Analog Devices’ Isolated Metrology Chipset Ensures Energy Meter Magnetic Immunity

Analog Devices Inc. introduced the industry's first fully isolated metrology chipset designed for polyphase energy metering applications. The ADE7978 metrology chipset includes the ADE7978 3-phase metrology IC combined with up to four ADE7933 fully isolated A/D converter ICs. The ADE7933 3-channel sigma-delta A/D converter incorporates Analog Devices' patented iCoupler® and isoPower® technologies to implement isolated signal transfer and dc-to-dc power conversion across a 5kV-rated insulation barrier. This enables the use of shunt resistor sensing elements instead of current transformers (CTs), thereby providing immunity to magnetic field interference and tampering. The use of shunts instead of CTs also reduces system cost and size.

"Designers of 3-phase electric meters are increasingly adopting shunt-based architectures over traditional CT-based meters to take advantage of size, cost, and magnetic immunity benefits," said Ronn Kliger, director, Energy Group, Analog Devices. "This new full-featured metrology chipset allows them to quickly leverage these benefits without compromising functionality or performance."

Chipset Key Features

* Computes active, reactive, and apparent energies for class 0.5 meters (ADE7978)

* Provides comprehensive power quality measurements including THD (ADE7978)

* Two versions of A/D converter IC available: three channel (ADE7933) and two channel (ADE7932)

* Integrated isoPower isolated dc-to-dc converter (ADE7933/ADE7932)Enables real time compensation for shunt temperature drift using on-chip temperature sensors (ADE7978 and ADE7933/ADE7932)

* Flexible SPI, I2C, and HSDC serial interfaces (ADE7978)

The EVAL-ADE7978EBZ evaluation board for the ADE7978 energy metering chipset is now available and priced at $350.00.