Seven ICs in One Chip

A new single-chip solution may replace as many as seven separate integrated circuits (ICs) in energy meters, enabling designers to bring products to market faster and for less cost. The solution could make it easier for manufacturers to bring LCD-based electronic meters to the $100 million-a-year residential meter market.

Developed by engineers at Analog Devices Inc. (ADI), the new solution incorporates an energy measurement core, microcontroller, on-chip Flash memory, Liquid Crystal Display (LCD) driver, analog-to-digital converter, real-time clock, temperature sensor and battery management circuitry. In many cases, those elements could require as many as six or seven discrete ICs, adding packaging size and cost to the design of energy meters, Analog Devices' engineers say.

"We've tried to put all the pieces in there that allow an engineer to design the right meter, and to do it inexpensively and reliably," notes Mark Strzegowski, senior product manager for ADI's metering group.

Solid state energy meters, used by gas and electric utilities, have gained popularity in recent years because they enable remote meter reading. Some utilities have balked at the cost of replacing aging electro-mechanical units, however, particularly with LCD-based models.

Known as the ADE7100 and ADE7500 families, the new chips could make it easier for utilities to incorporate LCD-based technologies in their meters. The new chip could enable that by incorporating intelligent battery modes that allow meters to maintain the time, sense temperature changes and run a Liquid Crystal Display read-out. With low-battery current consumption of 1.2 muA, the device reportedly uses 40 percent less power than predecessors in battery mode.

ADI engineers say they took special aim at LCD-related design issues with the new device families, adding such features as an LCD driver that integrates industrial temperature specifications and on-chip charge pumps controlled by digital-to-analog converters. The new features enable designers to adjust LCD contrast control without the addition of a discrete chip.

"For engineers, this means less time to market and lower cost," Strzegowski says. "It's just a simpler way to implement an LCD solution."