STMicroelectronics Automotive Grade Gate Drivers Increase Motor Control Flexibility

     ST's L9908 highly integrated automotive-grade three-phase gate drive unit (GDU) supports 12V, 24V or 48V automotive power systems, with flexible input and output channels, and can be used in traditional gasoline vehicles and hybrid/electric new energy vehicles. Realize a variety of applications. The L9908 provides dedicated source pins for each half-bridge to connect the upper and lower side FETs (field effect transistors), allowing the user to individually configure the output channels to drive different types of loads. In addition, the L9908 also provides six independent PWM (pulse width modulation) input pins, which can individually manage the pre-driver circuit to implement different motor control strategies.

     Three differential current monitors measuring ground current and three phase voltage real-time monitoring channels ensure monitoring accuracy. Diagnostic protection functions are also very rich. In applications such as low-pressure liquid pumps, air pumps and blowers for ventilation and cooling systems, as well as power seat controls, the highly integrated, flexible, and accurate L9908 can simplify design, save space, and improve control accuracy. The driver can also be used to design power motor inverters for mild-hybrid vehicles (ICE) and 48V pure electric scooters.

     With built-in diagnostics, the L9908 can also be used in safety systems such as Automatic Emergency Braking (AEB) and advanced Electric Power Steering (EPS), simplifying the ISO 26262 certification process. Safety features include SPI setting dead-time insertion and shoot-through short-circuit diagnostic protection; open-circuit load detection, short-to-ground diagnostics, and short-to-battery diagnostics; temperature warnings can be set and junction temperature measurement data can be read through the SPI bus. Additional diagnostics include ground loss detection, overvoltage and undervoltage detection of power pins and FET driver supplies; system clock monitoring, SPI window watchdog, and fault status flags.

     In single-battery (12V), double-battery (24V) and 48V car battery systems, the L9908 gate driver has high application flexibility because the motor power pins can withstand wide voltages from 4.5V to 75V, and the motor connection leads The pins can withstand voltages from -14V to 95V. The on-chip logic uses an internal 3.3V power supply, and the digital I/O ports are compatible with 3.3V and 5V logic levels.