permanently enabled circuit

[Peerasak T.]

for my on road vehicle project , there is requirement for permanently enabled output eg. hazard flashing indicator lights without ignition switched on.

If Vbatt is permanently connected, is there configuration setting to keep an output enabled after IGN SW pin becomes inactive ?

 

[Vaughan]

You could theoretically do a hold power type setup where the PDM keeps itself on until that output is switched off. How is that output switched (keypad or physical switch) and how long would it need to be on for? is there any reason to not have a separate ignition switch for the PDM so you can have it on when other things are off?

[Peerasak T.]

The output will be triggered by a physical switch. Example is hazard indicator light which can be turned on for hours when vehicle is broken down roadside, waiting for assistance. The whole PDM system should not need to be kept powered, similar to a stock car.

[Adamw]

There is not im sorry.  The Ign Sw pin disconnects the main power inputs.  You would have a significant parasitic draw if the micro and pull-ups etc stayed live all the time.  What most refer to as "24hr circuits", typically for security, hazards and park lights etc needs to come direct from the battery with a conventional fuse.