~ help to improve the power of industrial equipment and consumer electronic equipment ~

Rohm (headquartered in Kyoto, Japan), a world-renowned semiconductor manufacturer, has developed a thick film shunt resistor “ltr100l”, which is very suitable for current detection applications in industrial equipment and consumer electronic equipment.

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In recent years, in the field of industrial equipment and consumer electronic equipment, more and more attention has been paid to energy saving, such as trying to reduce the power consumption in the driving process by changing to variable frequency motor. In addition, in these fields, with the increasing power of application products, the protection circuit has become more and more important. Shunt resistor is a device used for current detection in motor drive circuit and battery protection circuit. In order to achieve high efficiency of application products and improve circuit reliability, its accuracy needs to be further improved.

Rohm is committed to expanding the product lineup of shunt resistors. Recently, the metal plate shunt resistor “gmr320” with maximum rated power of 10W has been put into mass production in February 2021. In addition, since April 2018, the “ltr50 low resistance series” of 2W rated power guaranteed thick film shunt resistor has also started mass production. The launch of this new product has expanded the product lineup of thick film shunt resistors to a higher power range.

The new product adopts improved resistor material and applies pin temperature derating in 3264 size (3.2mm × In the thick film shunt resistor of 6.4mm), the ultra-high 4W rated power in the industry is realized. The product is very suitable for the field of industrial equipment and consumer electronic equipment with increasing power, such as current detection applications of motor control circuit and overcurrent protection circuit. In addition, by optimizing the component structure, an excellent resistance temperature coefficient (TCR) * 1 has been achieved in the thick film shunt resistor industry. Since it is not easily affected by temperature, it can carry out high-precision and reliable current detection.

The new product “ltr100l” has been put into mass production at the scale of 1 million pieces per month (200 yen / piece, excluding tax) since September 2021. Rohm electronics Philippines, Inc. (Philippines) is the production base of the previous and subsequent processes. In addition, samples of new products can be purchased through the e-commerce platform ameya360, and one can be sold from now on (supplied gradually according to 10m Ω, 47m Ω and 91m Ω). In addition, Rohm’s official website also provides various materials and tools that can assist design, such as application notes (simulation models will be released in succession).

In the future, Rohm will continue to expand the resistor product lineup from low power to high power, which is conducive to energy saving and reliability improvement, and provide LSI and discrete product solutions, so as to give full play to the advantages of integrated semiconductor manufacturers and contribute to the development of industrial equipment and consumer electronic equipment.

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< new product features >

1. In the 3264 thick film shunt resistor, the industry’s ultra-high 4W rated power is realized

The new product adopts long side electrode packaging, with excellent heat dissipation performance. In addition, the new product adopts improved resistor material and applies pin temperature derating in 3264 size (3.2mm × In the thick film shunt resistor of 6.4mm), the ultra-high 4W rated power in the industry is realized. Compared with the previous products of the same size, the rated power is increased by about twice, so it is very suitable for the current detection application of industrial equipment and consumer electronic equipment that need to support high-power, such as motor control circuit and overcurrent protection circuit.

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2. Excellent resistance temperature coefficient helps to improve the reliability of application

By optimizing the component structure, the new product achieves excellent resistance temperature coefficient (TCR) below 300ppm / ℃ (when the resistance value is 10m Ω) in the working temperature range. Compared with ordinary products, the change of resistance value caused by temperature is reduced by about 50% ~ 65%, which can carry out high-precision current detection, so it is helpful to improve the reliability of application products.

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< tools that help significantly reduce design man hours >

It is expected that from November 2021, the corresponding online simulation environment will be provided on Rohm’s official website. Users can use the simulation environment to conduct thermal analysis by combining shunt resistors with power components and ICs (it is planned to be gradually launched from PSR Series). Using the simulation tool, the thermal design, which is the subject of application product design, can be simulated in advance, which will help to reduce the design time. In addition, Rohm also provides a current detection solution that helps to improve circuit efficiency and realize miniaturization by combining IC and discrete components. For example, in the circuit using motor, current detection circuit is required to provide control and overcurrent protection. Rohm makes high-precision current detection possible by combining ultra-low noise operational amplifier and shunt resistance.

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< product lineup of “LTR series” thick film shunt resistor >

Since the new product “ltr100l” is a thick film resistor, the resistance value is easy to expand, so it can provide a wide resistance range.

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< ltr100l application example >

It can be widely used in various fields dominated by industrial and consumer electronic equipment.

  • Industrial equipment (FA equipment, motor peripheral circuit, various power supplies)
  • Consumer electronic equipment (air conditioner, washing machine, refrigerator, vacuum cleaner)
  • Others (two wheeled headlights, electric vehicles, etc.)

< about the online simulation tool “Rohm solutionsimulator” provided by Rohm >

You can easily use the Rohm solutionsimulator by visiting the “Rohm solutionsimulator” special page on the following Rohm official website and logging in. In addition, documents required for using Rohm solutionsimulator are also published on Rohm’s official website. Rohm solution simulator special web page: https://www.rohm.com.cn/solution-simulator

< explanation of terms >

*1) TCR (abbreviation for temperature coefficient of resistance)

It refers to the “resistance temperature coefficient”. The lower the value, the smaller the change of resistance value relative to the change of ambient temperature, so as to suppress the fluctuation during equipment operation.

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