Anti-fuse latch self-test circuit and method
First Claim
1. A programmable latch circuit, comprising:
- a volatile latch circuit that latches a data value according to a potential difference between a first data node and a second data node;
an anti-fuse circuit that includes a first anti-fuse structure coupled between a program node and the first data node, and a second anti-fuse structure coupled between the program node and the second data node; and
a test circuit that includes at least a first test current path coupled to the first node that provides a first test current to the first node in response to a first test signal, and a controllable current source that establishes the magnitude of the first test current.
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Accused Products
Abstract
A programmable latch circuit (200) can include a volatile latch (206) that may regenerate a value determined by programmable section (202). In a test operation, a variable current source (216′) can generate a current (IBASE) that can be mirrored in test sections (252-0 and 252-1) and compared to a current drawn by either programmable element (210-0) or (210-1) by a latching operation of volatile latch (206). Variable current source (216′) can enable characterization of programmable elements (210-0 or 210-1) as well as adjustable test threshold limits. A program voltage (Vprog) applied to programmable elements (210-0 or 210-1) can be also be variable to allow for characterization of programmable elements (210-0 and 210-1) over a range of voltages.
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Citations
20 Claims
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1. A programmable latch circuit, comprising:
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a volatile latch circuit that latches a data value according to a potential difference between a first data node and a second data node; an anti-fuse circuit that includes a first anti-fuse structure coupled between a program node and the first data node, and a second anti-fuse structure coupled between the program node and the second data node; and a test circuit that includes at least a first test current path coupled to the first node that provides a first test current to the first node in response to a first test signal, and a controllable current source that establishes the magnitude of the first test current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A programmable latch circuit, comprising:
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a volatile latch circuit comprising a pair of latch transistors cross-coupled between a first data node and a second data node and formed in an integrated circuit substrate; at least a pair of anti-fuse structures coupled between a program voltage node and the first data node and the second data node; and at least one variable current source formed in the integrated circuit substrate that controls a magnitude of a first test current provided to the first data node and a magnitude of a second test current provided to the second data node. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method of testing antifuse devices of a programmable latch circuit, comprising the steps of:
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generating a programmed current according to the state of at least one antifuse device of the programmable latch circuit, the programmed current flowing through one storage node of a volatile latch circuit; generating a test current with a variable current source formed in the same substrate as the programmable latch circuit, the test current flowing through a different storage node of the volatile latch circuit; and latching a test data value based on a potential difference between the one storage node and the different storage node of the volatile latch circuit. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification