| 摘要 |
An output buffer circuit for driving a transmission line (7) in accordance with data to be transmitted, comprises a switch stage (1) having an input port (1H, 1L), an output port (OP, ON, OUT) for connection to said transmission line (7) and a control terminal (4). The switch stage comprises switches adapted for connecting the output port with the input port in accordance with a digital input signal (IN). Impedance means (15, 16) are connected to said switch stage (1) and have an impedance control input (C1, C2) for adjusting their impedance in accordance with a control signal. Means are provided for controlling the output impedance of the output port by means of adjusting the impedance of the impedance means (15, 16). A selector circuit (2) selectively connects the output port with a detection input of said controlling means (3), said selector circuit (2) being connected to receive a selection control signal having a fixed timing relationship with said digital input signal. |
