Modifying Another LTC3780 Board
I bought a new board on eBay, for ~ 10 Euros. Compared to the old ones, a few differences : No current limiting. Not a problem, we'll add a different one anyway. No tunable minimum voltage. It is hardcoded to ~ 5v Much better connectivity Bad thermal pad under the heatsink, you definitively need to set that right Now let's have a look at the feedback loop : So we have FB=Vout*3.3k/(3.3k+100k*Alpha) Which can be expressed as Vout=FB(1+30*Alpha) On the LTC, FB is 0.8v Vout=0.8*(1+30*Alpha) Vout is then between 0.8v and ~ 24v, that matches the spec. The components are not high accuracy ones, the 3.3k is measured as 3k.... That it that one :