150V differential DC signal acquisition solution

user6197310

Other Parts Discussed in Thread: INA149

Demand: DC signal, accuracy 0.1%.
Help recommend a plan.
The existing scheme is to use a resistor divider network plus a differential amplifier. The input impedance of the differential amplifier is generally within 1MΩ. The sum of the resistors of the voltage divider network must be less than 1kΩ. The resistance power is 22W, which is too large. The resistance is not good for selection.

over 6 years ago

0 LeonardEllis over 6 years ago

TI__Guru 71526 points

Hello user6197310,

I am not understanding what you are designing here. Please provide a block diagram or basic drawing. I am not clear on what the voltage divider is for, how the 22W is calculated, etc.

Please describe what the circuit is to accomplish.

Thank you,

~Leonard

0 user6197310 over 6 years ago in reply to LeonardEllis

Prodigy 170 points

Hello LeonardEllis：

Sorry i'm late.

Use resistor divider to collect 150V differential voltage. Because of common mode voltage, use differential op amp IN149 for signal buffering. Because the input impedance of IN149 is 800kΩ, the resistance of the voltage divider cannot be too large. If 1kΩ and 68Ω are used The calculated 1kΩ power is about 19W.