My monitor has 90W PD KVM. Unfortunately the monitor has coil whine while using the monitor to power my laptop.
My theory is that if I reduce the power output the whine should reduce as well.
I checked the dell SW and manuals and contacted support for options to reduce the output but alas.
I don’t see option on the laptop (Lenovo) sied either?
Do see any other options to reduce the power output?
Thank you in advance.
You can easily test this theory.
Charge your laptop to 100% and see if the coil whine is gone.
You can’t change the voltage output. it will be 20V always, only maybe the PD profile (instead of 90W it can be 60 or 45W).
The way it works is that the device asking for power (the laptop) has to ask for less, asking for less current means less power use.
There is a really easy test for this though. Run the monitor using an hdmi or displayport cable and power the laptop through something else. If the coil whine is still there, that means that the coil whine is not coming from the usb-c power on the monitor.
EDIT: just seen your post that you already said it’s only when connecting your laptop. Have you tried lower power devices on the usb-c port? Like a phone or tablet. That will tell you what the coil whine is with lower power. an idle and charged laptop is definitely not using 90W but more like 10-30W.
I was thinking about a PD trigger board, negotiate for power power with the display, and convert back to PD output for the laptop. But that wouldn’t work because PD trigger boards only negotiate for voltage and not current.
Maybe if you turn off fast charge on the laptop it should as for less than 90W.