Some applications require that an overcurrent condition disable the device momentarily during a fault condition and re-enables it after a preset time. This auto-retry functionality can be implemented with an external resistor and capacitor. During a fault condition, FAULT pulls EN low. Pulling EN below the turnoff threshold disables the part is disabled, and FAULT goes into the high-impedance state, allowing C_RETRY to begin charging. The device re-enables when the voltage on EN reaches the turnon threshold. The resistor-capacitor time constant determines the auto-retry time. The device continues to cycle in this manner until removal of the fault condition.

Figure 9-1 Auto-Retry Functionality

Some applications require auto-retry functionality and the ability to enable and disable with an external logic signal. Figure 9-2 shows how an external logic signal can drive EN through R_FAULT and maintain auto-retry functionality. The resistor-capacitor time constant determines the auto-retry time-out period.

Figure 9-2 Auto-Retry Functionality With External EN Signal