Patent ID: 7808268

Claim:
An apparatus for controlling the slew rate of a voltage driver circuit comprising: a driver circuit having an input signal and an output signal, the driver circuit structured and arranged to control the slew rate of the output signal; a delay circuit coupled to an output of the driver circuit, the delay circuit having a delay proportional to a desired target slew rate of the driver output signal; a first comparator for detecting when the driver output signal rises through a specified level; a second comparator for detecting when the driver output falls through a second specified level; and a phase detector coupled to outputs of the first and second comparators, in which one of the outputs of the first and second comparators is delayed by the delay circuit to provide an edge triggered digital error signal; and at least one charge pump coupled to receive the edge triggered digital error signal, wherein the at least one charge pump generates bias signals for the driver to control the output slew rate.