TIDUF28 November 2023
The LMG3422R030 GaN-FETs integrate overcurrent protection (OCP), short-circuit protection (SCP), overtemperature protection (OTP), and undervoltage lockout (UVLO). For details see the LMG3422R030 data sheet. The individual FAULT and the OC feedback signals of each of the three top-side GaN FETs are level shifted to 3.3 V through the ISO7741 quad-channel digital isolator. Each fault signal is low-pass filtered to attenuate high-frequency transient noise with a 300 Ω and 47-pF RC low-pass filter and logically combined using triple input AND gates for the three bottom-side and three top-side Gan-FETs, as shown in Figure 3-5. Hence the MCU can monitor fault and overcurrent events with the top-side or bottom-side GaN-FETs, respectively. The signals nOC_T, nOC_L, GaN_FAULT_L, and GaN_FAULT_T are routed to the C2000 controlCARD connector J2 and the MCU header J11.