D24V50F5 enable usage question

I have just found your site and some of the products here are exactly what I have been looking for, however, I do have a couple questions about the D24V50F5 voltage regulator. I am looking to use this in a car situation and am wondering about more information on the ‘enable’ function.

  1. What voltage will the enable pin take to be active? Will 12vdc be fine even if that is what is going into the Vin?
  2. What is the Vout when Vin stays at 12vdc but enable is driven low? the documentation states the current consumption in that state only.
  3. Will Vout immediately cut off when enable is driven low or is there a way to give it a 10 sec or so delay before going off?

To give some perspective of the background behind the questions: I am wanting to use this in a raspberry pi car computer situation in order to drive not only the pi but all other accessories would be using (3g dongle, gps, etc). My intention was to use the radio wiring for the power. Have the constant 12v wire going to the Vin and the switchable 12v wire going to enable. I need the circuit to provide power for ~5 sec in order to give the pi enough time to receive a shutdown signal and properly turn off instead of having a hard shutdown. And then when the ignition is turned back on, the pi will receive power once again and boot up.

Thanks for the clarification!

Hi, Jeff.

The enable pin on the D24V50F5 can be connected to voltages as high as the voltage of the source connected to VIN. When EN is driven low, the regulator’s output will be shut off (and drop to 0V). The exact amount of time it takes for the output voltage to fall will depend on your load, but in most cases it will be fairly immediate and would not give a Raspberry Pi enough time to shutdown.

I am not sure if this would work for your setup, but another forum member posted their circuit for doing a delayed shutdown for an Arduino, which you might find useful. That circuit uses our pushbutton power switch, so it requires a button to be pushed to turn on the power and then pushed again to start the power off sequence.