A fuse circuit includes a first power supply line, a second power supply line, a first current source connected between the first power supply line and an output terminal, a second current source connected between the second power supply line and the output terminal, the second current source having higher current supply capacity or current draw-out capacity than the first current source, and a fuse connected in series with the second current source between the second power supply line and the output terminal.
1. A fuse circuit, comprising:
a first power supply line;
a second power supply line;
a first transistor coupled between said first and second power supply lines to output a first output current;
a second transistor coupled between said first and second power supply lines and coupled to said first transistor to output a second output current;
a fuse coupled in series with said first transistor or said second transistor between said first and second power supply line;
another fuse coupled to said second power supply line;
an output terminal coupled to a node between said first and second transistors to output a signal in accordance with a magnitude relationship of the first output current and the second output current, wherein said magnitude relationship is inverted based on a size ratio of said second transistor and whether said fuse is cut or not;
a fuse cutting transistor coupled in series with said fuse between said first and second power supply lines;
a switch coupled to said fuse cutting transistor and selectively coupled to one of said fuse and said another fuse;
and
an additional transistor coupled to a node between said another fuse and said switch.
2. The fuse circuit according to claim 1 , further comprising:
a resistor coupled in series with said first transistor.
3. The fuse circuit according to claim 1 , wherein said first transistor is an MOS transistor or a bipolar transistor, and said second transistor is an MOS transistor or a bipolar transistor.
4. The fuse circuit according to claim 3 , wherein said first transistor is a bipolar transistor and said second transistor is an MOS transistor.
5. The fuse circuit according to claim 1 , further comprising:
a third transistor coupled between said first and second power supply lines and coupled to said second transistor to function as a first current mirror circuit with said second transistor.
6. The fuse circuit according to claim 5 , further comprising:
a fourth transistor coupled between said first and second power supply lines and coupled to said third transistor and said first transistor to function as a second current mirror circuit with said first transistor.
7. The fuse circuit according to claim 6 , further comprising:
a transfer gate coupled between said first and second power supply line; and
a fifth transistor coupled to said first power supply line and further coupled to a node between said transfer gate and said fourth transistor.
8. The fuse circuit according to claim 1 , wherein said size ratio of said second transistor is set so that said magnitude relationship is inverted based on whether said fuse is cut or not.
9. The fuse circuit according to claim 1 , further comprising:
a storage circuit coupled to said output terminal to latch a value of said signal.
10. The fuse circuit according to claim 6 , wherein a size ratio of said second transistor is the same as a size ratio of said fourth transistor.