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BLDC Motor Driver Helps Enable Smaller 48-V MHEV Systems

BLDC Motor Driver

Texas Instruments have introduced a highly integrated Grade 0 brushless DC (BLDC) motor driver for 48-V high-power motor control systems.

Global Semiconductor company Texas Instruments have introduced a highly integrated Grade 0 brushless DC (BLDC) motor driver for 48-V high-power motor control systems, such as traction inverters and starter generators in mild hybrid electric vehicles (MHEVs). The DRV3255-Q1 can help designers shrink their motor system size by as much as 30%, while providing the industry’s highest gate-drive current for increased protection and output power. Meeting the most stringent safety requirements, the new motor driver was designed according to TI’s TÜV SÜD-certified functional safety development process, helping enable up to Automotive Safety Integrity Level (ASIL) D.

To help decrease greenhouse gas emissions globally, automobile manufacturers are increasing the production of MHEVs, which use 48-V motor-drive systems to help reduce emissions from a vehicle’s internal combustion engine. The TI Functional Safety-Compliant DRV3255-Q1 allows manufacturers to design a motor-drive system to help enable MHEV systems up to ASIL D, supplying as much as 30 kW of motor power which can improve the response time of a 48-V motor-drive system in heavy vehicles.

“A 48-V system is a step-change that original equipment manufacturers [OEMs] can implement to meet goals around reducing emissions, while also adding power for advanced driver-assistance system features and managing power-hungry loads such as the heating, ventilation and air conditioning system,” said Asif Anwar, director of the powertrain, body, chassis and safety service at Strategy Analytics. “Combining leading-edge performance characteristics with functional safety and Grade 0 translates to real-world, system-level operational benefits that will help OEMs achieve these goals.”

Reduce board space by as much as 30%

The DRV3255-Q1 is the industry’s first three-phase, 48-V BLDC motor driver to integrate high- and low-side active short-circuit logic, which eliminates external transistors and control logic. By integrating the active short-circuit logic and dynamic fault response, the new motor driver enables designers to not only simplify their designs, but also supply as much as 30 kW of motor power, while reducing board space and bill-of-materials cost in 48-V motor-drive systems.

The active short-circuit logic feature gives system designers the flexibility to arrange metal-oxide semiconductor field-effect transistor (MOSFET) connections based on system needs, and helps prevent catastrophic system failures due to overvoltage. The dynamic fault response automatically switches the motor driver to active short-circuit mode in overvoltage conditions, which protects the vehicle’s motor and electrical components from overvoltage stress while optimizing system performance.

Improve response times while protecting 48-V motor-drive systems from harsh conditions

The DRV3255-Q1 supplies the industry’s highest output power levels to improve 48-V motor-drive system response times, allowing drivers even in heavy vehicles like SUVs and trucks to accelerate more quickly after stopping. For motors requiring currents as high as 600 A, the DRV3255-Q1 provides the industry’s highest gate-drive current, which can directly drive up to 1,000-nC gate-charge MOSFETs.

In addition, this Automotive Electronics Council (AEC)-Q100 Grade 0 motor driver protects 48-V powertrain systems from switching transients as high as 95 V and load-dump conditions at a wide temperature range (-40°C to 150°C), eliminating the need for protection circuitry.

Streamline ISO 26262 compliance up to ASIL D

Built with functional safety in mind, the DRV3255-Q1 was designed using TI’s certified functional safety hardware development process and includes built-in safety mechanisms and documentation such as failure modes, effects and diagnostic analysis and a functional safety manual. In addition to the safety mechanisms for the device’s internal failure modes, the digital input/output pins withstand up to 75-V absolute maximum ratings to protect the DRV3255-Q1 against an external 12-V power-supply overvoltage.

For more information on the Grade 0 BLDC motor driver you can download the white paper  “How to Build a Small, Functionally Safe 48-V, 30-kW MHEV Motor-Drive System.”

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