I have two voltage comparators based on a quad LM339. One output (temp monitor) produces logic 1 as default, and the other output (battery voltage) gives logic 0 as default. I want to input both these logic levels into CMOS gates to switch a power MOSFET controlling a 12 volt fan. There is no CMOS IC available to deal with my truth table (shown below). Can anyone help please? I need to keep supply current as low as possible. The two comparators are drawing 12mA already, which will drain the battery overnight unless reduced. Are the two unused comparators using current as well? I'm quite new to logic programming. Thanks
Logic levels (1=on, 0=off)
Temp Voltage Output(fan)
1 0 1
1 1 0
0 1 0
0 0 0
I have loads of NAND, NOR and AND gates available. Can the two unused comparators in the 339 be put to good use.