I'm not much of an Engineer but I'm trying the hat on for size...
I am trying to make a circuit with one power supply that powers two different loads. One that can have enough of a load to draw up to 6A. The other has a much smaller load that will only draw about 500mA. I've attached a simple image of what I'm talking about.
I'm having a problem with the 500mA side frying chips on me. I thought that each load will draw the amount of current it needs, independant of the other.
I need some kind of current regulating circuit to restrict the amount of current that can go through the 500mA circuit. Can you offer any suggestions? I've seen a couple different scenarios but none that seem to fit for my circuit.

 

If the loads take the same voltage, there should be no problem. The load decides how much current it needs, so all you have to do is provide a supply for the correct voltage (which can also source that necessary current). This is why your car's battery can supply all those different loads without regulators for each one.

 

The 500 ma circuit is responsible for using 500 ma. If it uses more than 500 ma, it is broken. Putting a current limiter in series with it will only reduce the voltage until only 500 ma flows, then it won't have the right voltage. That's why different scenarios don't fit your circuit. Repair the 500 ma circuit until it actually uses 500 ma.