Adaptive Minimization for loop

I have a DAC that I'm calibrating by measuring the values. I use a simple search to find the minimum between a voltage I desire and the measured voltage of the DAC. (don't worry, I know how to calibrate DAC's with a polynomial but I can't do that in this case.) Instead of using a stepped search where I change the values I would like to use an adaptive approach to make the algorithm faster.

I am using hardware in the loop. How can I use an adaptive algorithm to make the minimization faster?

findvalue = 0.5;%desired voltage
flagreached = 1;%flag if done finding voltage
count = 1;
while flagreached 

    voltage(count) =  voltagefromADC();%Measure voltage
    if count > 6 %wait 6 measurements before averaging
        meanv = mean(voltage(count-5:count));
        if meanv< findvalue - 0.5
           compdacV = compdacV + 100;
        elseif meanv< findvalue - 0.05
           compdacV = compdacV + 10;      
        elseif meanv< findvalue -0.005
            compdacV = compdacV + 1;
        elseif meanv <= findvalue
            %found value
            flagreached = 0;
        end
    end
    changeDAC(compdacV);%Set the DAC
    compdacVvec(count) = compdacV;
    count = count +1;
end