A monolithic buck converter using differentially enhanced duty ripple control

Abstract

This paper reports a monolithic DC-DC buck converter using the differentially enhanced duty ripple control (DE-DRC). Without any compensation circuit, this converter is stable over a wide input and output range. The switching frequency is kept constant by adjusting the on-time according to the input and output voltage. Because of the large duty ripple voltage with a big noise margin, the DE-DRC buck converter has better noise immunity than current mode and hysteretic control. The easily configured positive and negative differential difference amplifier (DDA) gains (K p and K n ) can adjust the high and low frequency portion of the loop transfer function to achieve fast load transient response. Load transient test also showed 5mΩ pure resistive output impedance of this converter to achieve the adaptive voltage position (AVP) function. We demonstrated a 1.85MHz single phase converter with wide conversion range of 10%–86.6%. This circuit was implemented in 0.5µm BCD process of TI.