The UVLO can be adjusted using the external voltage divider network formed by R₁ and R₂. R₁ is connected between VIN and the EN pin of the TPS7H4001-SP and R₂ is connected between EN and GND. The UVLO has two thresholds, one for power up when the input voltage is rising and one for power down or brown outs when the input voltage is falling. For the example design, the supply should turn on and start switching once the input voltage increases above selected voltage (UVLO start or enable). After the regulator starts switching, it should continue to do so until the input voltage falls below (UVLO stop or disable) voltage. Equation 2 and Equation 3 can be used to calculate the values for the upper and lower resistor values. For the stop voltages specified in Table 9-1, the nearest standard resistor value for R₁ is 10 kΩ and for R₂ is 3.4 kΩ.