# US 10,312,866 B2 · Process and temperature compensation in TIA using dual replica and servo loop > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,866 B2 - Document ID: US10312866B2 - Status: Granted - Kind: B2 - Application number: 14/997,940 - Filed: 2016-01-18 - Published: 2016-07-21 - Granted: 2019-06-04 - Earliest claimed: 2015-01-16 - Assignees: Luxtera, Inc. - Applicants: Luxtera, Inc. - Inventors: Stefan Barabas; Joseph Balardeta; Simon Pang; Scott Denton - Web page: https://patentgrep.com/patent/US10312866B2 ## CPC - H03F 1/30: Modifications of amplifiers to reduce influence of variations of temperature or supply voltage {or other physical parameters (in differential amplifiers H03F3/45479)} - H03F 1/086: {with FET's} - H03F 1/301: {in MOSFET amplifiers (H03F1/303, H03F1/305, H03F1/308 take precedence)} - H03F 1/56: Modifications of input or output impedances, not otherwise provided for - H03F 3/08: controlled by light - H03F 3/082: {with FET's (H03F3/085 takes precedence)} - H03F 3/087: {with IC amplifier blocks (H03F3/085 takes precedence)} - H03G 3/3084: {in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves (H03G3/32, H03G3/34 take precedence)} - H10F 30/10: the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors - H10F 77/95: {Circuit arrangements} - H03F 2200/129: there being a feedback over the complete amplifier - H03F 2200/132: Hybrid coupler placed in a feedback circuit of an amplifier - H03F 2200/156: One or more switches are realised in the feedback circuit of the amplifier stage - H03F 2200/453: Controlling being realised by adding a replica circuit or by using one among multiple identical circuits as a replica circuit - H03F: AMPLIFIERS - H03G: CONTROL OF AMPLIFICATION - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract Methods and systems for process and temperature compensation in a transimpedance amplifier using a dual replica and servo loop is disclosed and may include a transimpedance amplifier (TIA) circuit comprising a first TIA, a second TIA, a third TIA, and a control loop. The first TIA comprises a fixed feedback resistance and the second and third TIAs each comprise a configurable feedback impedance. The control loop comprises a gain stage with inputs coupled to outputs of the first and second TIAs and with an output coupled to the configurable feedback impedance of the second and third TIAs. The circuit may be operable to configure a gain level of the first TIA based on the fixed feedback resistance and a reference current applied at an input to the first TIA, and configure a gain level of the second and third TIAs based on a control voltage generated by the gain stage. ## Claims ### Claim 1 A method for communication, the method comprising: in a transimpedance amplifier (TIA) circuit comprising: a first TIA, a second TIA, and a third TIA, the first TIA comprising a fixed feedback resistance and the second and third TIAs each comprising a configurable feedback impedance, and a control loop comprising a gain stage with inputs coupled to outputs of the first and second TIAs and with an output coupled to the configurable feedback impedance of the second and third TIAs: configuring a gain level of the first TIA based on the fixed feedback resistance and a reference current applied at an input to the first TIA; configuring a gain level of the second and third TIAs based on a control voltage generated by the gain stage; and amplifying a received electrical current to generate an output voltage using the third TIA. ### Claim 2 (depends on 1) The method according to claim 1, wherein the reference current generates a reference voltage at one of the inputs of the gain stage. ### Claim 3 (depends on 2) The method according to claim 2, wherein the reference voltage controls the output of the gain stage that is coupled to the configurable feedback impedances of the second and third TIAs. ### Claim 4 (depends on 1) The method according to claim 1, comprising compensating for gain level changes with temperature of the second and third TIAs utilizing the configurable feedback impedances of the second and third TIAs, respectively. ### Claim 5 (depends on 1) The method according to claim 1, wherein the configurable impedances of the second and third TIAs each comprise a fixed resistor and a voltage-controlled resistance. ### Claim 6 (depends on 5) The method according to claim 5, comprising configuring the configurable impedances of the second and third TIAs by configuring a gate voltage of a transistor of the voltage-controlled resistance utilizing the output of the gain stage. ### Claim 7 (depends on 1) The method according to claim 1, comprising coupling the output voltage to a first input of a second gain stage wherein a second input of the second gain stage is coupled to an output of a fourth TIA. ### Claim 8 (depends on 7) The method according to claim 7, comprising generating a differential signal utilizing the output voltage and an output of the fourth TIA. ### Claim 9 (depends on 7) The method according to claim 7, comprising configuring the output of the second gain stage by configuring an input current of the third TIA. ### Claim 10 (depends on 1) The method according to claim 1, comprising receiving the electrical current from a photodetector. ### Claim 11 A system for communication, the system comprising: transimpedance amplifier (TIA) circuit comprising: a first TIA, a second TIA, and a third TIA, the first TIA comprising a fixed feedback resistance and the second and third TIAs each comprising a configurable feedback impedance, and a control loop comprising a gain stage with inputs coupled to outputs of the first and second TIAs and with an output coupled to the configurable feedback impedance of the second and third TIAs, the TIA circuit being operable to: configure a gain level of the first TIA based on the fixed feedback resistance and a reference current applied at an input to the first TIA; configure a gain level of the second and third TIAs based on a control voltage generated by the gain stage; and amplify a received electrical current to generate an output voltage using the third TIA. ### Claim 12 (depends on 11) The system according to claim 11, wherein the reference current generates a reference voltage at one of the inputs of the gain stage. ### Claim 13 (depends on 12) The system according to claim 12, wherein the reference voltage controls the output of the gain stage that is coupled to the configurable feedback impedances of the second and third TIAs. ### Claim 14 (depends on 11) The system according to claim 11, wherein the TIA circuit is operable to compensate for gain level changes with temperature of the second and third TIAs utilizing the configurable feedback impedances of the second and third TIAs, respectively. ### Claim 15 (depends on 11) The system according to claim 11, wherein the configurable impedances of the second and third TIAs each comprise a fixed resistor and a voltage-controlled resistance. ### Claim 16 (depends on 15) The system according to claim 15, wherein the TIA circuit is operable to configure the configurable impedances of the second and third TIAs by configuring a gate voltage of a transistor of the voltage-controlled resistance utilizing the output of the gain stage. ### Claim 17 (depends on 11) The system according to claim 11, wherein the TIA circuit is operable to couple the output voltage to a first input of a second gain stage wherein a second input of the second gain stage is coupled to an output of a fourth TIA. ### Claim 18 (depends on 17) The system according to claim 17, wherein the TIA circuit is operable to generate a differential signal utilizing the output voltage and an output of the fourth TIA. ### Claim 19 (depends on 11) The system according to claim 11, wherein the TIA circuit is operable to configure the output of the second gain stage by configuring an input current of the third TIA. ### Claim 20 A system for communication, the system comprising: a transimpedance amplifier (TIA) circuit, the TIA circuit comprising: a first TIA comprising a fixed feedback resistor and an output coupled to a first input of a first gain stage; a second TIA comprising a first configurable impedance and an output coupled to a second input to the first gain stage; a third TIA comprising a second configurable feedback impedance, an input for receiving an input electrical current, and an output that generates an output voltage of the TIA circuit; and a control loop that stabilizes the gain of the third TIA with temperature change, the control loop comprising the first gain stage with its output coupled to the first and second configurable impedances.