The UCC27532-Q1 device has an internal undervoltage-lockout (UVLO) protection feature on the VDD-pin supply-circuit blocks. To ensure acceptable power dissipation in the power switch, this UVLO prevents the operation of the gate driver at low supply voltages. Whenever the driver is in UVLO condition (when the VDD voltage less than V_ON during power up and when the VDD voltage is less than V_OFF during power down), this circuit holds all outputs LOW, regardless of the status of the inputs. The UVLO is typically 8.9 V with a 700-mV typical hysteresis. This hysteresis helps prevent chatter when low-VDD supply voltages have noise from the power supply. This hysteresis also prevents chatter when there are droops in the VDD bias voltage when the system commences switching and there is a sudden increase in I_DD. The capability to operate at voltage levels such as 10 V to 32 V provides flexibility to drive Si MOSFETs, IGBTs, and emerging SiC FETs.

Figure 7-1 Power Up