Description

The TIDA-01094 reference design implements a class 0.5 three-phase  transformerless energy measurement system with isolated shunt sensors by using isolated delta-sigma modulators. The delta sigma modulators have their output circuitry capacitively isolated from input circuitry: thereby providing transformerless data isolation. The high-side of each modulator is powered by a cap-drop supply that is also transformerless. Since a transformer is not used in this design: this design is inherently magnetically immune. In addition: the high-side cap-drop power supply reduces the entire system cost: has inherent low conducted and radiated emissions: and  reduces the current consumption drawn from the low-side power supply since the high-side is separately powered from Mains instead of being derived from the low-side power supply.