Allegro Microsystems Launches High-Bandwidth Current Sensors for EVs
Both current sensors are designed to improve efficiency in GaN and SiC power converters.
Allegro Microsystems recently announced two new high-bandwidth current sensors, the ACS37030 and ACS37032, to help designers achieve maximum performance, efficiency, and reliability from their SiC and GaN power systems.
To learn more about the sensors, All About Circuits spoke to two Allegro Microsystems representatives involved in their development: Current sensor produce line director Shaun Milano and product line manager Matt Hein.
The new ACS37030 and the ACS37032 high-bandwidth current sensors
“When you’re designing a power system, you want systems that maximize power density, meaning you need to be more efficient, more reliable, and more compact," Milano said. "That is really the motivation and the inspiration for our new products.”
Allegro's New Current Sensors: ACS37030 and ACS37032
Allegro's new current sensors take a dual-signal-paths approach: while one path captures high-frequency current data using an inductive coil, the other captures DC and low-frequency current information with Hall-effect elements.
Accuracy and noise performance are critical in current sensing applications, and the ACS37030 and ACS37032 excel at both. They offer a low sensitivity error of ±2% over the temperature range (-40°C to 150°C), a maximum offset voltage of ±10 mV, and an input referred noise limited to 50 mARMS. Depending on the SKU, the devices’ sensitivity can reach as low as 20.3 mV/A with a current sensing range of ±65 A.
"Because this is the first-to-market 5-MHz product, [designers] are not just going to find a bag of parts—they're going to find a way to sense the current,” Milano explained. “We're helping them meet all their objectives: It comes in a plug-and-play, fully integrated small form factor with very low resistance, allowing them to quickly design this and bring the bill of materials and PCB area down.”
ACS37030 functional block diagram.
Additionally, the ACS37030 and ACS37032 are marked by their immunity to external magnetic fields, achieved through differential sensing. This makes them robust in environments with high electromagnetic interference. Specifically, the ACS37030 includes a VREF output voltage for differential routing in noisy application environments, enhancing signal integrity. In contrast, the ACS37032 features a FAULT output for fast open-drain overcurrent detection, adding a layer of protection to the system by quickly identifying overcurrent conditions.
Another focal point of the sensors’ design was reliability. For instance, the compact surface-mount package of these sensors is designed for high isolation, with a rated isolation voltage of 3,500 VRMS. This is critical for applications requiring electrical safety and reliability, particularly in high-voltage environments. The basic and reinforced isolation voltages are specified at 840 VRMS / 1188 VDC and 420 VRMS / 594 VDC, respectively. The AEC-Q100 Grade 0 qualification makes these sensors suitable for automotive applications and other demanding environments.
High Bandwidth for Fast Control
The chief feature of the new current sensors is the ultra-high bandwidth they offer.
Fast control loops are pivotal for GaN and SiC-based power systems due to their inherent high-switching frequencies and the need for efficient thermal management. These advanced semiconductor materials operate effectively at high frequencies, which can lead to significant energy losses and thermal dissipation if not properly managed. Fast control loops enable fast responses to changes in the system, protecting against these critical issues and increasing the system's efficiency and reliability.
The frequency response of the ACS37030/2.
“If I want to have this control loop running at a much higher frequency, then I need the current feedback faster," Hein said.
"That's the excitement about this product: it is the first 5 MHz product on the market.”
With the ability to sense signals up to 5 MHz and a 40 ns typical response time, the ACS37030 and ACS37032 stand out for their unique ability to speed up control loops for wide-bandgap power systems and, consequently, enable more efficient power circuits.
Built for a Range of Power Systems
Combining high bandwidths and high accuracy in a compact AEC-Q100 Grade 0-qualified device, the ACS37030/2 is poised to unlock higher performance and efficiency in power systems ranging from EVs to servers.
“We have to understand our customer pain points, where they're headed, and then we have to react and develop solutions that meet those needs,” Milano said. “That's what we're doing with these current sensors, and that’s what we’ll continue to do.”
All images used courtesy of Allegro Microsystems.
Do we have LTspice model ACS37032?