ROHM has developed the thinnest metal plate shunt resistance on the market (H:0.03inch): PSR350. This high-power resistor is designed for automotive and industrial equipment. ROHM is expanding their PSR line with two metal plate shunt resistances that measure electrical current. The PSR100 has a capacitance of 0.2mO and the PSR330 features a 15W capacity. These are two of today’s smallest resistor sizes. Metal plate shunt resistance (MPS) are electronic components that monitor the current of an electrical circuit. Metal plate shunt resistances are made up of thin metal sheets with specific resistance values. When current is applied, they produce an electrical voltage across the plates, which allows for current measurement. These resistors are often used in industrial and automotive equipment where accurate measurement of current is crucial to the proper operation and control.
Power modules for industrial equipment have used shunt resistors for many years. In recent years, shunt resistors have been used in automotive power modules. These modules require thin, double-sided cooling power modules that include power device chips like IGBTs or SiC MOSFETs. Metal plate shunt resistances have a relatively high profile, which reduces cooling efficiency. However, reducing the height is difficult as various welding materials need to be tested before they can be evaluated.
ROHM’s strengths in manufacturing and designing allow it to create small-lot prototypes of power shunt resistances using various welding patterns and materials to meet market demands. This allows ROHM to manufacture some of the thinnest resistors available on the market. ROHM’s vertically integrated production system, material/process optimization techniques and their PSR350 have been used to achieve an incredible thickness of only 0.03inch (0.85mm). The thickness is approximately half that of the conventional 12W class product. The same technology was used to develop the industry’s smallest 15W-rated shunt resistance (PSR330). The compact design reduces the mounting area for high-power applications in various high power applications by around 65%, compared to other products of its class. This helps reduce mounting areas by about 75%. PSR100 is also soon to be available in a 0.2mO version, which will extend its lower limit beyond the existing 0.3mO versions for detection of higher currents.
ROHM’s metal plate shunt resistances will be continuously optimized to improve their performance in order to continue reducing the size and saving energy of applications. ROHM’s PSR Series high-power resistors are increasingly used in industrial and automotive equipment. It has always been difficult to meet both criteria at the same time, as there was a traditional imbalance between resistor sizes and rated powers. ROHM’s vertically-integrated production system allows for rapid product development by small-lot prototyping. The use of optimized materials and manufacturing processes can result in high-rated power compactly sized, with a lower temperature coefficient of resistance than general products.
