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I have multiple USB-C 5V chargers of the same type that do not charge connected android devices. Devices detect charging if these are turned off, but when turned on, no charging icon of any visual notification. I did multiple tests and found out that everything is correct except an USB-C plug itself.

I removed the plastic mold resulting in a small board showed below. When connecting 5V from an external power supply, it behaves exactly the same as with the whole charger - current consumption about 0.3A (@5V) and no charging icon. Multiple android devices tested. If I am testing other plugs with 5V from the same power supply, charging is instantly detected.

I see that D+ and D- are internally connected on the board but it seems ok as mimics a DCP.

What is possibly wrong with the presented plug?

USB-C Plug Board Top USB-C Plug Board Bottom

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  • \$\begingroup\$ it looks like only one two of the positive pins are connected. \$\endgroup\$
    – Jasen Слава Україні
    Commented May 23 at 21:05
  • \$\begingroup\$ I also found it - VBUS on the left side of the plug seems disconnected from right VBUS. I connected to the VIA but resistance between VIA and Positive input is low, so probably internally connected (is it possible?!) inside plug. I also tried permanently connecting VIA to positive input, but it was still not detected. \$\endgroup\$
    – kamillabaarnowak
    Commented May 24 at 6:34
  • \$\begingroup\$ Why don't you measure the voltage at that connector when the phone is on and when the phone is not on to see if you really have 5V? It could just be a cheap cable with high resistance. \$\endgroup\$
    – MOSFET
    Commented May 24 at 6:50
  • \$\begingroup\$ I too it into consideration: For tests I unsoldered the original cable from pads and soldered my cable connected to power supply, so there is no Chinese cable incorporated. The problem is on plug itself. \$\endgroup\$
    – kamillabaarnowak
    Commented May 24 at 7:09
  • \$\begingroup\$ Have you checked on the Android-side that it's really not charging? Android.SE - Get the charging rate without external hardware (e.g. multimeter.) \$\endgroup\$
    – Andrew T.
    Commented May 24 at 9:48

4 Answers 4

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It simply doesn't support higher power USB-C PD profiles. That is a "dumb" cable. In order to extract more juice from a USB-C PD compliant device, the client has to negotiate with the host for that to occur. In other words, the "fast chargers" have an active chip that manages the power delivery and negotiation. You basically have a glorified USB-A wire fitted with a USB-C connector.

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  • \$\begingroup\$ The topic has nothing with Power Delivery. It is 5V charger, that should be detected as charging. \$\endgroup\$
    – kamillabaarnowak
    Commented May 24 at 6:31
  • \$\begingroup\$ @kamillabaarnowak charging devices via USB-C has everything to do with Power Delivery. There is a whole standard on it. The android devices are likely protecting themselves from your cables that don't adhere to the charging standard/specification. It's much more than "just 2 wires carrying power" as shown in your pictures. \$\endgroup\$
    – MOSFET
    Commented May 24 at 16:06
  • \$\begingroup\$ @MOSFET Power Delivery is optional. Devices can indicate default of 900mA, 1.5A or up to 3A current at 5V, only by using resistors. Which of course are not present so this is not a valid Type-C charging adapter. \$\endgroup\$
    – Justme
    Commented May 24 at 18:58
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When your USB Type-C compliant Android devices are plugged in, they are expecting a few things from a mating cable and upstream device to allow for charging.

  1. A handshake message negotiated over the data lines
  2. Configuration resistors on the CC pins of the mating plug somewhere upstream.

Without both of these things, the downstream device will refuse to accept a charge. This is good in that if you were to say, plug a 5V compatible USB type-C device into a USB-PD charger brick that can supply up to 19V, you wouldn't want the charger to supply 19V and fry the device.

From what you describe, it sounds like the charger may not be fully USB Type-C compliant in that it only connects to the USB 2.0 specific pins (+5V, GND, D+, D-). This is fine if the device charging is only expecting USB 2.0 connectivity, but as soon as something smarter, say you phone, which is fully or close to fully compliant to the spec, is connected and doesn't see these indicators that it's OK to charge, it will refuse a connection to prevent damage.

For a more detailed primer, check out this link: https://www.embedded.com/usb-type-c-and-power-delivery-101-power-delivery-protocol/

You could conceivably modify the devices here and add in the requisite configuration resistors, but you're probably better off buying a charger plug and cable combo that just works.

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  • \$\begingroup\$ The topic has nothing with Power Delivery. It is more like connecting a phone to a legacy charger via USB-C to USB-A cable. There also won't be CCx resistors and D+/D- will be handled inside a charger - shorted or with some resistors divider. I see that VBUS on the left side of the plug seems disconnected from right VBUS, but connecting didn't helped. \$\endgroup\$
    – kamillabaarnowak
    Commented May 24 at 6:58
  • \$\begingroup\$ @kamillabaarnowak Type-A to Type-C cables are required to have a single CC resistor. Which must indicate 900mA default current. Any other indication is not allowed. \$\endgroup\$
    – Justme
    Commented May 24 at 19:02
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I finally discovered the issue: For correct detection of 5V charging in USB-C cables, it is necessary to connect CC1 to VDD through a 10k resistor. It is also necessary to short-circuit D+ and D-. Chinese plugins do not have a CC resistor, so they are not detected. The fact of connecting the power supply to only one side of the VBUS is a mystery to me, but after testing it is not an obstacle to the correct detection of the power supply.

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  • \$\begingroup\$ How many amps is the charger? 10k would be a value for 3A charger. \$\endgroup\$
    – Justme
    Commented May 24 at 15:23
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The plug is non-compliant.

It does not signal to the device that a charger with a specified amount of current is available.

It also does not have a bypass cap between VBUS and GND.

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