UCD90320U: analog power monitor more than 32 rails

Hello

if you need 32 analog rail, you may consider to add a UCD9090A along with UCD90320U together.

Regards

Yihe

 UCD9002U ??? 

If 2 UCD devices are cascaded and power rails in device 2 is dependent with first device is it possible to use DMON and corresponding EN signals where  the EN signals will be used as GPI dependent in second UCD device and DMON are triggered by LGPO which are controlled by individual power good ?

For the above scenario how latency (response time) within the cascaded devices?

Hi

We have a application notes about the cascading multiple devices. You can read here http://www.ti.com/lit/pdf/slva902

There are many way to cascade and you can select one to best fit you. It is not good to use EN as GPI for the 2nd device if the rail controlled by EN does not work. I am not sure what DMON is doing here?

The latency vary based on what approach. what is your accepted latency?

Regards

Yihe .

I will try to clarify my design so that you can help me better.We might want to change the power sequencing order at various debug stages.So all of our rails should be independently sequenceable.So what I was thinking of doing is as FOLLOWS.

Lets say I have 30 voltage Rails,So i can monitor 24 rails in one UCD (Master UCD) and rest in the second UCD (Slave UCD).

1. When I want to enable a voltage rail in slave UCD , I will use an enable pin of master UCD and make the said voltage rail GPI dependent on this EN signal .

2.Then the slave will monitor corresponding rail and through a LGPO (logical GPO) it will generate a power good signal.

3.This power good signal will be connected to the  DMON pin  corresponding  to the EN pin in 1 .

Is this technically workable? 

Hello

Does http://www.ti.com/lit/pdf/slva902 help you?

1. you have the enable pin of master connected to one of the GPI pin of slave. is the enable pin from master a ENABLE for a rail under master, or it is  just a signal from master.

how do you turn off the rails on the slave side?

2. the master will output a LGPO(PG) and this LGPO is connected to DMON of slave.

What does DMON do? does it monitor the power good from master to turn off rails of slave?

if so, you only need LGPO on the DMON and set this DMON as turn on dependencies for the rails on the slave side and also enable the UV fault response on the DMON. so when the LGPO is asserted, slave will turn on the rails and when LGPO is de-asserted, slave will turn off rails due to faults.

Regards

Yihe

1.No ,enable pin from the master is just to GPI pin of the slave where it used as GPI dependency 

http://www.ti.com/lit/ds/symlink/ucd90320u.pdf    page number 22. In slave the GPI pin will be configured in both turn on and turn off dependencies for corresponding rail.

2. The master isn't the one who outputs a LGPO (PG) ,it is the slave. The slave will monitor its rail and through LGPO it will provide power good signal. This will be monitored by master through master's DMON pin.