A/D Converter Performs As Power Meter On A Chip

The transition from widely used mechanical power meters that yield limited data to electronic meters that provide extensive information on customer energy usage is facilitated by the Crystal CS5460 A/D converter IC. Billed as a power meter on a single chip, the device consists of two precision delta-sigma converters, an on-chip reference, high-speed power calculation functions, and a standard bi-directional serial interface that connects to a microcontroller. The firm's ability to integrate analog and high-speed digital functions on the chip minimizes the need for external components. Measurement accuracy is 0.1% over the full operating temperature range of -40°C to 85°C, which supports Class 0.2 designs. Also included on the chip is a monitor that detects the quality of the chip's power supply. If it drops below a user-defined level, the CS5460 can alert the MCU to save the information in its on-chip registers. Also, the monitor enables the electric utility to proactively determine when a brownout or power outage has occured through use of the meter's communication capability. Samples and evaluation boards with software are available now.