Method And System for Accurate Gain Adjustment Of A Transimpedance Amplifier Using A Dual Replica And Servo Loop

A system for communication, the system comprising:

• a receiver comprising a first transimpedance amplifier (TIA);
• a second TIA;
• a third TIA;
• a fourth TIA, each TIA comprising a configurable feedback impedance;
• a control loop, the control loop comprising a gain stage with inputs coupled to outputs of the first and second TIAs and an output coupled to the configurable feedback impedance of the second and third TIAs;
• and
• a second gain stage with a first input coupled to an output of the third TIA and a second input coupled to an output of the fourth TIA, the receiver being operable to:
• configure a gain level of the first TIA by configuring its feedback impedance;
• configure a gain level of the third TIA by configuring a reference current applied to an input of the first TIA;
• and
• amplify a received electrical signal to generate an output voltage utilizing the third TIA.

A system for communication, the system comprising:

• a receiver comprising:
• a first transimpedance amplifier (TIA) comprising a first configurable impedance and an output coupled to a first input of a first gain stage;
• a second TIA comprising a second configurable impedance and an output coupled to a second input to the first gain stage;
• a third TIA comprising a third configurable feedback impedance, an input for receiving an input electrical current, and an output that generates an output voltage of the TIA circuit;
• a fourth TIA comprising a fourth configurable impedance;
• a second gain stage with a first input coupled to an output of the third TIA and a second input of the second gain stage coupled to an output of a fourth TIA;
• and
• a control loop for controlling the gain of the third TIA, the control loop comprising the first gain stage with its output coupled to the second and third configurable impedances.