Digital Control Dual Mode Power Converter Chip Design And Implementation

Digitally controlled power converter is increasingly attracting attention as power converter is required more strictly. With benefits of intelligence, flexibility, short design cycle, digitally controlled power converter’s market occupancy is extending, especially those product applied in workstation. Based on traditional linear compensation method, output voltage is sampled by ADC, with which digital compensator computes duty cycle, controlling power transistor through DPWM. Based on traditional compensation method, in this system, dual mode control is adopted to raise efficiency under light load.The idea and frame of this thesis are as follows:In Chapter1, what introduced are digitally controlled power converter’s background, status of development and this paper’s work.In Chapter2, what is covered are modeling of PWM loop, compensation method, quantization effect and limit cycle, especially the impact of sampling, criteria of limit cycle and evaluation of this system.In Chapter3, DPWM is covered in the following way. Several basic structures is introduced firstly, followed by detail description of the structure in this system. It is evaluated by the presentation of simulation results, chip photo and test results.In Chapter4, dual-mode control strategy is discussed. ADC and system timing is explained and PWM loop’s stabilization is confirmed. Then PSM control module is presented. Mode switch strategy is described, ruling out the possibility of mode oscillation. Finally soft start module, for system’s safety, is covered.In Chapter5, system’s simulation results are presented, including those of stable state and dynamic response. Finally, system’s several test results layout and chip photo are provided.In the last chapter, evaluation of this system is carried out. The author’s work is summarized and deficiencies of this work are presented.