Introduction
HCT5912 is a low-power, high-accuracy DC energy metering IC with UART/SPI interface. The chip operates from a single supply with an input voltage range of 2.6V to 3.6V, and features under-voltage detection. Its low-power design enables a typical operating current of approximately 1.6mA. The chip integrates two independent high-accuracy, low-offset Sigma-Delta ADCs dedicated to voltage and current sampling respectively. Within the current dynamic range, energy metering error is less than 0.1%. In addition to DC energy, the chip is also capable of metering harmonic energy. It provides raw waveform data, RMS values, and average values for both voltage and current signals, as well as instantaneous and average power, voltage RMS, and current RMS, each with different refresh periods. The chip supports software calibration, including RMS gain correction, offset compensation, and power offset compensation. It also features interrupt detection for rapid identification of overcurrent, overvoltage, and supply under-voltage conditions, as well as self-checking of register configuration parameters. Upon fault detection, an interrupt signal is output via the interrupt pin, and the specific interrupt source can be read from the corresponding register. An on-chip crystal oscillator circuit with integrated startup capacitors is included, along with crystal detection functionality; when no crystal is present or the crystal is damaged, the chip automatically switches to the internal RC clock. The internal RC clock has a deviation of ±1% over the -40~85°C range, supporting crystal-free applications. For communication, the UART interface supports half-duplex operation at baud rates of 2400/4800/9600/19200, with auto baud rate detection and synchronous frequency measurement; an internal clock frequency deviation coefficient is available for MCU readback. In addition, a data interface is provided for reading current and voltage signal waveform data. The temperature coefficient of the high-accuracy ADC voltage reference is typically 10ppm/°C. Operating temperature range is -40~85°C, storage temperature range is -55~150°C, and the device is available in a QFN16 package.
