Fuse blow circuit
First Claim
1. A fuse blow circuit for a VLSI chip comprising:
- a VLSI chip substrate having a plurality of fuses coupled to a fuse control circuit;
said VLSI chip having a plurality of I/O terminal pads used for other functions on said chip and coupled between the fuses and the fuse control circuit to enable addressing the fuses so that the fuses can be read, blown or electrically bypassed,a fuse latch-blow circuit on said chip having a fuse blow circuit, a fuse sense circuit, a fuse latch circuit, and I/O address buffers, and whereinsaid fuse control circuit and fuse latch-blow circuit provides means for permanently reading outputs from the I/O address buffers and the fuse sense circuit and for loading either one of those into the fuse latch circuit, wherebysaid fuse latch circuit will output the state of an address or a fuse according to the instructions of said fuse control circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A chip can be provide with circuits to electrically read, blow and latch fuses. The circuit allows use of existing I/O pads used for other functions on a chip to drastically reduce the number of I/O required to blow fuses. The circuits also share critical high current carrying lines with no impact on fuse functionality and device reliability. By offering of complex fuse operations such as electrical override, even after they had been blown, essential for product screening and product diagnostics. The circuit provides a fuse blow circuit fed by a fuse sense circuit and fuse latch circuit. Stored addresses in an address buffer addresses the fuses with two sets of inputs: one providing electrical override and/or fuse blow information; and the second one, normal fuse status. Fuse integrity before and after blow is maximized with a dual voltage source drive and low current sensing.
35 Citations
14 Claims
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1. A fuse blow circuit for a VLSI chip comprising:
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a VLSI chip substrate having a plurality of fuses coupled to a fuse control circuit; said VLSI chip having a plurality of I/O terminal pads used for other functions on said chip and coupled between the fuses and the fuse control circuit to enable addressing the fuses so that the fuses can be read, blown or electrically bypassed, a fuse latch-blow circuit on said chip having a fuse blow circuit, a fuse sense circuit, a fuse latch circuit, and I/O address buffers, and wherein said fuse control circuit and fuse latch-blow circuit provides means for permanently reading outputs from the I/O address buffers and the fuse sense circuit and for loading either one of those into the fuse latch circuit, whereby said fuse latch circuit will output the state of an address or a fuse according to the instructions of said fuse control circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification