The crossover frequency of the control loop is selected to be less than the RHP zero of the modulator small signal model to ensure stability and simplify the compensation component calculations. The control loop crossover frequency is selected to be 1/8 the RHP zero frequency. The crossover frequency can be increased based on the application requirements but it is not recommended to exceed 1/5 the RHP zero frequency for wide supply voltage ranges. Equation 22 calculates the crossover frequency at the worst case operating condition.

where

• D' is (1 -D) at the minimum supply voltage

The target crossover frequency at the worst case operating condition is selected to be 2.45kHz. Note this is the same value used to calculate the minimum output capacitance in Section 2.5.