I have the above simple requirement, and I'm frankly astonished that I can't find it as a simple chip.
- USB2 provides 5V on its power pins;
- USB2 assumes 100mA, but will provide 500mA upon negotiation;
- Most USB2 sources just provide 500mA anyway - but I want to be "official" and negotiate for it first;
- USB3 does "power delivery", but those chips are SO complex that they're overkill for my situation.
I have a 500mA, 3.3V circuit (330mA @ 5V) that I'd like to power from 5V USB. So I'm looking for a simple chip that has 4 USB pins (I assume the Data pins are part of the negotiation!) and one 3.3V output pin that can supply 500 mA - noting that ~750mA is the theoretical maximum. If there needs to be a couple of extra pins for support components (capacitors, inductors, etc.) then so be it, but I'd hope there wouldn't be many.
I've found all sorts of devices for USB chargers (on the "host" side - no good), USB Hub controllers (to even out multiple ports' requirements - too complex), USB peripherals with incidental output voltage (e.g. FTDI - way too complex), and even one 8-pin device that's almost ideal - but it stops at 200mA (300mA @ 3.3V).
Why isn't there a device that negotiates for 500mA, and then simply delivers it at 3.3V @ 750 mA (or close)?