SBAS789B October 2017 – April 2020 AMC1106E05 , AMC1106M05
PRODUCTION DATA.
ΔΣ ADCs are widely used for current measurement in electricity meters because of the high ac accuracy obtained over a wide dynamic range that is achieved by averaging in the digital filter. As a result of their inherent isolation, current transformers (CT) were commonly used as current sensors in 3-phase electricity meters in the past. A strong magnetic field can saturate a CT and stop proper energy measurement. Shunt resistors are immune to magnetic fields and can be used to design temper-free electricity meters. The input structure of the AMC1106 is optimized for use with low-impedance shunt resistors to minimize the power dissipation of the circuit. The transformerless galvanic isolation of the bitstream as implemented in the AMC1106 is tailored for shunt-based current sensing in modern 3-phase electricity meter designs.
Figure 49 shows a simplified schematic of the AMC1106 in a shunt-based, 3-phase electricity meter application.