Jetson AGX Orin can i read the input voltage?

Robotics & Edge Computing Jetson Systems Jetson AGX Orin
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1

Environment:
Module: Jetson AGX Orin Industrial
JetPack version: JetPack 6.2.1 (version may can be changed , if version matters i would like to get advices)
L4T version: L4T 36.4.4
Carrier board: Customm carrier board

Hello,

We are currently developing a project using a custom carrier board based on the NVIDIA Jetson AGX Orin Industrial Module.

For power validation, we are trying to utilize the Jetson power monitoring functionality described in the following documentation:

https://docs.nvidia.com/jetson/archives/r35.3.1/DeveloperGuide/text/SD/PlatformPowerAndPerformance/JetsonOrinNanoSeriesJetsonOrinNxSeriesAndJetsonAgxOrinSeries.html?#software-based-power-consumption-modeling

Based on our understanding, the power structure is approximately:

12V input
│
├─ 5V regulator
├─ 3.3V regulator
└─ 1.8V regulator

Our current monitoring plan is:

  • 12V rail: monitor via VDD_GPU_SOC

  • 5V rail: monitor via VIN_SYS_5V0

However, we have the following questions.

1. 3.3V monitoring

Is there any software-accessible sensor to monitor the 3.3V rail through the Jetson hwmon interface?

If not, is it recommended to add an external power monitoring IC (via I2C) on the carrier board for this purpose?

2. 1.8V measurement issue

We attempted to monitor VDDQ_VDD2_1V8AO using the following method:

sudo grep -R "VDDQ_VDD2_1V8AO" /sys/class/hwmon/hwmon*/in*label
-> /sys/class/hwmon/hwmon4/in2_label:VDDQ_VDD2_1V8AO

sudo cat /sys/class/hwmon/hwmon4/in2_input
-> 5016

The returned value corresponds to approximately 5V, while the rail name suggests 1.8V.

Could you please clarify why this value appears to be ~5V instead of 1.8V?

Is there any scaling or interpretation required for this reading?

Any guidance on the correct way to monitor 3.3V and 1.8V rails during power validation would be greatly appreciated.

Thank you.

3

Hi lyj2,

You can’t cleanly get “12 V / 5 V / 3.3 V / 1.8 V” from the on‑module INA3221; only 5 V is directly visible.

  • 12 V: Not measured by INA3221. VDD_GPU_SOC is a core rail (~0.x–1.x V), not 12 V. There is no sysfs node for the external 12 V input; you need an external monitor/ADC on the carrier if you must measure it.
  • 5 V: Use VIN_SYS_5V0 (I2C 0x40, channel 3). in3_input ≈ 5000 mV is your 5 V system rail.
  • 3.3 V: No dedicated INA3221 channel for generic 3.3 V rails on the standard AGX Orin devkit.
  • 1.8 V: VDDQ_VDD2_1V8AO (I2C 0x41, channel 2) measures the 5 V bus feeding the DDR/1.8 V rails, so in2_input ≈ 5 V is expected. It does not give you the 1.8 V rail voltage itself.
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Hello KevinFFF,

Thank you for your quick response. Your explanation was very helpful.

Since this appears to be a necessary feature for our validation process, it seems that we may need to redesign the board to include an additional I²C-based power monitoring IC in order to measure these rails.

Could you please advise if there are any recommended ICs or reference designs commonly used for this purpose in jetson AGX ORIN Industrial 64 GB?

We already have basic knowledge of Device Tree configuration and related topics described in the NVIDIA Jetson Linux Developer Guide, and our current system is already running with custom Device Tree modifications. Therefore, integrating an additional I²C device into the system should be feasible for us.

Any recommendations or reference materials would be greatly appreciated.

Thank you again for your support.