I thought I’d explained it? I’ll repeat using different words.
You need to reduce the diversity of voltages across all ports. As it happens , in general, as you lower the voltage the watts lowers too so even if the overall efficiency drops so does the total heat.
Have to concentrate on the math.
- total 4 ports 200W charger.
- USB PD is 100W maximum
- so you can use 2 ports each 100W (same 20 volts so they share the same DC-DC conversion and each get 5A)
- 200W 95% efficiency, 10W heat, total drawn is (200/0.95) 210W.
- add a use of a 3rd port, say you added a 45W port need. 45W has to be 15V which is different than 20V so you can’t deliver 200W total any more. Say it was 93% efficient (not 95% for single voltage) so 210x0.93=195W, so now 45W causes the other two ports to drop to 75W each.
- the consumer complains then when using 3 port it is no longer 200W, its 195W.
- you see the issue.
So I’m saying it is possible. But probably not in a USB PD compliant manner so I think what you ask for has to be a IQ3 product.
You see similar issue comparing these
This product only has to deliver 2 voltage types, and is 65W
This product, the same size, has to deliver 3 voltages when the two C and A ports used concurrently so it’s less than 65W, its 63W, to allow for the extra heat of more port voltage diversity.
The reduce the effect, although not eliminate it, we have GaN and physical shape.
GaN causes less heat for a given task.
Physical shape where is a slab like will shed heat better than a more cube like shape. The Slim form factor is a step in the direction of a slab like shape.