MMPF0100 LiCELL charge voltage and i.MX6 RTC operating voltage range

[george]

Dear all,

When connecting rechargeable battery to MMPF0100 and using it as backup for RTC on i.MX6, the charge voltage to battery is 2.5V (default).

=> Page 113 on http://cache.freescale.com/files/analog/doc/data_sheet/MMPF0100.pdf

That is, battery voltage goes up to 2.5V.

When an external power supply is not connected to a system, RTC needs to work by Battery charged to 2.5V.

However, the operating voltage range of i.MX6 VDD_SNVS_IN is 2.9V-3.3V.

We keep only RTC.

Is really more than 2.9V needed in order to keep RTC?

I think that lower voltage is available in order to keep RTC operation generally.

If it becomes so, since it is necessary to change charge voltage setting to Battery more than 2.9V.

Best Regards,

George

[igorpadykov · Accepted solution]

Hi George

yes it is necessary to change charge MMPF0100 voltage setting to

battery more than 2.9V since IMX6SDLCEC Table 9. Operating Ranges

defines backup battery supply range VDD_SNVS_IN as 2.9-3.3V

Also Table 8 Current Consumption Summary MMPF0100 datasheet :

Typical values are characterized at VIN = 3.6 V, VDDIO = 3.3 V, LICELL = 3.0 V,

VSNVS = 3.0 V and 25 °C, unless otherwise noted.

Best regards

igor

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[george]

Dear Igor,

Thanks.

BR

George