| 摘要 |
PURPOSE:To make it possible to drive a FET at a large duty ratio and without breaking down the FET by connecting the series circuit of the secondary winding of a transformer and a diode and a resistance berween the gate and source electrode of the FET. CONSTITUTION:Between gate electrode G and source electrodes S of FET5, the series circuit of secondary winding 3s of transformer 3 and diode 4, and resistance 6 are both connected. Then, driving voltage source 1, primary winding 3p of transformer 3, and transistor Tr2 are connected in series, and a pulse voltage, developed across secondary winding 3s of transformer 3 attending on the ON-OFF operation of Tr2, is applied to electrode G of FET5 via diode 4, thereby controlling a current which flows from terminal 7 to output terminal 8 by way of drain electrode D and electrodes of FET5. Further, ternary winding 3t of transformer 3 discharges an exciting current, accumulated in transformer 3, via diode 9 when Tr2 turns OFF, namely, rests the exciting current. |
