So long Schottky, nice knowing you!

[svetz]

The MAX40200 is an ideal diode current-switch that drops so little voltage that it approaches an order of magnitude better than Schottky diodes.

Dang! Ran across this while I was researching yesterday's post on the chip that lets you get more power from a panel while in partial shade.

 

[gnubie]

Unless you are pulling oids of amps through the diode the loss is minimal. As the current rating of a diode goes up the voltage drop also increases. A Schottky diode rated to carry 20 amps might have a drop of 0.5 volts. We can calculate the power loss across that diode at the typical 6 amps from a 44VoC panel. 0.5 x 6, 3 watts.

 

[efficientPV]

Not much you can use a 1A diode for and they require control circuitry. You really need to look into the specs of Schottky diodes. As they increase in voltage they generally have higher forward voltage. Best to use the lowest voltage you can get away with. As the current thru them increases so does the forward drop. I use dual 45A diodes in parallel to get about 0.3V drop in other uses. This panel leakage problem with shade is a little over exagerated.

 

[svetz]

 

[gnubie]

No one disputes that an ideal diode is not going to have less power loss than a real world diode. Using FETs to simulate the operation of a diode is nothing new either. There just isn't any practical purpose served in using the concept in a solar installation. The cost of the fets and control circuit compared to that of a diode isn't offset by the gain of a few watts.

In applications where every last milliwatt makes a difference ideal FETs are already used instead of diodes.