GSXR1181 said:
ONA---(ONB NOT)---MAX1672
0-----------0----------On
0-----------1----------Off
1-----------0----------On
1-----------1----------On
Now what I am using is a MAX887, which uses (SHDN Not). So when (SHDN Not) was high, the regulator was running. When (SHDN Not) went low the regulator was off.
So basicly I'm asking how I could get the MAX887 SHDN to work with something that was made for ONA and (SHDN Not)? Could I use some sort of flip flop or something? I'm very confused on what to do........
You want a gate, not a flip-flop. A flip flop can remember its state, and you don't want that here as the microcontroller does that.
You can get what you want with a NAND gate and an inverter. Invert the ONA signal to give you
(ONA NOT). The two inputs of the NAND gate are the
(ONA NOT) and the
(ONB NOT) signals. The ouput is high when either is low, turning on the MAX887
ONA---
(ONB NOT)---MAX1672---
(ONA NOT)---NAND---MAX887
0-----------0----------On--------------1----------1-----------On
0-----------1----------Off--------------1----------0-----------Off
1-----------0----------On--------------0----------1-----------On
1-----------1----------On--------------0----------1-----------On
If you use a CD4011 you get four NAND gates in one package. That IC will work on any voltage that the MAX887 will work on, so you don't need a regulator to supply it, and it takes just about no current at all.
You join the two inputs of a NAND to make an inverter. The unused gates should have all their inputs connected to ground.
I don't know what supply voltage you have, or exactly what feeds the inputs. There is a possible problem with levels if the supply voltage is large. If the supply is 10V, the inputs of the CD4011 have to be above 7V to be sure to be high, and this won't be possible if you are using a 5V output.