1. Soft-Switching DC-DC Converter Is to shape the voltage or the current waveform by creating a resonant condition to: Force the voltage across the switching device to drop to zero before turning it ON  Zero-Voltage Switching (ZVS) Force the current through the switching device to drop to zero before turning it OFF  Zero-Current Switching (ZCS)

2. Overview • Many soft-switching dc-dc converter families were introduced in the open literature • The objectives of these topologies are to develop high switching frequency converters with high power density and high efficiency • This was accomplished by adding additional components to the power stage. • Steady-state analysis tend to be time consuming. • Provided little insight into the converter switching-cell operation.

3. Hard-Switching and Soft-Switching Hard-Switching Zero-Voltage Switching Zero-Current Switching

4. Why Soft-Switching? • Reduce switching losses especially at high switching frequencies • Increase the power density, since the size and weight of the magnetic components is decreased by increasing the operating frequency • Reduce the Electromagnetic Interference (EMI)

5. Conventional DC-DC Converters(Hard-Switching) Boost Buck Buck-Boost Cuk Zeta Sepic

6. Switching-Cell Sharing All the Conventional DC-DC Converters shares the same switching-cell With different orientation of the cell in a specific converter The Conventional DC-DC Switching-Cell

7. Analyzed Soft-Switching Cells

8. Zero-Voltage-Switching Quasi-Resonant ZVS-QRC Switching-Cell ZVS-QRC Cell Basic Switching-Waveforms

9. ZVS-QRC Family ZVS-QRC Boost ZVS-QRC Buck ZVS-QRC Buck-Boost ZVS-QRC Cuk ZVS-QRC Zeta ZVS-QRC Sepic

10. Zero-Current-Switching Quasi-Resonant ZCS-QRC Switching-Cell ZCS-QRC Cell Basic Switching-Waveforms

11. ZCS-QRC Family ZCS-QRC Buck ZCS-QRC Boost ZCS-QRC Buck-Boost ZCS-QRC Cuk ZCS-QRC Zeta ZCS-QRC Sepic

12. ero-Current-Transition PWM Cell ZCT-PWM Switching-Cell ZCT-PWM Cell Basic Switching-Waveforms