Current detection is the "invisible bottleneck" of design

​Current sensors are essential in power equipment designs such as motor control, battery management, EV chargers, and solar inverters.

This component, which is the key to power control, protection, and monitoring, plays an important role that is directly linked to product performance.

In fact, the current sensor market is expanding year by year against the backdrop of advances in electrification and energy conservation.

According to a DATA BRIGE study, the global current sensor market is expected to be valued at US$3.65 billion in 2024 and reach US$12.46 billion by 2032(1).

*1Source: DATA BRIGE "Global Current Sensor Market Size, Share, and Trend Analysis Report – Industry Overview and Forecast to 2032"

Global Current Sensor Market Size, Share, and Trend Analysis Report – Industry Overview and Forecast to 2032

However, there is no end to the following voices being heard at the design site:

・Current sensor selection is difficult

- Annoyed by noise and heat

・Overcurrent detection is not possible in time

In fact, current detection is an "invisible bottleneck" that can be difficult to identify during design and can affect product performance.

Comparison of current detection methods

To select the optimal current sensor for your design, it is essential to first understand the features of each method. There are three main methods for current detection.

The method you choose will have a major impact on the overall design balance, including detection accuracy, response speed, heat generation, insulation structure, and size.

Therefore, it is important to select the optimal method depending on the application and design environment.

1. Shunt resistor method
A shunt resistor is placed in the path to be measured, and the amount of current is detected by reading the voltage across the shunt resistor.

　
2. Electromagnetic core type
The magnetic core is used to collect the magnetic force generated around the path being measured, and the magnetic sensor inside the current sensor detects the amount of current.

　
3. Electromagnetic coreless system
Without using a magnetic core, the current flowing through the current paths and bus bars on the board is drawn into the IC, and the amount of current is detected by the magnetic sensor inside the current sensor.

Comparison of advantages and disadvantages of each method

Here we will summarize the features of each method from the perspectives of heat generation, size, insulation, detection accuracy, and ease of mounting.

Image of each method

  

As such, each method has its own advantages, and the method you choose will depend on the design conditions and priorities.

What current sensing challenges do designers face?

Current sensors are important components that affect product performance, but they are also a field that presents many challenges for designers.

Difficult to select

There are multiple types of current sensors, and they must be selected according to the application and environment. However, there is fragmented information available, and many people find it difficult to determine which is best.

・Noise countermeasures are difficult

In designs that handle high frequency environments or large currents, false detections due to noise are likely to occur, leading to control instability and malfunction.

・Heat generation and insulation design is complex

The shunt resistor method inevitably generates heat, requiring heat countermeasures and insulation design, which leads to a more complex design and an increased number of components.

- Slow overcurrent detection

To function as a protective circuit, it must detect overcurrent instantaneously. A delayed response increases the risk of damage to the circuit or components.

- Low degree of freedom in implementation

Sensors with significant size and shape restrictions impose limitations on board layout and housing design, reducing design freedom.

Coreless current sensors give you design freedom

Conventional shunt resistor and magnetic core methods have many limitations, such as heat generation, insulation, and mounting layout.

​Coreless current sensors, which detect current without using a magnetic core, have emerged and are attracting attention as an option that breaks through the limitations of the past.

・Noise resistant

The type that supports differential measurement cancels out disturbance magnetic fields, enabling stable detection and preventing false detection even in high-frequency environments.

Low fever

Since current does not pass directly through the sensor, there is almost no heat generation, simplifying thermal design.

・Easy to insulate

The non-contact method using magnetic detection simplifies the insulation design and improves safety.

High degree of freedom in implementation

Many of the sensors are small and thin, and can be flexibly adapted to bus bars and current paths on the board, greatly increasing design freedom.

・Supports overcurrent detection

Some products are capable of high-speed response and can also serve as protection circuits.

These features make coreless current sensors particularly recommended for designers facing the following challenges:

• I'm having trouble with noise in power supply circuits and motor control
• High-precision current detection is required for EV chargers and inverters
• Insulation design and heat countermeasures are required
• Want to increase the degree of freedom in board design?
• I want to implement overcurrent protection

Want to know more about coreless current sensors?

This article summarizes the most common current detection methods and their respective features and challenges.

The next article focuses on Infineon 's coreless current sensors and introduces practical information useful for design, such as the detection principle (differential measurement), implementation points, and product lineup.

If you are looking to optimize your design, be sure to check this out.