Power supply considerations for Jetson Nano Developer Kit

This came in the mail today, delivered a full week early. So far it’s working perfectly.

https://www.amazon.com/SMAKN-Switching-Supply-Adapter-100-240/dp/B01N4HYWAM/ref=sr_1_3?m=A2OCOGC9B25845&marketplaceID=ATVPDKIKX0DER&qid=1555629873&s=merchant-items&sr=1-3

Along with the label for J48 missing, what is the orientation/pin ordering for J40?

There are eight pins, and designed to be jumpered across in pairs, but the doc doesn’t indicate, nor does the board AFAICT, whether pin1, pin2 are at the North or South in the board diagram in Jetson_Nano_Developer_Kit_User_Guide.pdf

• Pins 7 and 8 disable auto power-on.
• Pins 1 and 2 initiate power-on if auto power-on is disabled.
• Pins 5 and 6 reset the system.
• Pins 3 and 4 put the developer kit into Force Recovery Mode if they are
connected when it is powered on.

I tried to jumper pin3/pin4 (assuming pin1/pin2 is northernmost in layout) with barrel connector PSU for the Force Recovery mode, and the board’s power light does not come on. And it is not seen by Host USB, though I would expect the Jetson Nano to be in recovery mode. And when I remove the jumper, Jetson Nano Dev Kit boots normally (it does not enter in/do recovery mode)

When I use SDKManager in “Automatic” mode (without any jumper on J40 bridged), it works to flash the µSD.

They’re labeled on the underside of the board too.

Are you referring to J40?
Is pin1/pin2 at the northernmost or southernmost orientation in the user guide figure??? (figure also above in this thread)

My board is currently screwed into a JetBot chassis, so I cannot see the silkscreen on the underside.

Hi idcrook, pin #1 is at the southeast corner of J40 header, with the board oriented as it is in the user guide and this figure.

There is a little silkscreened arrow printed on the top of the board pointing to pin #1.

Thanks! Now I see the index arrow on the topside silkscreen after you pointed it out.

A couple suggestions for improvements then :)

  1. Place markers for indexed 1 pin for both J40 and J41 in the said figure. There's already mention of adding missing label for J48
  2. Make a note that the stand-alone J40 diagram orientation in the User Guide and it relation to other diagram (it's essentially upside down with respect to board diagram) I would include a screencap of this figure if I could figure out how to easily upload one to this forum

Thanks for your feedback, I’ll check with the document author about adding these things. I do know that we’ve already corrected the missing label for J48 in the pending release of the next version of the doc.

Yeah, the actual pinout is in the doc on the next page. But that got me for a bit too.

After some readings about it. I’d like to ask another question (possibly silly):

5V Regulators often shows 0-4a, 0-5A, 0-8A and so on. Is there any kind of danger if I use a regulator of 5V 0-8A with a 14.8V 4000mAh LiPo straight to barrel jack? As a layman on electrical stuff, I’m concerned if it’s possible Nano to draw more than 4a (since regulator can provide up to 8a) or the regulator itself to send more than 4a to the board, both cases resulting damages. I believe it’s a basic electrical doubt here.

A device will draw as much amperage as it requires, so a power-supply meets its needs must be used. The regulator will not push more power than what is needed by the device. I used a 5V 10A power-supply with no issues and a happy board. Currently using a 5v 4A supply which works perfectly.

LEICKE 5V 4A PSU seems to be working nicely. Enough reserves to drive some USB connected stuff like KB/Mouse/SSD, no heat. https://www.amazon.de/Leicke-Netzteil-Ladegerät-Externe-Laufwerke/dp/B01HRR9GY4

Does Jetson Nano in micro-usb at 5W mode peak anywhere between 1.5A to 2A during boot? I’m using a USB tester to check current and while my smartphone reaches 5.23V ~ 1.84A charging, when I plug it into my Nano, it keeps 5V varying from 4.99V to 5.1V and seems to power off when trying to draw something over 1A. Is there some kind of setting I can check?

Also, I noticed when I replace a small cable with a longer cable in smartphone tests, the maximum reached is 5.2V ~ 1.49A to 1.52A. I read somewhere about cable length and its impact on supplying.

This sounds more like communication between charger and target. I would not try to use this as a PSU. I have used an Anker 5V 3A dual charger for the first days with the Nano, using one of the 5V sockets with no issues. It also has a smart charging socket with varying output. To work properly, there would be some kind of protocol between charger and target. I paid extra attention not to use this one. For reference: https://www.anker.com/deals/poweriq The problem is, you can’t see what is what on a charger that is supplied with another device.

I have a original TX2 power supply with 12V and 5A. While I put the TX2 power supply into the Nano Power Jack, the LED light has no reponse. While I put the microUSB-USB from the Nano the Ubuntu host machine, the LED light can normally work.
I know the Jetson Nano use 5V/2A power supply, Can I need to purchase such a power supply for the Jetson Nano?

There is a jumper (J48) that needs to be set to use the barrel jack PSU. The MicroUSB socket is then disabled.

Photo of J48

Original TX2 power supply is 19V 4.74a. Even if it was 12V,don’t use it with jetson Nano AT ALL. It will fry your board!!
If you set your J48 jumper and plug TX2 power supply on it, you probably should lose your board.

Good catch. That’s a problem with all these power supplies out there witch the same barrel jack.

I’ve read that an Adafruit 5.25 volt power supply is recommended. What are the maximum voltages allowed for the barrel and microUSB connectors?

I have ordered a couple of 5.25 volt, 2.4 Amp power supplies from eBay that say they are specifically designed for the Raspberry Pi. They are $3.99 plus $1.49 shipping. I ordered 5 supplies and the shipping was only $3.85. So a total of $4.76 each, delivered.

https://www.ebay.com/itm/5-25V-2-4A-Micro-USB-Switching-AC-Power-Supply-Adapter-Charger-for-Raspberry-Pi/253843567493?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

5.3V is the maximum recommended voltage for the MicroUSB connector. The DC barrel jack has over-voltage protection, so it will disconnect to protect the device if it’s over a nominal 5V.

The DC barrel jack has over-voltage protection, so it shouldn’t fry your Nano, but yes this is not recommended to try. It should just disable itself and not power up in this case, until you plug in a 5V supply again.

Another Working fine Power supply Microusb is the charger of some mobiles of samsung 5V and 2A (i.e S6, S6 Edge, S7, S7 Edge and Note 4) holding without problems.