Patent ID: 6040731
Filing Date: 2000-03-21
Classification: H03D,H03G

Abstract:
A differential pair gain control stage with offset, comprising:a first differential pair comprising first and second transistors having respective control inputs and respective current circuits controlled by said control inputs with said current circuits connected at a common junction, said common junction forming a current input, said first transistor's current circuit providing a current output and said second transistor's current circuit connected to a line that is adapted to receive a fixed supply voltage, anda drive circuit comprising a second differential transistor pair having respective control inputs and respective current circuits controlled by said control inputs, said control inputs connected to receive a differential input signal, said current circuits connected to a supply voltage line through respective loads to produce respective drive signals which vary with said differential input signal and are connected to said control inputs of said first differential pair to control the flow of current between said current input and said current output,said loads arranged to introduce an offset into the transfer function between said differential input signal and said drive signals that increases the range over which said first transistor conducts current for a symmetrical differential input signal.