The QMX-PowerplAy is designed to power the QRP Labs QMX as well as the 50W PA off a USB PD Powerbank.
Designed for ultimate portability for SOTA / POTA activations, the board can negotiate 15V or 20V with 3A or 5A for the PA.
A 12V, 5A switching regulator powers the QMX. Power Negotiation can be selected with simple Jumpers.
The main component is the AP33771C which takes care of USB PD negotiations.
Output Voltage and Current can be set through Jumpers JP1 and JP2.
The Barrel Jack J2 (5.5mm) directly connects to the negotiated power from USB.
J3 (5.5mm) is connected to the stepped-down 12V for supplying the QMX
PCBs can be ordered with the gerbers in fabrication.
The Component BOM [powerplay/bom/ibom.html] lists all neccessary components for soldering.
Be aware of Capacitor Voltage ratings (>= 20V) for capacitors connected to USB power.
The case is entirely 3D printable and files can be accessed in the Case folder.
The 12V output is labled QMX and the USB power (15V or 20V) is labled PA.
No Substantial Load should be attached to the barrel jacks when powering up.
The QMX and PA can be connected during power-up.
Successfull power negotiation is indicated by LED 2 (D2) breathing.
LED 1 (D1) indicates if power is present at all.
In case of failiure to negotiate the requested power level either the highest possible negotiated power is present (e.g. 20V, 3A even though 100W werer requested) or only 5V are present on the PA port.
The step-down (12V output) only works if the USB voltage is > 12V.
Jumpers JP1 and JP2 can be used to change the negotiated power according to the capabilities of the used supply.
The Power select Jumpers are NOT hot-swappable. Change them only when the device is unconnected.
This board has been developed specifically for SOTA and POTA purposes by Pol (HB9IKL) and Lennart (HB9IKK).
This work is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License. (http://creativecommons.org/licenses/by-sa/3.0/)