| 摘要 |
PURPOSE:To prevent distortion of an AC signal gate by connecting a bipolar transistor (TR) and an MOSFET in parallel and passing a minute signal through the MOSFET. CONSTITUTION:When a voltage at a terminal 1 starts rising, while a signal turning on a semiconductor switch is applied between terminals 3 and 4, a current flows to MOSFETs M12, 22 at first, and when the current reaches a point A, the MOSFETs M12, 22 are clamped by the diode characteristic between the source and substrate. A collector-emitter voltage of bipolar TRs B1, B2 reaches a voltage flowing an on-base current and the TRs B1, B2 are turned on. The characteristic after a point A depends on the bipolar TRs because the current drive capacity of the bipolar TRs is large. Thus, the current flows via the MOSFETs even when the voltage between terminal 1 and 2 is nearly zero thereby preventing distortion. |
