Gao, Di (2015-11). Multi-harmonic Modeling of Low-power PWM DC-DC Converter. Master's Thesis. Thesis uri icon

abstract

  • Modeling and simulation of switched-mode Pulse Width Modulated (PWM) DC-DC converters form an essential ingredient in the analysis and design process of integrated circuits. In this research work, we present a novel large-signal modeling technique for low-power PWM DC-DC converters. The proposed model captures not only the time-averaged response within each moving switching cycle but also high-order harmonics of an arbitrary degree, hence modeling both the average component and ripple very accurately. The proposed model retains the inductor current as a state variable and accurately captures the circuit dynamics even in the transient state. By continuously monitoring state variables, our model seamlessly transitions between the continuous conduction mode (CCM) and discontinuous conduction mode (DCM), which often occurs in low-power applications. The nonlinearities of devices are also considered and efficiently evaluated resulting in a significant improvement in model accuracy. With a system decoupling technique, the DC response of the model is decoupled from higher-order harmonics, providing additional simulation speedups. For a number of converter designs, the proposed model obtains up to 10x runtime speedups over transistor-level transient simulation with a maximum output voltage error less than 4%.

publication date

  • December 2015