Energy efficient peak-current state-machine control

This dissertation begins by introducing the most common DC-DC converters, such as linear power supplies and switch-mode power supplies, using Pulse-Width Modulation (PWM) control. These supplies have drawbacks in terms of efficiency and the large amount of switching losses at light loads. Thus, the focus of my research and this dissertation is to introduce a completely new type of peak-current control that addresses these important issues.;The peak-current control that is modeled in this dissertation is a novel variable-frequency control that maintains regulation in a flyback converter by enabling and disabling cycles instead of modulating the pulse-width, which allows for elimination of feedback compensation and can provide for peak power 3 times higher than the rated full load power without increasing the power s8upply component sizes. This form of control is referred to as Peak Current State Machine on-off Control in this dissertation. In this form of control, a state machine sets the peak current of each enabled cycle, based on the load requirements. The variable frequency nature of this control scheme reduces switching losses significantly at light loads, while the lowering of the peak current by the state machine reduces the output ripple and audible excitations of the transformer. The state machine control is completely modeled for the first time, including modeling for the maximum power deliverable in CCM, the peak-current ratio between states, the number of states required for stability, the minimum number of counts for state transitions required for stability, and modeling for a new peak state with double the maximum switching frequency, which provides peak power during brief peak loads, without requiring an over-rated transformer [1-3]. Characterization of a power supply converter that was designed around the monolithic IC that uses this control scheme is also provided.