UCD90320U: Power Off sequence not respected when UV FAULT

Daniel Waleniak

Part Number: UCD90320U

Tool/software:

Dear TI Team,

I would like to report the following issue:

Issue: Soft OFF Sequence is not respected in case of UnderVoltage Fault happening on some of the Rails, but Soft OFF Sequence is respected in case of OverVoltage Fault.

I have created a project to show the issue :

3 Rails are Powered on with PSRS pin GPIO 0 : All ON / All OFF with Soft OFF
Rails are Powered ON one after another and power OFF in the reverse order
An LGPO is connected to the PSRS GPIO 0 pin to apply a POWER OFF / ON cycle in case of UV and OV FAULT happening.

In this situation the Power sequence ON and OFF must be applied the same way for all rails when there is a UV or an OV on any rails.

But it’s not the case.

For Rail 2 and 3, the sequences are respected in case of OV, but not in UV.

For Rail 1, the sequences are respected in both OV and UV.

Is there an explanation ?

Thank you,

Daniel Waleniak

22 days ago

0 yihe 22 days ago

TI__Guru 66250 points

Please share your configuration file and hardware sch

Regards

Yihe

0 Julien JOLY 20 days ago in reply to yihe

Prodigy 20 points

Hi,

I am at the origin of this ticket.

Here is the config file in XML.

Here is a diagram of my schematic.

It is straightforward. I am using the UCD90320U dev kit form TI that I interface with DAC to simulate power supplies and IO Expanders to interface GPIO, and I control these with an Arduino.

UCD90320U 3.0.0.3321 Address 17 Project File.xml

0 yihe 20 days ago in reply to Julien JOLY

TI__Guru 66250 points

1. Please specify the connection between LGPO and GPIs

2. please capture the voltage on all rails if the off sequence does not match. The off dependencies is for the voltage only. Once the rail is below POWER_GOOD_OFF threshold, It is considered as OFF to meet dependency

Regards

Yihe

Power management

Power management forum

UCD90320U: Power Off sequence not respected when UV FAULT