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For a hobby project that I am doing, I would like to measure the voltage across a shunt resistor with a differential ADC. I am thinking to use the ADS1292 of TI.

However, I have the following question. Since I also expect a negative voltage across the shunt resistor. I would like to generate a bipolar reference Voltage for the ADC

How can I best accomplish that? I have a 4.5V power supply and want to use a rail splitter. Is that stable enough for a precision measurement? If there is a better way of doing that I am open to suggestions.

Best Regards

EmbedWise

Embedded Systems Enthusiast

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  • \$\begingroup\$ Could we see some schematics? Is the voltage on the terminals of the ADC lower than Vss? \$\endgroup\$ – kva Jun 11 '17 at 6:39
  • \$\begingroup\$ Currently, I only have a block schematic and I am looking at the common mode input range. If I use it in differential mode then the voltage across the shunt should not increase above the Vss if I am correct. So even if the line voltage is e.g. 20V if the voltage across the shunt does not exceed Vss I am good right? \$\endgroup\$ – EmbedWise Jun 11 '17 at 7:12
  • \$\begingroup\$ Why the ADS1292? \$\endgroup\$ – Andy aka Jun 11 '17 at 8:41
  • \$\begingroup\$ Because of the cost/resolution ratio. Other suggestions are welcome \$\endgroup\$ – EmbedWise Jun 11 '17 at 10:17
  • \$\begingroup\$ I found a nice article about current sensing techniques link. This also gives the answer for the Common mode input range. I cannot assume that if the Line/Bus voltage is above Vss my design will work. I will need the reexamine my assumptions. Anybody has an idea how this dealt with in the uCurrent design link \$\endgroup\$ – EmbedWise Jun 11 '17 at 12:37

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