[sdiy] Dual Transistor Expo-Converter Question

[mskala at ansuz.sooke.bc.ca]

On Sun, 22 May 2016, Richie Burnett wrote:
> It implements something called "dominant pole compensation" around the
> negative feedback loop of the servoing op-amp, to keep it from going unstable.

Is that really dominant-pole compensation?  I thought (based on the TI
document at http://www.ti.com/lit/ml/sloa079/sloa079.pdf) that
dominant-pole compensation involved adding a capacitor from the op amp
output to ground - the basic idea being that op amps are unstable when
they have a certain amount of capacitance on the output, and the added
capacitor, in parallel with that capacitance, guarantees that the total
will be more than the unstable amount.  The standard exponential-converter
circuit, with a capacitor from output to inverting input, looks more like
what that document calls "lead compensation."

-- 
Matthew Skala
mskala at ansuz.sooke.bc.ca                 People before principles.
http://ansuz.sooke.bc.ca/