Measuring Power Consumption with PAC1934

The PAC1934 are four-channel power and energy monitoring devices. A high-voltage multiplexer sequentially connects the inputs to a bus voltage monitor and current sense amplifier that feed high-resolution ADCs. Digital circuitry performs power calculations and energy accumulation. This enables energy monitoring with integration periods from 1 ms up to 36 hours or longer. Bus voltage, sense resistor voltage, and accumulated proportional power are stored in registers for retrieval by the system master or by the embedded controller. The sampling rate and energy integration period can be controlled over SMBus or I2C. Active channel selection, one-shot measurements, and other controls are also configurable by SMBus or I2C. The PAC1934 device uses real-time calibration to minimize offset and gain errors. No input filters are required for this device.