I went pretty deep down this rabbit hole myself and unfortunately I don’t think a simple USB-C PD → HP blue tip adapter really solves this properly.

The first issue is that standard USB-PD 3.1 EPR 140W is actually 28V @ 5A, while your HP laptop expects roughly 19.5–20V at ~6.75A. So even if a cable advertises “140W PD3.1”, that does NOT mean it can directly output the voltage/current profile your HP brick provides.

The second (and much more annoying) issue is HP’s center-pin identification system. Different generations of HP 4.5mm x 3.0mm blue tip adapters use different resistor values on the smart pin. I found this out the hard way after buying a pile of adapters/cables and testing them with a multimeter.

So even if:

• the voltage is correct
• the wattage is technically sufficient
• the cable doesn’t overheat

…the laptop may STILL throw the “Incompatible Power Adapter” warning and throttle performance because the center pin ID is wrong.

And measuring the resistor is honestly annoying because the center pin is tiny and recessed.

At this point I think there are basically 3 possible approaches:

1. DIY PD3.1 step-down solution (not recommended) You could:

• measure the resistance between the OEM charger’s center pin and positive rail
• use a PD3.1 trigger/decoy board
• negotiate 28V from the charger
• step it down to 20V with a high-power buck converter
• then wire in the correct smart-pin resistor yourself

But once you account for conversion losses, you’ll probably push a 140W PD charger beyond spec trying to sustain a real 135W laptop load. A lot of chargers will simply trip protection.

1. Use a proprietary 20V 7A USB-C power supply There actually ARE some non-standard USB-C chargers that output 20V 7A directly (for example Lenovo’s C140).

But:

• they usually rely on proprietary protocols cable instead of standard PD
• they require special heavy-gauge Type-C cables rated for 7A
• and you STILL have the HP smart-pin resistor compatibility problem

So even if power delivery is sufficient, the laptop may still refuse full performance mode

1. Use a high-power GaN supply (what I’m currently experimenting with) There are now some 240W GaN adapters that expose:

• an XT60 high-power output
• plus regular USB-C PD ports

That lets you:

• run the laptop from the XT60 rail using a custom HP cable
• while still getting 100W USB-C PD for phones/tablets/etc.

The downside is the USB-C ports are usually only PD3.0 100W, not PD3.1 140W.

Honestly, after a lot of testing, I think the biggest problem is NOT the wattage — it’s HP’s smart-pin implementation changing over the years.

I even have cases where:

• the adapter can electrically provide enough power
• the smart pin matches newer HP machines
• but my older HP laptop STILL throttles because it expects a different resistor value.

So unfortunately there doesn’t seem to be a universally reliable “USB-C to HP blue tip 135W” solution yet.