7.4.1 Undervoltage and Overvoltage Shutdown

During normal operation (6 V < V_(VIN) < 40 V), when the supply voltage at the VIN pin drops below 4 V during cranking, each boost controller is disabled (when previously in normal operation). As long as the battery voltage stays above 3.5 V, both PWM dimming FETs are still controllable through the PWMINx pins, and the V_CC regulator is still active. The supply voltage recovering above 4 V re-enables each boost controller (which was working normally before the supply voltage drop). When supply voltage at the VIN pin drops below 3.5 V, the device enters standby due to battery undervoltage. From standby mode, re-enabling the device can only occur when the supply voltage is above 6 V and one or both PWMINx pins are high for t > t_{(CH_ON)}). See the state diagram in Figure 13. When the supply voltage at the VIN pin goes above 40 V during load-dump, the device disables both boost controllers due to battery overvoltage, and switches both PWM dimming FETs off. The V_CC regulator is still active. Once the battery voltage is below 40 V, the device recovers from this global failure state after a global disable-and-enable cycle (active shutdown by pulling both PWMINx pins low for t > t_{(CH_OFF)}, and setting one or both PWMINx pins high for t > t_{(CH_ON)}). See the state diagram in Figure 13.