Centmo
Member level 3
Hi, I would like to measure the individual cell voltages of a 14S LiPo battery pack with high accuracy. I am currently using voltage dividers to accomplish this, but since the highest voltage is 14*4.2=58.8V, I need to divide it down quite a bit to sample it with the 3.3V 12-bit ADC in my MCU. High precision resistors are expensive, and I'd prefer not to have to calibrate the voltage dividers and store the offsets in Flash.
I have been doing some research, and it seems the better method for measuring cell voltages in a stack is to use an op-amp circuit (see attached image).
Now, the problem is that I can't find a suitable op-amp IC that can handle 60V. They exist, but are bulky and built to handle high current, and are pretty much all one op-amp per IC. Ideally, I'd want something like the TL431 (quad op-amp, cheap and small, up to 32V), but a version that could handle 60V. Any ideas?
If I can't find a suitable op-amp, I may consider the MAX14921 but it is quite a bit of circuit re-design to accomodate it.
Thanks.
I have been doing some research, and it seems the better method for measuring cell voltages in a stack is to use an op-amp circuit (see attached image).
Now, the problem is that I can't find a suitable op-amp IC that can handle 60V. They exist, but are bulky and built to handle high current, and are pretty much all one op-amp per IC. Ideally, I'd want something like the TL431 (quad op-amp, cheap and small, up to 32V), but a version that could handle 60V. Any ideas?
If I can't find a suitable op-amp, I may consider the MAX14921 but it is quite a bit of circuit re-design to accomodate it.
Thanks.
