INA283-Q1: extend common-mode voltage range

Hello,

Please note that we do have a bidirectional, 600-VDC amplifier called the TMCS1101 and TMCS1100. You may want to look into these.

When the circuit only needs to measure unidirectional currents, it is much easier to float the current sense amplifier (CSA) (with a Zener diode) and level shift the output signal to low-voltage. See the following documentation showing how. You could use two unidirectional CSAs (e.g., INA139) to measure currents in both directions. Or you could use two of the Howland current pump circuits using a bidirectional CSA and op amp (both floating with a Zener diode) to measure both directions of the current.

https://www.ti.com/lit/ug/tidu833/tidu833.pdf?ts=1616537102844&ref_url=https%253A%252F%252Fwww.google.com%252F

https://www.ti.com/lit/an/sboa358/sboa358.pdf?ts=1616537119933&ref_url=https%253A%252F%252Fwww.google.com%252F

Another option is to float the digital current sense amplifier and level shift the digital output signals with a isolated digital buffer as shown here:

https://www.ti.com/lit/ug/tidu361a/tidu361a.pdf?ts=1616536537752&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FINA226

The much less practical method is to try to divide down the input voltage at each pin of INA283, but this will create huge error since the input is relatively low resistance and the dividing resistors will load down the input and cause gain and offset error. This video explains why:

https://training.ti.com/ti-precision-labs-current-sense-amplifiers-input-filter-error

Hope this helps.

Best,

Peter