SWITCHING POWER SUPPLY APPARATUS

• Main Authors: NAKAHIRA KOJI, TANI RYUTA
• Format: Patent
• Language: English
• Published: 10.01.1995
• Edition: 6
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION

PURPOSE:To reduce a difference in an operating point for the protection of an overcurrent irrespective of a fluctuation in an input voltage. CONSTITUTION:When an input voltage is high, an electric charge in a capacitor C2 is charged much via a resistance RA and a Zener diode DA, and a charging charge which is charged in the backward direction in the capacitor C2 is reduced even when a voltage generated from a feedback winding NB is high. Consequently, near an operating point for protection of an overcurrent, the time which elapses until a switching element Q1 is turned off by the charging operation of the capacitor C2 from a resistance R3 becomes short. Thereby, the shift width of the operating point can be reduced. When the input voltage is low, the charging charge of the capacitor C2 is small inversely, and a charging charge, in the backward direction, which is charged by the feedback winding NB becomes much. Consequently, the time which elapses until the switching element Q1 is turned off by the charging operation of the capacitor C2 from the resistance R3 becomes long. Thereby, the shift width of the operating point can be reduced.