Regulate peltier cell power

[jremington]

Useful Peltier application and test note here: https://www.ti.com/lit/an/slua979a/slua979a.pdf

Conclusion:

This application report shows that with a reasonable amount of power budget (2.5 V at 1 A, 2.5 W), even though the Peltier is not cooling anything, significant temperature differences were obtained, which can be interesting in some applications.

Moreover, constant current drive is definitively preferred over PWM drive. If the design requires the ability to reverse polarity, the full bridge is the most flexible option but it significantly reduces the efficiency. The buck boost TPS63020 is an alternative. Finally, testing for five months continuously (3600 hours) does not seem to have any significant measurable performance influence.