CS5490 Two Channel Energy Measurement IC Features Description The CS5490 is a high-accuracy, two-channel, energy measure- Superior Analog Performance with Ultra-low Noise Level & High SNR ment analog front end. Energy Measurement Accuracy of 0.1% over a 4000:1 th The CS5490 incorporates independent 4 order Delta-Sigma an- Dynamic Range th alog-to-digital converters for both channels, reference circuitry, Two Independent 24-bit, 4 -order, Delta-Sigma and the proven EXL signal processing core to provide active, re- Modulators for Voltage and Current Measurements active, and apparent energy measurement. In addition, RMS and Configurable Digital Output for Energy Pulses, Interrupt, power factor calculations are available. Calculations are output zero-crossing, and Energy Direction via a configurable energy pulse, or direct UART serial access to Supports Shunt Resistor, CT, and Rogowski Coil Current on-chip registers. Instantaneous current, voltage, and power Sensors measurements are also available over the serial port. The On-chip Measurements/Calculations: two-wire UART minimizes the cost of isolation where required. - Active, Reactive, and Apparent Power - RMS Voltage and Current A configurable digital output provides energy pulses, zero-cross- - Power Factor and Line Frequency ing, energy direction, or interrupt functions. Interrupts can be - Instantaneous Voltage, Current, and Power generated for a variety of conditions including voltage sag or Overcurrent, Voltage Sag, and Voltage Swell Detection swell, overcurrent, and more. On-chip register integrity is assured Ultra-fast On-chip Digital Calibration via checksum and write protection. The CS5490 is designed to in- terface to a variety of voltage and current sensors, including shunt Configurable No-load Threshold for Anti-creep resistors, current transformers, and Rogowski coils. Internal Register Protection via Checksum and Write Protection On-chip functionality makes digital calibration simple and ultra UART Serial Interface fast to minimize the time required at the end of the customer pro- On-chip Temperature Sensor duction line. Performance across temperature is ensured with an On-chip Voltage Reference (25ppm/C Typ.) on-chip voltage reference with low drift. A single 3.3V power sup- Single 3.3 V Power Supply ply is required, and power consumption is low at <13mW. To Ultra-fine Phase Compensation minimize space requirements, the CS5490 is offered in a low-cost Low Power Consumption: <13 mW 16-pin SOIC package. Power Supply Configurations: ORDERING INFORMATION - GNDA = 0 V, VDDA: +3.3 V See Page 57. Low-cost 16-pin SOIC Package VDDA VDDD RESET CS5490 IIN+ 4th Order Digital HPF PGA Modulator Filter IIN- Option UART RX Serial TX Interface VIN+ 4th Order Digital HPF 10x Calculation Modulator Filter Option VIN- Configurable VREF+ Digital DO Voltage Temperature Output Reference Sensor VREF- System Clock Clock Generator GNDA XIN XOUT MODE Cirrus Logic, Inc. Copyright Cirrus Logic, Inc. 2013 MAR13 CS5490 TABLE OF CONTENTS 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2. Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1 Analog Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.1 Voltage Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.2 Current Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 2.1.3 Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.1.4 Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2 Digital Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.1 Reset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.2 Digital Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.3 UART Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.3.1 UART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.4 MODE Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 3. Characteristics & Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 4. Signal Flow Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.1 Analog-to-Digital Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.2 Decimation Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.3 IIR Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.4 Phase Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.5 DC Offset & Gain Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 4.6 High-pass & Phase Matching Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.7 Digital Integrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.8 Low-rate Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.8.1 Fixed Number of Samples Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.8.2 Line-cycle Synchronized Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.8.3 RMS Current & Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.4 Active Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.5 Reactive Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.6 Apparent Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.7 Peak Voltage & Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.8.8 Power Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.9 Average Active Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 4.10 Average Reactive Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 5. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.1 Power-on Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.2 Power Saving Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.3 Zero-crossing Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.4 Line Frequency Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 5.5 Energy Pulse Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 5.5.1 Pulse Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 5.5.2 Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 5.6 Voltage Sag, Voltage Swell, and Overcurrent Detection . . . . . . . . . . . . . . . . . . . . .21 5.7 Phase Sequence Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 5.8 Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 2 DS982F3