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ADN8834 Calc RC and RV for V and I limits of TEC

UG-858  has table 1 on page 3 to calculate RV1 and RV2, but sets abitraily RV2=10k which doen't work for most TECs.

Similarly table 2 on page 4 shows RC1 and RC2 for pre-established current ratio.

Equation for flexible V and I ratio shall be supplied and may look like:

Say desired VTECMAXCool = 1.4V,  VTECMAXHeat=1.0V

Because of the Avlim=2V/V, one finds

VLIMcool= 0.7V and VLIMheat=0.5V

Since Isink_Vlim = 10uA, one can find

RVp = RV1||RV2  =  (VLIMcool - VLIMheat)/Isink_Vlim =  (0.7-0.5)/10u =  20kohms

also

Vratio=RV1/Rv2=(Vref-Vrv1)/rv1=1.8V/0.7V=2.57

Then one can calculate

RV1 = RVp * (1+ Vratio) = 71.4 kohms

RV2 = RVp * (1 + 1/Vratio) = 27.8 koms

Same principle can be applied for RC1 and RC2  where the Isink_Ilim=40uA. 



Corrected with Vratio
[edited by: Optobru at 7:41 PM (GMT -5) on 7 Feb 2022]