Analysis of a monolithic buck converter's pMOS switch during turn off

Abstract

This paper describes the behavior of a monolithic DC-DC buck converter's active switch during its on-to-off commutation, under de presence of parasitic inductances due to package pins and bond wires. The parasitic inductances inbuilt in the power supply path cause a voltage spike when commuting the converter current from the active (high side) switch to the passive (low side) switch. This study is of major importance in order to guide the development of techniques to limit the internal power supply voltage spike with minimum impact on the efficiency of the DC-DC converter.