The TPS61094 has a built-in undervoltage lockout (UVLO) circuit to make sure the device works properly. When the voltage at the VIN pin is above the undervoltage lockout (UVLO) rising threshold (typically 1.7 V), the TPS61094 can be enabled. After the TPS61094 starts up and the output voltage is above 1.7 V typically, the TPS61094 can work with SUP pin voltage as low as 0.6 V and input voltage down to 0 V. When the voltage at the VIN pin is down to 0 V and the voltage at the SUP pin are below the undervoltage lockout falling threshold (typically 0.6 V), the TPS61094 goes into Shutdown mode to avoid malfunction. In this condition and in Auto boost mode, the TPS61094 disconnects the bypass switch and high-side switch to prevent the reverse current from the VOUT pin to the VIN pin and SW pin when the V_OUT voltage is above 1.6 V.

When the voltages at the VIN pin and SUP pin are below 1.7 V (typical) and the voltage at V_OUT is below 1.6 V (typical), the TPS61094 goes into Shutdown mode.