Difference between Controlled and Uncontrolled power down sequence of Jetson-TX2
I am developing my custom carrier board to integrate Jetson-TX2 module on it. The system will work as a camera frame grabber. I am powering up my Camera from the same carrier board through Power Over Camera Link (POCL). Camera and every IC other than Jetson-TX2 is getting powered ON only after Jetson-TX2 is powered up and CARRIER_PWR_ON is asserted. But I cannot differentiate between the Controlled and Uncontrolled Power Down Cases mentioned in Page-12 of 'Jetson TX2 OEM Product Design Guide'. How the controlled power down sequence will start? In Jetson TX2 Module Datasheet, it is mentioned only about Controlled Power Down Sequence that [b]"On receiving a Shutdown request the Jetson TX2 will assert the RESET_OUT# signal, allowing the carrier board to put any components into a known state."[/b] What kind of shut-down request Jetson-TX2 will receive to start controlled power-down sequence? It is obvious that uncontrolled power down sequence starts when VDD_IN begins to ramp down. But what will be the status of VDD_IN in case of Controlled power-down sequence and when can VDD_IN start ramping down? It is not clear in the controlled power down sequencing diagrams given in both the datasheets. Can somebody please help me clearing my confusion?
I am developing my custom carrier board to integrate Jetson-TX2 module on it. The system will work as a camera frame grabber. I am powering up my Camera from the same carrier board through Power Over Camera Link (POCL). Camera and every IC other than Jetson-TX2 is getting powered ON only after Jetson-TX2 is powered up and CARRIER_PWR_ON is asserted.

But I cannot differentiate between the Controlled and Uncontrolled Power Down Cases mentioned in Page-12 of 'Jetson TX2 OEM Product Design Guide'. How the controlled power down sequence will start? In Jetson TX2 Module Datasheet, it is mentioned only about Controlled Power Down Sequence that "On receiving a Shutdown request the Jetson TX2 will assert the RESET_OUT# signal, allowing the carrier board to put any
components into a known state."
What kind of shut-down request Jetson-TX2 will receive to start controlled power-down sequence?

It is obvious that uncontrolled power down sequence starts when VDD_IN begins to ramp down. But what will be the status of VDD_IN in case of Controlled power-down sequence and when can VDD_IN start ramping down? It is not clear in the controlled power down sequencing diagrams given in both the datasheets.

Can somebody please help me clearing my confusion?

#1
Posted 12/07/2017 10:00 AM   
Hi mehjabin, To activate RESET_OUT# will trigger controlled power down, that could be pressing RESET button or some SW controlled pulling RESET_OUT# pin to low. The uncontrolled power down sequence is triggered by VDD_IN removal, removal of the VDD_IN/VDD_MUX supply causes IN_PWR_BAD# to go active which causes Jetson TX2 to initiate a controlled shut down.
Hi mehjabin,

To activate RESET_OUT# will trigger controlled power down, that could be pressing RESET button or some SW controlled pulling RESET_OUT# pin to low.

The uncontrolled power down sequence is triggered by VDD_IN removal, removal of the VDD_IN/VDD_MUX supply causes IN_PWR_BAD# to go active which causes Jetson TX2 to initiate a controlled shut down.

#2
Posted 12/08/2017 02:24 AM   
Thank you for the reply Trumany. Can you please elaborate on the last sentence "The [b]uncontrolled[/b] power down sequence is triggered by VDD_IN removal, removal of the VDD_IN/VDD_MUX supply causes IN_PWR_BAD# to go active which causes Jetson TX2 to initiate a [b]controlled[/b] shut down." How uncontrolled power removal initiates controlled shut-down in Jetson-TX2? PMIC on the module takes 20ms to shut-down in case of controlled power down or uncontrolled power removal? I have one more doubt. CARRIER_PWR_ON is given as open drain signal and from your reply on another post on the forum I got to know that a pull-up is present on the module. But this will make the signal active low though it's given as active-high output from Jetson-TX2 on the datasheets.
Thank you for the reply Trumany.

Can you please elaborate on the last sentence "The uncontrolled power down sequence is triggered by VDD_IN removal, removal of the VDD_IN/VDD_MUX supply causes IN_PWR_BAD# to go active which causes Jetson TX2 to initiate a controlled shut down."

How uncontrolled power removal initiates controlled shut-down in Jetson-TX2?

PMIC on the module takes 20ms to shut-down in case of controlled power down or uncontrolled power removal?

I have one more doubt. CARRIER_PWR_ON is given as open drain signal and from your reply on another post on the forum I got to know that a pull-up is present on the module. But this will make the signal active low though it's given as active-high output from Jetson-TX2 on the datasheets.

#3
Posted 12/09/2017 04:47 AM   
Hi, mehjabin, 1. About VDD_IN removal, please refer to figure 6 of OEM DG 2. The controlled shut down takes ~20ms to complete so the internal PMIC supply needs to stay above ~2.9v for >~20ms. 3. CARRIER_PWR_ON is active high, the pull up voltage can only be enabled when module power active, please refer to related info in table 5
Hi, mehjabin,

1. About VDD_IN removal, please refer to figure 6 of OEM DG

2. The controlled shut down takes ~20ms to complete so the internal PMIC supply needs to stay above ~2.9v for >~20ms.

3. CARRIER_PWR_ON is active high, the pull up voltage can only be enabled when module power active, please refer to related info in table 5

#4
Posted 2 hours ago   
[quote]the internal PMIC supply needs to stay above ~2.9v for >~20ms[/quote] At what current draw? If it's for the entire module at the maximum load, 15W at 5V is 3A, and 3A with 2V voltage drop over 20 ms requires 30,000 uF of low-ESR capacitance. What happens if it doesn't?
the internal PMIC supply needs to stay above ~2.9v for >~20ms


At what current draw? If it's for the entire module at the maximum load, 15W at 5V is 3A, and 3A with 2V voltage drop over 20 ms requires 30,000 uF of low-ESR capacitance.

What happens if it doesn't?

#5
Posted 14 minutes ago   
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