[FAQ] AM625 / AM623 / AM620-Q1 / AM62Ax / AM62Px / AM62D-Q1 / AM62L / AM64x / AM243x Design Recommendations / Custom board hardware design – Dynamic Voltage Scaling for SOC core (VDD_CORE), Peripheral Core and Analog supplies

Kallikuppa Sreenivasa

Guru**** 214550 points

Part Number: AM625
Other Parts Discussed in Thread: AM623, TPS65219

Tool/software:

HI TI experts,

I have a question on the SOC ROC and Dynamic Voltage scaling.

I see the Core Voltage being 0.75V or 0.85V

Does the AM6x processor families support dynamic voltage scaling

over 1 year ago

0 Kallikuppa Sreenivasa over 1 year ago

TI__Guru**** 214550 points

Hi Board designers,

Thank you for checking. This is an important query. Switching VDD_CORE after device reset has not been characterized or validated. The behavior or liability impact is unknown.

Refer below inputs for SOC ROC and dynamic voltage scaling:

Our datasheets only define fixed voltage ranges for each supply. Refer to the below section of the data sheet:

7.5 Recommended Operating Conditions
This implies that dynamic voltage scaling is not supported.

If voltage scaling was supported, we would have defined larger operating ranges and the valid operating ranges for each OPP would be defined in the Device Operating Points table similar to what was done in the AM335x datasheet.

The SOC is recommended to be held in reset condition during supply ramp. We do not support any code execution when dynamically changing from one valid core operating range to the other valid core operating range.

AM62x devices do not support dynamic voltage change of VDD_CORE after reset has been released.

AM62x devices do not support voltage scaling (switching). Scaling (switching) VDD_CORE after device reset is released has not been characterized or validated. The behavior or liability impact is unknown.

Changing the core voltage is not allowed after the device has been released from reset. If you turn off the core supply, we expect you to turn off all power rails and ramp them down per the power-down sequence and wait until they all decay below 300mv before turning on power again.

AM62x devices only support CPU frequency scaling.

PMIC use case:

AM62A does not support dynamic voltage scaling (DVS). The required VDD_CORE voltage must be pre-configured on the PMIC NVM settings by default.

References

(+) AM623: Dynamic voltage scaling (0.75V/0.85V) for Vcore? - Processors forum - Processors - TI E2E support forums

(+) AM625: AM62x + TPS6521901: Change VDD_CORE during boot to 0.85V - Processors forum - Processors - TI E2E support forums

(+) AM625: problem voltage scaling pmic TPS65219 - Processors forum - Processors - TI E2E support forums

(+) AM62A7: Changing the VDD_CORE voltage for thermal analysis - Processors forum - Processors - TI E2E support forums

(+) AM625: Change CPU frequency - Processors forum - Processors - TI E2E support forums

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa over 1 year ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 214550 points

Hi All,

Additional inputs.

Refer below FAQ related to SOC ROC.

(36) [FAQ] AM625 / AM623 / AM62A / AM62D-Q1 / AM62P / AM62L / AM64x / AM243x Design Recommendations / Custom board hardware design – SOC ROC Recommended Operating Condition - Processors forum - Processors - TI E2E support forums

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa 4 months ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 214550 points

HI Board Designers,

Inputs related to dynamic Voltage Switching

(+) AM620-Q1: VDD_CORE max. current consumption - Processors forum - Processors - TI E2E support forums

here is the answer to your questions on previous messages:

AM62 has not been validated/characterized to support Dynamic Voltage Scaling (DVS) so it is currently not supported.
We do not recommend increasing the PMIC output voltage to mitigate the IR drop in the design.
We reviewed the inputs in your PET capture. These inputs are specific to your application but having a 100% utilization on high power resources like A53, DDR, etc seem unrealistic for a typical use case.
The "Power Estimation Mode" field in the PET allows to select worst case manufacturing process corner (MAX) for the transistors leakage power.

(+) AM62A7: Changing the VDD_CORE voltage for thermal analysis - Processors forum - Processors - TI E2E support forums

The GPIO6 of the PMIC was configured to set the voltage on Buck1/2/3 with the following polarity:

High: Buck1/2/3 = 0.85V
Low: Buck1/2/3 = 0.75V

AM62A does not support dynamic voltage scaling (DVS). The required VDD_CORE voltage must be pre-configured on the PMIC NVM settings by default.

(4) AM623: VDD_core supply - Processors forum - Processors - TI E2E support forums

For Sitara Am623, just want to double confirm: If I want to run the A53 core at 1.4Ghz, is the VDD_core MUST be 0.85V?

For TPS6521901, is the Vout of BUCK1 adjustable or fixed?

All output voltages on the TPS65219 PMIC are configurable and re-programmable but the AM62 processor does not support DVS on the CORE rail so the PMIC needs to come with the correct output voltage on Buck1 by default. Is the application you are supporting using DDR4? For applications using DDR4 and 0.85V on VDD_CORE, we recommend using the TPS6521907 which is a new variant that will be added to the AM62 Apps note. The image below shows the block diagram. Please sends us an email if customer is interested on pre-production samples.

(+) AM625: 0.75 V vs. 0.85 V Core - Changing Voltage (with TPS65219) - Processors forum - Processors - TI E2E support forums

Regards,

Sreenivasa