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I wish to detect when a USB C PD charger is turned on (i.e. provides power):

CHARGER ---> (DETECTOR)
         |
          -> Notebook

So I wish to keep it as simple as possible. Charger needs to charge a notebook, so full PD negotiation is needed, as notebook needs 20V3A.

My goal is to have sensor which can detect that charger is connected into mains.

The sensor will provide this information to a microcontroller.

I thought on current sensors, but I don't wish to have that sophisticated information: I only want to know if the charger is on or off.

I also thought on voltage detection on CC1 and CC2 pins (CC and VCONN), which I kindof like, however, as the C cable is reversible, I either need to build or use 2 ADCs, or I must interconnect CC1 and CC2 (with protection).

(How) can I trust on these CC1 and CC2 pins to detect voltage on the charger's output?

Daniel
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  • 2 blocking diodes and a adc pin plus a ground connection seems like all you need. – Passerby Jul 25 '22 at 07:17
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    USB-C won't provide power unless it's activated, so are you trying to detect whether is able to deliver power or whether it actually IS delivering power? – Finbarr Jul 25 '22 at 11:02
  • Very valid question! I wish to detect whenever the charger is *ready* (able) to deliver power without anything connected to it (yet). – Daniel Jul 25 '22 at 11:11
  • Then the only way is by monitoring the CC1 and CC2 pins, as part of their role is essentially to advertise the availability of power. – Finbarr Jul 25 '22 at 11:18
  • *Monitoring the CC1 and CC2*: shall I make them common with those *blocking diodes* @Passerby mentioned, or that would ruin the charging behavior? – Daniel Jul 25 '22 at 11:47
  • The blocking diodes prevent you from ruining the charging behaviour. What's important is that you don't put any significant load on the pins as that might. – Finbarr Jul 25 '22 at 11:51
  • I'm anyway planning to isolate these CC pins from the sensing circuit, so my idea is to use an opto-isolator. Max current I need would is around 10mA, to light up the opto-isolator's LED. Is 10mA considered *significant* in the context of CC pins? – Daniel Jul 25 '22 at 12:09
  • The maximum current you can take from CC1 or CC2 is about 500uA so yes, 10mA is significant. [Take a look at how CC pins are implemented here](https://electronics.stackexchange.com/questions/574317/usb-c-and-5v-power-supply/574324) – Finbarr Jul 25 '22 at 14:07

0 Answers0