| 摘要 |
PURPOSE:To improve switching speed at the OFF of an FET by providing a switching element between gate sources of the FET and also connecting the control terminal of the switching element to a node between one end of the secondary side of a transformer drivng the FET and a diode. CONSTITUTION:When a pulse from a control circuit CONT is turned off, flyback voltage generating negative potential on the output terminal 1 of the transformer T1 by energy accumulated in the transformer T1 is generated. during the period generating said flyback voltage, a transistor (TR) 1 is separated from the transformer T1 because a diode X1 is reversely biased. Since current is supplied to a TR2 through a resistor R1 by the flyback voltage of the transformer T1, the TR2 is turned on. When the TR2 is turned on, the gate and source of the FET TR1 is shortcircuited so that charge accumulated between the gate and source of the FET TR1 is instantaneously discharged and the FET TR1 is instantaneously turned off. |
