Current Sensors
Precision current sensing for efficient, high-voltage designs.
Allegro’s current sensors deliver galvanic isolation, lossless operation, and high-precision accuracy—enabling maximum efficiency and power density in compact systems. Designed for EV traction and auxiliary inverters, DC-DC converters, on-board chargers, solar inverters, and industrial power systems, our solutions offer isolation ratings up to 5 kVRMS, ultra-low conductor resistance down to 0.1 milliohms, and bandwidths up to 5 MHz for GaN/SiC power electronics.
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Field Current Sensors
Achieve unparalleled accuracy in current sensing with our field current sensors, designed for robust performance with stray field immunity and advanced diagnostics in demanding automotive and industrial applications.
Integrated Current Sensors
Our integrated current sensors combine precision measurement with built-in isolation for compact, high-efficiency designs.
Documentation & Resources
Technical Article
Deconstructing Current Sensor Accuracy Understanding Dynamic and Environmental Errors New
Master real-world current sensor accuracy. Learn how environmental drift, supply noise, and physical stress impact sensitivity and offset errors.
Application Note
PCB Ground Plane Optimization for Coreless Current Sensor Applications
AN296277 - This application note provides guidelines on how a PCB ground plane around the sensor location should be designed to achieve optimum performances.
Application Note
New Approaches to High-Efficiency Current Sensing: Integrated Hall Sensor ICs Save Power and Space
AN296100: Allegro current sensor ICs allow design engineers to use Hall-effect based current sensor ICs in new applications where increased energy efficiency or new operating features are required. Wherever current sensing is needed, an integrated Hall-effect IC can provide a solution.
Application Note
Current Sensing for Power Delivery
AN296256 - This article will discuss the advantages of various current sensing methods in power delivery.
Video
ACS780 & ACS781: High Current Density Fully Integrated Current Sensor ICs
Allegro’s new family of fully integrated current sensor linear ICs in a new core-less package designed to sense AC and DC currents up to 100 A.
Video
ACS712 Low-Noise 2100 VRMS Hall-Effect Current Sensor IC
The Allegro ACS712 provides economical and precise solutions for AC or DC current sensing in industrial, commercial, and communications systems. The device package allows for easy implementation by the customer. Typical applications include motor control, load detection and management, switched-mode power supplies, and overcurrent fault protection.
Application Note
Advantages of Filters on the Input and Output Terminals of the Current-Sense Amplifier New
AN296384 - This application note provides recommendations for the use of filters on the input and output terminals of the current-sense amplifiers in Allegro motor-gate drivers.
Blog
Beyond the Datasheet: Mastering Current Sensing Selection
Master current sensor selection with expert guidance on technology trade-offs to design safer, more efficient, dependable solutions.
Application Note
Improved Performance and Features of Allegro’s Next Generation, High Power Density CB Package Current Sensors
This application note will describe the use of the new high current ACS772 Hall-effect current sensor integrated circuit (IC) from Allegro MicroSystems and will give an overview
of its features and improvements from previous Allegro high-current sensors.
Application Note
Improving Efficiency in Smart Grid Applications With Fully Integrated Current Sensing ICs
With increasing concerns about the global demand for energy and environmental awareness, power electronics applications are under pressure to improve efficiency.
Technical Article
Hall Effect Current Sensing in Hybrid Electric Vehicle (HEV) Applications
This note provides an understanding of hybrid electric vehicle (HEV) power systems and the contribution Hall-effect sensing technology can provide to improving the performance and cost-effectiveness of these systems.
Application Note
Secrets of Measuring Currents Above 50 Amps
It can be challenging to sense currents exceeding 50 A because the task often involves thermal management, must take place in a limited PCB area, and in some cases, requires a voltage isolation device. Two widely used methods for sensing high currents are a sense-resistor/op-amp approach, and Hall-based current sensing.
Technical Article
Crank Sensor IC for Stop-Start
This article describes start-stop operation and enabling Hall-effect integrated circuits, in particular the Allegro MicroSystems ATS694 and the previous generation ATS658, which are used in this application.
Application Note
Integrated Current Sensing Without a Shunt in a Tiny 5-Pin SOT23-W Package
This application note discusses the highlights of the LH package, showcasing how it outperforms traditional shunt current sensing solutions and brings unparalleled performance to a wide array of applications.
Application Note
Achieving Closed-Loop Accuracy in Open-Loop Current Sensors
Closed-loop current sensing technology is employed in many industrial and automotive applications for accurate current sensing. Allegro MicroSystems has developed magnetic-based current sensor IC solutions that achieve near closed-loop accuracy using an open-loop topology.
Application Note
A Micro-Packaged Linear Current Sensor IC
Traditionally, current sensing has been accomplished with sense resistors or current transformers that can take up a large PCB area. Sense resistor values from 10 to 50 mΩ can burn a significant amount of power at higher currents.
Technical Article
Overcoming Size Challenges in PCB Design with Magnetic Current Sensors
Magnetic current sensors provide a compact and efficient alternative to traditional current measurement techniques that significantly reduce the size of components on PCBs.
Application Note
Current Sensing in Motor Drives
One of the more popular uses of the current sensor is the broad application of motor drives. Motors are electro-mechanical systems, converting electrical energy (voltage and current) into mechanical energy (torque and speed).
Technical Article
Rethink PCB Current Sensing
This article will discuss two new innovative approaches to measure currents up to 600 A in PCB: a near-lossless Hall-based current sensor with an integrated conductor and a non-invasive standalone core-free and shield-free differential Hall current sensor.
Application Note
Techniques to Minimize Common-Mode Field Interference When Using Allegro Current Sensor ICs (ACS724 and ACS780)
This application note will discuss the mechanism of CMR and focus on how to best use this mechanism through optimized circuit board design and layout for sensors that need an external magnetic core, sensors that have a core built into the package, and sensors that have an integrated current-carrying loop but no core.
Application Note
Shifting the Offset Voltage of Current Sensors
Most of the Allegro™ unidirectional current sensor ICs are trimmed such that the zero ampere output is at 0.1 × VCC . The advantage of having the output voltage at 0.1 × VCC is that the output can swing slightly lower than this value before saturating.
Application Note
Hall Effect Current Sensing in Electric and Hybrid Vehicles
Improved energy efficiency in HEVs and EVs can be attained by using electrically-driven actuators instead of belt-driven and hydraulic actuators. For instance, in traditional internal combustion engines a fan belt drives the cooling fan, which operates continuously while the engine is running.
Application Note
Guidelines for Designing a Concentrator for High-Current Sensing Applications with an Allegro Hall-Effect Sensor IC
A concentrator focuses magnetic flux lines, which are generated by electrical current flowing through a conductor, at the center of the air gap, where the Hall-effect magnetic sensor IC is positioned.
Technical Article
Current Sensing For Renewable Energy
In grid-tied photovoltaic systems, designers must focus on minimizing cost per watt to deliver the best possible return on investment.
Application Note
High-Current Measurement with Allegro Current Sensor IC and Ferromagnetic Core: Impact of Eddy Currents
AN296162 - The technique of measuring bus bar current with a surrounding ferromagnetic core is common knowledge. For highcurrent measurement above 200 A, Allegro recommends using a linear IC of the A136x family
Application Note
Differential Current Sensing with the 1 MHz Bandwidth ACS733
AN296154 - This application note describes the use of the new highly isolated, high bandwidth ACS733 Hall-effect current sensor integrated circuit (IC) from Allegro MicroSystems and gives an overview of its features and advantages over a highspeed current transformer (CT) current sensing solution.
Application Note
An Effective Method for Characterizing System Bandwidth in Complex Current Sensor Applications
This application note describes multiple methods for measuring
and characterizing system bandwidth, with a focus on
the impulse response method. Allegro’s ACS720 is the perfect device to validate the test methods outlined here.
Application Note
Vias-in-Pad Improves Thermal Performance for Allegro Current Sensors
This application note discusses the effectiveness of using vias-in-pad and other additional printed circuit board (PCB) layout techniques to improve heat dissipation for current sensors with integrated conductors.
Application Note
How to Analyze and Compare Allegro Current Sensor and ADC Error Components
AN296282: Allegro offers a wide variety of current sensors with analog voltage outputs, and in many applications, an analog-to-digital converter (ADC) converts the output voltage to a binary code.
Brochure
Brochure: Industry's First ASIL-C Field Current Sensor for eMobility
The ACS37601 is Allegro’s latest and most advanced linear Hall-effect sensor IC for core-based current sensing, developed in accordance with the ISO 26262 functional safety standard to achieve an ASIL C safety rating.
Brochure
Driving Change by Advancing Personal Mobility Through Cutting-Edge Technology
Our advanced sensor and power IC solutions are engineered specifically to meet the unique requirements of these designs, providing superior performance and reliability in harsh environments and under complex operating conditions.
Application Note
DC Current Capability and Fuse Characteristics of Current Sensor ICs with 50 to 200 A Measurement Capability
Allegro MicroSystems offers a wide range of current sensor IC solutions that fall into two main categories: ICs having an integrated current-carrying conductor and ICs designed to be used with an external magnetic core.
Application Note
Hysteresis Mitigation in Current Sensor ICs Using Ferromagnetic Cores
AN269114 - Traditional open-loop current sensor ICs, like the Allegro ACS758CB and ACS770CB families, have ferromagnetic cores that act as magnetic concentrators. They concentrate the magnetic flux density, the B field, generated by current flowing through a conductor onto the Hall-effect sensor IC.
Application Note
AN295045- Recent Trends in Hall-Effect Current Sensing
This paper presents recent advances in integrated Halleffect–based current sensor ICs. It covers the various packaging concepts for integrating the primary current path into the system, the major improvements in IC parameters, as well as a few examples of typical application circuits for uninterruptible power supplies (UPS), inverters, and battery ...
Application Note
Managing External Magnetic Field Interference When Using ACS71x Current Sensor ICs
AN26030 - In applications where large magnetic fields may be present, care must be taken in the alignment and spacing of the Hall element relative to those fields.