Semiconductor memory device
View Patent ↗The present invention provides a semiconductor memory device that includes: a fuse circuit having multiple fuse elements; and a fuse selection circuit connected to an internal address signal line that receives an address signal externally inputted. The fuse circuit is connected to the fuse selection circuit to receive an output from the fuse selection circuit, is supplied with an externally inputted trigger signal that permits nonvolatile recording of the fuse elements, and, in response to the output and the trigger signal, records the fuse element corresponding to the internal address signal line among the plurality of fuse elements while recording at least one of the plurality of fuse elements other than the fuse element thus recorded.
1. A semiconductor memory device comprising:
a fuse circuit having a plurality of fuse elements; and
a fuse selection circuit connected to an internal address signal line that receives an address signal externally inputted, wherein
the fuse circuit is connected to the fuse selection circuit to receive an output from the fuse selection circuit, is supplied with an externally inputted trigger signal that permits nonvolatile recording of the fuse elements, and, in response to the output and the trigger signal, records the fuse element corresponding to the internal address signal line among the plurality of fuse elements while recording at least one of the plurality of fuse elements other than the fuse element thus recorded.
2. The semiconductor memory device according to claim 1 , wherein
the output of the fuse selection circuit includes: an element specification signal to specify a certain one among the fuse elements in response to the internal address signal line; and a fuse circuit specification signal to specify whether to record the fuse element in the fuse circuit.
3. The semiconductor memory device according to claim 2 , wherein
the fuse circuit outputs a state signal showing a recording state of the at least one fuse element, and
the fuse selection circuits generate the fuse circuit specification signal in response to the receipt of the state signal.
4. The semiconductor memory device according to claim 3 , in which
the fuse circuit is a first fuse circuit,
the state signal is a first state signal,
the fuse selection circuit is a first fuse selection circuit, and
the output of the first fuse selection circuit is a first output, the semiconductor memory device further comprising:
a second fuse circuit having another plurality of fuse elements; and
a second fuse selection circuit connected to the second fuse circuit and to the internal address signal line, wherein
the second fuse circuit receives a second output from the second fuse selection circuit, is supplied with the trigger signal, and, in response to the second output and the trigger signal, records the fuse element corresponding to the internal address signal line among the other fuse elements while recording at least one of the other fuse elements other than the fuse element thus recorded.
5. The semiconductor memory device according to claim 4 , wherein
the second fuse circuit outputs a second state signal showing a recording state of the at least one fuse element, and
the second fuse selection circuit is connected to the first fuse circuit, receives the first state signal and the second state signal, and generates the second output in response to specified logic of the first and second state signals.
6. The semiconductor memory device according to claim 5 , still further comprising:
a first latch circuit that is connected between the first fuse selection circuit and the first fuse circuit, receives and holds the first output, and then provides the first output to the first fuse circuit; and
a second latch circuit that is connected between the second fuse selection circuit and the second fuse circuit, receives and holds the second output, and then provides the second output to the second fuse circuit, wherein
each of the first and second latch circuits includes: an element specification latch corresponding to the element specification signal; and a fuse circuit specification latch corresponding to the fuse circuit specification signal,
the fuse circuit specification latch of the first latch circuit is set in response to a value of the fuse circuit specification latch of the first latch circuit, and
the fuse circuit specification latch of the second latch circuit is set in response to a value of the fuse circuit specification latch of the second latch circuit, and to the fuse circuit specification latch of the first latch circuit.
7. The semiconductor memory device according to claim 6 , wherein after both of the element specification latch and the fuse circuit specification latch of each of the first and the second latch circuits are set, a corresponding one of the first and the second fuse circuits is provided with an output of each of these latches in parallel, and records in each of the fuse elements in response to the trigger signal in common.