AM572x GP EVM power consumption

prachi panse1

Other Parts Discussed in Thread: TPS659037, TPS51200

Hi,

I am planning to use the TPS659037 PMIC for the power supply for AM572x processor. However, the power dissipation of the PMIC is very high due to which the junction temperature of the device is exceeded beyond the permissible limit.

Can you share the power consumption details of the GP EVM? I can use that as a reference to verify our values.

Regards,

Prachi

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

Check this wiki: processors.wiki.ti.com/.../AM57xx_Power_Consumption_Summary

0 prachi panse1 over 9 years ago in reply to Biser Gatchev-XID

Intellectual 980 points

Hi,

Thanks for sharing the link for the AM57xx_Power_Consumption_Summary. I have a few queries regarding it:

1. Which DDRs are used for deriving these power numbers? Also, what is the number of DDRs present on the board?
2. What load was present on the DDR for this current consumption on VDDS_DDR?
3. The VDDS_DDR current is only for the two EMIF controllers and does not include the VTT termination current. Please confirm.
4. Is the VDD_DDR supply current a total of the current on VDDS_DDR and the VTT termination current?
5. Why is the VDD_DDR supply voltage 1.34V? We understand that it should be equal to VDDS_DDR voltage.
6. Which PMIC IC and OTP are used in this case?

7. We are using the TPS51200 DDR linear regulator to generate the VTT supply for the fly-by termination for DDR3 address and

control lines. We are calculating the current requirement as follows:
I_vtt = Vtt/R_term = 0.675V/47 = 14.36mA
Total current drawn for both EMIF controllers = 2* number of control and address lines * I_vtt = 2 * 25 * 14.36 mA = 718mA.
However, we see that the current on the VDD_DDR is seen to be around 500mA in the various use cases, which is lower than our

calculated value.
Can you please explain how the VTT termination current is calculated?

Regards,
Prachi

0 Biser Gatchev-XID over 9 years ago in reply to prachi panse1

TI__Guru**** 393215 points

I don't have information about the board design calculations. You can find the AM572x GP EVM schematic here: www.ti.com/.../tmdsevm572x Documents

0 prachi panse1 over 9 years ago in reply to Biser Gatchev-XID

Intellectual 980 points

Dear Biser,

We have gone through the AM572x schematics. However, the AM57xx Power Consumption Summary sheet mentions that the measurements have been performed on an internal test evaluation reference system and not on the AM572x evaluation module (TMDXEVM5728).
Can you please forward my query to the concerned person?

Regards,
Prachi

0 kshin over 9 years ago in reply to prachi panse1

TI__Genius 16690 points

Hi Prachi,

The internal EVM used for creating the power consumption summary is the EVM you mentioned in your previous post. So, please refer to the schematics for the details you are looking for.

>2. On Vayu EVM, LDO1 output of the PMIC (TPS659039) is used as the power source for VDDSHV8 (MMC1 power group) pins of the processor.
>The VDD for the SD card is sourced by the 3.3V supply generated by the external SMPS- TPS43351QDAPRQ1 via two load switches.
>In this case the VDD is fixed to 3.3V. Can this scheme support 1.8V SD signaling modes on Vayu EVM? Are these modes tested on the EVM?

0 ayusman over 9 years ago in reply to kshin

Intellectual 745 points

Hi Shin,

In the link

http://processors.wiki.ti.com/index.php/AM57xx_Power_Consumption_Summary#Dhrystone_:_Dual_Core_-_MPU_domain_at_HIGH

We see that the VDDS_DDR consumption is mentioned as 1.34V and 431mA. I believe this is the power consumption of DDR and the termination voltage. Can you please let us know how has this value been arrived?

Regards

Ayusman

0 kshin over 9 years ago in reply to ayusman

TI__Genius 16690 points

Hi Ayusman,

The link above is the measured power for Dhrystone benchmark on both A15 cores.
There are two separate DDR related power supplies. VDDS_DDR is SoC DDR interface IO power supply. VDD_DDR is external DDR3L device power supply. Here are measured data for each power supplies from the table.

VDDS_DDR 1.35 V 281.8 mA 380.4 mW
VDD_DDR 1.34 V 445.4 mA 597.8 mW

I think 431 mA you are reffering in above post is for current for external DDR3L devices with active termination. This is measured value via current shunt resistor on the EVM.

processors.wiki.ti.com/.../AM57xx_Power_Consumption_Summary

VDD_DDR 1.34 V 431.0 mA 578.1 mW

0 ayusman over 9 years ago in reply to kshin

Intellectual 745 points

Hi Shin,

Thanks. You have mentioned that 431mA is the consumption of the external DDR3L devies and the active termination.

Just wanted to know what is the consumption due to the active termination. Since the shunt resistor will give the total current values, can you please share for how much active termination current you have designed.

Regards

Ayusman

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AM572x GP EVM power consumption