L9908 Automotive 3-Phase Motor Gate Driver

STMicroelectronics' L9908 is designed to drive six N-channel FETs for brushless motors in automotive applications. L9908 is a flexible 3-phase motor driver. Each of the three half-bridge driver channels (HS/LS couples) can be independently configured, allowing different load driving. Moreover, through six dedicated parallel inputs, the pre-driver stages can be controlled, independently supporting duty cycle operations from 0% to 100% and allowing the implementation of all kinds of electric motor control strategies. L9908 can withstand -14 V to +95 V excursion on the motor's pins.

Using a dedicated combination of regulators, charge pumps, and bootstrap circuits, L9908 is suitable to operate in passenger, commercial, or hybrid vehicles. L9908 guarantees high accuracy in the brushless motor control through three independent high accuracy current monitor channels with SPI-configurable input differential voltage ranges for ground referenced current measurements.

L9908 ensures safe operation of half-bridges by shoot-through diagnosis, dead-time, short to battery, short to ground, open load detection, and real-time phase voltage monitoring. L9908 implements external and internal supply, ground level, and internal temperature diagnostics.

A 32-bit out-of-frame SPI-secondary interface is implemented for communication up to 10 MHz between L9908 and uC. SPI communication is safe-guarded by a 5-bit CRC, 1-bit frame counter, frame length check, and an SPI-configurable Window Watchdog.

Features

• Motor supply voltage range from 4.5 V to 75 V for working in single (12 V systems), double (24 V systems), and 48 V battery applications
• Fully ISO26262 compliant, ASIL-D systems ready
• Six separate N-channel FET pre-drivers
• Three differential high accuracy current monitors for ground referred current measurements
• Three real time phase voltage monitor channels
• Protection and diagnostic (SPI programmable and protection in on-state; SPI programmable dead time protection; SPI programmable shoot-through diagnostic and protection; open load, short to GND and short to battery diagnostic in off-state; overtemperature diagnostic and protection with SPI programmable warning flag; SPI readable T_J measurement; ground loss diagnostic; system clock monitoring; over-voltage and under-voltage diagnostic on power supply pins and FET driver supply; SPI Window Watchdog; Fault status flag output)
• 32-bit - 10 MHz SPI interface with 5-bit CRC and 1bit frame counter for internal setting, self-test and full diagnostics