To regulate the output, a 500kHz feedback PWM signal turns on and off the resonant transformer switching action. Analog Devices does this instead of directly controlling the CMOS switches because this approach separates the energy regulation from energy conversion, allowing optimized power transfer while maintaining regulation. The PWM is generated by a modified proportional-plus-integral controller integrated on the secondary side and fed back using an iCoupler data transformer. All compensation elements are implemented on-chip. The PI controller compares the output from the error amplifier to the output from a constant frequency ramp waveform generator.