william-dalley
New member
Hello,
I'm developing a project of a portable device using a Teensy 4.0 with a LiPo battery. The battery is a 3.7V LiPo pouch cell that is connected via power path/charger management + a boost converter to power the required 5V supply.
I'm using the On/Off function on the Teensy to sleep and wake the device via a button when required. When the device is Off, I would like the RTC to remain on, which is achieved by supplying power into the VBAT pin. The Teensy creates and manages files using date and time stamping so I need to keep this function alive even after power cycling via the On/Off function.
The design of my portable device is compact and I would ideally prefer not to need a secondary coin cell battery to supply VBAT. Could it be possible to use the LiPo battery in some way to power the VBAT pin to retain the RTC function without the need for a secondary battery? I could compromise and use a small coin battery, such as a CR1220, however, with many other forums highlighting the lifespan of the battery under CR2032 size, I'd prefer to use the LiPo which can be easily re-charged.
I have looked at the MIMXRT1062DVL6B datasheet and spotted that the VDD_SNVS_IN pin has an absolute maximum rating of 3.6V, which is lower than the LiPo voltage when at full capacity (4.20V). I could use a voltage divider to reduce this down to 3V but I don't know the current requirements on the VBAT pin and thus the appropriate resistor values.
Any help would be greatly appreciated,
Thanks.
I'm developing a project of a portable device using a Teensy 4.0 with a LiPo battery. The battery is a 3.7V LiPo pouch cell that is connected via power path/charger management + a boost converter to power the required 5V supply.
I'm using the On/Off function on the Teensy to sleep and wake the device via a button when required. When the device is Off, I would like the RTC to remain on, which is achieved by supplying power into the VBAT pin. The Teensy creates and manages files using date and time stamping so I need to keep this function alive even after power cycling via the On/Off function.
The design of my portable device is compact and I would ideally prefer not to need a secondary coin cell battery to supply VBAT. Could it be possible to use the LiPo battery in some way to power the VBAT pin to retain the RTC function without the need for a secondary battery? I could compromise and use a small coin battery, such as a CR1220, however, with many other forums highlighting the lifespan of the battery under CR2032 size, I'd prefer to use the LiPo which can be easily re-charged.
I have looked at the MIMXRT1062DVL6B datasheet and spotted that the VDD_SNVS_IN pin has an absolute maximum rating of 3.6V, which is lower than the LiPo voltage when at full capacity (4.20V). I could use a voltage divider to reduce this down to 3V but I don't know the current requirements on the VBAT pin and thus the appropriate resistor values.
Any help would be greatly appreciated,
Thanks.