Patent ID: 6525586
Filing Date: 2003-02-25
Classification: H03K

Abstract:
A programmable delay element for delaying a digital input signal, comprising:a discharge capacitor being precharged to a predetermined voltage in response to a first transition of said digital input signal; a transistor switch of a first type precharging said discharge capacitor to said predetermined voltage; a discharge current source connected via a sense node to said discharge capacitor discharging said capacitor in response to a subsequent opposite transition of said digital input signal; a transistor switch of a second type connecting said discharge capacitor to said discharge current source and thereby discharging said discharge capacitor; a reference voltage source applying a reference voltage to a reference node; and a comparator having a first input connected to said sense node and a second input connected to said reference node, such that an output of said comparator generates a delayed version of said digital input signal wherein said subsequent opposite transition is delayed by an amount equal to a time for said capacitor to discharge to a voltage equal to said reference voltage.