I’m working on a design which requires three different voltage rails (3.3V, 5V, 12V) all driven from a 24V DC input. Total power is probably ~10W max, more or less evenly distributed across the rails.
My question is: is it preferable in general to run the three stages in parallel from the 24V input, or to chain them? Chaining them will obviously increase the loading on each higher stage, but that may be beneficial in terms of regulator efficiency. Are there any other trade-offs (particularly w.r.t. EMI) for either case?