Other Parts Discussed in Thread: AMC3311, , UCC33411, INA500
Tool/software:
Hello,
I need to design a high-voltage sensing circuit for an industrial application that requires high creepage (>30mm), clearance (>15mm) and isolation (>13kVpk) between the HV sensing section and the microcontroller section. Due to the high isolation requirements, I have adopted a dual isolation amplifier approach, i.e., there are two back-to-back isolation amplifiers between the HV section and the microcontroller instead of just one. The screenshot below shows the approach I plan on taking.
I plan on using two AMC3311 isolated amplifiers back-to-back for the HV sensing. Between the two isolated amplifiers, I need a differential amplifier to converter the differential-ended output of the first AMC3311 to a single-ended input for the second AMC3311. I found the INA105 Unity Gain Differential Amplifier during my search, which is almost perfect for my application. I say almost perfect because although it has a maximum power supply input range of 0-36V, the recommended is at least 10V. I would like to use the UCC33411 power supply IC, which is a 3.3V/3.7V isolated DC-DC converter, to power the AMC3311 and the INA105 closer to the HV section.
The AMC3311 outputs a maximum differential voltage of 2V and a maximum common-mode voltage of 1.44V. With an INA105 power by a 3.7V single supply rail, would I be able to measure the output of the AMC3311 accurately? Is there a more appropriate unity gain differential amplifier IC that you would like to recommend, or ever a better approach for this application in general?
