Multi-harmonic nonlinear modeling of low-power PWM DC-DC converters operating in CCM and DCM

Abstract

DC-DC converters form an essential component of modern low-power integrated circuits. This paper presents a novel nonlinear modeling technique for pulse-width modulated (PWM) DC-DC converters for low-power applications. Our enhanced model not only predicts the dc response, but also captures harmonics of arbitrary degrees. The proposed full-order model retains the inductor current as a state variable and accurately captures the circuit dynamics even in the transient state. Furthermore, by continuously monitoring state variables, our model seamlessly transitions between continuous conduction mode (CCM) and discontinuous conduction mode (DCM), which often occurs in low-power applications while also accounting for the non-idealities of the circuit devices. The proposed model, when tested with a system decoupling technique, obtains up to 10X runtime speedups over transistor-level simulations with a maximum output voltage error that never exceeds 4%.