3 Summary

This article introduced several ways to generate a negative power supply from a positive input power supply. A charger pump has a very simple circuit. The drawback is the output voltage in most cases cannot be adjustable and less than 300mA maximum output current. An inverter converter can output large current and only requires one inductor. The circuit is simple but the drawback is the input and the output must have good filters to obtain good performance. There are less options in the market to obtain an inverter converter. The inverter buck-boost converter is exactly same with the inverter converter in topology and the designer has more options. However, the inverter buck-boost converter is not straightforward and needs good input and output filter if the designer expects good performance. Cuk topology has good input and output performance but requires two inductors. The second shortage is there are less Cuk inverters in the market. Designer can use a boost converter to build a Cuk converter and must add an inverter amplifier in the feedback loop. The drawback of PSR flyback is that designers require a design for a specific transformer. In the actual design, the designer can select a design to meet the specific application for the circuit size, and so on.