A ∑Δ based DC-DC converter with supply noise suppression

An architecture that reduces the effects of supply noise on the regulated output of a DC-DC converter has been proposed. The structure consists of a sigma-delta modulator which drives the half bridge switches directly. The output of the quantizer is taken as the feedback for the sigma-delta as usual, but this feedback signal goes to a one-bit digital-to- analog converter that uses the noisy voltage supply as a reference to suppress the supply noise at the output. The proposed structure, designed and simulated using a 2.5V TSMC 0.25u process, shows supply ripple suppression.