78M6610+PSU Energy Measurement Processor for Single-Phase Power-Supply Units DATA SHEET FEATURES DESCRIPTION Delta-sigma ADC with precision voltage The 78M6610+PSU is a single-core energy measurement reference processor for single-phase power supplies. It is designed Internal or external oscillator timing reference specifically for real-time monitoring at the input of AC/DC 2 power converters used in data centers and IT server rooms. SPI, I C, or UART interface options with It is available in either a 24-pin QFN or 16-pin TSSOP configurable I/O pins for alarm signaling, package for optimal space savings. address pins, or user control The 78M6610+PSU provides four analog inputs (two 24-bit energy measurement processor (EMP) differential and two single ended) for interfacing to voltage, with integrated firmware and flash memory current, and two optional temperature sensors. Scaled provides the user with: voltages from the sensors are fed to the single converter o True RMS calculations for current, front-end utilizing a high-resolution delta-sigma converter. voltage, line frequency, real power, An embedded 24-bit energy measurement processor (EMP) and firmware performs all the necessary computation, reactive power, apparent power, and compensation, and data formatting for accurate, real-time power factor reporting to the host. With integrated flash memory, the o Compensation for ambient temperature, 78M6610+PSU is a completely autonomous solution sensor tolerances, offsets, and EMI filter capable of storing nonvolatile data such as calibration coefficients and input configuration settings. components o Real-time data accumulation based on an The 78M6610+PSU is designed to interface to the host 2 integer number of AC cycles processor via the UART interface. Alternatively, SPI or I C may also be used. Supported current sensors include o Quick calibration routines for Current Transformers (CT) and Resistive Shunts. manufacturability o Up to two voltage inputs for optional connection to thermal sensors Single Converter Voltage Measurement Front End UART Sensor Processor Current Sensor Digital Host MUX ADC RAM SPI I/O Controller Thermistor FLASH I2C Thermistor 78M6610+PSU 19-6396 Rev 3 8/14 Rev 3 1 78M6610+PSU Data Sheet Table of Contents 1 On-Chip Resources Overview ........................................................................................................... 5 1.1 Clock Management ...................................................................................................................... 6 1.2 Power-On Reset, WD Timer, and Reset Circuitry ....................................................................... 7 1.3 Analog Front-End and Conversion .............................................................................................. 8 1.4 24-Bit Energy Measurement Processor (EMP)............................................................................ 8 1.5 Flash and RAM ............................................................................................................................ 8 1.6 Communication Peripherals ......................................................................................................... 8 1.7 Multi-Purpose Digital I/O Pins ...................................................................................................... 9 1.8 Alarm Pins (ACFAULT, ACCRIT) ................................................................................................ 9 2 Functional Description and Operation ........................................................................................... 10 2.1 Voltage and Current Inputs Conditioning ................................................................................... 10 2.1.1 High Pass Filters (HPF) and Offset Correction .............................................................. 10 2.1.2 Phase Compensation .................................................................................................... 10 2.2 Current and Voltage RMS Calculations ..................................................................................... 11 2.3 Power Calculations and Power Factor ....................................................................................... 12 2.3.1 Active Power Calculation ............................................................................................... 12 2.3.2 Apparent Power ............................................................................................................. 12 2.3.3 Power Factor.................................................................................................................. 12 2.3.4 Reactive Power .............................................................................................................. 12 2.4 Fundamental and Harmonics Calculations ................................................................................ 13 2.5 Accumulation Interval ................................................................................................................. 13 2.6 Zero-Crossing Detection ............................................................................................................ 14 2.7 Alarms ........................................................................................................................................ 14 2.8 Voltage and Current Min/Max and Peak Tracking ..................................................................... 15 2.8.1 Voltage and Current Min/Max Tracking ......................................................................... 15 2.8.2 Voltage and Current Peak Tracking .............................................................................. 15 2.9 X+Y Capacitor Current and I/R Voltage Drop Compensation ................................................... 15 2.9.1 X+Y Capacitor Compensation ....................................................................................... 15 2.9.2 I/R Voltage Drop Compensation .................................................................................... 16 2.10 External Temperature Monitor ................................................................................................... 16 2.11 Voltage Sag and Surge Detection ............................................................................................. 17 2.12 Relay Control ............................................................................................................................. 18 2.12.1 Autonomous Mode ......................................................................................................... 18 2.12.2 Slave Mode .................................................................................................................... 18 2.12.3 Activation Delay ............................................................................................................. 18 2.13 On-Chip Calibration Routines .................................................................................................... 20 2.13.1 Voltage and Current Gain Calibration ............................................................................ 20 2.13.2 Offset Calibration ........................................................................................................... 20 2.13.3 X+Y Capacitor and R Compensation Coefficient Calibration ........................................ 20 2.13.4 On-Chip Temperature Calibration.................................................................................. 21 2.13.5 External Temperature Calibration .................................................................................. 21 3 Data Access and Configurability ..................................................................................................... 22 3.1 Register Descriptions ................................................................................................................. 22 3.2 Scaling Registers (Iscale, Vscale, Pscale, Tscale, Fscale) ....................................................... 24 3.3 Output Registers ........................................................................................................................ 25 3.4 Input Registers (Setup and Calibration) ..................................................................................... 27 3.5 Relay Configuration ................................................................................................................... 29 3.6 DIOState Register ...................................................................................................................... 30 3.7 Alarms and Alarms Configuration Registers .............................................................................. 31 3.7.1 Alarms Status Register (address 0x30) ......................................................................... 31 3.7.2 AlarmSticky Register (address 0x54) ............................................................................ 32 3.7.3 AlarmMask1 (address 0x09) and AlarmMask2 (address 0x51) .................................... 33 3.7.4 AlarmSet Register (address 0x0C) ................................................................................ 34 3.7.5 AlarmReset Register (address 0x0F) ............................................................................ 35 3.7.6 Alarms Configuration Registers (Thresholds and Hold-Off Time) ................................. 36 2 Rev 3