How to achieve this logic function simply?

Question

I need logic gate that behaves like this:

A=1, B=1, Y=1

A=0, B=0, Y=1

A=0, B=1, Y=1

A=1, B=0, Y=0

The tricky part is (A=1, B=0, Y=0) while (A=0, B=1, Y=1), AFAIK no logic gate distinquish between A or B inputs so dont think its possible with normal gate, is it possible at all?

Answer 1

I believe this is the simplest way to achieve what you are looking for:

^{simulate this circuit – Schematic created using CircuitLab}

Edit: As KingDuken points out in the comments, this is known as an imply gate.

Answer 2

If you're looking for a single logic gate that provides the output you desire, there is no such thing. User @evildemonic has given you the appropriate solution for the most minimal logic gates you can have to achieve your output.

Here is a circuit with transistor logic that can be rather minimal, based on @evildemonic's answer.

^{simulate this circuit – Schematic created using CircuitLab}

At the end of the day, logic gates are made of these transistors (that behave like switches under the right conditions) so technically this is the most minimal you can design what you're looking for.

Answer 3

Practically it's not likely to be able to do this with a single gate (unless you're doing an ASIC design), but you could do it with a single chip, using a dual (or quad) NAND part:

^{simulate this circuit – Schematic created using CircuitLab}