In recent years, the automotive and industrial sectors have seen increased demands for lower energy consumption in higher-power applications. This, in turn, requires shunt resistors capable of handling high power and providing highly accurate current sensing for efficient operation across a wide range of applications. ROHM's GMR and PSR series shunt resistors offer highly accurate current protection, even at high temperatures, making them ideal for high-power applications in the automotive, industrial, and consumer sectors.
The newly developed GMR320 series is available in a resistance range of 5 mΩ to 100 mΩ and a power rating of 10 W, making it ideal for electronic control units in automotive motors and headlights, as well as for motors and power supplies in industrial equipment and household appliances. The unique materials and structure of the GMR320 series reduce surface temperature rise by 23% compared to standard products, ensuring high robustness against overcurrent loading, even while being the smallest 10 W resistor available on the market. Furthermore, a high-performance metal alloy in the resistive material provides a low temperature coefficient of resistance (TCR), enabling reliable and highly accurate current sensing even at low resistance values.
On the other hand, for the PSR series, which is widely used as a high-power shunt resistor, the maximum power rating has been increased to 15 W, and the TCR value has also been improved by applying a terminal temperature reduction method. Ultra-low resistance values from 0.1 mΩ to 3.0 mΩ are available, and higher power ratings and high current sensing accuracy are provided in a compact package, contributing to further miniaturization in automotive and industrial applications, similar to the GMR series.
Furthermore, starting in October 2021, thermal simulation models of shunt resistors will be available on the ROHM website. This will allow for simulations to be performed before designing actual products, even in high-power applications where thermal design is particularly complex, thus significantly reducing design time.
ROHM is committed to further expanding its range of resistors (a fundamental product) from low to high power and to providing various tools and other technical support to contribute to the evolution of vehicles and industrial equipment by promoting significant energy savings and miniaturization.
Key features:
ROHM has recently developed the GMR320 series of high-power, low-ohm resistors, while also extending the power rating of the high-power, ultra-low-ohm resistor PSR series to cover the high-power range up to 15W. Furthermore, both series are rated according to the AEC-Q200 automotive reliability standard for passive components, guaranteeing a maximum operating temperature of 170°C, which provides high reliability even in vehicle environments where temperatures can be particularly harsh, such as in the engine compartment.
Design support tools that significantly reduce the design workload.
Starting in October 2021, thermal simulation models for shunt resistors will be available on the ROHM website. These models allow for advance simulation of the thermal design (an important factor during application design), thus reducing design workload.
ROHM also offers current sensing solutions that combine ICs with discrete components, contributing to greater efficiency and circuit miniaturization. For example, in motor drive circuits requiring current sensing for protection and control, the adoption of our class-leading, low-noise operational amplifiers, along with shunt resistors, enables high-precision current sensing.
Ultra-high power, low ohmic value shunt resistors: GMR series range
(Fig. 4)
High power, ultra-low ohmic value shunt resistors: PSR series range
(Fig. 5)
Availability: in mass production
Application Examples
Both the PSR and GMR series can be used universally in high-current sensing applications
GMR Series
• Automotive (Electronic control units for engines and headlights)
• Industrial equipment (factory automation equipment, motor peripheral circuits and power supplies)
• Household appliances (air conditioners, washing machines, refrigerators and vacuum cleaners)
PSR Series
• Automotive (electric power steering, electric compressors, DC/DC converters)
• Industrial equipment (photovoltaic inverters and power tools)
• Lithium-ion batteries
