SRAM based cell for programmable logic devices
First Claim
Patent Images
1. A programmable logic device having a plurality of inputs and a plurality of outputs connected to an AND-OR array for defining logic functions to be performed by the device, comprising:
- a plurality of SRAM cells arranged in a regular matrix for storing program information defining connections in the AND-OR array; and
logic gates connecting outputs from selected SRAM cells together to perform logic functions thereon, said logic gates generating outputs which define product terms of the AND-OR array.
1 Assignment
0 Petitions
Accused Products
Abstract
A programmable cell for use in programmable logic devices utilizes CMOS SRAM technology. True and complement cells are paired, and generate a signal which can be combined with other such signals to give a product term. SRAM bits store program information, and drive the generated signal as a function of values at its true and complementary inputs. The generated signal goes through a full CMOS voltage swing, so that no sense amplifiers are required for the product term.
92 Citations
17 Claims
-
1. A programmable logic device having a plurality of inputs and a plurality of outputs connected to an AND-OR array for defining logic functions to be performed by the device, comprising:
-
a plurality of SRAM cells arranged in a regular matrix for storing program information defining connections in the AND-OR array; and logic gates connecting outputs from selected SRAM cells together to perform logic functions thereon, said logic gates generating outputs which define product terms of the AND-OR array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An AND-OR array for a semiconductor integrated circuit programmable logic device, comprising:
-
a plurality of linear arrays of SRAM cells, each linear array corresponding to a product term of the AND-OR array; wherein each SRAM cell contains a programming bit defining a connection in the AND-OR array; a plurality of first logic gates, each of said logic gates connected to at least two of the SRAM cells in a single linear array; and at least one additional logic gate having inputs connected to outputs of selected first logic gates or to outputs of selected additional logic gates, wherein said additional logic gates combine signals from the SRAM cells so as to generate an output signal which is defined as a product term for each of said linear arrays. - View Dependent Claims (10, 11, 12)
-
-
13. A method for generating product term signals in a semiconductor integrated circuit programmable logic device, comprising the steps of:
-
storing data in an array of SRAM cells; providing input signals to the array; generating output signals from the SRAM cells which are a function of input signals applied thereto and the data stored in the cells; and combining selected groups of SRAM cell outputs in logic gates to form product term signals. - View Dependent Claims (14, 15, 16, 17)
-
Specification