Conditional latch circuit

摘要

A conditional latch circuit is selectively operable as a latch or as an OR gate. The circuit comprises an OR gate having at least three inputs, each connected to the output of separate ones of three AND gates. A fourth AND gate has an inverted output connected to an input of two AND gates and a non-inverted output connected to an input of the third AND gate. The output of the OR gate is connected to a second input of the third AND gate. With one input of the fourth AND gate connected to a binary clock source, the circuit will operate as a latch to store binary signals received at the second input of the first and second AND gates when the second input of the fourth AND gate is connected to binary one. When the second input of the fourth AND gate is connected to a binary zero, the circuit will operate as an OR circuit.