| 摘要 |
<p>An emitter follower circuit has series circuits, each consisting of an emitter follower transistor (Q3, Q4), a current source, and a current source resistor connected to the emitter side of the emitter follower transistor (Q3, Q4). The source resistors are MOS transistors (N4, N5), which are switched on and off by control signals so that they have conduction and cutoff states. Between the source and the drain of each MOS transistors (N4, N5), current path means (R1, R2) is provided which has a resistance greater than the on-resistance of the MOS transistors to permit a very small current to flow, at least when said MOS transistors are rendered nonconductive. <H0> Abstract </H0> In an emitter follower circuit including an emitter follower transistor (Q3, Q4), and a series-connected circuit connected to the emitter of the emitter follower transistor and including a current source (Q3, Q4) and a current source resistor, the current source resistor being formed by a MOS transistor (N4, N5), the emitter follower circuit being switched to active and inactive states by switching the state of the MOS transistor (N4, N5) by a control signal, there is provided current path means provided between the source and drain of the MOS transistor, for providing a resistance considerably larger than a resistance of the MOS transistor provided during conducting when the MOS transistor is at least cut off and passing an extremely small current passes therethrough at that time.</p> |
