PSoC 6 Vbackup current

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taas_3144281
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Hi.

My customer use PSoC 61 (CY8C6136BZI-F14).

My customer use the RTC built into PSoC 6.

My customer use an external oscillator attached to the WCO

The power supply of VBACKUP of Backup domain including RTC uses a coin battery.

Power supplies other than VBACKUP supply 3.3V from the DCDC converter.

What is the current consumption of VBACKUP?

Best Regards.

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Vasanth
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Hello Moto san,

There is an error in the excel sheet it seems. I will do necessary steps to correct the data generated. Meanwhile you can check the PSoC6 datasheet Table 40. The block current is confirmed to be 0.38uA to 1uA.

Best Regards,
Vasanth

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Vasanth
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Hi ,

It depends on the application. In your case WCO runs from VBACKUP, so WCO current consumption is the primary sink on the VBACKUP. In addition, if you have any IO driven in P0, that is sourced from VBACKUP as well. For instance, if you have connected an LED on P0[2], then the current consumed by the LED will be from VBACKUP as that is the IO supply for P0.

Best Regards,
Vasanth

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MotooTanaka
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Hi,

I'm working with taas-san.

The customer wants to estimate the battery life for their product.

The condition is

(1) Use the internal RTC

(2) WCO is attached

(3) Power Supply for the Backup domain, including the RTC, is a coin battery

(4) Except the Backup all other power is provided from V3.3

(5) They want to keep RTC running even without V3.3.

(6) They've tried to find the power dissipation from the Datasheet but they could not.

So would you provide us the "number" for the VBACKUP power consumption?

Meantime, I found the following KBA

How to Reduce XRES Current on BACKUP Domain for PSoC 6 MCU – KBA227474

According to the KBA, RTC consumption is 380 nA typical and 1 uA max,

can this be the official answer to them?

Or do you have more specific information?

moto

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MotooTanaka
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Hi,

The customer noticed another information from

PSoC 6 Power Calculator (version 1).xlsx

https://www.cypress.com/file/506616/download

According to this calculator, when wco is enabled it shows 63 uA.

There seems to be a rather large difference of the number for wco (and RTC)

1uA max vs 63uA.

So I wonder what is the reliable power consumption for WCO and RTC?

moto

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Vasanth
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Hello Moto san,

There is an error in the excel sheet it seems. I will do necessary steps to correct the data generated. Meanwhile you can check the PSoC6 datasheet Table 40. The block current is confirmed to be 0.38uA to 1uA.

Best Regards,
Vasanth

MotooTanaka
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Dear Vasanth-san,

Thank you very much for confirming the value.

001-Table_40.JPG

Now we can inform the customer that the value is 0.38 ~ 1 uA.

Best Regards,

1-Jul-2020

Motoo Tanaka

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taas_3144281
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Dear Vasanth-san

Thank you for your answer.

Best Regards,

Asanuma

MotooTanaka
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Dear Vasanth-san,

Can we assume that the currents for "ECO  with 32k Crystal" and "WCO with 32k Crystal" are the same?

Although that is what we expect, since I could not find the statement about WCO in the datasheet,

let me confirm it.

Meantime, if their current consumption are are the same,

how can we estimate the Vbackup current consumption during hibernate with WCO and RTC alive?

According to the datasheet, Vbackup can go down to 1.4V when VDDD is removed,

I wonder what is the current consumption with this condition?

Best Regards,

6-Jul-2020

Motoo Tanaka

(Edited)

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Vasanth
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Hi Motoo san,

To confirm your first question. Yes , both are the same.

Regarding the second part, 1.4V is the minimum voltage when VDDD is removed. You can use the same block current values for calculation in this condition too.

Best Regards,
Vasanth

MotooTanaka
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Dear Vasanth-san,

Thank you very much for your quick response!

Best Regards,

7-Jul-2020

Motoo Tanaka

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taas_3144281
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Dear Vasanth-san

Thank you for your answer.

We would appreciate it if you could contact us when you have finished modifying the Excel sheet.

Best Regards,

Asanuma

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