I wish to power my Raspberry Pi 4 from a 12V DC battery and to do that I purchased these two products:
I tested the regulator and it works beautifully – by powering the Pi via its GPIO power rail pins 4 and 6 – it sustained a ~2.4A load with no problems at 4.98-4.99V.
For the life of me I don't understand what I'm doing wrong on the USB Type-C cable part, I get ~4.8V and dropping hard when increasing load when I try to attach the USB connector.
Steps taken so far:
- removed the 5.11kΩ pull-down resistors on CC
- attached a 10kΩ pull-up on each of the two CC ports (supposedly advertising a 3A capable source if I read the USB Spec correctly).
- shorted D- and D+ together
I tested the USB Type C cable with an AC adapter and a native DC 5V powerbank so that's not the culprit.
Do I really need a Power Delivery controller or am I missing something?
PS: this is the consumer's (Raspberry Pi's schematic), it seems to correctly be wired as a sink with 5.11kΩ pull-down:
Best Answer
Apparently the problem you are facing has been reported before, and it lies on the pull-down resistors of the Raspberry 4. In short, there should be independent resistors for the
CC1
andCC2
lines in order to detect the operating mode according to the following:Quoting the prossible problem description:
$$R_{T}=R_a || R_b = 1k\Omega || 5k1\Omega=836\Omega$$
Possible solutions
Solution 1:
Solution 2(source):