Backup for LPC54608

[TEMCEFF]

Hi,

I'm using LPC54608 Controller in my application. I want to safely shutdown my controller when the main supply is off.

1 or 2 minutes backup is more than enough for my requirement. But I don't understand how to provide that backup for 2 minutes. 

Thanks in advance.

BR,

Avinash.

[frank_m]

You could use a larger electrolytic cap for the power supply, and some NVM to save relevant states.

The larger cap just keeps up the supply voltage some milliseconds, long enough to save the state values.

Would add some BOM costs, but allow for arbitrary long power outages.

I used this method some while ago for lighting equipment, wher this was a requirement of the standard the devices satisfied.

[diego_charles]

Hi Avinash,

The first that comes to my mind is to use a backup battery and an external logic.

Following this idea,  you could design or implement a circuit to help   your application to  perform a transition between main supply  to backup battery   and  help  to  disconnect the backup battery after two minutes.

Please, let me know If I can help you further.

Regards,

Diego.

[TEMCEFF]

Thanks for your reply,

                       For 2 minutes backup supercapacitor may be the right choice. Is there any recommended circuit for NXP controller with a supercapacitor.

Regards,

Avinash.

[diego_charles]

Hi Avinash,

Thank you for your reply as well,

Currently, we do not have recommended circuit schematics for a supercapacitor back up supply for the LPC54608 that I could provide you.

However, you can follow:

• Power, clock, and debug connections diagram of the LPC54608
• This NXP RTC chip, user manual provides background and  calculations for implementing a super capacitor.  Although they are different devices ,this may help you to get a better idea on super capacitor applications.   

I apologize for my late reply .

Regards,

Diego