Patent ID: 6333654
Filing Date: 2001-12-25
Classification: H03K,H04L

Abstract:
A supply voltage control circuit for determining a variable delay before a selection of a power supply to supply a higher voltage to a driver that applies an encoder signal to a communications path, comprising:a) a threshold detector for receiving the signal and determining when an amplitude of the signal crosses at least one predefined threshold;b) a slew start controller that receives output from the threshold detector and a signal encoder, and determines a delay before a change to supply the higher voltage to the driver is required, based on a peak amplitude of the signal with respect to the higher voltage output by a power supply;c) a supply voltage selector for selecting the higher voltage based on an output of the threshold detector, after the delay determined by the slew start controller; andd) a slew rate controller for limiting a rate of transition to the higher voltage selected by the supply voltage selector.