Qinheng PD decoy chip CH224K test

justd0

Qinheng PD decoy chip CH224K test [Copy link]

 

I attended another EEworld event some time ago, where I needed a fast-charging 20v power supply, and I paid attention to the CH224K chip from Qinheng. The forum happened to hold this event, so I took the opportunity to test the CH224K.

I received the development version a few days ago, and my first impression was that it was unexpectedly simple. The key components are just an IC, two resistors, and a capacitor, that's it. Oh, and there's also a Type-C connector.

Why is it unexpected? Because a few days ago I drew a test module based on the recommendations in the data sheet.

The simplest method of using only the PD protocol in the recommended circuit requires 8 resistors and one capacitor:

So I honestly drew all the suggested resistors and capacitors.

I got the test board I drew, soldered the resistors according to the design, and tested it with a QC3.0 fast charging head at home. No matter how I adjusted the resistors, the output was always 5.2v (I hadn't received the test module from Qinheng at this time). I once suspected that this chip didn't support the QC protocol of the fast charging head. So I quickly ordered a gallium nitride fast charging head that supports the PD protocol, which cost me more than 200 RMB.

During the two days I was waiting for the fast charging head, Qinheng's test module arrived. . I saw the few components on the board and was skeptical. I plugged it into the QC3.0 fast charging head and tested it. It actually output 20v directly. .

In other words, this chip supports QC. I searched on Baidu and found that the PD protocol is compatible with QC. It really hurts.

Then, on my own test board, I removed the unused resistors according to Qinheng's test module, connected the CFG pin to VUSB with 10K, and tested again, and successfully output 20V. . Amazing

Interestingly, I used an oscilloscope to observe the output voltage and the signal on DP, and found that the decoy used the PD protocol to increase the charger output voltage little by little.

USB D+ to ground signal waveform

lugl4313820

Qinheng's chip design is still worthy of praise.

littleshrimp

Why does the circuit recommended in the data sheet not output 20V?

hailiuhengli

littleshrimp posted on 2022-8-1 07:24 Why does the circuit recommended in the data sheet not output 20V?

First of all, your charger supports PD, because QC, AFC and other A-port protocols generally can only reach a maximum of 12V. Another thing is whether the chip works properly. If you are sure that the charger supports fast charging, it deceives 20V, but only 5V actually comes out, then there is a problem with your chip.

littleshrimp

hailiuhengli published on 2022-8-5 17:17 First, your charger supports PD, because QC, AFC and other A-port protocols generally can only reach a maximum of 12V. In addition, whether the chip works properly. If you...

Was there something wrong with the circuit you referred to before?

justd0

littleshrimp posted on 2022-8-5 18:38 Was there something wrong with the circuit you referred to before?

There may be something wrong with my resistor matching.

mars4zhu

justd0 posted on 2022-8-8 17:08 It should be a problem with my resistor matching

This chip has two matching modes, one is resistance mode and the other is CFG1/2/3 level mode. You need to select the required mode and the settings under the corresponding mode to output the correct voltage.

Read the manual carefully! ! ! ! !