原标题：Cirrus CS5484高精度四路能量测量模拟前端解决方案

　　Cirrus公司的CS5484是高精度四路能量测量模拟前端(AFE),每路集成了4阶24位Delta-Sigma模数转换器(ADC),基准电路,并提供EXL信号处理核,以进行有用,无用和表观功率测量.支持并联电阻,CT和Rogowski线圈电流传感器, 动态范围4000:1的能量测量精度0.1%,动态范围1000:1的电流RMS测量精度0.1%,单电源3.3V工作,功耗低于13mW.本文介绍了 CS5484主要特性,方框图, 单相三线I2S电表的典型连接框图,以及CDB5484U评估板主要特性,框图,采用CDB5484U评估板的并联传感器, 电流变压器和Rogowski线圈电流传感器的电表框图,评估板电路图,材料清单以及PCB元件布局图与走线图.

　　The CS5484 is a high-accuracy, four-channel, energy measurement analog front end.

　　The CS5484 incorporates independent 4th order Delta-Sigma analog-to-digital converters for every channel, reference circuitry, and the proven EXL signal processing core to provide active, reactive, and apparent energy measurement. In addition, RMS and power factor calculations are available.

　　Calculations are output through a configurable energy pulse, or direct UART/SPI™ serial access to on-chip registers. Instantaneous current, voltage, and power measurements are also available over the serial port. Multiple serial options are offered to allow customer flexibility. The SPI provides higher speed, and the 2-wire UART minimizes the cost of isolation where required.

　　Four configurable digital outputs provide energy pulses, zero-crossing, energy direction, and interrupt functions. Interrupts can be generated for a variety of conditions including voltage sag or swell, overcurrent, and more. On-chip register integrity is assured via checksum and write protection.

　　The CS5484 is designed to interface to a variety of voltage and current sensors including shunt resistors, current transformers, and Rogowski coils.

　　On-chip functionality makes digital calibration simple and ultra-fast, minimizing the time required at the end of the customer production line. Performance across temperature is ensured with an on-chip voltage reference with low drift. A single 3.3V power supply is required, and power consumption is low at <13mW. To minimize space requirements, the CS5484 is offered in a low-cost, 5mm x5mm 28-pin QFN package.

　　CS5484主要特性:

　　• Superior Analog Performance with Ultra-low Noise Level and High SNR

　　• Energy Measurement Accuracy of 0.1% over 4000:1 Dynamic Range

　　• Current RMS Measurement Accuracy of 0.1% over 1000:1 Dynamic Range

　　• 4 Independent 24-bit, 4th-order, Delta-Sigma Modulators for Voltage and Current Measurements

　　• 4 Configurable Digital Outputs for Energy Pulses, Zero-crossing, or Energy Direction

　　• Supports Shunt Resistor, CT, and Rogowski Coil Current Sensors

　　• On-chip Measurements/Calculations:

　　- Active, Reactive, and Apparent Power

　　- RMS Voltage and Current

　　- Power Factor and Line frequency

　　- Instantaneous Voltage, Current, and Power

　　• Overcurrent, Voltage Sag, and Voltage Swell Detection

　　• Ultra-fast On-chip Digital Calibration

　　• Internal Register Protection via Checksum and Write Protection

　　• UART/SPI™ Serial Interface

　　• On-chip Temperature Sensor

　　• On-chip Voltage Reference (25 ppm/℃ Typ.)

　　• Single 3.3V Power Supply

　　• Ultra-fine Phase Compensation

　　• Low Power Consumption: <13 mW

　　• Power Supply Configurations

　　- GNDA = GNDD = 0 V, VDDA = +3.3 V

　　• 5mmx5mm 28-pin QFN Package

　　图1.CS5484方框图

　　图2.CS5484典型连接框图(单相三线I2S电表)

　　CDB5484/80/90U 评估板

　　The CDB5484U is an extensive tool designed to evaluate the functionality and performance of Cirrus Logic’s CS5484 power/ energy measurement device.

　　Multiple analog input connection options, configuration input filters, direct and isolated digital interfaces, multiple power supply options, an onboard programmable microcontroller, and visual LEDs with an LCD panel make the board a flexible and powerful customer development tool for various power/energy measurement applications.

　　The GUI software provides easy and complete access and control to the onboard CS5484 device. It also includes the function of raw ADC data collection with time domain, frequency domain, and histogram analysis.

　　The board is partitioned into two main sections: analog and digital. The analog section consists of the CS5484, passive anti-aliasing filters, and a high-voltage section with attenuation resistor networks. The digital section consists of the C8051F342 microcontroller, LCD, hardware test switches, reset circuitry, and USB interface. The board also has a user-friendly power supply connection.

　　CDB5484U评估板主要特性:

　　• Standalone Power Meter Application

　　• Voltage and Current Interfaces

　　• Low- and High-voltage Sensor Connections

　　• Adaptable Sensor Filters Onboard

　　• USB Communication with PC

　　• UART/SPI Optically Isolated Communication

　　• Onboard C8051F342 Microcontroller

　　• Single Supply Operation USB or 5V

　　• Onboard DC-DC Converter and Regulator

　　• LCD Power Monitor Display

　　• LabWindows®/CVI® GUI Software

　　– Full Register Setup and Chip Control

　　– Simplified Register

　　– Quick Calibration Control

　　– FFT Analysis

　　– Time Domain Analysis

　　– Noise Histogram Analysis

　　• Voltage Reference Access

　　图3. CDB5484U评估板外形图

　　图4. CDB5484U评估板方框图

　　图5. CDB5484U并联传感器电表框图

　　图6. CDB5484U电流变压器电表框图

　　图7. CDB5484U Rogowski线圈电表框图

　　图8. CDB5484U评估板电路图:模拟输入

　　图9. CDB5484U评估板电路图:CS5484和插座

　　图10. CDB5484U评估板电路图:MCU和USB接口

　　CDB5484U评估板材料清单:

　　图11. CDB5484U评估板 PCB元件布局图:顶层