DRIVE CIRCUIT OF SWITCHING TRANSISTOR

摘要

PURPOSE:To prevent a storage time from being increased at a light load and to prevent a loss from being increased at a heavy load by providing a steady- state base current path comprising resistors to a base circuit of a transistor (TR) and providing a series circuit comprising a capacitor and a diode connected in parallel with the resistor and an over drive current path comprising diodes connected between a common connection point of the capacitor and diode and a collector of the TR. CONSTITUTION:When the load is light, an over-drive current I is supplied to a base of a TRQ via a capacitor C and a diode D. Then the TRQ is saturated immediately. When the collector voltage is sufficiently low, the over drive current I is shunted to the diode D. Through the operation above, the quantity of over drive supplied to the base of the TRQ is balanced automatically and automonously to an optimum amount.