VOXL2 5v on J3 max current

[dew54]

Hi everyone,

I'm struggling with VOXL2 J3 connector,
I desgined my own add-on board that hosts a microHard module for 2.4Ghz, taking microhard-usb-carrier as example.

The thing seemed to work properly but suddenly the add-on board stopped working (while VOXL2 is still functioning).
I double checked by plugging an usb add-on and i discovered that not only an usb device is detected by VOXL, but testing with a V-meter i measured zero volt on USB port.
It seems that J23's 5V regulator on VOXL2 is dead.

Is it possible that microhard drawn too much current? Which is the maximum current limit of J23's 5V?

I'm confused because on microhard-usb-carrier, it's stated in the block diagram that you can choose between VOXL2 or external 5V powering albeit in the following section is written that 5V external power is required.

Thanks,
dew54

[Alex Kushleyev]

@dew54 , if you look at the diagram for the microhard usb carier,

There are two 5V inputs:

• VDCIN_V5 - that is provided directly from VOXL2 power input (typically from APM). So if VOXL2 itself is running, then this power rail should be OK.
• USB2_VBUS - on VOXL2, this is connected to the same VDCIN_5V rail, but it has a on/off switch, which is controllable by VOXL GPIO 157 (on by default after boot)

In the microhard carrier board, main source of power is VDCIN_5V, and VBUS is used for detection only (it seems). @Vinny can correct me if I am wrong :). The on/off switch for USB2_VBUS is rated for 2A.

The Alternate 5V DC Power Input and USB connectors are designed for use cases when the carrier board is not plugged into VOXL2. However, if the carrier board is plugged into VOXL2, you should not be connecting additional power to VOXL2 power rails.

J3 pinout : https://docs.modalai.com/voxl2-connectors/#j3-pin-out

The usb port in usb add-on (M0141) is powered by USB VBUS by default (it has a stuffing option to be powered by the main 5V supply), so if you are not seeing 5V on VBUS when using M0141 then it is possible that the on/off switch for VBUS on VOXL2 is not working.

Does your design pull main power from VDCIN_5V or USB2_VBUS?

Alex

[Vinny]

Hi @dew54 ,
Are you willing to share your schematic with us? We always perform a courtesy review of any customer design.
What Alex said is true but there are some more subtle nuances because our Microhard design pre-dates Voxl 2. Everything was designed to be backwards compatible but a custom design can certainly step on some toes of the 5V network.
Let us know if you are willing to share and we'll email you to exchange the Sch.
Thanks!