In the current power architecture of server motherboards, synchronous buck converters (SBCs) are used as point-of- load (POL) power supplies for low-voltage, high-current CPU rails. Due to hard-switching transitions in SBCs, these POLs not only incur high switching loss but cause significant EMI emissions as well. This high-frequency noise emission impacts the digital communication between the POLs and the CPU. This issue is typically addressed either by adopting advanced device structure or sophisticated noise cancellation techniques or by introducing additional circuit overheads. But these approaches either increase the complexity of IC design and fabrication or compromise the POL efficiency. An alternative solution to this problem could be to introduce soft-switched quasi-resonant SBCs for POL application. But the possibility of incorporating bootstrap gate driving in these topologies needs to be explored. This paper presents bootstrap operation in full-wave ZCS quasi-resonant synchronous buck converter (FWZCS QRSBC). Detailed mode analysis is performed, which reveals soft-switching in the bootstrap diode for FWZCS QRSBC.
.jpeg.jpg "Anwesha Mukhopadhyay, MTech photo")