I am a little big confused by the function header labels:
1 - 3V3
2 - EN
3 - GND
4 - 5V
3 - GND
5 - BAT
3 - GND
6 - USB
Am I correct in understanding that:
3V3 is the 3.3V at 250mA output?
5V is 5.0V at 2.4A output?
(I know that GND is Ground)
I could not understand from the documents what the EN, BAT and USB pins are for.
This is, again for a model train set-up. The plan is to attach a suitable LiPo battery and a 12-volt step up board to power a WiFi DCC controller and DCC chip. The DCC Sound chips are usually rated at 1amp or 2amp continous, but in reality mine generally do not draw more than 300-400mA at 12 volts.
The attraction for using this style of board is to make it possible to use a USB-C charger to recharge the battery packs in model locomotives rather than have to disassemble the model to get the batteries out for charging.
If my reading of the schematic is correct:
EN is a logic level control to enable/disable the 5V power output (the same control as the switch).
BAT is the battery voltage - likely provided for a voltage display, or other measurement reporting.
USB is the voltage at the USB “C” connector (clamped to 5V), perhaps for an external undervoltage protection circuit.
Note that the ‘5v’ pin would probably not be suitable for 2.4A - the PCB traces are likely to be too thin. The 5V load should be through the USB connector.
There is a fuse between VUSB and the positive of the “C” connector.
You could, but it would be easier to use the existing socket. The maximum current you could safely draw at the pin header would depend on the construction of the PCB, and is probably not part of the specs. 2.4A would likely be within the rating of the pin header, but that would depend very much on the female connector used.
Hi Martin
What sort of battery do you have in mind.
2.4A @ 5V equates to 3.24A @ 3.7V. If you factor conversion efficiency which could be 85% then at this figure the required current @ 3.7V would be something like 3.82A.
I think if you are contemplating a usual 18650 (one) cell it would be really struggling. You would need several in parallel I think.
Cheers Bob
If I understand you correctly, I wire an SPST switch from the EN to the +5V with a 10K Resistor and this gives an on-off switch that I could wire remotely from the board. The application here is that I can wire up a power pack inside a model locomotive or wagon and have an SPST switch somewhere accessible so I can switch it off without having to take off the body shell.
Would this Digital LED Volt Meter be appropriate? If I understand correctly, red wire to the BAT and black wire to GND?
I was hoping to find an appropriate battery pack with larger capacity, or perhaps something connected to a 2x 18650 holder or even a larger capacity pack like this:
There are also some higher-capacity or high-draw 18650 batteries made by Samsung that I would consider using in an appropriate battery holder.
The only bit of the specification that matters is that “Range: 2.5VDC — 30VDC” includes 5V with a bit of room either side. Otherwise it’s just a matter of what best suits the purpose.
Hi Martin
If you multiply my above numbers by 0.625 you will have the new numbers for a current of 1.5A @ 5V from a 3.7V cell. Still 2.39A. Still a bit border line for a single cell I reckon.
Cheers Bob
