INTEGRATED CURRENT SENSORS

Current sensors have to be smaller, smarter, cheaper. LEM’s R&D is actively developing a range of ICS to reduce the footprint of the current sensing function and simplify the integration of current measurement in a wide range of applications in automotive, industrial, or residential.

At low currents, shunts remain a viable solution, but they have isolation challenges and cannot provide the current sensing function alone. They require amplifiers and/or analogue-digital conversion (ADC) for signal treatment of the measured voltage drop.

Thanks to technical progress in semiconductor manufacturing and packaging, it is now possible to integrate all the stages of a current sensor in 1 single package. Current flows through the device, the induced magnetic field is sensed by two Hall-effect plates, the operation is contactless and provides inherent galvanic isolation, the voltage signal is treated inside an application-specific integrated circuit (ASIC) and this very ASIC also allows to add other ad hoc features.

As a leader in electrical measurement for 50 years, LEM is constantly developing new technologies to fit customers evolving needs. The company is now building a complete ICS range to serve evolving needs as well as new applications.

GO series

Standard package and small footprint
Cost effective
A perfect compromise for small drives, robots, solar inverters, e-bikes etc.

Main features

1% accuracy at 25°C
Low drifts (offset: 75uV/°C, Gain: 200ppm)
17mA power consumption
Fixed and ratiometric output

HMSR series

SOIC 16 compatible footprint
Great accuracy: Typical accuracy is 0.5% over temperature and the measurement range -Small hysteresis of <<0.5%
Strong immunity

Main features

Current range 6-30 Arms continuous at 125°C (75 A peak)
Isolation: 4,950 Vrms
Global accuracy -25°C: 0.78 %
Global accuracy -Over T° C: 1.4 %

FHS Series

Standard package and small footprint
Cost effective
Standard SOIC 8 surface mount PCB

Main features

Hall effect current sensor with Integrated Magnetic Concentrator (IMC)
Magnetic field measurement range ±3.3 mT
Low power consumption
High bandwidth: 160 kHz

More about LEM’s Integrated Current Sensors

What is an Integrated Current Sensors?

Integrated Current Sensors are Hall-effect based sensors that integrate the current conductor, the sensing elements, the signal treatment die, some dedicated features such as fault detections, and the isolation, all in one single package to reduce the footprint of the current sensing function.

Why use an IC Sensor?

For low current, shunts remain an alternative, but they have isolation issues and require additional electronics parts to fully complete the current sensing function. ICS are highly integrated products that work seamlessly in every application. At LEM they are the result of leveraging 50 years of fundamental electrical knowledge, customers applications understanding and product innovation. Integrated sensors are the most optimized pieces of hardware to sense the current in every environment.

What is the technology used in LEM’s Integrated Sensors?

IC sensors can use Hall-effect technology for current sensing.

Hall-effect sensing is one way to do contactless measurement of the current-induced magnetic field. A Hall cell is a sensing element that converts a change in the magnetic field into a change of its resistance. When a constant current goes through the hall cell, it will give a voltage output change proportional to the magnetic field.

Contrary to traditional Hall-effect current sensors, integrated current sensors are not using a ferrite core around the current conductor and the sensing elements to concentrate the magnetic field. They are using differential measurement.

Thanks to differential measurement, it is possible to get rid of the ferrite core while keeping a good response to external fields perturbations. Differential measurement uses 2 sensing elements (the Hall cells). They both receive the magnetic field to be measured, one with a positive factor, and the other with a negative factor. They also receive any external fields with the same incidence. When making the difference between the fields seen by the 2 cells, the unwanted fields cancel each other.

5 advantages of LEM IC Sensors as current sensors

Integrated current sensors take advantage of differential measurement by not using a ferrite core. Getting rid of the magnetic core offers several benefits for embedded applications:

Reduce cost
Increases power density on sensing side – up to 75A in 800V applications for LEM IC Sensors products.
Current measure is not subject to offset from magnetic hysteresis.
Operating temperature not limited to the Curie temperature above which a ferrite can experience demagnetization (105°C), but rather by the maximum junction temperature of the device.
Frequency and bandwidth are not limited by the inherent saturation of the magnetic element of the core.

What are the applications where IC sensors can make the difference?

ICS are suitable for a wide range of applications where accurate control, efficiency and protection is needed. They allow designers to realize the current sensing function with a plug-and-play approach, with virtually all their challenges solved using only one part.

In DC/AC inverters and motors drives for example, LEM GO and HMSR can increase compactness and simplify design :

Low power loss integrated sensors can be put closer to heat sources such as microcontroller and transistors
Integrated isolation simplifies PCB layout
Built-in OCD makes sure the microcontroller can put the system in safe state with minimal delay.

STILL WANT TO KNOW MORE ABOUT INTEGRATED SENSORS?

Standards and certificates

GO Series	HMSR Series
IEC 61800-5-1: 2007	IEC 61800-5-1: 2007
IEC 62109-1: 2010	IEC 62109-1: 2010
IEC 62368-1:2018 (supersedes IEC 60950-1: 2005)	IEC 60950-1: 2005
UL 1577: 2014	UL 1577: 2014 (pending)
UL 62368: 2019.