A feedback control circuit design technique to suppress power noise in high speed output driver

In today´s sub-micron CMOS integrated circuit technology, high speed output switching signals interacting with external inductance and capacitance produce noise which contaminates output signals and power buses. A Feedback Control Slew Rate Output Driver (FCSROD) which reduces the noise spike down to approximately 64% of a conventional output buffer without incurring the penalty of the propagation delay and even the rise/fall time is described. This effective power noise suppression is achieved by using distributed and weighted switching driver segments in conjunction with feedback control to control the output driver´s slew rate. Dynamic short circuit current which is generated while both pFET and nFET are conducting is also minimized to reduce di/dt noise. FCSROD was compared with a conventional and the controlled slew rate output buffer, showing 64% noise reduction comparing to the conventional driver, and 22% improvement in both propagation delay and rise/fall time comparing with the controlled slew rate output driver