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US 6,586,970 B1Granted
Address decoder with pseudo and or pseudo nand gate
AssigneeLSI Logic Corporation
InventorChang Ho Jung
Life of this patent
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Abstract
The present invention describes a multi-stage decoder and method of decoding utilizing a pseudo NAND or pseudo AND gate in one of the stages. This invention presents a decoder comprising a first stage circuit having two or more first inputs which generates one or more first outputs; and a second stage circuit having at least one second input and at least one second output, wherein the one or more first outputs are the same as the at least one second input, wherein at least one of the group consisting of the first stage circuit and the second stage circuit includes either a pseudo AND gate or a pseudo NAND gate. This invention presents a method of decoding, comprising the steps of generating a signal responsive to two or more address bits and enabling a decoder by the generated signal.
Claims20
A two stage decoder circuit, comprising:
- a first stage circuit suitable for receiving a first portion of address bits from an address bus to generate a control signal, the first stage circuit including a pseudo AND gate;
- a second stage circuit suitable for receiving a second portion of address bits from the address bus, the second stage circuit including a plurality of subcircuits, each of the plurality of subcircuits being suitable for receiving an address bit from the second portion of address bits from the address bus, each of the plurality of subcircuits generating a word line signal and having a discharging current;
- and
- a discharging transistor controlled by the control signal of the first stage circuit through a single critical path, the discharging transistor providing a common discharge path for the discharging currents of the plurality of subcircuits of the second stage circuit,
- wherein the pseudo AND gate comprises
- first and second PMOS transistors arranged in parallel, drains of the first and second PMOS transistors being connected to a node and sources of the first and second PMOS transistors being connected to a positive power supply;
- first and second NMOS transistors, a source of the first NMOS transistor being connected to a drain of the second NMOS transistor, a drain of the first NMOS transistor being connected to the node, and a source of the second NMOS transistor being connected to either a negative power supply or ground;
- and
- an inverter having an output terminal connected to a gate of one of the first and second PMOS transistors and an input terminal connected to the node.
6 more elements
A two stage decoder circuit, comprising:
- a first stage circuit suitable for receiving a first portion of address bits from an address bus to generate a control signal;
- a second stage circuit suitable for receiving a second portion of address bits from the address bus, the second stage circuit including a plurality of subcircuits, each of the plurality of subcircuits being suitable for receiving an address bit from the second portion of address bits from the address bus, each of the plurality of subcircuits generating a word line signal and having a discharging current, each of the plurality of subcircuits of the second stage circuit including a pseudo AND gate;
- and
- a discharging transistor controlled by the control signal of the first stage circuit through a single critical path, the discharging transistor providing a common discharge path for the discharging currents of the plurality of subcircuits of the second stage circuit,
- wherein the pseudo AND gate comprises
- first and second PMOS transistors arranged in parallel, drains of the first and second PMOS transistors being connected to a node and sources of the first and second PMOS transistors being connected to a positive power supply;
- first and second NMOS transistors, a source of the first NMOS transistor being connected to a drain of the second NMOS transistor, a drain of the first NMOS transistor being connected to the node, and a source of the second NMOS transistor being connected to either a negative power supply or ground;
- and
- an inverter having an output terminal connected to a gate of one of the first and second PMOS transistors and an input terminal connected to the node.
6 more elements
A method for decoding for a two stage decoder, comprising the steps of:
- receiving a first portion of address bits from an address bus by a first stage of the two stage decoder;
- receiving a second portion of the address bits from the address bus by a second stage decoder;
- generating a control signal by the first stage of the two stage decoder for switchably controlling a switch through a single critical path;
- and
- controlling a plurality of subcircuits of the second stage of the two stage decoder through the switch to enable the second stage of the two stage decoder by discharging current from the portion of subcircuits of the second stage of the two stage decoder through a common discharge path through the switch,
- wherein the first stage of the two stage decoder includes a pseudo AND gate,
- wherein the pseudo AND gate comprises
- first and second PMOS transistors arranged in parallel, drains of the first and second PMOS transistors being connected to a node and sources of the first and second PMOS transistors being connected to a positive power supply;
- first and second NMOS transistors, a source of the first NMOS transistor being connected to a drain of the second NMOS transistor, a drain of the first NMOS transistor being connected to the node, and a source of the second NMOS transistor being connected to either a negative power supply or ground;
- and
- an inverter having an output terminal connected to a gate of one of the first and second PMOS transistors and an input terminal connected to the node.
8 more elements
A method for decoding for a two stage decoder, comprising the steps of:
- receiving a first portion of address bits by a first stage of the two stage decoder;
- receiving a second portion of the address bits by a second stage decoder;
- generating a control signal by the first stage of the two stage decoder for switchably controlling a switch through a single critical path;
- and
- controlling a plurality of subcircuits of the second stage of the two stage decoder through the switch to enable the second stage of the two stage decoder by discharging current from the portion of subcircuits of the second stage of the two stage decoder through a common discharge path through the switch,
- wherein each of the plurality of subcircuits of the second stage of the two stage decoder includes a pseudo AND gate,
- wherein the pseudo AND gate comprises
- first and second PMOS transistors arranged in parallel, drains of the first and second PMOS transistors being connected to a node and sources of the first and second PMOS transistors being connected to a positive power supply;
- first and second NMOS transistors, a source of the first NMOS transistor being connected to a drain of the second NMOS transistor, a drain of the first NMOS transistor being connected to the node, and a source of the second NMOS transistor being connected to either a negative power supply or ground;
- and
- an inverter having an output terminal connected to a gate of one of the first and second PMOS transistors and an input terminal connected to the node.
8 more elements
Dependencies are inferred from the claim text.