Automatic gain control circuit with high linearity and monotonically correlated offset voltage

An automatic gain control (AGC) circuit, comprising:

• a high gain amplifier having a differential input and a differential output;
• a first series of resistors coupled between a first polarity input signal and a first polarity of the differential output of the high gain amplifier, the first series of resistors forming first and second intermediate nodes;
• a second series of resistors coupled between a second polarity input signal and a second polarity of the differential output of the high gain amplifier, the second series of resistors forming third and fourth intermediate nodes;
• the first and third intermediate nodes forming a first intermediate differential node pair and the second and fourth intermediate nodes forming a second intermediate differential node pair;
• a first transconductance amplifier having a differential input coupled to the first intermediate differential node pair, a differential output coupled to the differential input of the high gain amplifier and a first bias current control device that controls transconductance of the first transconductance amplifier;
• and
• a second transconductance amplifier having a differential input coupled to the second intermediate differential node pair, a differential output coupled to the differential input of the high gain amplifier and a second bias current control device that controls transconductance of the second transconductance amplifier;
• wherein the first and second transconductance amplifiers are each configured to be linear across a relatively wide input voltage range.