Soft Switching Buck Converter with Three-switch Cell Structure
For high conversion ratio and high frequency applications, such as high frequency 12V input voltage regulator (VR), due to the larger switching loss, it is very difficult for conventional PWM DC/DC converter to achieve high efficiency. In these applications, soft switching, duty cycle extension and self-driven are three methods that can be used to increase efficiency. A single phase self-driven soft switching DC/DC converter that has all of these three benefits is proposed. The essence of this novel circuit is revealed as cascading quasi-square-waveform (QSW) buck and buck converter with tapped inductor. The soft switch benefit comes from QSW operation; duty cycle extension benefit comes from cascading structure and tapped-inductor; self-driven operation comes from cascading structure, but the driving voltage is increased by using tapped-inductor.