Quick Charge - Hack¶
Get (almost) any voltage with QC - (3.6V - 20V)¶
See original QC project documentation by Nicolas Decoster¶
“The QuickCharge protocol lets you “negotiate” voltage through USB on smart power supplies.” Read Nicolas’ detailed documentation to learn more about the project.
QC-Hack Original board¶
QC Hack - Redesign¶
As an excercize in KiCad I decided to redesign the QC hack board by Nicolas. I wanted to route everything instead of using fill. I also needed to make adjustments since my lab did not have the correct size Screw terminal. The original board had 5mm pitch Screw Terminal but we only had 3.5mm Terminal. I also made a small change for the UPDI programming pin.
QC-Hack Redesigned board¶
The idea is simple, use a QuickCharge USB-A charger to power your circuit and either in code or using a potentiometer you can change the output voltage to be anywhere from 3.6V to 20V. This is useful for projects that require more than 5V.
Be careful when picking a charger. Make sure it outputs up to 20V if that is what you need for your project.
Example 20V output current charger
Example 12V output current charger
KiCad project¶
The redesigned board is not all that different from Niclas’ design. The difference is in the screw terminal size and routing tracks instead of using fill. This design may be helpful if you intend to incoroporate a QC-hack in your board.
Generate Gerber files¶
To generate Gerber files from KiCad go to File - Fabrication Outputs - Gerber Files (.gbr)
Make sure to include F.Cu and Edge.Cuts layers - Select an Output directory and hit the Plot button. ALso hit the Generate Drill Files… button to get the drill hole cuts.
Generate .png milling files from Gerber files¶
Go to Gerber2Png website to generate .png files. Drag and drop all your gerber files.
Under Quick Setup select Top Trace and hit the generate PNG button to generate the PCB Trace file.
Then again under Quick Setup select Top Cut and make sure the Drill layer is visible, hit the Generate PNG button to generate the PCB Cut file with drill holes included.
For your convenience here trace and cut .png files ready for milling.
jpeg renders of milling files
Bill of Material - BOM¶
| Designator | Quantity | Value | DigiKey Link |
|---|---|---|---|
| C1 | 1 | 1µF-10µF | DigiKey |
| D1 | 1 | LED | DigiKey |
| J2 | 1 | Screw_Terminal_01x02_P3.5mm | DigiKey |
| J4 | 1 | Conn_PinHeader_1x01_P2.54mm_Horizontal_SMD | DigiKey |
| P1 | 1 | Conn_USB_A_Plug | DigiKey |
| R1 | 1 | 2.2k | DigiKey |
| R2, R5 | 2 | 10k | DigiKey |
| R3, R4 | 2 | 1k | DigiKey |
| R6 | 1 | 47k | DigiKey |
| R7 | 1 | 4.7k | DigiKey |
| RV1 | 1 | R_POT_10K_Trimmer | DigiKey |
| U1 | 1 | ATtiny412-SS | DigiKey |
| U3 | 1 | lm3480-3.3 | DigiKey |
Code¶
There are several ways to upload the code to the ATtiny 412 which I will not go into detail here.
If you know exactly what voltage you need, for example you know you need 12V for a device in your project you can set the output voltage in the code. Make sure that line 96 is not commented out and TARGET_DCV is set to 120 (12V).
This will override the potentiometer so in this case you don’t actually need to populate the board with a potentiometer as the code won’t look at it.
However, if you need a different voltage, for example if you need up to 20V you first need to make sure that line 96 is commented out and you need to make sure that line 104 uses CLASSB. CLASSB is defined on line 99 and is set to 200 (20V).
Use CLASSA if you only need up to 12V.
With these changes you can use the potentiometer to set the current to any value between 3.6V - 12V (CLASSA) - 3.6V - 20V (CLASSB). This is good for testing purposes. Once you find the voltage that suits your project it might be good to uncomment line 96 at set TARGET_DCV to a value that you know works, for example 180 if you need 18V. In that case you no longer need the potentiometer. I would recommend making a board with a potentiometer, comment out line 96 and have line 104 use CLASSB while testing. Then in your production project create a new board with no potentiometer and defining the right voltage in code.
Note
Make sure the USB charger you use actually outputs 20V if that is what you need.
In this case the USB charger only outputs up to 12V.