| 摘要 |
PURPOSE:To allow suppression of output voltage rise by a constitution wherein a pulse is delivered from a pulse distributor when the DC power supply voltage enters into overvoltage state and a switching element identical to a chopper element is turned ON to consume the energy stored in a reactor within a closed circuit. CONSTITUTION:When an output voltage V0 is lower than an overvoltage level, pulse signal from a transistor(Tr) Q1 is turned ON whereas pulse signal from a Tr Q2 in a chopper element is turned ON/OFF repeatedly at a predetermined period. When an all load interrupted state is subsequently brought about, voltage of a smoothing capacitor 6, i.e., an output voltage V0, increases because of the energy stored in a reactor 3 and a level comparator 11 detects V0 exceeding an overvoltage level. Consequently, a pulse distributor 14 turns a pulse signal from the Tr Q1 OFF and turns a pulse signal from the Tr Q2 ON. In other words, a closed circuit for consuming the energy stored in the reactor 3 through the Tr Q2 diode is formed and input current to positive terminal is interrupted through turn OFF of the Tr Q1. |
