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UCD3138ALLCEVM150: Current sensing

Part Number: UCD3138ALLCEVM150
Other Parts Discussed in Thread: UCD3138ACCEVM149,


Our system is UCD3138ACCEVM149 and UCD3138ALLCEVM150.

On this application the current sense goes to three different AD inputs:

  1. -IOSEN- and IOSEN+ to the EADC#2, the current measure coming from a shunt resistor sensor. The signal amplitude is around 28mV @ full load
  2. EADC_IOSENSE to the EADC#1, the same measure as before, but after a differential amplifier. The signal is around 1V@full load
  3. IO_SENSE, to the AD13 that I understand is just for monitoring, no for control.

Can you please explain why there are two different ways to input the Current Sense feedback to the current control loop?

In our project we need to measure another current (battery current) and we don’t understand if it’s necessary to measure the current twice.

Thank you.

  • You do need the EADC for loop control and the ADC 12 for monitoring, but you don't need the very low gain signal.  I believe it was put in for an unsuccessful test of using a very low gain current measurement.