US Patent 7432730 Time based driver output transition (slew) rate compensation

Apparatus and method for controlling the driver output slew rate. The apparatus includes a driver circuit having an input signal and an output signal, where the driver circuit is structured and arranged to facilitate control of the slew rate of the output signal. A delay circuit having a time delay proportional to a desired transition time of the driver output signal is coupled to the output of the driver circuit. A first comparator detects when the driver output signal rises through a specified level, and a second comparator detects when the driver output falls through a second specified level. A phase detector is coupled to outputs of the first and second comparators and an output of the delay circuit for aligning the phases of the comparator outputs and the delayed comparator outputs by adjusting the driver output slew rate.