原标题：Maxim MAXQ3181三相电表前端方案

　　Maxim 公司的MAXQ3181是三相电表测试前端,能收集和计算多相电压.电流,有源功率和能量以及多相负载的其它许多计量参数.和三相/三线,三相/四线和其它的三相制式兼容,有源功率和能量线性误差0.1%,RMS压和电流线性误差0.5%,单电源3.3V工作,低功耗(典型值35mW),主要用在3相电表测量.本文介绍了MAXQ3181主要特性,方框图, 简化时钟源框图, RMS值计算框图, 能量计算相位补偿框图以及取样电流和电压输入电路, 典型应用电路.

　　The MAXQ3181 is a dedicated electricity measurement front-end that collects and calculates polyphase voltage, current, active power and energy, and many other metering parameters of a polyphase load. The computed results can be retrieved by an external master through the on-chip serial peripheral interface (SPI™) bus. This bus is also used by the external master to configure the operation of the MAXQ3181 and monitor the status of operations.

　　The MAXQ3181 performs voltage and current measurements using an integrated ADC that can measure up to seven external differential signal pairs. An eighth differential signal pair is used to measure the die temperature.

　　An internal amplifier automatically adjusts the current channel gain to compensate for low-current channel-signal levels.

　　MAXQ3181主要特性:

　　♦ Compatible with 3-Phase/3-Wire, 3-Phase/4-Wire, and Other 3-Phase Services

　　♦ 0.1% Active Power and Energy Linearity Error

　　♦ 0.5% Apparent Power and Energy Linearity Error

　　♦ 0.5% Linearity Errors for RMS Voltage and RMS Current

　　♦ Neutral Line Current Measurement

　　♦ Line Frequency (Hz)

　　♦ Power Factors

　　♦ Phase Sequence Indication

　　♦ Phase Voltage Absence Detection

　　♦ Programmable Pulse Width

　　♦ Programmable No-Load Current Threshold

　　♦ Programmable Meter Constant

　　♦ Programmable Thresholds for Undervoltage and Overvoltage Detection

　　♦ Programmable Threshold for Overcurrent Detection

　　♦ Amp-Hours in Absence of Voltage Signals

　　♦ On-Chip Digital Temperature Sensor

　　♦ Precision Internal Voltage Reference 2.048V (30ppm/°C typical), Also Supports An External Voltage Reference

　　♦ Active Power and Energy of Each Phase and Combined 3-Phase (KWh), Positive and Negative

　　♦ Apparent Power and Energy of Each Phase and Combined 3-Phase

　　♦ Supports Software Meter Calibration

　　♦ Up to 3-Point Multipoint Calibration to Compensate for Transducer Nonlinearity

　　♦ Power-Fail Detection

　　♦ Bidirectional Reset Input/Output

　　♦ SPI-Compatible Serial Interface with Interrupt Request (IRQ) Output

　　♦ Single 3.3V Supply, Low Power (35mW typical)

　　MAXQ3181应用:

　　3-Phase Active Energy Electricity Meters

　　图1.MAXQ3181方框图

　　图2.MAXQ3181简化时钟源框图

　　图3.MAXQ3181工作框图

　　图4.RMS值计算框图

　　图5.MAXQ3181能量计算相位补偿框图

　　图6.MAXQ3181取样电流输入电路

　　图7.MAXQ3181取样电压输入电路

　　图8.MAXQ3181典型应用电路