Auto power-on implementation based on OEM Product Design Guide

Hi,

Glad to be here and keep using Nvidia products.

I am currently working on an IC circuit as shown in OEM Product Design Guide Page 16 (Option 2 supervisor IC) to enable the auto power-on function.
I find out that the CHARGER_PRSNT# is connected to port J27 from some previous TX1 posts. However, I still cannot locate the VIN_PWR_BAD# on the devkit board. Anyone knows about that?

Thanks in advance,

There is schematic of carrier board in download center. Pin B8 of main connector J13 is the VIN_PWR_BAD_L, do you mean this?

Should be.
Thanks, Trumany!

Hi Ray,

Jetson TX2 includes circuitry on the module to support Auto-Power-On. This allows the platform to power on when VDD_IN is
first powered, instead of waiting for a power button press. In order to enable this feature, the CHARGER_PRSNT# pin should
be tied to GND (which can be done by installing a 0ohm resistor at R313 near the Charge Control receptacle).

So there are four options to meet this requirement and allow Auto-Power-On are described:

▪ Built-in Auto-Power-On circuit: Not available on Jetson TX1.
▪ Microcontroller: Recommended if a microcontroller is already being used to control power-on.
▪ Supervisor IC: Using a supervisor IC and related discrete devices to meet the sequencing requirements.
▪ Discrete Circuit: Circuit using only discrete devices to meet the sequencing requirements.

These info will be included in latest OEM DG in download center.

Hi Trumany,

This seems like a much easier solution. My TX2 will arrive next Monday and I will definitely try this built-in circuit first. I haven’t got my unit yet so I have a question. Do I need to replace the original R313 with an O ohm resistor or there is nothing soldered in that spot?

Thanks again! Support from Nvidia is so awesome!
Ray

Nothing soldered, only need to put an 0 ohm resister there.

Hi Trumany,

My TX2 just arrived today. Could you help me locate the R313?
Some crops from the official guide are as follows and there are two candidate spots near J27 but I couldn’t figure out which one is for R313.
https://www.dropbox.com/s/d7req8xl6cklccl/J27.PNG?dl=0
https://www.dropbox.com/s/1rdurwyvonn5lge/J27_2.PNG?dl=0
Also, what is the size of that resistor? I feel it is 0402 in imperial code.

Thanks a lot!

The down-most one in your picture is R313. It is 0402 as schematic says.

Thanks!

Hi, I’m looking at the schematic for R313 but I can’t tell which resistor is R313 on the TX2 board layout. I see two NS (No Stuff?) resistor spots starting at the arrow for the ‘J27’ writing on the board. The upper resistor spot is aligned with part of the arrow just above the ‘J27’ writing and the lower resistor spot is aligned with ‘J’ in the ‘J27’ writing. Which one of these spots is R313? Is the other spot R271?

The one aligned with ‘J’ is R313, another one is R271.

Could you provide a picture or otherwise clearly identify where R313 is located? On my TX2 board I don’t see any notation that shows where it is. I also can’t find mention of this in any of the official documentation.
Thanks.

Please find the chars of ‘J27’ on carrier board first.

Thanks. Works like a charm.

Thank you so much for posting the picture. I was also looking for auto power on.

I could not open CAD files as don’t have that softwares.

Which part/device location you want to get?

I don’t have the facility to solder directly onto the board, but it looks from the schematic for CVM 1.0 on Page 4 of P2597_B04_Concept_schematics.pdf that CHARGER_PRSNT is labelled ACOK and therefore actually connects to J27 marked on the diagram of CHARGER CONTROL HDR on Page 16.

According to that circuit diagram, Pin 1 of the header is connected to J27 and pins 11 and 12 are connected to ground (although a different ground to the one R313 connects to).

The actual charger control header is a 0.8mm pitch IDC part number 50208-01001-001. If I can find a suitable plug to plug into the header, would wiring Pin 1 directly to Pin 12 have the same affect as soldering across R313?

Many thanks in advance for any help.

Sure, that’s same as shorting R313.

Looking at the board, which side of j27 is pin 1 and which pin 10? There is a text “Charge Control” on the right side of j27. Is pin 1 the first one to the text or the last one?

Also, if I manage to find that connector to buy, I would short pin 1 with the ground (can I use GND pin on J21?) with 4.7kOhm resistor, and that would allow to auto start?

Yes, also the white triangle mark is to the pin 1.