The STMicroelectronics L9908 three-phase automotive gate-driver unit (GDU) operates on 12, 24 or 48 V systems and has flexible input and output channels to suit a variety of conventional and hybrid/electric vehicle applications.
Dedicated source connections to the top and bottom side FETs (field effect transistors) of each half-bridge allow users to configure the output channels independently to drive various types of loads.
Additionally, six separate PWM (pulse width modulation) input pins enable independent management of the pre-driver stages for different motor control strategies.
High accuracy is guaranteed, with three differential current monitors for ground-referenced measurements and three channels for real-time phase voltage monitoring. There is also a rich set of diagnostic and protection features.
By combining high integration, flexibility and precision, the L9908 simplifies design, saves space and enhances control of low voltage fluid pumps, pumps and blowers in ventilation and cooling systems, and electronic seat controls. It can also be used in traction inverters for mild hybrid internal combustion engine (ICE) vehicles and 48V all-electric city cars.
Additionally, the L9908's onboard diagnostics enable use in safety-related systems such as Autonomous Emergency Braking (AEB) and Advanced Electronic Power Steering (EPS), simplifying certification to ISO 26262.
Safety features include SPI programmable dead time insertion with diagnostics and trip protection, open load detection, and short-to-ground and battery short diagnostics. There is also an SPI-programmable temperature warning and SPI-readable junction temperature measurement.
Other diagnostics include ground loss detection, overvoltage and undervoltage detection on power supply pins and FET driver power, system clock monitoring, SPI window watchdog, and a fault status flag.
The flexibility to use the L9908 gate driver in single (12V), dual (24V), and 48V battery applications comes from its wide motor supply voltage range, from 4.5 to 75V, with the ability to tolerate -14 to 95 V on the engine. connecting pins. The on-chip logic is provided by an internally generated 3.3V supply and the digital I/O is 3.3 and 5V compatible.
