Grade 0 BLDC motor driver reduces MHEV drive systems

An integrated brushless DC (BLDC) motor driver has been introduced by Texas Instruments, targeting the mild hybrid electric vehicle (MHEV) market. The DRV3255-Q1 is claimed to be the first three-phase 48-V BLDC motor driver to integrate high- and low-side active short-circuit logic. This integration eliminates external transistors and control logic to reduce the size of 48-V motor drive systems used in traction inverters and starter generators in MHEVs by up to 30%.

The three-phase 48-V BLDC motor driver integrates the active short circuit logic and dynamic fault response to supply up to 30kW of motor power in MHEV systems to improve the response time of a 48-V motor drive system in heavy vehicles to reduce emissions and add power for ADAS. In addition to simplifying design, the level of integration reduces board space and bill of materials (BoM) costs.

The active short circuit allows MOSFET connections to be arranged according to system needs to prevent over-voltage and ensuing failures. The dynamic fault response automatically switches the motor driver to active short circuit mode in over-voltage conditions.

The high output power improves motor drive system response times, for fast acceleration after stopping. For motors which require currents as high as 600A, TI claims that the DRV3255-Q1 provides the industry’s highest gate-drive current, which can directly drive up to 1,000-nC gate-charge MOSFETs.

The AEC-Q100 Grade 0 motor driver protects 48-V powertrain systems from switching transients as high as 95V and load dump conditions across a temperature range of -40°C to 150°C. This also reduces the BoM by negating the need for protection circuitry.

The motor driver has been designed to a TÜV SÜD-certified functional safety development process, for compliance with functional safety ISO 26262 up to ASIL D. Development includes built-in safety mechanisms and documentation, e.g. failure modes, effects and diagnostic analysis and a functional safety manual. There are also safety mechanisms for the device’s internal failure modes. Other safety features are digital I/O pins which withstand up to 75-V absolute maximum ratings to protect against an external 12-V supply over-voltage.

The DRV3255-Q1 is available now in a 64-pin quad flat package. Full and custom quantity reels are available.