What logic gate is this ?

[xmen_xwk]

I have been using a multifunctional logic gates to make it work like this.



But they all comes in one gate per IC. I'm wondering what these gates are called, because I need IC that can have 4 or more gates.

I tried with "AND gate with one inverted input" but couldn't find specific IC. All I can think of is one inverter gate IC and one AND gate IC and make them work together. But it would be nice if there was all in one IC.

 

[andre_luis]

You could use a single IC with 4 NAND gates, so by inverting the output and one input would have the same result of the above truth table.

 

[KlausST]

Hi,

Nowadays I'd use the simplest/cheapest PLDs for such a function.
Even a good old 16V8 can do the job.
Additional benefit: you may place the inputs and outputs very flexibly to ease PCB layout design.

If you want to build this circuit with ready to buy logic ICs, then you may use an
* AND circuit combined with an INVERTER
* or you use all NOR gates. 2 per function. One to invert input signal B (refering to your post#1 circuit):
/A AND B = A NOR /B

Klaus

 

[d123]

Hi,

Have a search for e.g. quad input configurable logic chips

These are TIs selection, the CD4048B is maybe adaptable to your circuit or too complex/doesn't fit, not sure.

 

[vGoodtimes]

The operation is called "and not" in some cases.

This is seen in SSE2's ANDNPD instruction. I suspect the gate might be called and-not or andn.

 

[xmen_xwk]

Hi,

Nowadays I'd use the simplest/cheapest PLDs for such a function.
Even a good old 16V8 can do the job.
Additional benefit: you may place the inputs and outputs very flexibly to ease PCB layout design.

If you want to build this circuit with ready to buy logic ICs, then you may use an
* AND circuit combined with an INVERTER
* or you use all NOR gates. 2 per function. One to invert input signal B (refering to your post#1 circuit):
/A AND B = A NOR /B

Klaus

Using PLDs seems overkill and needs to program them on power up.
AND and INVERTER is only choice left.
How can NOR gates do this ? Can you please explain ?

@d123, its not that

 

[KlausST]

Hi,

Using PLDs seems overkill and needs to program them on power up.

What do you mean with "overkill".
For low quantities the effort with an PLD may be sammer than with glue logic.
They don´t need to be programmed at each power up. They usually are non volatile.
You may program them onece and then assemble them on the PCB.
You may assemble them on the PCB and then program them once.
You may buy them pre-programmed with your code. Ask your distributor.

How can NOR gates do this ? Can you please explain ?

The answer is already given:

* or you use all NOR gates. 2 per function. One to invert input signal B (refering to your post#1 circuit):
/A AND B = A NOR /B

What exactely you dont understand?
all the three circuits do exactely the same:


Klaus

 

[FvM]

because I need IC that can have 4 or more gates

Obviously no hardwired 4 gate IC with the intended function is available. Using 4xNOR2 IC to get 2 gate functions in a package seems to be the next best approach. As said, a CPLD can be a more compact alternative. CPLDs are usually non-volatile and programmed once before or after assembly. The effort can be charged up against the higher package count of hardwired solution.

 

[ElectricalEngineering]

You could use a single IC with 4 NAND gates, so by inverting the output and one input would have the same result of the above truth table.

Andre's solution looks neat. Since it goes with single piece. I'was considering two IC's one having AND and other NOT for NAND A input.

 

[xmen_xwk]

- - - Updated - - -

Hi,


What do you mean with "overkill".
For low quantities the effort with an PLD may be sammer than with glue logic.
They don´t need to be programmed at each power up. They usually are non volatile.
You may program them onece and then assemble them on the PCB.
You may assemble them on the PCB and then program them once.
You may buy them pre-programmed with your code. Ask your distributor.


The answer is already given:

What exactely you dont understand?
all the three circuits do exactely the same:
View attachment 142227

Klaus

The NOR gate will do the job