Hello, Nvidia.
We are using several Orin NX 16 modules purchased at different times together with our custom carrier boards.
For power control, we use the LTC2955 controller.
When power is shut down at the module’s request, the Shutdown_req signal goes to the Kill input of the LTC2955, which then disables Power_en.
We have found an issue:
On some modules (photo 4), the duration of the Shutdown_req pulse is normal square form about 10 µs to 0V, and the controller triggers correctly, shutting down the Jetson.
On other modules (photo 1), the duration of the Shutdown_req pulse abnormal form is less than 1 µs only to 5v and the controller does not trigger, so the Jetson is not shut down.
Also we tested Shutdown_req with software “poweroff” on original carrierboard - have a same problem, so we think that the promblem with Shutdown_req pulse is on some versions of modules.
Photos of the modules, waveforms, and schematic are attached.
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Based on the provided context, I’ll attempt to provide a comprehensive answer to the question.
The issue described involves the varying pulse durations of the SHUTDOWN_REQ* signal, which affects the shutdown behavior of the Jetson Orin NX modules. The signal is sent to the LTC2955 controller, which disables power to the module upon receiving the signal.
The context mentions that the NVIDIA carrier board reference design implements a power button supervisor using the EFM8SB10F2G-A-QFN20 MCU. This supervisor is responsible for intercepting push-button switches and controlling ON/Enable signals to the module Power Sequencer or PMIC and main processor.
Comparing the provided photos and waveforms, it appears that the modules with shorter pulse durations (less than 1 s) are not triggering the LTC2955 controller correctly, resulting in the Jetson not shutting down properly.
The reason for the different signal pulse durations is not explicitly stated in the provided context. However, it’s possible that the issue is related to the power button supervisor’s behavior or the specific implementation of the power control circuitry on the custom carrier boards.
To increase the duration of the SHUTDOWN_REQ* signal pulse, you may consider the following options:
Check the power button supervisor’s configuration: Verify that the power button supervisor is configured correctly, and its timing requirements are met. Refer to the NVIDIA carrier board reference design and the EFM8SB10F2G-A-QFN20 MCU documentation for more information.
Adjust the discharge circuits: As mentioned in the context, if the carrier board 3.3V or 1.8V supplies are not low in the specified times, discharge may be required. Check the discharge circuits and adjust them to meet the timing requirements.
Modify the LTC2955 controller’s configuration: Investigate if the LTC2955 controller’s configuration can be adjusted to accommodate the varying pulse durations. Consult the LTC2955 documentation for more information.
Implement a pulse stretcher circuit: Consider adding a pulse stretcher circuit to the power control circuitry to ensure a minimum pulse duration is maintained. This can be a simple RC circuit or a more complex solution using a dedicated IC.
To further troubleshoot the issue, it’s recommended to:
Verify the power button supervisor’s behavior and timing requirements.
Check the custom carrier board’s power control circuitry for any differences or issues.
Consult the NVIDIA documentation and support resources for more information on the power button supervisor and power control circuitry.
Consider seeking assistance from NVIDIA support or a qualified engineer to help resolve the issue.
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LLM, thank you for your answer)
We tried your recommendation and read documentation, but cant find answers…
We think that the problem is with some versions of modules.
