Dynamic Losses in CMOS Inverters: Analysis and Design

This lecture discusses the dynamic losses in CMOS inverters, focusing on energy dissipation during charging and discharging processes. The instructor begins by correcting exercises related to the topic, emphasizing the role of resistances R1 and R2 in the inverter circuit. The lecture explains how energy is dissipated in the PMOS and NMOS transistors during operation, highlighting that half of the energy is lost in the PMOS resistance while the other half is stored in the output capacitance. The influence of R1 and R2 on charge and discharge times is analyzed, noting that these resistances affect the timing rather than the energy loss itself. The instructor also addresses the mobility differences between holes and electrons, which impact the resistance of PMOS and NMOS transistors. The lecture concludes with a discussion on inverter dimensioning, illustrating how to achieve balanced charge and discharge times by adjusting the widths of the PMOS and NMOS transistors. This comprehensive analysis provides insights into the design considerations for efficient CMOS inverter operation.