Design of zero-order dynamics controller and 10 MHz current mode controller for DC-DC converter

Abstract

In Chapter 1, zero-order controls for boost converter are challenging due to the difficulties in reduc-ing dynamics of converter coming from the output loading effect. To eliminate output loading effect, output voltage is controlled by comparator. However, comparator control cannot guarantee the stable operation in steady-state. To overcome this limitation, the zero-order control using sawtooth is proposed. Analysis and Experiments for a 3.7 V input, 8V -0.3A output converter demonstrated its validity. In Chapter 2, current mode controls for synchronous buck converter at 10 MHz are challenging due to the difficulties in sensing inductor current. To sense inductor current even at 10 MHz, quadratic current sensor is proposed. Also, to guarantee a stable and accurate operation of the buck converter, high speed comparator using two cross-coupled positive feedback is proposed. Experiments for a 3.7 V input, 2V -0.4A output converter demonstrated its validity.