Digital synthetic ripple modulator for DC-DC converter

The digital control based synthetic ripple modulator generates the duty ratio with inverse relation to a sampled converter parameter. The on-time and off-time duration of the switches forming the duty ratio is generated by successively accumulating the sampled inductor voltage. The accumulated output forming the synthetic ripple is added to the error between output voltage and reference voltage which act like feed forward system. The carrier signal thus generated is modulated between the higher and lower hysteretic thresholds, thus generating the duty ratio. A scaling process also allows the implementation of programmable switching frequency for synchronous buck converter.