Each channel of the ADS131A0x is identical, giving designers the flexibility to sense voltage or current with any channel. Simultaneous sampling allows the application to calculate instantaneous power for any simultaneous voltage and current measurement. Figure 95 shows an example system that measures voltage and current simultaneously.
In Figure 95, channel 1 is dedicated to measuring the voltage between phase A and phase B and channel 2 is dedicated to measuring the current on phase A.
The resistors R1 and R2 form a voltage divider that steps the line voltage down to within the measurement range of the ADC. R1 can be formed by multiple resistors in series to dissipate power across several components. This configuration is also valid if the voltage is measured with respect to neutral instead of between phases.
Channel 2 is dedicated to measuring current that flows on phase A. Resistor R3 serves as a burden resistor that shunts the current flowing across the secondary coil of the current transformer (CT). Current can also be measured using a Rogowski coil and an analog integrator or by performing integration digitally after a conversion.
The RC filters formed by RFILT and CFILT serve as antialiasing filters for the converter. If an application requires a steeper filter roll-off, a second-order RC filter can be used.