High Power Ultra-Low-Ohmic Shunt Resistors | ROHM Semiconductor - ROHM Co., Ltd.
High Power Ultra-Low-Ohmic Shunt Resistors
5W class ideal for current detection in automotive and industrial applications
ROHM has recently announced the development of high power ultra-low-ohmic shunt resistors ideal for current detection in applications with increased power requirements, such as automotive systems and industrial equipment. The new PSR series includes PSR400, which is rated at 4W, and PSR500, guaranteed up to 5W.
Resistors in current detection applications are typically used to detect overcurrent conditions or remaining battery level. And although current sense resistors have been widely adopted in the automotive and industrial sectors, the recent trend towards greater sophistication and computerization has increased current requirements, leading to a need for high power components. This includes a demand for high accuracy resistors with superior temperature coefficient of resistance (TCR) for stable operation in extreme temperature environments and that feature ultra-low resistance values in order to minimize power consumption.
In response, ROHM utilized high quality resistor technology cultivated for the low-power sector to develop a new lineup of high power low-ohmic shunt resistors. In addition, high-yield precision welding technology made it possible to guarantee high rated power in the 5W class, while a high-performance alloy was adopted in the resistive metal for superior TCR in the low-ohmic region. This ensures sufficient margin even in applications with stringent temperature requirements, such as automotive systems and industrial equipment, while lightening design load.
1. Exclusive precision welding technology utilized for improved rated power (5W)
To support high power requirements and ensure high measurement accuracy even in the ultra-low-ohmic region (0.2mΩ), technology for bonding copper electrodes without variations is required. ROHM employed original precision welding technology to join the resistive metal to thick copper electrodes, achieving high heat capacity with excellent thermal dissipation characteristics. This increases power-handling capability (5W class) while improving productivity.
2. Superior temperature coefficient of resistance, even in the ultra-low-ohmic region
Generally, as resistance value decreases the temperature coefficient of resistance increases. In response, ROHM utilized a high-performance alloy material for the resistive metal, ensuring superior temperature coefficient of resistance even at ultra-low resistances.
Application Circuit Diagrams
・TCR (Temperature Coefficient of Resistance)
The lower this value is the smaller the change in resistance value in response to changes in ambient temperature, making it possible to suppress variations in device operation.