Hey #electronics lazyweb #AskFedi, does anyone know what the WCH CH224 family does if you configure the sink to request 20V but the source can’t do that? Specifically I’d like to know how it responds to both a “dumb” 5V source, and a PD source that only goes up to 12V.
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@jpm it defaults to 5V output, but the “PG” LED doesn’t go off IIRC.
@jpm hold on I have a PD trigger USB analyser and a CH224 here, lemme do some science
@jpm ok so the CH224 overrides any PD triggers along the chain to get what it wants. If I chuck dumb 5V in, it will put 5V out but the PG LED pin will go silent. Unfortunately I don’t have a charger on me right now that does protocols other than the full 65W suite (ie 9/12*/15/20) so I can’t tell you much more than that for now.
@ThermiteBeGiants yep I figured dumb* 5V would end up with 5V because there’s always voltage on VBUS
@jpm I think what you need to do is hook the PG pin up to a MOSFET for output gating if you want to make sure you’re getting the right output, but I’d have to look at the docs to get the full PG pin behaviour
@ThermiteBeGiants if anything I need the opposite of that - I’d like the wall wart to spit out 20V, or 12V, or anything at all really, but the higher the better.
@jpm ok so fallback to the highest possible voltage? I don’t think it does that normally
@ThermiteBeGiants yeah which is why I’m asking the question because the docs don’t make it clear either.
(Ping @Unixbigot I suspect you’ve (ab)used CH224’s extensively)
@jpm hmmmn, i think I have some but i dont think i’ve used them yet. Lemme check.
