How To Simplify Switching Power Supply Design

- Dec 26, 2019-

Over the past 15 years, the design of switching power supplies has gradually become mainstream. Now, the design of switching power supply is no longer an expert's task, anyone involved in system design can finally design their own switching power supply.


Fortunately, people of all levels of expertise can use National Semiconductor's WEBENCH® online tool to design switching regulators. Because professionals often want to modify their designs for specific components or target performance, these tools also allow for custom designs. This means that it is possible to optimize a design that worked perfectly to an unstable state. Online tools can be used to find and correct problems, perfectly matching the development of engineer ideas.


take the first step


The first step in online power supply design is to define the power requirements, including voltage range, output voltage, and load current. Possible solutions are automatically evaluated and one or two recommended solutions are presented to the user. This is also the first place where designers can run into trouble: if the requirements are incorrectly expressed (for example, if the actual input voltage range is higher or lower than the input value), unsuitable solutions are also displayed. Users can try multiple sets of requirements, but they must have a clear concept of system requirements.


When the regulator solution is selected, the components of the circuit can be determined. The tool will display the number of the component. The user can change to a preset alternative or enter a custom component. For component values and all critical


There are guidelines for parasitic parameter values. If a custom component that differs greatly from the recommended value is used, I am afraid that the performance will be greatly reduced.


Performance evaluation


Once the circuit components are selected, it's time to evaluate performance. Generally, performance evaluation depends on frequency response values (crossover frequency and phase margin), peak current and voltage, and thermal performance values (efficiency, junction temperature, and component temperature). Although these calculations are model-based, the simulation results match well with the workbench data.