ST Microelectronics has released a new three-phase, gate driver unit (GDU) for Automotive applications. The GDU is capable of controlling 6N-channel FETs for brushless motors used in fans, oil pumps required for steering and transmission, etc. The module has 3 current sensors and is capable of operating in 12V, 24V, and 48V system, and also have flexible I/o channels. The L9908 also features a built-in diagnostics system on external/ internal supply, ground level, and internal temperature.
According to the company, the module features dedicated source connections to both the low-side and high-side FETs of each half-bridge which allows the user to independently configure the output channels to drive different types of loads and withstand voltage between -14V to 95V excursion on the motor’s pin. There are 6 separate PWM input pins that give control of pre-driver stages for better motor control.
The L9908 is the successor of STM’s L9907 and has taken many features from its predecessor. The digital I/O supports both the 3.3V and 5V logic and can handle 12V and 24 V batteries with an input supply voltage of just 4.5V. The module is AEC-Q100 and ASIL-D compliant, thus making it suitable for automotive applications.
STM’s L9908 features three differential current monitors for ground referred current measurements, 3 real-time phase voltage monitor channels along with the 32-bit – 10 MHz SPI interface with 5-bit CRC and 1bit frame counter for internal setting, self-test and full diagnostics.
According to many studies and consumer reports a larger battery can help improve efficiency, thus reducing fuel consumption, and emissions while providing higher power. Hence, a 48V battery is better than a 12V or 24 V battery. To make electric vehicles more secure the ISO requirements demand that GDUs supporting 48 V applications safely handle supply voltage of up to 75 V. Furthermore, the L9908 uses its 32-bit SPI interface to offer diagnostic and protection features. It has real-time phase voltage monitoring, along with open load detection and a few others.
To ease the prototyping phase, STM has designed AEK-MOT-3P99081, a development board that has L9908 to drive a BLDC motor with Hall sensors. The development board will help in speeding up the prototyping phase, thus reducing cost and resources, which will lead to an increase in the adoption of the new L9908 module.