UVLO functions are implemented for both the V_CC1 and V_CC2 supplies between the V_CC1 and GND1, and V_CC2 and V_EE2 pins to prevent an underdriven condition on IGBTs and MOSFETs. When V_CC is lower than V_{IT+ (UVLO)} at device start-up or lower than V_IT–(UVLO) after start-up, the voltage-supply UVLO feature holds the effected output low, regardless of the input pins (IN+ and IN–) as shown in Table 7-2. The V_CC UVLO protection has a hysteresis feature (V_hys(UVLO)). This hysteresis prevents chatter when the power supply produces ground noise; this allows the device to permit small drops in bias voltage, which occurs when the device starts switching and operating current consumption increases suddenly. Figure 7-5 shows the UVLO functions.

When V_CC1 or V_CC2 drops below the UVLO1 or UVLO2 threshold, a delay, t_{UVLO1_rec} or t_{UVLO2_rec}, occurs on the output when the supply voltage rises above V_IT+(UVLO) or V_IT+(UVLO2) again. Figure 7-5 shows this delay.

Figure 7-5 UVLO Functions