The LMG352xR030-Q1 is a high-performance power IC, GaN device with integrated gate driver. The GaN device offers zero reverse recovery and ultra-low output capacitance, which enables premium efficiency in bridge-based topologies. A Direct Drive architecture is applied to control the GaN device within the power IC. When the driver is powered up, the GaN device is controlled directly by the integrated gate driver. This architecture provides superior switching performance compared with the traditional cascode approach. The integrated driver solves a number of challenges in GaN applications.
The integrated driver ensures the device stays off for high drain slew rates. It also helps protect GaN device from overcurrent, short-circuit, undervoltage, and overtemperature. Regarding fault signal reporting, LMG352xR030-Q1 provides different reporting method which is shown in Table 9-1. Refer to Section 9.3.6 for more details. The integrated driver is also able to sense the die temperature and send out the temperature signal through a modulated PWM signal.
Unlike Si MOSFETs, there is no p-n junction from source to drain in GaN devices. That is why GaN devices have no reverse recovery charge. However, the GaN device can still conduct from source to drain in third-quadrant of operation similar to a body diode, but with higher voltage drop and higher conduction loss. Third-quadrant operation can be defined as follows: when the GaN device is turned off and negative current pulls the drain node voltage to be lower than its source, the voltage drop across the GaN device during third-quadrant operation is high. Therefore, TI recommends to operate with synchronous switching and keep the duration of third-quadrant operation at minimum.