| 摘要 |
PURPOSE:To decrease the steady loss of a main transistor (TR) and to vary the conduction ratio greatly, by allowing a base driving circuit to drive the main TR with a base current consisting of a pulse train which has a short-period cutoff time shorter than the storage time of the main TR. CONSTITUTION:The main TRQ2 is turned on at a period tau1 for a conduction time tau2 and a basic signal for it is represented as e1. Further, the pulse train which has a period tau3 and pulse width tau4 much less than the period tau1 is generated as a signal e2. Those signals e1 and e2 are applied to terminals A and B of an AND circuit 16, whose output is applied through a resistance R3 to the base of a TRQ1 for on-control, which turns on for the period of the time tau4 and turns off for the period of time tau3-tau4. Consequently, the steady loss of the TRQ2 is decreased and its conduction ratio is controlled 0-100%. |
