
SAITOU YOSHIKATSU
TAKAYAMA TOMIO
TAKAYAMA TOMIO
Application Number:
JP1641879A
Publication Date:
August 22, 1980
Filing Date:
February 15, 1979
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
H02M3/338; H02M3/335; (IPC1-7): H02M3/335