Features and Benefits
- Highly accurate; supports IEC 60687, IEC 61036, IEC 61268, IEC 62053-21, IEC 62053-22, and IEC 62053-23
- Compatible with 3-phase/3-wire, 3-phase/4-wire, and other 3-phase services
- Less than 0.1% active energy error over a dynamic range of 1000 to 1 at 25°C
- Supplies active/reactive/apparent energy, voltage rms, current rms, and sampled waveform data
- Two pulse outputs, one for active power and the other selectable between reactive and apparent power with programmable frequency
- Digital power, phase, and rms offset calibration
- On-chip, user-programmable thresholds for line voltage SAG and overvoltage detections
- See Data Sheet for Additional Information
The ADE7758 is a high accuracy, 3-phase electrical energy measurement IC with a serial interface and two pulse outputs. The ADE7758 incorporates second-order Σ-Δ ADCs, a digital integrator, reference circuitry, a temperature sensor, and all the signal processing required to perform active, reactive, and apparent energy measurement and rms calculations.
The ADE7758 is suitable to measure active, reactive, and apparent energy in various 3-phase configurations, such as WYE or DELTA services, with both three and four wires. The ADE7758 provides system calibration features for each phase, that is, rms offset correction, phase calibration, and power calibration. The APCF logic output gives active power information, and the VARCF logic output provides instantaneous reactive or apparent power information.
The ADE7758 has a waveform sample register that allows access to the ADC outputs. The part also incorporates a detection circuit for short duration low or high voltage variations. The voltage threshold levels and the duration (number of half-line cycles) of the variation are user programmable. A zero-crossing detection is synchronized with the zero-crossing point of the line voltage of any of the three phases. This information can be used to measure the period of any one of the three voltage inputs. The zero-crossing detection is used inside the chip for the line cycle energy accumulation mode. This mode permits faster and more accurate calibration by synchronizing the energy accumulation with an integer number of line cycles.
Data is read from the ADE7758 via the SPI serial interface. The interrupt request output (IRQ) is an open-drain, active low logic output. The IRQ output goes active low when one or more interrupt events have occurred in the ADE7758. A status register indicates the nature of the interrupt. The ADE7758 is available in a 24-lead SOIC package.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
This documentation describes the ADE7758 evaluation kit Hardware and Software functionality. The evaluation board (watt/VA/VAR-hour meter) is configured via the parallel port of a PC. The data interface between the evaluation board and the PC is fully isolated. Windows™ based software is provided with the evaluation board, which allows it to be quickly configured as an energy meter.
The ADE7754/ADE7758 evaluation board and this documentation, together with the ADE7758 data sheet, provide a complete evaluation platform for the ADE7758. The ADE7758 evaluation board can be configured by setting jumpers.
The evaluation board has been designed so that the ADE7758 can be evaluated in the end application, i.e., Energy Meter. Using the appropriate transducers on the current channels (e.g., CTs) the evaluation board can be connected to a test bench or high voltage (240 V rms) test circuit. On-board resistor divider networks provide the attenuation for the line voltages. This application note also describes how the current transducers should be connected for the best performance. The evaluation board requires two external 5 V power supplies (one is required for isolation purposes) and the appropriate current transducers.
Documentation & Resources
RF Meets Power Lines: Designing Intelligent Smart Grid Systems that Promote Energy Efficiency3/5/2010
IC Technology and Failure Mechanisms - Understanding Reliability Standards Can Raise Quality of Meters6/1/2004
Reactive Energy Measurement Made Simple12/31/2003
Measuring Harmonic Energy with a Solid State Energy Meter9/30/2003
Software & Systems Requirements
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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