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Melexis unveils the MLX91229, a conventional-Hall current sensor featuring a sigma-delta digital output to improve signal integrity in electrically noisy environments. Supporting current sensing from 200 A to 2000 A, the new IC is optimized for traction inverters and other automotive systems where local power electronics typically disrupt standard sensor transmissions.
As electrified powertrains continue to evolve toward higher voltages and faster switching technologies such as silicon carbide (SiC) and gallium nitride (GaN), the electromagnetic environment within vehicles is becoming more challenging. These conditions can introduce disturbances along the signal path between the sensor and the microcontroller (MCU), particularly in systems where longer PCB traces or wiring are required. While analog current sensing remains widely used and effective, ensuring signal integrity in these environments can require careful design and multiple development iterations.
Improving Signal Integrity in High-Power Automotive Systems
The MLX91229 addresses these challenges by shifting the signal transmission from the analog domain to a digital domain. In conventional analog implementations, the measured current is represented by small voltage variations, meaning any disturbance coupled into the signal path directly translates into measurement error. By contrast, the MLX91229 encodes the measured current into a sigma-delta bitstream, where information is carried through the density of digital pulses rather than absolute voltage levels. This creates an inherent noise margin, allowing the signal to tolerate disturbances during transmission without significantly impacting the reconstructed measurement at the MCU.
By maintaining signal integrity between the sensing element and the receiving MCU, the device helps reduce the impact of noise introduced along the signal path. This is particularly relevant in traction inverter systems, where high currents and fast switching events generate significant electromagnetic interference (EMI) and place increased pressure on PCB design and signal routing.
Furthermore, as the MLX91229 shares the same footprint as existing analog Hall-effect solutions, it allows engineers to easily evaluate digital output sensing without significant changes to system layout. The sigma-delta output also provides flexibility at the system level, enabling engineers to select demodulation strategies that balance bandwidth, noise, and response time according to application requirements.
“As power electronics environments become more demanding, ensuring signal integrity is becoming increasingly critical,” said Bruno Boury, Product Line Director at Melexis. “With the MLX91229, we are enabling the shift toward digital current sensing in real automotive systems, delivering more robust performance in electrically challenging environments.”
The MLX91229 builds on proven technology already demonstrated in industrial environments and is now being made available for automotive and mobility applications. By introducing digital output into its current sensing portfolio, Melexis aims to support engineers as they face evolving system requirements.
About Melexis
Melexis (melexis.com) engineers microelectronic solutions. These solutions facilitate the work of our customers. By easy integration. By taking innovation one step further. By providing a competitive advantage. Our technology makes cars and other products smarter, safer and greener. Our sensors capture data from the analog world and comprehend these data digitally. Our drivers make sure customers can bring their products to life. As we always have a plan, we come with the right products at the right moment so our customers stay one step ahead of the competition. That’s what we call inspired engineering.
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