Reply by Pamela ●June 26, 20222022-06-26
On 23:07  25 Jun 2022, Dave Platt said:

> In article <XnsAEC1DC911997C37B93@88.198.57.247>,
> Pamela  <pamela.private.mailbox@gmail.com> wrote:
>>
>>How does Qualcomm Quick Charge sense the presence on another compatible 
>>device.
>>
>>Is it looking for voltage on certain USB pins?
> 
> Basically, yes.  There's a whole negotiation process which takes place
> between the device, and the dedicated charging port.  Take a look at
> the data sheet for the On Semiconductor NCP4371 for some of the
> details.


I found it here.  https://www.onsemi.com/pdf/datasheet/ncp4371-d.pdf

It looks rather complicated to me but it seems there's some suprisingly 
elaborate signalling involved. Figure 20 seems to suggest that 2 if not 3 
leads get utilised for signalling.
Reply by Lasse Langwadt Christensen ●June 25, 20222022-06-25
s&oslash;ndag den 26. juni 2022 kl. 00.07.44 UTC+2 skrev Dave Platt:

> In article <XnsAEC1DC9...@88.198.57.247>,
> Pamela <pamela.priv...@gmail.com> wrote: 
> >How does Qualcomm Quick Charge sense the presence on another compatible 
> >device. 
> > 
> >Isit looking for voltahe on certain USB pins?
> Basically, yes. There's a whole negotiation process which takes place 
> between the device, and the dedicated charging port. Take a look at 
> the data sheet for the On Semiconductor NCP4371 for some of the 
> details.


and QC4 now also supports USB-PD over USB-C
I assume in preperation for the EU mandate that phones/tablets etc. must charge via USB-C, and support USB-PD if the higher power is needed
Reply by Dave Platt ●June 25, 20222022-06-25
In article <XnsAEC1DC911997C37B93@88.198.57.247>,
Pamela  <pamela.private.mailbox@gmail.com> wrote:

>How does Qualcomm Quick Charge sense the presence on another compatible 
>device.
>
>Isit looking for voltahe on certain USB pins?


Basically, yes.  There's a whole negotiation process which takes place
between the device, and the dedicated charging port.  Take a look at
the data sheet for the On Semiconductor NCP4371 for some of the
details.
Reply by a a ●June 25, 20222022-06-25
On Saturday, 25 June 2022 at 22:41:38 UTC+2, Pamela wrote:

> How does Qualcomm Quick Charge sense the presence on another compatible 
> device. 
> 
> Isit looking for voltahe on certain USB pins?

quick charge devices detect higher charging voltage and accept higher voltage since current is limited by diameter of the wire/s in the charging cable and by internal circuit board.
Reply by Pamela ●June 25, 20222022-06-25
How does Qualcomm Quick Charge sense the presence on another compatible 
device.

Isit looking for voltahe on certain USB pins?