The input voltage feedforward modulator converts the integrated current error signal, ILerr, into an inductor on-time that provides a controlled volt-second balance across the inductor over each full switching period that simplifies the current error integration loop design. The modulator produces a full-cycle averaged small signal Vcntrl to dIL/dt transfer function given by Equation 1:

Equation 1.

Thus the inductor current modulator gain is given by Equation 2:

Equation 2.

This natural integration 1/f function allows the current loop to be compensated by the mid-band gain of the error current integrator.