Another constant current / power load

[rounin]

Hi all,

I decided i needed an analog project to learn how to use op amps (previously being a programmer who moved into digital, and then a bit into power electronics) so I drew up a constant power/current load bank, with active overcurrent/overpower shutdown. It uses a TI current sense amplifier, a AD633 multiplier, and some opamps, comparator, and a latch. Power is provided by a LTC3260EMSE inverting chargepump + dual ldo. I'm hoping for operation at 20V/20A/400W, potentially with forced air cooling over a decent size heat sink.

Any feedback on part selection or methodology would be appreciated, thanks.