BLDC AND DC MOTOR CONTROLLERS FOR SAFE AUTOMOTIVE APPLICATIONS - More power in less space

In modern-day vehicles, small electric drives perform a wide range of tasks – from cooling the battery and adjusting seats to controlling flaps and blowers (Fig. 1). The number of drives continues to grow steadily, especially in electrified architectures – where space is often limited. Brushless DC motors (BLDC) are becoming increasingly popular, as they take up less space, operate more efficiently and require less maintenance than conventional DC motors. At the same time, ever-more stringent requirements are being placed on functional safety, cybersecurity and electromagnetic compatibility (EMC). There is also a growing demand for compact, robust, and integrated control solutions that are economically viable both during the development stage and full-scale manufacture.

This is where the further developments of Infineon’s MOTIX MCU series come to the fore, in particular the B6 bridge driver (TLE995x) and the H bridge driver (TLE994x). They are designed for use in an array of small to medium-sized motor applications in vehicles where compact design, cost efficiency and functional safety are top priorities. 

Functional integration for decentralized control

A special area of application is the thermal management of electric and hybrid vehicles. Several smaller pumps and blowers are needed to regulate the temperature of the battery, power electronics and vehicle interior. These systems are typically installed in areas where space is limited, often close to heat sources or in humid environments. This demands compact, robust and reliable control units. The TLE995x series offers the ideal platform to meet these priority needs: Based on a 32-bit Arm Cortex-M23 core (40 MHz, 0.98 DMIPS/MHz, supported by 72 kB Flash and 6 kB RAM), it integrates not only the motor driver stage but also the power supply and a LIN communication interface in a TSDSO-32 package with good thermal properties and a footprint measuring just 6 mm × 9 mm (Fig. 2). 

Comfort functions, such as electrically adjustable seats, window lifts, sun roofs and cargo bed covers, require cost-sensitive solutions that need to incorporate protection and diagnostic functions. This is the only way to ensure blockage detection, current limits or error communication via LIN. The fully integrated LIN interface and diagnostic functions facilitate system integration into existing vehicle architectures. Despite its lower core power compared to the predecessor model (TLE987x), the TLE995x meets the high demands placed on modern motor controls. This is supported by efficient algorithms, such as field-oriented control (FoC) in dual-cycle operation, which are provided by software partners. 

Table 1: TLE987x vs. TLE995x

Focus on safety functions

The primary innovation focuses on integrated safety and protective mechanisms. The architecture was developed in accordance with ISO 26262 and meets requirements up to ASIL B. The ARM core supports safe computing, thereby enabling the implementation of safe communication, and has a safety shutdown path for the output stage. When it comes to cybersecurity, ARM TrustZone technology is applied. It ensures that sensitive data and processes that are critical to system security are executed in a protected zone shielded from manipulation and unauthorized access. 

Further properties: 

• Peripherals for the motor control: The CCU7 Advanced Timer Unit supports symmetrical and asymmetrical PWM generation and is directly connected to the bridge driver. This driver features a three-step sequencer and a high-speed sequencer for VDS slope timing. As such, the rise and fall times can be set and controlled, for example. The dual-stage charge pump supports a 100% duty cycle and can switch on the reverse polarity protection FET.
• The current sense amplifier enables differential voltage measurements via an external shunt and is directly connected to the ADC. The voltage range can be adjusted, and the current sense amplifier offers a high level of accuracy and low gain drift. An overcurrent shutdown feature is also integrated.
• Diagnostics: The controller delivers comprehensive diagnostic and protection functions, which are integrated into the MOTIX 32-bit motor control system-on-chip. They include adjustable overvoltage and undervoltage detection and shutdown, overcurrent detection and shutdown for external MOSFETs and OFF-state open load detection.
• 12-bit SAR ADC: The ADC offers complex post-processing functions, such as averaging and thresholds, and can independently detect the back EMF and make it available internally.

System-in-package offers advantages to developers

The TLE9954QSW40-33 system-in-package solution is available for applications with higher power requirements. It combines the TLE9954 motor controller with six OptiMOS 7 MOSFETs in a single package, making it the first fully integrated 12 V automotive solution for motor applications up to approx. 150 W.

Direct integration of the power semiconductors with the bridge driver offers several technical advantages:

• Reduced line inductances between driver and MOSFETs cut switching losses and minimize downtime.
• Less EMC emissions, as the length of the conductor is minimized.
• Reduction of external components, especially for gate triggering and the protective design.
• More compact design, which enables the use of smaller control units.

The package measures 9.5 mm × 9.5 mm and is designed for applications in a power range up to approx. 150 W, depending on the general thermal conditions. The thermal connection of the SiP (system-in-package) in this highly integrated approach is crucial for the overall performance of the system. 

Software and development support

An extensive software package is available for the TLE995x series. This includes ASPICE and MISRA-compliant components, peripheral drivers, sample applications and reference projects. Access is via the Infineon Developer Center.

Commercial software solutions are available from partners for integration in applications. MOTEON and EONAS offer field-oriented control (FOC) algorithms and other motor control software. ihr GmbH provides a LIN stack optimized for the TLE995x. This tool and software support simplifies the development of robust control units that comply with relevant standards. 

 The SiP variant TLE9954QSW40-33 is in the sampling phase, with initial test samples already being used by customers. Serial production is planned for mid-2026. The variants TLE995x and TLE994X have been in production since June. Appropriate design guidelines and reference PCBs are available for evaluation.

Looking to the future, it is to be assumed that requirements for functional safety, energy efficiency and networking will continue to rise. Infineon is, therefore, already planning to expand its portfolio to include industrial applications (IFX995x, IFX994x). The solutions are aimed at developers looking for space and cost-efficient small drive controls without compromising on safety, diagnostics and EMC.

 

For more information and a direct ordering option, please visit our e-commerce platform at www.rutronik24.com.

Subscribe to our newsletter and stay updated.