With a contribution by
Tom Egel, Mentor Graphics Corporation
This case study illustrates how VHDL-AMS can be used for the detailed design of a DC-DC switching power supply. For the RC airplane system, a step-down converter is required to convert the 42 V battery voltage used to power the propeller motor to the 4.8 V needed for the on-board servo electronics. In this case study we briefly introduce switched-mode power supply theory, and then perform a detailed design of a simple step-down (buck) converter. We discuss averaging techniques that facilitate analysis of the closed-loop system and use VHDL-AMS simulations to perform system-level design tradeoffs.