Allegro’s New ACS37800 Simultaneously Monitors Voltage, Current, and Power

The new series of four closely related ICs makes it possible to easily add power monitoring in DC and single phase AC applications

 

Image courtesy of Allegro

 

Allegro’s ACS37800 is a galvanically isolated, Hall-effect based sensor that measures current by detecting the magnetic field from an internally integrated conductor, eliminating the need for the space-eating external components that would otherwise be needed, resulting in a lower BOM count, increased reliability and lower overall costs. 

 

Block diagram of the ACS37800. Image courtesy of ACS37800 datasheet

 

"Our newest power monitoring chip is a gamechanger for IoT devices, smart lighting, data centers, and telecom applications, in particular," says 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." 

 

Reducing Dependence on the MPU

The ACS37800 calculates the active, reactive, and apparent power for fast power triangle analysis. It also provides instantaneous as well as RMS values for current, voltage, or power. The units, by themselves, will also calculate one minute averages of these parameters, useful when dealing with asymmetric waveforms.

 

Choice of I2C or SPI Interface

The device is available in two versions each employing the I2C and SPI communications buses. 

 

Modified image courtesy of ACS37800 datasheet

 

I2C versions support multiple addressing and also provide a pinout for zero-crossing detection, useful for LED dimming control. Users will also be able to program the thresholds for under-voltage, overvoltage and overcurrent via EEPROM, available over dedicated I/O pins.

 

Specific Parameters

• The ACS37800 features a current sensing range of up to 90 amps, maximum continuous current is 60 amps
• It sports a 1 kHz bandwidth.
• Because of the 0.85 mΩ primary current resistance, the device will not be a cause of wasted power
• Over-current reporting can be programmed for as fast as 5 µseconds (typ)
• The ACS37800 factory calibrated. The user can readily add application specific configuration via downloadable GUI-based software. 

 

Applications

• Smart lighting
• Industrial applications
• Motor control
• Telecom and server power supplies
• Smart appliances
• IoT edge device power tracking
• Asymmetric AC waveform applications    

 

Physical Considerations

Dimensions

The SOIC16W package size is 10.30 by 7.50 mm, with a footprint of 10.30 by 10.30 as illustrated below.

 

Image courtesy of ACS37800 Datasheet

 

Allegro cautions that the illustration is for reference only, not for tooling use. Operating temperature range: -40 to +125℃

 

Regulatory Concerns

Certified to UL 60950-1 (ed. 2) and UL 62368-1 (ed. 1) for reinforced isolation up to 517 VRMS 

The units are described as RoHS compliant, but conditions apply

Working Voltage for Basic Isolation - Maximum approved working voltage for basic (single) isolation according to UL 60950-1 (edition 2) and UL 62368-1 (edition 1)

• VPK or VDC: 1480
• VRMS: 1047

 

ESD Ratings

• Human body model: ±5 kV as per JEDEC JS-001
• Charged device model: ±1 kV as per KEDEC JS-002