The design of these front-end power supplies pose unique challenges from their requirements. This article is intended to give you a basic understanding of high-voltage power-supply design, and how design tools can make it simple to design for these applications.
There are three main things that you need while designing for your AC/DC or high-voltage DC/DC application.
Understand the system requirements
Normally it is known where the end equipment will be used and whether it will need a universal voltage range (85V to 265V) or region-specific voltages such as U.S. (120V), Japan (100V), U.K. (230V) or China (220V). Also, are you designing for a charger-type application or an on-board power supply? Are you designing for a supply that needs tight output-voltage regulation? What type of isolation requirements do you have?
The answers to each of these questions will help you make appropriate trade-offs while you design. Designing for universal voltage ranges ensures operability across different parts of the globe at the expense of higher voltage-/current-rated components, which come at a higher price and footprint. Charger-type supplies typically require a constant-voltage/constant-current (CV/CC) characteristic. So selecting a controller that meets this requirement is essential.
If your power supply requires tight regulation of the output, you need to consider secondary-side regulated controllers that tightly regulate the voltage on the secondary, versus primary-side controller regulators where the output could vary with changes in the transformer or secondary diode parameters. Certain applications require that your transformer provide a certain class of isolation for safer, robust end equipment.
TI’s WEBENCH High-Voltage Power Designer is an easy to use tool to design an AC/DC or HV-DC/DC application. You simply enter your voltage and current requirements and find solutions that work for your application. With the optimizer dial, you can optimize your design for cost, footprint and efficiency based on your system needs. To get started, visit the WEBENCH panel on ti.com. Figure 1