Block 1 - Overvoltage protection (1) (1)

D1 + D2 set a 38.4V breakvoltage. Once this voltage is surpassed, the transistor Q2 ideally conducts sending the signal OV_Prot. At the same time, Q1 starts to conduct, disabling the zener D2. When this occurs, the circuits becomes normal only when the voltage is lower than 36V (since D2 is disabled).