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I have developed this USB-C Power Delivery board using HUSB238 IC: https://capuf.in/usb-c-pd-power-delivery-board-65w/

Datasheet of HUSB238

Problem What I have observed is using the Iset pin. If I make it open(I verified with a multimeter that >600K ohms is what I see between Iset and GND), it sets to the 3.25A setting as per datasheet. But, when I plug in the USB PD charger, the output is on 20V and switches to 5V, telling me that 3.25A setting doesn't work.

Other settings like 1.5, 2.0, 3.0A works fine. Even all settings for voltage 5/9/12/15/20A work fine.

The PD charger I am using says it works for 3.25A. It is written/printed on the charger.

Picture of the charger, you can see what is written

Any idea what could be the issue?

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  • \$\begingroup\$ It is written/printed on the charger. ... that does not really count, unless the manufacturer is reputable ... what does the power supply datasheet say? \$\endgroup\$
    – jsotola
    Commented Nov 5, 2023 at 21:28
  • \$\begingroup\$ There is no datasheet. These are USB-PD chargers I bought for Phone charging. Let me add Picture in the original question. \$\endgroup\$ Commented Nov 5, 2023 at 21:39

1 Answer 1

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Simple, your Type-C cable has no e-Mark IC in it so it does not indicate support for beyond 3A, so you can't get 3.25A with your Type-C cable.

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  • \$\begingroup\$ I am using the cable which came with the charger itself. Won't my PD board do that same, telling PD charger over CC lines that now give more than 3A i.e 3.25A? \$\endgroup\$ Commented Nov 5, 2023 at 22:01
  • \$\begingroup\$ @PallavAggarwal I don't know what your cables support even if they came with your charger. And no your PD board actively refuses to negotiate 3.25A if it cannot detect a cable that supports over 3A. It's the cable that must also indicate support for over 3A, likely your PD adapter would work if you had proper cable. I assume chargers have disconnectable cable, not a captive cable? \$\endgroup\$
    – Justme
    Commented Nov 5, 2023 at 22:13
  • \$\begingroup\$ One has disconnectable cable, other one is fixed with the charger. My logic says cable chip in between PD charger and my PD sink board doesn't make sense. Let me try to find some more chargers and will try the E-mark chip cable also. \$\endgroup\$ Commented Nov 5, 2023 at 22:17
  • \$\begingroup\$ @PallavAggarwal The one with captive cable should work. The disconnectable cable must have a chip to indicate support for over 3A, it reads in the standard even you think it makes no sense. There are cables that can handle only 3A for 60W and cables beyond that which support up to 5A for 100W must be able to indicate that it is safe to pass over 3A, so that 3A cables don't melt when trying to pass 5A. Makes more sense? \$\endgroup\$
    – Justme
    Commented Nov 5, 2023 at 22:21
  • \$\begingroup\$ The one with Captive Cable also doesn't work. I understand the logic that cable should tell that it can handle more than 3A, but does that mean Echip and my PD board talk to the PD charger over the same CC lines? Let me read more about the E-mark chip thing. \$\endgroup\$ Commented Nov 5, 2023 at 22:23

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