IC integrates power, voltage, and current monitoring

7th January 2021

Alex Lynn

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Allegro MicroSystems has announced the launch of the ACS37800, a Hall-effect power monitoring IC for single-phase AC and DC solutions in a small PCB footprint. Allegro’s ACS37800 also has an integrated power monitoring chip that 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, reducing the solution BOM size, cost, and complexity.

"Our newest power monitoring chip is a gamechanger for IoT devices, smart lighting, data centers, and telecom applications, in particular," said Shaun Milano, Business Unit Director for Current Sensors at Allegro. "We’ve improved on our 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, our customers can eliminate many expensive components on their PCBs. The ACS37800 dramatically simplifies measuring power in a unique single-chip solution."

The new ACS37800 allows devices to easily track power consumption and to optimise energy use by detecting reduced power efficiency for predictive maintenance. This makes the ACS37800 well suited for motor control, building automation, and a variety of green industrial applications.

Offered in an efficient SOIC16 footprint, the ACS37800 further reduces PCB size and significantly reduces bill of materials (BOM) cost and complexity by eliminating the need for many components that competitive solutions require in similar conditions. For example, the integrated 517 Vrms reinforced isolation enables current sensing without expensive opto-isolators, Rogowski coils, oversized current transformers, isolated operational amplifiers, or shunt resistors.

Thanks to its onboard regulator, the ACS37800 can be powered from the same voltage supply as the system microprocessor (5V or 3.3V).

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. Furthermore, the ACS37800 is able to average these parameters with many instantaneous measurements over a one minute period, avoiding inaccuracies when waveforms are asymmetric. These features reduce the reliance on microcontroller unit (MCU) resources for critical calculations.

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

Combining Allegro's factory programming of sensitivity and offset with vast user programmability allows designers to balance between time-to-market and customisation in the increasingly competitive energy-efficient applications, such as: