Patent ID: 6084460
Filing Date: 2000-07-04
Classification: G06G

Abstract:
A four quadrant multiplying circuit for multiplying a first input voltage and a second input voltage, comprising:a first voltage compression circuit, including a differential amplifier circuit comprising transistors of a first conductivity type, for converting a differentially input first input voltage and reference voltage to lower values at a predetermined ratio, reducing the potential difference between said first input voltage and reference voltage and outputting said potential difference;a second voltage compression circuit, including a differential amplifier circuit comprising transistors of a second conductivity type, for converting a differentially input second input voltage and the reference voltage to lower values at a second predetermined ratio, reducing the potential difference between said second input voltage and reference voltage and outputting said potential difference;a current converting circuit, comprising transistors of the first conductivity type, for outputting a first and a second constant current on the basis of the second input voltage and the reference voltage converted to lower values at the second predetermined ratio output by said second voltage compression circuit;a first voltage converting circuit, including a differential amplifier circuit comprising two transistors of the first conductivity type, wherein the first constant current output by said current converting circuit is received by the sources of said two transistors of the first conductivity type of said first voltage converting circuit, the first input voltage after compression output by said first voltage compression circuit is received by the gate of one of the two transistors of the first conductivity type of said first voltage converting circuit, and the reference voltage after compression is received by the gate of the other of the two transistors of the first conductivity type of said first voltage converting circuit;a second voltage converting circuit, including a differential amplifier circuit comprising two transistors of the first conductivity type, wherein the second constant current output by said current converting circuit is received by the sources of said two transistors of the first conductivity type of said second voltage converting circuit, the first input voltage after compression output by said first voltage compression circuit is received by the gate of one of the two transistors of the first conductivity type of said second voltage converting circuit, and the reference voltage after compression is received by the gate of the other of the two transistors of the first conductivity type of said second voltage converting circuit; anda Gilbert cell for multiplying together the outputs of said first and second voltage converting circuits and outputting the multiplied outputs.