公开(公告)号：US06313659B1

公开(公告)日：2001-11-06

申请号：US09667473

申请日：2000-12-27

申请人： Robert J. Bosnyak ,  Jose M. Cruz ,  Robert L. Drost

发明人： Robert J. Bosnyak ,  Jose M. Cruz ,  Robert L. Drost

IPC分类号： H03K1716

CPC分类号： H03K19/0005

摘要： A CMOS impedance matching circuit includes an amplifier and a feedback circuit. The amplifier allows control of the impedance by controlling the V/I characteristic. The amplifier is sized to provide the desired impedance. The feedback circuit clamps the maximum excursions of the input signal, thereby maximizing signal speed. It also provides a higher impedance to noise beyond the dead band. In one embodiment of the present invention, the amplifier includes an amplifier circuit in parallel with an amplifier buffer. The amplifier buffer provides no gain and simply performs the inverting function when no gain is required for impedance matching. In one embodiment, the amplifier circuit includes a plurality of switchable amplifiers coupled in parallel with each other. Each of the switchable amplifiers has a different gain, and the one with the right amount of gain for the needed impedance matching is chosen using control inputs. Each of the switchable amplifiers is preferably constructed using pull up and pull down circuits, which ensure that the voltage is within the compliance range of the remote driver circuit. In the absence of an input, the feedback circuit biases the transmission line to the trigger level of the remote receiver circuit, ensuring a quick response when an input is received.

摘要翻译： CMOS阻抗匹配电路包括放大器和反馈电路。 该放大器允许通过控制V / I特性来控制阻抗。 放大器的大小可以提供所需的阻抗。 反馈电路钳位输入信号的最大偏移，从而使信号速度最大化。 它还为死区之外的噪声提供更高的阻抗。 在本发明的一个实施例中，放大器包括与放大器缓冲器并联的放大器电路。 当阻抗匹配不需要增益时，放大器缓冲器不提供增益，只需执行反相功能即可。 在一个实施例中，放大器电路包括彼此并联耦合的多个可切换放大器。 每个可切换放大器具有不同的增益，并且使用控制输入来选择具有所需阻抗匹配的正确增益量的增益。 每个可切换放大器优选地使用上拉和下拉电路构成，其确保电压在远程驱动器电路的合规范围内。 在没有输入的情况下，反馈电路将传输线偏置到远程接收器电路的触发电平，确保在接收到输入时的快速响应。