Other Parts Discussed in Thread: LMR14050
The value of the output inductor of a switching regulator is greatly affected by the output current. I first sized the inductor based on the max LMR14050 output current of 5A. However, if based on the most expected use of say 1A the inductor is 5 to 7 times larger which costs a lot more and takes up much more board space. Guessing it more prudent I went with the higher value. How much would it matter? That is, is it worse to run a high current through a larger than spec inductor or low current through a smaller than spec inductor?
Second, the regulator's input voltage from a rectified AC supply filtered through bulk capacitance varies continuously. The voltage on the capacitors will drop linearly (ignoring the high frequency on/off saw tooth tiny variances) until it is less than the AC driving voltage. This can take roughly 1/2 to 2/3 of each cycle and the differences are not small. I calculate that with a 5A load current the input voltage will vary from about 16V to 25V over a half-cycle or so. My question is what V-in should be used in calculations, the peak which lasts maybe 0.1% of the time, or maybe the average, or what?
