Integrated power monitoring IC optimizes energy efficiency, saves space

Allegro MicroSystems has released the ACS37800, an integrated Hall-effect power monitoring IC for single-phase AC and DC solutions in a small printed-circuit-board (PCB) footprint. Saving board space and cost as well as reducing design complexity, the integrated power monitoring IC allows simultaneous measurement of power, voltage, and current for AC and DC signals with an isolation rating of up to 1480 Vpk in a small SOIC16W package.

The new power monitoring chip is an improvement over the company’s first-generation integrated solution “by adding the ability to measure voltage, current, and power in AC as well as DC at the same time – and with reinforced isolation, said Shaun Milano, Allegro’s business unit director for current sensors, in a statement. Applications include IoT devices, smart lighting, smart appliances, data centers, and telecom applications.

The ACS37800 allows devices to track power consumption and to optimize energy use by detecting reduced power efficiency for predictive maintenance, said Allegro. Key applications that can leverage this feature include motor control, building automation, and a variety of green industrial applications.

The ACS37800 simplifies common power triangle measurements by calculating parameters such as the active, reactive, and apparent power as well as instantaneous and RMS values of the current, voltage, or power. It also can average these parameters with many instantaneous measurements over a one minute period, avoiding inaccuracies when waveforms are asymmetric, said Allegro. Another benefit is that these features reduce the reliance on microcontroller (MCU) resources for critical calculations.

The power monitoring IC’s high integration and power triangle calculations in combination with a small footprint reduces the bill of materials (BOM) cost and design complexity. For current sensing, one example cited is the elimination of opto-isolators, Rogowski coils, oversized current transformers, isolated operational amplifiers, or shunt resistors due to the integrated 517 Vrms reinforced isolation.

In addition, the ACS37800 can be powered from the same voltage supply as the system microprocessor (5 V or 3.3 V) thanks to the onboard regulator, said Allegro.

The device’s high configurability allows users to program the ACS37800 to fit a variety of application needs. For examples, designers can choose from a factory-programmed I2C or SPI interface, depending on whether the user prefers low noise or multiple addressing—and in I2C mode, and it provides zero-crossing detection pinout for easier LED dimming control. Users can also program thresholds for under/overvoltage, current/voltage gain and offset, and overcurrent trip point via EEPROM, allowing them to optimize their system from ±30 A to ±180 A and from –40°C to 125°C.