You may have seen that I had already covered an article on CH224K in which I have designed a power supply which then I fed into a buck converter and attached a multi turn potentiometer. It was one of my works, but it was pretty old and I am also designing a newer version with a better controller, buck and onboard power monitoring circuit. Most of the time I am away from my loved stuff, My LAB! Sometimes I need different voltages to work on, because I carry my electronics in a box with me, the projects I am working on. It gave me little happiness in this world of full randomness. Now because I can not carry the big bulky adapter with me having different voltages and all, that’s why I purchased a 65W one, which has USB C and it can power all my accessories from earbuds to macbook.

My adapter supports a lot of changing protocols and one of them is USB-C Power Delivery (PD). Though it is capable of delivering 9 V, 12 V, 15 V, and 20 V at high power levels. And my idea is to make a simple PD interfacing device as small as possible so that it can be inserted into small housings. USB PD supports 100W but according to the design of PCB and power integrity I am still able to utilize the 40-45W from my adapter keeping the size of PCB in mind.

USB-C PD Idea:

I have been working with SMPS, more than 4 years but they lack portability very much and need wires to carry. One major drawback is they only deliver one voltage. But my concern here is to develop a device which can be configured to deliver a specific voltage from the PD. If I am working on say 5V project I can configure it to that voltage and carry with me, if 9, 12, 15 or so then also.

CH224K:

The CH224K is a USB-C PD fast-charging protocol receiver chip. It is designed to request higher voltages from a PD adapter without using a microcontroller.

Features:

• Supports USB PD 3.0 (up to 100 W)
• Supports 5 V / 9 V / 12 V / 15 V / 20 V
• Simple resistor (pull-up/down
• Built-in internal regulator and protection features
• Require minimum external components

The CH224K handles the entire PD handshake, allowing the board to behave like a smart power jack. JUST plug in a USB-C PD adapter, and the required voltage appears at the output.

Components Required:

• CH224K PD IC
• USB type C
• 100nf, 1uf, 10uf ceramic 0603 capacitors
• 1K, 10K 0603 resistors
• LED indicator
• PCB for CH224K
• Multimeter for voltage setting

Circuit Diagram:

The CH224K allows voltage selection using configuration pins (CFG1/CFG2/CFG3) or resistors. For a minimal design, Voltage is fixed at PCB level. So no frequent switching is required between the voltage hence I made a circuit according to that. The configuration resistors are put on the bottom layer in the PCB so they are easily accessible and we can change the voltage. According to the datasheet, CH224K supports requesting up to 20 V using simple pin configurations, without requiring I²C or dynamic control.

• USB-C CC pins connected directly to CH224K
• Configuration pins strapped for desired voltage
• Local decoupling and output decoupling capacitors are mandatory

There are no high-frequency components, making the design electrically quiet and easy to debug.

PCB Design:

It is not easy to design the PCB for 100W of power in such a low form factor and I am not focusing on that right now. Because I made this board to power small projects and referencing the voltage hence no certain standard is followed but the traces are maximized to carry the highest power. Since the chip negotiates voltages up to 20 V. I have routed the main traces first and then less priority ones. The final PCB is extremely small, making it suitable for embedded use inside enclosures where traditional adapters simply don’t fit.

At the time of assembly, as I have followed the hand soldering method, it is not easy to put the components like USB type C hence soldered first. It is better to solder smaller pitch components on the first go. Download the Gerber, BOM and...