AM4378: Current comsumption of AM437x and Output current of TPS65218

Hiroyasu Tazawa1

Guru 12350 points

Part Number: AM4378
Other Parts Discussed in Thread: TPS65218

Hi,

Let me talk about Power consumption of AM437x and TPS65218.

Power consumption of CAP_VDD_RTC and VDDS_RTC are described in AM437x datasheet.
They are Max 2 and 5mA

but Power consumption of DCDC5/6's output current is described in TPS65218 datasheet.
It is Max 100μA

(1)In this case, I want to confirm maximum current value consumed by the RTC of AM 437x.
(2)Can AM437x accept this current worst case at battery backup of RTC?

Best Regards
Hiroyasu

over 6 years ago

0 Yordan Kovachev over 6 years ago

TI__Guru**** 161600 points

We're looking into this. Feedback will be posted here.

Best Regards,
Yordan

0 Hiroyasu Tazawa1 over 6 years ago in reply to Yordan Kovachev

Guru 12350 points

Hi, Yordan

Thank you for your reply.
I got it. I wait for your reply.

Best Regards
Hiroyasu

0 Yordan Kovachev over 6 years ago

TI__Guru**** 161600 points

Hi,

(1)In this case, I want to confirm maximum current value consumed by the RTC of AM 437x.

This is as stated in the Am437x Data Manual.

(2)Can AM437x accept this current worst case at battery backup of RTC?

You mean can the AM437x accept 2 mA and 5 mA from a battery backup of RTC? In this case yes, this should be possible.

For additional power consumption calculations you can check this wiki & the Power Estimation spreadsheet:
processors.wiki.ti.com/.../AM437x_Power_Estimation_Tool

Best Regards,
Yordan

0 Hiroyasu Tazawa1 over 6 years ago in reply to Yordan Kovachev

Guru 12350 points

Hi, Yordan

Thank you for your reply.

I do not understand why it is possible

My qestion's point is

-Maximum Current DCDC5/6 of TPS65218 is 100uA

but

-Consumption of CAP_VDD_RTC and VDDS_RTC for AM437x are 2 and 5mA.

Why is this accetable ?

Best Regards

Hiroyasu

0 Yordan Kovachev over 6 years ago in reply to Hiroyasu Tazawa1

TI__Guru**** 161600 points

Hi Hiroyasu,

Sorry, obviously I didn't get your question the first time.. Let me check this with the hardware team.

Best Regards,
Yordan

0 JJD over 6 years ago in reply to Hiroyasu Tazawa1

TI__Guru 68880 points

Hiroyasu-san,

The TPS65218 spec shows two maximum output currents for DCDC5/6 depending on mode:

max: 100uA in coin cell mode (Vin_bu=0)

max: 25mA when main power is active (Vin_bu between 2.7 and 5.5V)

The AM437x datasheet just specs the maximum possible current consumption of the rails you mention, regardless of mode. So the TPS65218 can handle the maximums when main power is active.

Regards,

James

0 Hiroyasu Tazawa1 over 6 years ago in reply to JJD

Guru 12350 points

Hi, James

Thank you !
I got it.

Best Regards
Hiroyasu

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AM4378: Current comsumption of AM437x and Output current of TPS65218