Research And Design Of DPWN In Digitally Controlled DC-DC Converters

With the development of Digitally Controlled Power Converter in the field ofPower Management, it has been one hot topic in the academic and industrial world.Because of its efficiency, flexibility and short design cycle, Digitally Controlled PowerConverter is favored by designers. As an essential part, Digital Pulse Width Modulation(DPWM) proves the stable output in the controlled loop, so its quality determines theperformance of controlled loop. All above, the DPWM which has high efficiency andresolution is needed. The idea and frame of the thesis are in the following.Firstly. Based on the history and the current situation, the whole structure andfunction of Digitally Controlled DC-DC Converter will be introduced. In order todesign the most important parts of digitally controlled loop, which are anAnalog to Digital Converter(ADC), a Digital Proportional Integral Differential(DPID)module and a DPWM, this thesis would analyze the z-domain of the whole loop,considering the influence of delay and sampling particularly.DPWM is the core of the whole thesis. There has been four structures of DPWM inthe field. Considering the advantages and disadvantages of these four DPWMs, anAnalog/Digital Hybrid DPWM and an All Digital Hybrid DPWM are designed in thispaper. The former one utilizes a new structure of two-stage delay-line in order to limitthe power assumption of Power Converter, and save the area of the chip. Similarly, theAll Digital Hybrid DPWM applies the Dichotomy in the design of controlling part,improving the linearity of the delay-line and the performance of DPWM.Finally, a PWM/PSM Digitally Controlled DC-DC Converter is analyzed andsimulated so as to get a stable and high efficient converter. It would switch betweenthese two modes automatically according to the load. As the result, the highestefficiency of the power converter is95.6%, and the maximum load is1.155A. ThisDigitally Controlled DC-DC Converter is realized in0.13μm CMOS process. Thewhole circuit is designed, simulated and taped out successfully.