Depending on the input and output conditions, ENA pin voltage, as well as the device temperature, the UCC14240-Q1 operates in one of the below operation modes.

1. Disable mode. In this mode, the module is off, but waiting for ENA pin becoming high to start operate.
2. Soft-start mode. In this mode, the module starts to deliver power to the secondary side. The primary-side operation duty cycle and secondary-side references are raised gradually to reduce the stress to the module.
3. Normal operation mode. In this mode, the module operates normally, delivers power to the secondary side.
4. Protection mode, auto-recovery. In this mode, the module is off, due to the input UVLO or OVLO protection. After the input voltage fault is cleared, depending on the ENA pin voltage condition, it either becomes disabled mode if the ENA pin voltage is low, or it goes through soft-start mode to the normal operation mode.
5. Protection mode, latched-off. In this mode, the module is off, due to other protections. The module remains off even the fault causing the protection is cleared. Recycling V_VIN operation must ensure the input voltage goes below the analog UVLO falling threshold (V_{VIN_ ANALOG_UVLOP_FALLING} ) first to reset the latch-off state, or the ENA pin is toggled Low (OFF) then High (ON).

Table 7-1 lists the supply functional modes for this device. The ENA pin has an internal weak pull-down resistance to ground, but TI does not recommend leaving this pin open.