ROHM’s New Current Sense Amps Tackle High and Negative Voltages
As vehicle electrical systems diversify and 48V architectures become more common, the demand for high-accuracy current monitoring across a wide range of voltages is growing. To meet this need, ROHM Semiconductor has introduced two new series of current sense amplifiers that cover both high-voltage and negative-voltage conditions—while also simplifying design complexity for automotive engineers.
Designed for Today’s Mixed-Voltage Automotive World
The BD1423xFVJ-C series targets high-voltage systems with support for input voltages up to +80V, making it well-suited for 48V domains such as DC-DC converters, auxiliary batteries, redundant power supplies, and electric compressors. These devices are packaged in TSSOP-B8J and are available in three gain configurations (30, 60, and 100 V/V) to offer engineers flexibility depending on application requirements.
Meanwhile, the BD1422xG-C series addresses space-constrained, lower-voltage automotive systems—think 5V/12V body electronics and drivetrain ECUs. Packaged in compact SSOP6, these devices support input voltages up to +40V and are also offered in three gain options (20, 50, and 100 V/V), enabling designers to optimize for precision and board real estate.
Precision Current Monitoring with Simpler Designs
Current sense amplifiers work by amplifying the small voltage drop across a shunt resistor, giving the system a readable signal for current monitoring. Traditionally, this might involve a separate op-amp and carefully selected discrete components—but ROHM’s integrated solution offers a more compact, reliable approach.
At the heart of these devices is a two-stage amplifier structure: a chopper amplifier at the input for excellent low offset performance, and an auto-zero amplifier at the output to maintain accuracy. Combined with internal resistor matching for gain setting, this architecture achieves ±1% sensing accuracy—even across varying temperatures.
Critically for automotive systems, the amps can tolerate up to -14V, which protects against reverse connection, back-EMF, and other negative voltage conditions that could otherwise damage sensitive circuitry. And since current detection remains accurate even when an external RC filter is added for noise suppression, engineers can focus less on analog design headaches and more on system-level functionality.
Supporting the Shift to Smarter Power Architectures
As OEMs ramp up vehicle electrification and implement more sophisticated distributed electronics, accurate power sensing across domains is essential for functions like overcurrent protection, battery health monitoring, and load management. ROHM’s new current sense amplifiers help engineers maintain precision across increasingly complex vehicle networks.
From body ECUs in 12V systems to auxiliary battery control in 48V zones, this latest lineup aligns with industry needs for higher reliability and reduced design time—especially as pressure mounts to shorten development cycles without compromising quality.
The Big Picture
The release of these new amplifiers signals ROHM’s ongoing commitment to analog innovation in the automotive space. With integrated solutions that replace discrete implementations, support for a wide range of voltage conditions, and features that enhance design flexibility, ROHM is helping engineers keep pace with the rapid evolution of vehicle electronics.
Whether you’re building for high-voltage auxiliary systems or fine-tuning current control in tight spaces, these current sense amps offer a robust foundation for power monitoring in today’s complex vehicles—and tomorrow’s.
