Patent ID: 6163290
Filing Date: 2000-12-19
Classification: H03F,H03M

Abstract:
A folding amplifier that generates a folded and level-shifted differential output voltage at a differential output port in response to a differential input voltage at a differential input port, comprising:first and second current sources;first and second level-shift resistors that have first ends and second ends wherein first ends are coupled to respective ones of said current sources and are differentially coupled through output paths to said differential output port;first and second differential pairs of transistors that have offset voltages between control terminals and first current terminals wherein said control terminals are differentially coupled through input paths to said differential input port and said first current terminals are joined at the second ends of respective ones of said level-shift resistors; andfirst and second current-to-voltage converters that each generate at least one correction voltage that substantially matches the offset voltage of one of the transistors of a respective one of said differential pairs when said differential input voltage has one polarity and the offset voltage of another of the transistors when said differential input voltage has a different polarity;wherein said correction voltage is oriented in at least one of said input paths and said output paths to substantially correct variations in the offset voltages of one of said differential pairs adjacent a polarity transition of said differential input voltage.