We have designed the Jetson Nano into an end product.
We are using Nvidia part 900-13448-0020-000.
We have connected a Panasonic BR1255A battery to Nano pin 235 PMIC_BBAT via a Nexperia RB751S40 diode as per reference design.
Problem is that UL will not approve, they say that the diode is sufficient to stop current flowing back to battery, but they want a resistor in-line to limit the current flowing into the Nano in case of short circuit within the Nano.
Jetson Nano RTC backup battery internal protection is similar and Trumany explains that protection is not necessary but says that Nvidia can not give out details as PMIC is 3rd party.
How can we assure UL that the battery circuit is safe?
Hello,
Welcome to the Nvidia forums. I am moving this topic to the Jetson category for visibility.
This was a problem for us too. Luckily we got feedback early enough that we could design in a series resistor with a diode. Unfortunately NVIDIA was unable to provide anything beyond assuring that the battery is safe in these forums. It would be really great for them to formally certify that protection is unnecessary so we do not have to add redundant hardware to appease UL.
Hi, the charging is monitored by PMIC. The backup battery charger is a constant voltage (CV) and constant current (CC) style charger with a series output resistance as shown in below, the maximum current is 800uA.
Hi Trumany,
Yes, I understand the explanation, but how are your customers going to prove to UL to their satisfaction that the Nvidia recommended circuit with only a diode is safe to UL standards?
BR, Trev
Jetson nano devkit has passed some certs as listed in package: https://developer.nvidia.com/jetson-nano-devkit-p3450-regulatory-and-compliance-documents
Is the P3450_UL_Cert.pdf in package what you asked for?
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