# 4 bit binary signal to select one of 4 different ref V to output

Discussion in 'General Electronics Chat' started by elRey, Feb 26, 2009.

1. ### elRey Thread Starter Well-Known Member

Feb 23, 2009
65
0
Hello,

I have a 4 bit binary input on 4 leads. And I have 4 different ref Vs.

i.e.
refV_1 = 1.0V
refV_2 = 2.2V
refV_3 = 3.75V
refV_4 = 4.9V

binary input would be one of five values hi/low off 4 wires:
0000
1000
0100
0010
0001

How do I get the output of the circuit to be one of the 4 ref Vs (including 0V) for a specific binary input:

0000 = 0V circuit output
1000 = 1.0V circuit output
0100 = 2.2V circuit output
0010 = 3.75V circuit output
0001 = 4.9V circuit output

output will be used as an input ref V for another circuit (comparator). Little current if any.

Please keep in mind that the Ref Vs are user set/adjustable by 4 pots.

Thanks,
Rey

Last edited: Feb 26, 2009
2. ### eblc1388 AAC Fanatic!

Nov 28, 2008
1,543
104
Since your binary input selection is mutually exclusive for each voltage, you can simply use a CD4066 CMOS Quad Bilateral Switch to do the switching.

Connects one terminal of each of the four switches together as your output and feeds in different voltage to the other terminal.

You may need to use an output resistor of a large value like 100K to 0V so the output voltage is zero when all four switches is opened.

Connects the control input of each switch to the desire binary line.

3. ### elRey Thread Starter Well-Known Member

Feb 23, 2009
65
0
Thank you. I'll try to pick one up tomorrow.