SLUA963B June 2020 – October 2022 UCC21710-Q1 , UCC21732-Q1 , UCC5870-Q1
UVLO and OVLO functions are implemented for all three gate driver power supplies, VCC1, on the primary, and VCC2 and VEE2, on the secondary. The VCC1 UVLO ensures a valid supply is connected for the required logic interface. The UVLO/OVLO for VCC2 and VEE2 ensure valid supplies based on the type of transistor used (SiC MOSFET or IGBT). The UVLO function prevents overheating damage to the IGBTs/MOSFETs from being under-driven while OVLO is implemented to prevent gate oxide degredation (shortened lifetime) of the IGBT or MOSFET due to over-voltage when turned on.
The UCC5870-Q1 Analog Built-In Self-Test (ABIST) function runs diagnostics automatically on all under-voltage comparators monitoring VCC1, VCC2, and VEE2, and internal regulators during the power up process. During the test an over-voltage and under-voltage condition is simulated while the actual voltage rails remain unchanged, and the disturbance is not observable. A failure in this routine will set a fault.