Flip-flop having shared feedback and method of operation
View Patent ↗A method of operating a circuit includes receiving a first data signal at a first node. The first node is coupled to a second node to couple the first data signal to the second node. After coupling the first node to the second node, an inversion is enabled from the second node to a third node. An inversion from the third node to the fourth node is provided. After the enabling the inversion from the second node to the third node, the first node is decoupled from the second node. After the enabling the inversion from the second node to the third node, the second node is coupled to the third node. An inversion from the fourth node to the third node is enabled and the second node is decoupled from the fourth node.
1. A circuit comprising:
a first transmission gate having a first terminal coupled to a first node and a second terminal coupled to a second node;
a first inverting element having an input coupled to a third node and an output coupled to a fourth node;
a second transmission gate having a first terminal coupled to the second node and a second terminal coupled to the fourth node; and
a logic circuit having a first input coupled to the second node, a second input coupled to the fourth node, complementary clocked inputs coupled to receive a first pair of complementary clock signals for selecting one of the first and second inputs, and an output coupled to the third node, wherein the selected input is inverted and provided on the output to the third node, wherein:
the second transmission gate is clocked by a second pair of complementary clock signals,
the first transmission gate is clocked inversely to the second transmission gate, and
the second pair of complementary clocks is generated from a clock signal of the first pair of complementary clock signals and is delayed with respect to the first pair of complementary clock signals.
2. The circuit of claim 1 , wherein:
the logic circuit has a logic equivalence, comprising:
a first AND circuit having an input as the first input of the logic circuit coupled to the second node, a second input for receiving a true clock input of the first pair of complementary clock signals, and an output;
a second AND circuit having an input as the second input of the logic circuit coupled to the fourth node, a second input for receiving an inverse clock input of the first pair of complementary clock signals, and an output;
a NOR circuit having a first input coupled to the output of the first AND circuit, a second input coupled to the output of the second AND circuit, and an output as the output of the logic circuit coupled to the third node.
3. The circuit of claim 1 , wherein the complementary clocked inputs of the logic circuit are clocked by a second pair of complementary clocks.
4. The circuit of claim 3 , wherein:
the first transmission gate is conductive to couple an input signal from the first node to the second node;
the logic circuit is to invert the input signal and provide an inverted input signal on the third node when the first input of the logic circuit is selected;
the first inverting element is to provide an inversion from the third node to the fourth node;
the second transmission gate is conductive to couple the third node to the second node when the first transmission gate is non-conductive; and
the logic circuit is to provide an inversion from the fourth node to the third node when the second input of the logic circuit is selected.
5. A circuit comprising:
a clock circuit configured generate a first pair of complementary clock signals and a second pair of complementary clock circuits from a clock signal, wherein the second pair of complementary clocks is delayed with respect to the first pair of complementary clock signals;
a first transmission gate having a first terminal coupled to a first node, a second terminal coupled to a second node, a first clock input coupled to an inverse clock of the second pair of complementary clocks, and a second clock input coupled to a true clock of the second pair of complementary clocks;
a first inverting element having an input coupled to a third node and an output coupled to a fourth node;
a second transmission gate having a first terminal coupled to the second node, a second terminal coupled to the fourth node, a first clock input coupled to the true clock of the second pair of complementary clocks, and a second clock input coupled to the inverse clock of the second pair of complementary clocks; and
a logic circuit having a first input coupled to the second node, a second input coupled to the fourth node, inputs coupled to receive the first pair of complementary clock signals for selecting one of the first and second inputs, and an output coupled to the third node, wherein the selected input is inverted and provided on the output to the third node.
6. The circuit of claim 5 , wherein:
the logic circuit has a logic equivalence, comprising:
a first AND circuit having an input as the first input of the logic circuit coupled to the second node, a second input for receiving a true clock input of the first pair of complementary clock signals, and an output;
a second AND circuit having an input as the second input of the logic circuit coupled to the fourth node, a second input for receiving an inverse clock input of the first pair of complementary clock signals, and an output;
a NOR circuit having a first input coupled to the output of the first AND circuit, a second input coupled to the output of the second AND circuit, and an output as the output of the logic circuit coupled to the third node.