• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 31 subscribers
  • Views 401 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MCU core running on Vbat supply

Saisivarajagopal KS
Prodigy 50 points

Hi All,

We are looking for MCU which can work on Main supply voltage as well as with non rechargeable battery when main supply voltage is absent.

During the absence of main supply i want  MCU to switch from main Supply to battery  and power the MCU core and peripherals with battery voltage and Once the main power resumes , MCU need to switch again  from Vbat to Main supply. Can any one Suggest the MCU which can  supports the above functionality?  We have got some MCUs with battery source but it  powers only the backup domain such as RTC, calendar, some GPIOS only. I am looking for MCU which powers the Core and peripherals also with Vbat.

Thanks.

  • 0
    TI__Mastermind 25570 points

    Hi are there any peripherals you need for this device?

    Regards,

    Luke

  • 0 in reply to Luke Ledbetter
    Prodigy 50 points

    Hi Luke,

    Currently we are looking for the possible approach for  Switching between Main supply (LDO) and Vbat Operation. 

    We have Two backup supplies requirement , Battery and supercap. Either one of the backup supplies is selected but provision should be provided. (either one of the backup circuit component will be mounted) and other is made DNI(Do not populate)

    Super cap back supply is only for RTC and monitor and logging the tampering Events connected to Vbat pin  (if Super cap is selected as backup supply by enduser)

    we have also have one ADC monitoring 24V from which the 3.3V is derived.

    Also there is energy hold up circuit  for 3.3V upto 500ms (upto which LDO supplies powe to MCU) to shutdown the MCU as soon the Main power outage .

    Battery backup is for RTC , Event logging and also the Peripherals and Core of the MCU  and it act as a alternate option for short duration when Main Supply (LDO Voltage) is not present

    If Battery backup is selected by enduser, then Vbat pin will not be connected.  Also Does VDD pins Power to Backup circuitry such as RTC? and Tamper GPIOS?

    We have considered some of below approaches and provided  thoughts  on MCU possible operation mode  for Battery and main Backup switching circuit, Whether controller can able to  detect and differentiate the power source based on 24V Monitoring ADC able to operate between the run mode and Low power mode during Vbat and again resume to run mode when main power is present. 

  • 0 in reply to Saisivarajagopal KS
    TI__Mastermind 25570 points

    Our MSP430F677x devices could fit your needs. A full product list can be found here on the MSP Product Page and the MSP430x5xx and MSP430x6xx Family User's Guide can give you further information. On the product page in the Part Number search bar, enter in F667 to filter the devices to these devices.

    I have some concerns though. I see the 24V going into the ADC and you won't be able to directly plug that voltage into the device, it will fry the circuits. You can use a voltage divider to lower the voltage going into the device, but will lose some resolution by doing this. 

    Regards,

    Luke