This document introduces the application range and features of viper20 products
This application note explains how to design non-isolated power supplies (1W to 5W) using the VIPer20 integrated switching device. It covers two main topologies: Buck and Inverter (Buck-Boost), detailing their schematics, operation principles, and differences. The document highlights that the VIPer20 replaces conventional PWM driver circuits and high-voltage MOSFETs, offering a compact and cost-effective solution for applications like home appliances and industrial motor control where galvanic isolation is not required.
The note provides design methodologies for selecting switching frequency, duty cycle, and inductor values. It discusses the startup sequence, output voltage regulation via the internal error amplifier, and specific considerations for low input voltage conditions, such as the need for zener diodes in Buck topology to prevent overvoltage. Detailed schematics and formulas for calculating component values are included for both topologies.
| Output Power Range | 1W to 5W |
|---|---|
| Minimum Turn On Time | 500 ns typ. |
| Recommended Switching Frequency Range | 20 kHz to 30 kHz |
It replaces the conventional PWM driver circuit, associated high voltage Power MOSFET switch, and a full set of other passive components, allowing for simple, robust, and compact designs.
The switching frequency is chosen just above audible values, in the 20 kHz to 30 kHz range.
In Buck topology, a zener diode is needed to clamp overvoltages during startup or low input voltage conditions. In Inverter topology, the charge of the tank capacitor is independent from the load, preventing such overvoltages.