Design and Implementation of FPGA-based Digitally Controlled Quadratic Buck Converter

Current electronic equipment has higher requirements for power supply performance. Traditional switching power supplies have the disadvantages of a single control method, complex circuit structure and low accuracy. Digital control technology can improve the reliability and stability of the system and achieve flexible control algorithms. Based on this, this paper proposes a digital switching power supply based on FPGA control. The main content of this paper is to design an FPGA-based digitally controlled quadratic buck DC-DC converter using the voltage feedback PWM control mode, including the design of the main circuit parameters, the design of the analogue-to-digital converter parameters, the design of the discrete PID controller and the design of the discrete PWM generator. Among them, the main circuit components are analysed and designed based on their output voltage ripple, then, the small signal model of the system is established through the state space averaging model to derive the small signal transfer function from control to output, and the resolution of the analogue-to-digital converter is determined on the basis of the main circuit design; the design of the discrete PID controller is to first design the continuous domain PID controller, and then converted to a discrete domain PID controller controller. The DPWM generator is designed according to the system accuracy requirements, the resolution requirements are determined and the counting method is used for the design. The control strategy is therefore feasible and the overall performance of the system meets the design requirements.