Hi, I'm using the 3.3v version of the lm4040. I was testing with the sparkfun 45a INA169 shunt monitor. It outputs 3.3v @44.7a, so it would work out like that. I'm swiching to the IN226 though, which communicates over i2c. In that situation, I could ditch the voltage reference, but it doesn't output an analog signal. The real benefit of using the INA226 is that it can detect bus voltage as well as current. That's all I need, so I wouldn't need the ADC at all.
The whole idea is for over current protection. I'm using 4x 2W 4mOhm shunt resistors in parallel. When the voltage drop across them goes over 100mV I'd like to enable the interrupt. I don't actually have the INA226 yet, but I can post everything up when I get it.
I was thinking the input had to be higher than the reference to enable to interrupt. The internal reference would be awesome, but how would that work when the input would only be up to 100mV or so?
EDIT:The INA226 has an alert pin with functions like shunt voltage over limit, which could work, but I'm hoping it's fast enough. I'm going to try that as well. I was just hoping the interrupt could be enabled as quick as possible. Looks like 140µs conversion time. Add that to the interrupt input-output time and I think it's around 263µs.