An All-Passive Emulated Ripple Control Technique for Constant-On-Time Buck Converters in CCM

An all-passive Emulated Ripple Control (ERC) technique is proposed to ensure the stability of buck converters operating in Continuous Conduction Mode (CCM) with Constant-On-Time (COT) controllers. The proposed technique eliminates the poor DC load regulation limitation associated with conventional ERC control techniques, and reduces the variable DC offset associated with COT controllers in general. This is accomplished without compromising the converter's stability or speed, and without requiring additional error amplifiers or comparators. Thus, quiescent current and silicon area can be significantly reduced. Simulation results show that the DC load regulation using the proposed ERC technique is improved from 100 mV/A to 78 μV/A, and the maximum output voltage offset is reduced from 89.5 mV to 0.82 mV compared to conventional ERC implementations.