This is a tricky one, and will make you think outside the box...
I have a constant current source of 5 amps. In addition to what the 5 amps normally does, I need it to power a 12v fan. The simplest solution would be a resistor, but then you have it consuming 5*12 = 60 watts! I can handle 20 watts being wasted in addition to the 5 the fan draws, but this is excessive.
So, what would you guys suggest? Since the current through 2 parallel resistors is only dependent on their ratio, I'm considering putting two *small* resistors in parallel, and sort of siphoning off maybe 1/2 an amp with a current mirror. With a 24 ohm resistor, I can get 12 volts while dissipating much less power. Thoughts?
I have a constant current source of 5 amps. In addition to what the 5 amps normally does, I need it to power a 12v fan. The simplest solution would be a resistor, but then you have it consuming 5*12 = 60 watts! I can handle 20 watts being wasted in addition to the 5 the fan draws, but this is excessive.
So, what would you guys suggest? Since the current through 2 parallel resistors is only dependent on their ratio, I'm considering putting two *small* resistors in parallel, and sort of siphoning off maybe 1/2 an amp with a current mirror. With a 24 ohm resistor, I can get 12 volts while dissipating much less power. Thoughts?