Semiconductor device

1. A semiconductor device, comprising:

a signal output unit including m pieces of (where m is an integer and m≧2) of fuses provided on a semiconductor substrate and an output terminal that outputs a binary signal depending on a disconnection status of said m pieces of fuses; and

a decision unit deciding whether n or more pieces (where m≧n≧2) of fuses are disconnected out of said m pieces of fuses, and outputting a result of the decision,

wherein said output terminal always outputs a potential signal of a first magnitude when at least one of said m pieces of fuses is disconnected, and always outputs a potential signal of a second magnitude when none of said m pieces of fuses is disconnected, and

wherein said decision unit always outputs said potential signal of said first magnitude when n or more pieces of fuses are disconnected, and always outputs said potential signal of said second magnitude when less than two pieces of fuses are disconnected, and

wherein said m pieces of fuses are connected to said decision unit without by way of said output terminal, and said m pieces of fuses are connected to said output terminal without by way of said decision unit.

2. The semiconductor device according to claim 1 , wherein said decision unit includes a logic gate that receives a potential of an end of said fuse as an input signal, so as to output said result of said decision in a form of an output signal of said logic gate.

3. The semiconductor device according to claim 2 , wherein said decision unit includes a NAND gate or a NOR gate having said m pieces of input terminals connected to an end of each of said fuses.

4. The semiconductor device according to claim 1 , wherein said fuse is an electrical fuse.

5. The semiconductor device according to claim 2 , wherein said fuse is an electrical fuse.

6. A semiconductor device, comprising:

a signal output unit including m pieces (where m is an integer and m≧2) of antifuses provided on a semiconductor substrate and an output terminal that outputs a binary signal depending on a connection status of said m pieces of antifuses; and

a decision unit deciding whether n or more pieces (where M≧n≧2) of antifuses are connected out of said m pieces of antifuses, and outputting a result of the decision,

wherein said output terminal always outputs a potential signal of a first magnitude when at least one of said m pieces of antifuses is connected, and always outputs a potential signal of a second magnitude when none of said m pieces of antifuses is connected, and

wherein said decision unit always outputs said potential signal of said first magnitude when n or more pieces of antifuses are connected, and always outputs said potential signal of said second magnitude when less than two pieces of antifuses are connected, and

wherein said m pieces of antifuses are connected to said decision unit without by way of said output terminal, and said m pieces of antifuses are connected to said output terminal without by way of said decision unit.

7. The semiconductor device according to claim 1 , wherein said decision unit includes a second output terminal, which is different from said output terminal of said signal output unit.

8. A semiconductor device, comprising:

m pieces (where m≧2) of fuses provided on a semiconductor substrate;

a first decision unit that outputs a binary signal depending on a disconnection status of said m pieces of fuses; and

a second decision unit that decides whether n or more pieces (where m≧n≧2) of fuses are disconnected out of said m pieces of fuses, and outputting a result of the decision,

wherein said first decision unit and said second decision unit do decisions in a different manner from each other,

wherein said first decision unit always outputs a potential signal of a first magnitude when at least one of said m pieces of fuses is disconnected, and always outputs a potential signal of a second magnitude when none of said m pieces of fuses is disconnected,

wherein said second decision unit always outputs said potential signal of said first magnitude when n or more pieces of fuses are disconnected, and always outputs said potential signal of said second magnitude when less than two pieces of fuses are disconnected, and

wherein said m pieces of fuses are connected to said first decision unit without by way of said second decision unit, and said m pieces of fuses are connected to said second decision unit without by way of said first decision unit.

9. The semiconductor device according to claim 1 , wherein said decision unit is connected to an end of the m pieces of fuses.

10. The semiconductor device according to claim 8 , wherein both said first decision unit and said second decision unit are connected to an end of each of the m pieces of fuses.

11. The semiconductor device according to claim 8 , wherein an output of said second decision unit is not input into said first decision unit.

12. The semiconductor device according to claim 8 , wherein said decision unit includes a logic gate that receives a potential of an end of said fuse as an input signal, so as to output said result of said decision in a form of an output signal of said logic gate.

13. The semiconductor device according to claim 12 , wherein said decision unit includes a NAND gate or a NOR gate having said m pieces of input terminals connected to an end of each of said fuses.

14. The semiconductor device according to claim 8 , wherein said fuse is an electrical fuse.

15. The semiconductor device according to claim 12 , wherein said fuse is an electrical fuse.

16. The semiconductor device according to claim 8 , wherein said first decision unit includes a first output terminal, and said second decision unit includes a second output terminal, which is different from said first output terminal of said first decision unit.