J4 what ? What board ? -050 or -001 ?
If -050 regulator Vin rating is 18V, what you also have to be
concerned with is Pdiss, because if it hits an internal Tj of 150C
it will shutdown.
Sorry, yes, J4 on the CY8CKIT-050.
So to close the thread out what you care about is excess Pdiss in regulator.
For each 100 mA you use, with 15 Vin, and 5V out, thats 1W of Pdiss, which
is a lot of power for an SMT part w/no heatsink other than Cu pad area. So
if you plan on a lot of laods, like LEDs, you need to be aware of heat in the 5V