EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: implor on June 27, 2025, 07:18:46 pm
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I have limited experiance with USB-PD IC. I have used one by Ti before but it was very complicated and we where not impressed with it.
For my current project I need something simple to negotiate PD up to 12V. I found ST STUSB4761 that looked like it will do everything I want and is bare bones.
What I'm confused about is the power-path. It can do 5 PDO but it only has one power path (TI IC I used before had one for each voltage). So now i'm wondering it will act like a step-down converter?
Datasheet say "Regulating voltage and current according to PD contract" on page 2.
And on page 9 there is a section on Voltage regulation.
"Input voltage is sensed on VDD pin. Until a PD contract is negotiated, regulation is set to 5 V. In power delivery
mode, the regulation aligns VBUS value on negotiated voltage value. Voltage regulation accuracy is 3% worst
case."
It feels like i'm miss-interpreting the datasheet or if it can do step-down, datasheet is missing a lot of information I would expect form a dc/dc step-down datasheet. :-//
What do you think?
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I haven't used that particular IC. It looks like it adjusts the feed back of the primary side with the Opto_DRV output to adjust the primary output voltage.
Check the schematic in section 5.2 of the data sheet.
So when a different voltage is negotiated, it adjusts the primary side to raise the voltage. It doesn't do any DC-DC conversion itself.
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I haven't used that particular IC. It looks like it adjusts the feed back of the primary side with the Opto_DRV output to adjust the primary output voltage.
Check the schematic in section 5.2 of the data sheet.
So when a different voltage is negotiated, it adjusts the primary side to raise the voltage. It doesn't do any DC-DC conversion itself.
Totally missed that optocoupler. Then it makes sense. It's then not suitable for my use case. Back to drawing board |O