ADN8831 - Linear Amplifier

Good morning,

I am currently studying the schematic of ADN8831 TEC Controller.

Purpose: analyse the loop gain and find an adequate setting for the thermal compensation (performed through chop2 amplifier).

Problem: I am currently struggling with the LINEAR AMPLIFIER.
The Detailed Block Diagram does not describe how LFB, LNGATE and LPGATE pins are connected.
I guess LFB, LNGATE and LPGATE are related (since they are outputs of the same opamp) and also LNGATE and LPGATE are the differential arrangement of LFB.

Please, is there someone able to give me the detailed schematic of such an OPAMP configuration?

Thanks in advance!

Antonello Laneve

PS: See attached Detailed Block Diagram and Evaluation Board schematic to understand what I am talking about

Detailed Block Diagram Evaluation Board Schematic

  • The linear driver stage is used to drive positive side of the TEC module. LNGATE and LPGATE drive an NMOS and a PMOS respectively. The actual output voltage of linear stage is fed back to LFB to complete the feedback control of the linear side; similar to how SNGATE, SPGATE, and SFB pins are connected.

    The linear amplifier here refers to the power stage driver, it's different from the chopper amps for thermal PID loop.

  • Hello ytu,

    I know it generates two signals driving the LNGATE and the LPGATE respectively.

    I was attempting to unravel the driving circuitry inside the linear amplifier (to have a better understanding of circuit limitations).

    Anyway, I was carrying out the loop gain: it should have no effect because of the feedback.