This design example is powered by a rechargeable battery that can be a building block in many portable applications. Noise-sensitive portable electronics require an efficient small-size solution for their power supply. Traditional LDOs are known for their low efficiency in contrast to the low-input, low-output voltage (LILO) LDOs such as the TPS7A11. The use of a bias rail in the TPS7A11 allows the device to operate at a lower input voltage, thus reducing the power dissipation across the die and maximizing device efficiency. Equation 7 calculates the efficiency for this design.

Equation 7 reduces to Equation 8 because the design example load current is much greater than the quiescent current of the bias rail.