HT7038

The HT7038 series is a multi-function, high-precision three-phase energy metering IC, suitable for three-phase three-wire and three-phase four-wire applications. It integrates 6-channel second-order sigma-delta ADCs, a voltage reference circuit, and DSP circuitry for all power, energy, RMS, power factor, and frequency measurements. It is capable of measuring per-phase and combined active power, reactive power, active energy, and reactive energy, as well as per-phase current RMS, voltage RMS, power factor, phase angle, frequency, and other parameters — fully meeting the requirements of three-phase multi-rate multi-function energy meters. Supports all-digital gain and phase calibration, i.e., pure software-based meter calibration. The active and reactive energy pulse outputs CF1 and CF2 provide instantaneous active and reactive power information, and can be connected directly to a reference meter for error calibration. An SPI interface is provided for convenient transfer of metering and calibration parameters between the chip and an external MCU; all metering and calibration parameters are readable via the SPI interface. The built-in voltage monitoring circuit ensures normal operation during power-up and power-down events.

Key features

• High accuracy, non-linearity measurement error less than 0.1% within input dynamic range (5000:1)
• Active energy measurement compliant with Class 0.2S and 0.5S, supporting IEC62053-22:2003 and GB/T17215.322-2008
• Reactive energy measurement compliant with Class 1 and Class 2, supporting IEC62053-23:2003 and GB/T17215.323-2008
• Active/reactive power/energy and CF pulse output
• Power factor, phase angle, line frequency, and voltage phase angle parameters
• Voltage RMS and current RMS output, RMS accuracy better than 0.2%
• Three-phase voltage vector sum and current vector sum RMS output
• Phase loss detection and voltage/current phase sequence detection
• Interrupt support: zero-crossing interrupt, sampling interrupt, energy pulse interrupt, calibration interrupt
• Active and reactive reverse energy indication
• Selectable absolute value summation or algebraic summation for combined phase energy
• Adjustable meter constant
• Adjustable startup current
• Accurate measurement of active, reactive, and apparent power/energy up to 41st harmonic
• Gain and phase compensation, small-current non-linearity compensation
• SPI communication interface, up to 10Mbps
• Built-in temperature sensor
• Three-phase three-wire and three-phase four-wire mode support
• On-chip reference voltage with optional external reference voltage
• Pulse doubling function for small-signal calibration
• ROSI coil support
• LQFP32 package
• 3.3V supply voltage
• Crystal 5.5296MHz