Static, low current sensing circuit for sensing the state of a fuse device
First Claim
1. A fuse sensing circuit comprising:
- a first circuit including a first fuse, the first circuit being coupled to receive first and second voltage supplies;
a second circuit coupled to the first circuit in a current mirror configuration and coupled to receive the first and second voltage supplies, the second circuit including a reference resistance;
a first output node coupled to the first circuit to indicate a state of the first fuse, a potential on the first output node being within a first range if the first fuse is un-programmed or within a second range if the first fuse is programmed; and
a first margin test device coupled to the first circuit, the first margin test device changing the potential on the first output node when the first margin test device is turned on such that the state of the first fuse is identified as being marginal if the changed potential is not within either of the first or second ranges.
1 Assignment
0 Petitions
Accused Products
Abstract
A fuse sensing circuit comprises a first branch includes a first sensing transistor, and a fuse coupled to the source of the first sensing transistor. The fuse has a programmed state characterized by a first resistance, and an unprogrammed state in which the fuse has a second resistance. A second reference branch is coupled to the first branch in a current mirror configuration and includes a second sensing transistor, and a predetermined reference resistance coupled to the source of the second sensing transistor. The reference resistance is matched to the fuse device in an un-programmed state. The potential at an output node coupled to the first sensing transistor is determined by the state of the fuse device, such that the potential of the output node is within a first voltage range if the fuse device is programmed, and a second voltage range if the fuse device is un-programmed.
-
Citations
24 Claims
-
1. A fuse sensing circuit comprising:
-
a first circuit including a first fuse, the first circuit being coupled to receive first and second voltage supplies; a second circuit coupled to the first circuit in a current mirror configuration and coupled to receive the first and second voltage supplies, the second circuit including a reference resistance; a first output node coupled to the first circuit to indicate a state of the first fuse, a potential on the first output node being within a first range if the first fuse is un-programmed or within a second range if the first fuse is programmed; and a first margin test device coupled to the first circuit, the first margin test device changing the potential on the first output node when the first margin test device is turned on such that the state of the first fuse is identified as being marginal if the changed potential is not within either of the first or second ranges. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A fuse sensing circuit comprising:
-
a current mirror including two circuit branches coupled in a current mirror configuration, the current mirror coupled between first and second voltage supplies; a first fuse coupled between a first branch of the two circuit branches of the current mirror and the first voltage supply; a reference resistance coupled between a second branch of the two circuit branches and the first voltage supply; a first output node coupled to the first branch, a potential on the first output node indicating that the first fuse is un-programmed if the potential is within a first range, the potential indicating that the first fuse is programmed if the potential is within a second range; and first and second margin test devices coupled to the first branch and coupled to the second voltage supply, each of the first and second margin test devices changing the potential on the output node when enabled to indicate that the first fuse is marginal if the changed potential is outside of the first and second ranges. - View Dependent Claims (13, 14, 15)
-
-
16. A fuse sensing circuit for sensing a state of at least a first fuse, the fuse sensing circuit comprising:
-
a first circuit including a first fuse having one terminal coupled to a first supply voltage and an opposite terminal coupled to a first terminal of a first sensing transistor, a second terminal of the first sensing transistor coupled to a second supply voltage; a second circuit including a reference resistance coupled to the first supply voltage and to a first terminal of a second sensing transistor, a second terminal of the second sensing transistor coupled to the second supply voltage, the first and second sensing transistors being coupled in a current mirror configuration; a first output node coupled to the second terminal of the first sensing transistor to indicate the state of the first fuse by a sensed potential, the sensed potential on the first output node being within a first range if the first fuse is un-programmed, the sensed potential being within a second range if the first fuse is programmed; and a first margin test device having one terminal coupled to the second terminal of the first sensing transistor, the first margin test device changing the sensed potential on the first output node when the first margin test device is turned on such that the first fuse is identified as being marginally un-programmed if the changed potential is outside the first range and the sensed potential is within the first range. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
-
Specification