Research And Implementation Of Digital Switching Power Supply Based On DSP

Switching power supply is the power supply device under the high-frequency on-off state, with the characteristics of high efficiency, low wastage and low heating. Now, it is widely applied in many fields including the industrial automatic control, LED lighting, communication equipment and electronic digital products. Currently, the switching power supply generally uses the traditional analog control method, which cannot get rid of the problems of nonlinearity, error, drifting and ageing existing in the analog control circuit. With the continuous development of the power electronic technology and control technology, in order to enhance the performance of the switching power supply and enrich the control ways of the switching power supply, the digital switching power supply has been the new hot topic of the research.This paper conducts the design and research based on the DSP digital switching power supply. It adopts the single-ended flyback converter as the main circuit to adapt to the output field with the small power. In terms of the principle, it makes the specific introduction on the work process of the flyback converter and establishes the small-signal linearized modeling. In hardware, combining with system indicators of design, the filtered rectifier circuits, flyback main circuit and clamp protection circuit arc analyzed at length; and the selecting principles are identified. In controller, the high-performance TMS320F2812is selected as controlling core. In order to ensure the stability of DSP, the isolation sampling is made by high-precision linear optocoupler and isolation driver is made by high-speed non-linear optcoupler. Online identifying the parameters of system and updating real-time PID controlling parameters don’t need accurate mathematic model of switching power supply, and it resolve the problem of unsatisfactory controlling result due to slow change of circuit parameters while power supply is working. The stimulation experiment result shows that, on the basis of the self-tuning control of the flyback power, it improves the steady-state performance of the system, accelerates the response speed and strengthens the disturbances attenuation performance.To sum up, this topic realizes the digital power supply design based on DSP, to lay the foundation for the further development of high-performance digital power source.