SLUU885C March 2012 – June 2024 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
There are two levels of OVP that exist. Under fault condition if the output voltage reaches 420 V, a non-latched OV protection is activated. Under this condition the output oscillates between 420 V and 380 V.
In the event of a more severe overvoltage condition, if the output reaches to 435 V, the latched over-voltage protection is activated and the unit is completely shut off.
The FIQ is currently used only for latched over-voltage protection. It is triggered by the comparator on AD06 (Comparator F). Comparator F’s threshold is set above the limit for the DC bus voltage, and the logic on DPWM1 and DPWM2 is set up to turn off DPWM1B and DPWM2B when the threshold is exceeded. In the current configuration, the only way to restart the PFC after a latched OVP fault is to reset the processor.