I've been spec'd a MID400 in a high voltage A/C power monitor circuit. After receiving the prototype (board is done), I've determined this device is for power on/off application. Problem is I need to detect brown out conditions where service voltage is below an acceptable value. EXAMPLE 240VAC 1/PH application. Anything less than 180VAC needs to trigger an alarm.
MID400 spec sheet states current > 4mA = "Saturated" mode and <.15mA = "Off" mode. Spec sheet also calls out a condition called "unsaturated", which is current between the 4mA and .15mA. Spec sheet states "Under these conditions the device makes an attractive, simple 120Hz clock generator that is free from most of the normal power line transients for many digital applications."
My thinking is to monitor the output of the MID400 via microcontroller analog configuration and increase dropping resistor to create a acceptable voltage range (EX:510kΩ in 240VAC application) thus operating the MID400 in unsaturated mode and use the analog configuration to detect brown out and brown out return.
I have been in contact with MID400 mfg to ask what their design requirements (current threshold) are to attain this "attractive clock generator" feature. They have been of no help. My testing shows no consistency regarding current and 120Hz. Very random results per individual MID400.
I am trying to salvage this project but am nearing the point of restarting. Anyone have any input on MID400 "unsaturated" mode? Experience or suggestions?