TDK should introduce high-speed TMR front-end IC for highly demanding EV motor control

Key summary

● The ASA 2310, a new TMR analog front-end, provides optimized signal conditioning for TMR bridge Angle sensors, as well as enhanced application compensation capabilities and safety monitoring

● ASA 2310-based rotor position sensing solutions with highly robust output buffering provide easy-to-use differential or single-ended SIN/COS outputs for remote sensing applications with best-in-class EMC performance.

● Rotor position sensing solutions based on TAS series and ASA 2310 analog TMR sensors provide a smaller, more flexible sensing system than inductive rotary transformers

TDK complements its existing TMR sensor portfolio with the new Micronas signal conditioning integrated Circuit (IC) ASA 2310 for high-speed automotive and industrial motor applications. The ASA2310 is a low-temperature, low-noise, customer-programmable TMR front-end IC with differential or single-ended SIN/COS input and analog output. ASA 2310 sample is now available. Production is scheduled to begin in late 2023.

ASA 2310 is designed as an interface for TAS series of TMR sensors with high precision analog signals. Powered and monitored by ASA 2310, the sensor detects the direction of the magnetic field in the x-y plane and provides a SIN/COS analog voltage output that is used as an input to ASA 2310. The ASA 2310 sensor interface and signal tuning are optimized for TMR bridge signals. By programming ASA 2310's non-volatile memory, it is possible to adjust major characteristics such as gain, bias, (absolute) 0 Angle, and orthogonality using integrated channels. The different coarse tuning Settings ensure that the product can support TDK's various TMR full and half Bridges. ASA 2310's amplified single-ended or differential output signals allow the rotation Angle of the magnet to be calculated with very high accuracy by external A/D converters and electronic control units (ECUs).

The ASA 2310-based new rotor position sensing solution provides high-resolution and accurate position measurements at high speeds up to 650,000 rpm. This allows high-speed motors to maximize torque and improve efficiency, which is critical for hybrid and electric vehicles to achieve maximum driving range. In addition, the sensor system configuration works independently of the number of motor pole pairs, so there is no need for complex hardware changes, which is a major advantage over induction rotary transformer technology. This provides more flexibility for future development of hybrid and electric powertrains.

With its overvoltage and reverse polarity protection (+/-18V), the ASA2310 has excellent electrical robustness. Compared to off-the-shelf amplifier ics, the ASA 2310 is better suited for applications with high safety requirements because the signal regulating IC simplifies the external circuitry and thus reduces the FIT rate. In addition, total system size, bill of materials and assembly process costs are reduced.

According to ISO 26262, the product is defined as SEooC (Independent Security Unit) ASIL B ready. For the most efficient fault location and elimination, ASA 2310 provides more than 97% of the single Point of failure metric (SPFM), exceeding even the standard requirements of the ASIL B classification. If the ASIL decomposition is applied to the system level, this product can also be integrated into the ASIL D system. In addition to various integrated safety monitoring of the IC itself and the external TMR bridge, the ASA2310 features an optional and unique fluxless self-check feature that allows the system to test the full signal path inside the device before normal operation begins. In application Settings, this test can be used to check the integrity of the entire signal path, including wiring, external output capacitors, and ECUs. Finally, the diversity of security monitoring helps to increase diagnostic coverage and simplify external security monitoring on the ECU side.

"ASA 2310 is a high performance IC that extends the capabilities of high-precision simulation TMR sensors and reduces the impact of noise and associated factors caused by remote application Settings where the sensor module is separated from the ECUs and connected via a long harness," Frederik Berstecher, product market manager for magnetic position sensors at TDK-Micronas. "When combined with TDK's TMR TAS sensor family, customers can commercially expand their application Settings based on accuracy, EMC or functional safety requirements, as the ASA 2310 can operate up to four TMR half-bridge sensors simultaneously. As a result, ASA 2310-based rotor position sensing solutions can be used in a variety of applications with high safety requirements, such as power steering, brake booster or traction motors." 

The TMR TAS sensor is available in a wide range of package combinations (single chip, dual chip), and the ASA 2310 signal conditioning IC comes in a very compact 3 x 3mm DFN12 SMD package. Reference evaluation boards with magnetic design and signal conditioning chipset sensors are available upon request from TDK.

Main application

● Brushless direct current (BLDC) and permanent magnet synchronous (PMSM) motors are reversed in a safety-related environment, with long wiring harnesses between the sensor and the ECUS
● Rotor position of traction motor for electric vehicle (BLDC, PMSM, PMSR...)
● Electric power steering motor
● Substitute spin
● Brake booster
● Lidar mirrors

Main features and benefits

● TMR full bridge and half bridge support for various TDKS
● Various analog output configurations
-   Differential or single-ended SIN/COS analog output signal (no demodulation required)
-   Non-ratio or ratio analog output related to the supply voltage
● Inherent signal adjustment with real-time on-chip calibration and integrated safety monitoring reduces the workload on the ECU side
● Optimized TMR signal adjustment, such as output gain, bias, 0 degree Angle and orthogonal correction
● Integrated protection of external TMR bridge for power supply
● Suitable for applications up to 650,000 rpm
● Working power supply and supervision voltage: 3 V to 5.5V
● Absolute maximum supply voltage: ±18 V
● Programming through the output pins of the product, no additional programming pins are required
● Low power consumption
● Optimized for the automotive ambient temperature range from -40°C to 160°C, integrated protection circuits provide excellent ESD and EMC robustness
● ISO 26262 Development: ASIL B ready SEooC ((PMHF, SPFM, LFM) according to ASIL C)
● Small size DFN12 3x3 mm package