High-Power Ultra-Low-Ohmic Shunt Resistors

ROHM announces 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 PSR series includes PSR400, which is rated at 4 W, and PSR500, guaranteed up to 5 W.

Resistors in current detection applications are typically used to detect overcurrent conditions or remaining battery level. 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.

Features

• Exclusive precision welding technology utilized for improved rated power (5 W)
To support high power and ensure high measurement accuracy even in the ultra-low-ohmic region (0.2 mΩ), 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 results in improved power (5 W class) along with high productivity.
• 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.