Yeah the LM317 datasheet says it can only provide the minimum 1.5 amps down to a 15 volt drop from it's supply voltage. I'd rather just drop a few volts to help keep it cool and maintain the 1.5 amp output capability.
I'll look at the 2N3055 option though. I'm not married to using an LM317. I just thought using an adjustable regulator/SMPS combo would be a good way of getting the linear performance without the heat and wasted power issues. I figure most of the usage of this supply will operate at 12 volts or below. That could be a lot of heat at even an amp.
Zener D10 is reverse polarity.
Isn't that the way it should be so that I get a negative 5.6 (or whatever the zener value is) volts out the junction of D10 and R17?
I'd drop the shunt resistor R1 and the INA193 in favour of one of the Hall effect current sensors like ACS712
I will definitely look into that.
What's the D2/R8/R11 combo meant to do if you're feeding the output from the DAC U6 to the non inverting input of U4?
What I'm trying to do here is allow the output of U4 go down to -1.25. D2 would be a 1.25V zener. I'm trying to subtract that value from the output of the DAC. If the output of the supply is 0-25 volts then I need the output of U4 to be -1.25 to 23.75 volts. I get the basics of op amps but I struggle with some applications of it. I got this configuration from somewhere on the internet.
Thanks for the feedback guys. I could always copy someone's design online, and trust me I've considered it at times, but there is something cool about coming to the same conclusions yourself. It's how I learn.