| 摘要 |
PURPOSE:To reduce the loss of a switching transistor(TR) by providing a diode having almost the same time of reverse recovery as an ON operation time of the switching TR between a collector and an emitter of the switching TR in the polarity opposite to that of the power supply voltage. CONSTITUTION:Since a voltage across a diode 1b takes a low voltage for a time, at least trr1 in a reverse recovery time trr of the diode 1b, a collector- emitter voltage of a TR 1a for on-time is specified by the low voltage across the diode 1b and reaches a small voltage. Since the impedance of the diode 1b increases gradually from zero for a time trr2, the on-current flowing in the inside of the TR 1a gradually increases and only the on-current of the TR 1a remains finally and a collector current is stopped when the gate is turned off. That is, lots of current during the ON-time of the TR 1a flows from the diode 1b and since the collector-emitter flowing time is short, then the loss is reduced. |
