Integrated circuit having fuse circuit
First Claim
1. A detection circuit for an integrated circuit having a fuse with first and second terminals and said detection circuit for detecting whether the fuse has blown, said detection circuit comprising:
- a first voltage source supplying a first voltage;
a second voltage source, coupled to the first terminal of the fuse, supplying a second voltage lower than the first voltage;
a first circuit comprising a first transistor, having a source coupled to the second terminal of the fuse and a gate coupled to the first terminal of the fuse; and
a second circuit comprising;
a second transistor having a source and a gate; and
a resistor, coupled between the source and gate of said second transistor, said first and second circuits being coupled in series between said first and second voltage sources at a junction point, generating a detection signal, indicating whether the fuse has been blown, at said junction point.
1 Assignment
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Accused Products
Abstract
This invention is related to an integrated circuit (IC) having a fuse circuit. In such an IC device, it is very difficult to hold a specific gain of the IC because of a leakage of a gap between the fuse terminals called "re-glown fuse" or "glown-back fuse", and the IC suffers from malfunction. The present invention provides a fuse circuit to detect whether a fuse has been blown or not, by judging whether the fuse resistance is larger or smaller compared to a predetermined threshold resistor, which generates a judging potential corresponding to a fuse condition. Thus the IC can be used without malfunction.
42 Citations
12 Claims
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1. A detection circuit for an integrated circuit having a fuse with first and second terminals and said detection circuit for detecting whether the fuse has blown, said detection circuit comprising:
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a first voltage source supplying a first voltage; a second voltage source, coupled to the first terminal of the fuse, supplying a second voltage lower than the first voltage; a first circuit comprising a first transistor, having a source coupled to the second terminal of the fuse and a gate coupled to the first terminal of the fuse; and a second circuit comprising; a second transistor having a source and a gate; and a resistor, coupled between the source and gate of said second transistor, said first and second circuits being coupled in series between said first and second voltage sources at a junction point, generating a detection signal, indicating whether the fuse has been blown, at said junction point. - View Dependent Claims (2, 3, 4)
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5. A detection circuit for an integrated circuit having a fuse which has first and second terminals, said detection circuit detecting whether the fuse has blown, said detection circuit comprising:
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a first voltage source supplying a first voltage; a second voltage source, coupled to the first terminal of the fuse, supplying a second voltage lower than the first voltage; a first circuit, comprising a first transistor having a source coupled to the second terminal of the fuse and a gate coupled to the first terminal of the fuse; and a second circuit, comprising a second transistor having a source and a gate coupled to each other, said first and said second circuits being coupled in series between said first and said second voltage sources at a junction point and generating a detection signal, indicating whether the fuse has been blown, at said junction point. - View Dependent Claims (9, 11)
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6. A detection circuit for an integrated circuit having a fuse which has first and second terminals and said detection circuit detects whether or not said fuse has blown, said detection circuit comprising:
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a first voltage source supplying a first voltage; a second voltage source, coupled to the first terminal of the fuse, supplying a second voltage lower than the first voltage; a first circuit comprising a first transistor, having a source coupled to the second terminal of the fuse; and a second circuit comprising a second transistor, having a source and a gate; a mirror circuit comprising a third transistor, a fourth transistor, and an impedance element, said third and said fourth transistors each having a gate, a source, and a drain, the sources of said third and said fourth transistors being connected to said first voltage source, the gates of said third and said fourth transistors being coupled to each other, the gate of said fourth transistor being further connected to the drain of said fourth transistor, said impedance element being connected between the drain of said fourth transistor and said second circuit, said first circuit being connected between the drain of said third transistor and said second voltage source, said second circuit being connected between said impedance element and said second voltage source, the gates of said first and said second transistors being connected to each other, and said first and said second circuits being coupled in parallel with each other and coupled to said mirror circuit, a detection signal indicating a blown condition of said fuse being generated at the drain of said third transistor. - View Dependent Claims (7, 8, 10, 12)
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Specification