inverter type

This method converts the input 4 (or 3) times and outputs the result as follows

1. Convert commercial power supply or other AC input to DC
   (or use DC from the start)
2. Convert to high-frequency AC using an inverter
3. Convert voltage with a transformer
4. Convert to DC with a rectifier circuit

Since step 3 involves a transformer, the input and output can be electrically isolated, and there is the advantage of being able to change the voltage level arbitrarily.