UPS for 2 min safe shutdown only


After looking around for any solution I hope to have some help from this forum.

We use the board in Automotive Applications. Input voltage can be between 12 V /( Cars) -28 V DC ( Trucks). We have a Linux application running on the board that will go down when vehicle switch off. In the Truck world it means the main voltage goes to 0V. We need then to do some closing of the files and also to transfer some data for this we see 120s maximum is needed. After this the device need to see 0V. When customer then apply +12-28V DC it will wake up, all fine again. USB C ups, does not work as it stays alive for hours. We would need 120s. And we like to have the board small too built in. In my world i see a DC/DC in combination with a small battery pack, super Caps would be too small to handle 400mA 12V in 120s. I would love to see a USB C extreme small UPS, 12V, then the main voltage goes down on the board <12V the USB C port would use the energy from the UPS for 120s then it could be drained. Would like to hear if there anyone that have the same problem?

Power the board by using the lead-acid battery from the trucks directly. The Board power ON/OFF signal come from the 12V provide after the engin2 is on.

Hi Bruce, Is it possible to supply the board with 5V internally, so we can use any other power pack. The USB C is not possible to charge the pack so therefore it does not work for us. To power the board from the Truck need a DC/DC as the power is +24 usually, and I guess the input of the Odyssey can only take 19V max. I don´t understand really how to connect this 12V signal, can you supply a more detailed description please?

I’m not familiar with ODYSSEY but if you can live with it being turned on and off with a relay then turning on that relay with a darlington pair might do the trick. With the base of the transistor(s) being fed via a resistor from the charge on a reasonably large capacitor the relay will be held on for a time determined by the size of the capacitor, the size of the resistor and the gain of the transistor which can be very high. The downside is that the relay coil and the collector emitter junction will be permanently connected across the battery (unless you incorporate an auxiliary switch for the system) but the leakage current will be low.

Happy to clarify further with possible component values if this sounds like an idea…