What is Power Domain in UPF?

Power Domain is common term used in UPF language. Power Domain is abstract way to include the instances/block . Instances/block that shares the same supply should be included in one power domain.  At the end all design instances should be part of any Power domain . Also one instance can not be part of more than one power Domain. If user has not included any instance in any Power Domain using create_power_domain command then it will be a part of it's ancestor's Power Domain.

Defining Power Domain is necessary to implement all Low Power checks.

Let us consider below example .

In My Soc I have three block.i.e Block1 , Block2, Block3 .

Now in order to do low power checks on this Soc , Based on the architectural level details i.e which block can work on what voltage and when any block can be shutoff , User needs to create power domains as a starting point in UPF.

Let us say as per spec Block1 and Block2 will always operate on same voltage then I can place them in 1 power Domain .And As Block 3 can operate on different voltage and can be shutoff independently I will put in other domain.

And TOP block where all of this block will be instantiated will be placed in 1 domain.

This can be coded in UPF as below.

UPF code:

create_power_domain TOP -elements {.}
create_power_domain PD1 -elements {Block1 Block2}
create_power_domain PD2 -elements {Block3}


This way you can partition your design instances in separate power domain based on the power specification .