Tested: Usb-Pwr PAK02A-based USB-C PD + Legacy Trigger/Decoy Board

After my recent misadventures with the WCH CH224K-based HW-443 USB-C PD Trigger Board that simply wouldn’t work properly with USB-C PD but managed to work on legacy fast-charging protocols, I was contacted by a reader with an offer of a better version that would work.

Thanks to Platima (YouTube | GitHub), I’ve been given this PAK02A-based trigger board that they also sell in their shop for a very reasonable AU$4 at the time of writing.

Unbagging

The board is packed in a sealed static shielding bag.

The PCB is purple coloured and is a bit “fatter” than I would expect. There are no terminal blocks on this unit – so either you can bring your own, or you can solder wires directly to the larger holes or use the smaller holes which can accommodate standard 2.54mm headers for breadboarding. The DIP switches are a bit smaller on this unit, surface mounted with protective polyimide tape that is still attached. To switch this, you’re best to use a toothpick or thin flat-blade jewellers’ screwdriver.

On the rear is the logic table – where a 1 is switched to “on”. It seems the 12V S1 setting got “eaten up” by the vias – a lesson for those designing PCBs to avoid silking critical details over vias.

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In terms of chips, there is a single HT7550 linear 5V voltage regulator which has a very low quiescent (~2.5uA typical) and up to 24V input. The controller is a PAK02A for which no datasheet can be found – but it seems to be a direct clone of the CH224K although I cannot guarantee there are no differences. Aside from that, a single red LED indicates the availability of power, but there is no VBUS switch, so you can expect 5V to be present on the output for a bit during negotiation.

Testing

This section focuses on the obtained results from testing with various pieces of test equipment, including the Keithley 2450 SourceMeter SMU, Fnirsi FNB58 Tester and Thermal Master P3 Thermal Camera.

Quiescent Current

The quiescent current is important to know, as this is the power lost to the trigger board itself. For portable applications, more efficient boards will mean your power bank might run for a bit longer.

In the case of this Usb-Pwr board, it seems the quiescent current is mostly stable across the voltage band, less after I modified the board to cut out the power LED. To be sure the measurements were accurate, I also measured the power consumption of the non-emarked USB-A to USB-C cable with no board attached, just in case it had internal CC resistances.

Zooming in, it seems that the quiescent current is around 4.2mA to 4.4mA with the LED as provided, reducing to about 2.5 to 2.8mA with the LED clipped out of the circuit. That’s not the lowest I’ve met – I’ve seen some pre-made barrel-jack replacement cables as low as 1mA, but it’s quite a bit less than the 6.5mA or so of the YZX Studio boards I’ve previously used.

Thermal Image

As expected, the main heat comes out of the linear regulator when run at 20V. But with such limited currents, the board only got around 8 degrees higher than ambient. Covering the board with heatshrink is unlikely to cause any issues with heat.

USB-C PD Mode

As the above images show, triggering all listed voltages of 5V, 9V, 12V, 15V and 20V is possible on power supplies that support all these PDOs (in this case, an Iniu 65W 25000mAh power bank). If you attach it to a power supply that does not support the 12V PDO (as that’s not “standard”), then it seems to choose 15V instead (so beware, for equipment that might not be 15V tolerant). Depending on the ratings of your USB-C PD source, in theory, 100W could be available (20V/5A) from standard adapters assuming you use an eMarked cable or 60W (20V/3A) otherwise.

Another interesting benefit is that if you change the DIP switches in real-time, the input voltage is renegotiated immediately. So if you’re only using it for one voltage, you might consider securing the DIP switches in some way to avoid accidents (e.g. a blob of hot glue, or covering the whole board in heatshrink).

USB-A Qualcomm Quick-Charge (QC)

Another benefit over pure USB-C PD trigger boards like the YZX Studio boards I’ve previously used is that they support some legacy fast-charging protocols. In this case, I tested Qualcomm Quick Charge protocol by using a USB-A connection and USB-A to USB-C cable. The board successfully negotiated 9V and 12V. Few QC sources support the higher voltages of 20V which are allowed by the QC standard. But do note that the currents available are more limited from most QC chargers – at 12V, a maximum of 1.5A is common; at 9V, 2A. Due to standards similarity, it should also interoperate with Samsung AFC.

Negotiation of legacy modes seems to take place after PD modes are attempted, so there is a noticeable delay from insertion to voltage changing, around one second seems typical.

Conclusion

It seems the other CH224K-based board took one shortcut too far with regards to powering the chip resulting in USB-C PD instability. This board, I’m glad to report, has no such issue and reliably negotiates both USB-C PD and Qualcomm Quick Charge in my testing. It’s got a decent quiescent current especially when the LED is removed from the board and can renegotiate voltage if the DIP switches are changed during operation. Like many low-cost boards, it doesn’t have a Vbus switch, so you’ll get a short flash of 5V on the output before the higher voltage is requested, but this is often not a major issue.

Perhaps the only hurdle for some is the slightly chunky footprint and the need to solder, as there’s no terminal blocks on this. For me, that’s no major issue as I like making solid soldered connections and I’ve got large heatshrink thanks to working on Li-Ion batteries, but it’s definitely something to consider.

If you’d like some of your own, you can get some at Platima Tinkers Shop or you can find them at various online marketplaces. Thanks to Platima (YouTube | GitHub) for sending these through for review.