Datasheet ADE7769 (Analog Devices)

Energy Metering IC with Integrated Oscillator and No-Load Indication ADE7769 FEATURES
The ADE7769 specifications surpass the accuracy require-
On-chip oscillator as clock source
ments of the IEC62053-21 standard. The AN-679 Application
High accuracy, supports 50 Hz/60 Hz IEC62053-21
Note can be used as a basis for a description of an IEC61036
Less than 0.1% error over a dynamic range of 500 to 1
(equivalent to IEC62053-21) low cost, watt-hour meter
Supplies average real power on frequency outputs F1 and F2
reference design.
High frequency output CF calibrates and supplies instantaneous real power
The only analog circuitry used in the ADE7769 is in the Σ-Δ
CF output remains logic high when ADE7769 is under
ADCs and reference circuit. All other signal processing, such as
no-load threshold
multiplication and filtering, is carried out in the digital domain.
Logic output REVP indicates a potential miswiring or
This approach provides superior stability and accuracy over
negative power
time and extreme environmental conditions.
Direct drive for electromechanical counters and 2-phase stepper motors (F1 and F2)
The ADE7769 supplies average real power information on the
Proprietary ADCs and DSPs provide high accuracy over
low frequency outputs, F1 and F2. These outputs can be used to
large variations in environmental conditions and time
directly drive an electromechanical counter or interface with an
On-chip power supply monitoring
MCU. The high frequency CF logic output, ideal for calibration
On-chip creep protection (no-load threshold)
purposes, provides instantaneous real power information.
On-chip reference 2.45 V (20 ppm/°C typical) with external overdrive capability
The ADE7769 includes a power supply monitoring circuit on
Single 5 V supply, low power (20 mW typical)
the VDD supply pin. The ADE7769 remains inactive until the
Low cost CMOS process
supply voltage on VDD reaches approximately 4 V. If the supply falls below 4 V, the ADE7769 also remains inactive and the F1,
GENERAL DESCRIPTION
F2, and CF outputs are in their nonactive modes. The ADE77691 is a high accuracy electrical energy metering IC. Internal phase matching circuitry ensures that the voltage and It is a pin reduction version of the ADE7755 with an enhanced, current channels are phase matched, while the HPF in the precise oscillator circuit that serves as a clock source to the chip. current channel eliminates dc offsets. An internal no-load The ADE7769 eliminates the cost of an external crystal or threshold ensures that the ADE7769 does not exhibit creep resonator, thus reducing the overall cost of a meter built with when no load is present. During a no-load condition, the CF this IC. The chip directly interfaces with the shunt resistor. pin stays logic high. 1U.S. Patents 5,745,323; 5,760,617; 5,862,069; 5,872,469; others pending. The ADE7769 has a 16-lead, narrow body SOIC package.
FUNCTIONAL BLOCK DIAGRAM VDD AGND DGND 1 6 13 ADE7769 POWER SUPPLY MONITOR SIGNAL PROCESSING BLOCK V2P 2 + ...110101...
Σ
-
Δ
ADC V2N 3 MULTIPLIER PHASE LPF CORRECTION V1N 4 ...11011001...
Σ
-
Δ Φ
ADC HPF V1P 5 + INTERNAL DIGITAL-TO-FREQUENCY OSCILLATOR CONVERTER 2.5V 4k
Ω
REFERENCE 7 11 8 10 9 12 14 16 15
05332-001
REF RCLKIN SCF S0 S1 REVP IN/OUT CF F1 F2
Figure 1.
Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. or otherwise under any patent or patent rights of Analog Devices. Trademarks and Tel: 781.329.4700 www.analog.com registered trademarks are the property of their respective owners. Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS TIMING CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS ESD CAUTION TERMINOLOGY PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS FUNCTIONAL DESCRIPTION THEORY OF OPERATION Power Factor Considerations Nonsinusoidal Voltage and Current ANALOG INPUTS Channel V1 (Current Channel) Channel V2 (Voltage Channel) Typical Connection Diagrams POWER SUPPLY MONITOR HPF and Offset Effects Digital-to-Frequency Conversion Connecting to a Microcontroller for Energy Measurement Power Measurement Considerations INTERNAL OSCILLATOR (OSC) TRANSFER FUNCTION Frequency Outputs F1 and F2 Example Frequency Output CF SELECTING A FREQUENCY FOR AN ENERGY METER APPLICATION Frequency Outputs NO-LOAD THRESHOLD NEGATIVE POWER INFORMATION EVALUATION BOARD AND REFERENCE DESIGN BOARD OUTLINE DIMENSIONS ORDERING GUIDE