Patent ID: 6268753
Filing Date: 2001-07-31
Classification: H03K

Abstract:
A precision variable delay system that is invariant of process, voltage, and temperature variations comprising:a delay line having two or more delay elements cascaded together;a voltage controller, said voltage controller operatively connected to said delay line, said voltage controller controlling the output voltage swing of said delay line;a decoder, said decoder operatively connected to said delay line, said decoder selecting the overall delay outputted from said delay line;a switch bank, said switch bank operatively connected between said decoder and said delay line, said switch bank having one or more switches enabled by said decoder; anda controller operatively connected to said delay line, said controller controlling the amount of delay for the two or more delay elements in said delay line wherein said controller comprises:a current source said current source supplying a current that is independent of process, voltage, and temperature variations;a D/A converter operatively connected to said current source, said D/A converter controlling the amount of delay of the two or more delay elements in said delay line;a second controller operatively connected to said D/A converter, said second controller controlling the delay of the two or more delay elements to compensate for chip-to-chip delay variations of the individual said two or more delay elements; anda converter operatively connected to said second controller, said converter converting current from said second controller to voltage.