Memory circuit arrangement for accurate and secure read
The present disclosure is directed to arranging user data memory cells and test memory cells in a configurable memory array that can perform both differential and single ended read operations during memory start-up and normal memory use, respectively. Different arrangements of the user data memory cells and the test memory cells in the memory array result in increased effectiveness of memory array, in terms of area optimization, memory read accuracy and encryption for data security.
1. A device, comprising:
a primary memory array that includes:
a plurality of bitlines;
a plurality of rows of memory cells;
a column multiplexor coupled to the plurality of bitlines; and
a sense amplifier coupled to the column multiplexor, the sense amplifier includes:
a first current to voltage convertor:
a second current to voltage convertor; and
a reference current generator memory cell array coupled to the second current to voltage convertor.
2. The device of claim 1 wherein the reference current generator memory cell array includes:
a plurality of rows of reference current memory cells;
a column multiplexor; and
a current mirror.
3. The device of claim 2 wherein the column multiplexor of the reference current generator memory cell array is coupled between the current mirror and the plurality of rows of the reference current memory cells.
4. The device of claim 1 wherein the column multiplexor of the primary memory array includes:
a plurality of bitline selection transistors;
a plurality of group selection transistors coupled to the plurality of bitline selection transistors;
a plurality of mode selection transistors coupled to the plurality of group selection transistors and the sense amplifier, a first one of the plurality of mode selection transistors coupled to the reference current generator memory cell array.
5. A method, comprising:
forming a primary memory cell array including a plurality of rows of memory cells and a reference current generator memory cell array including a plurality of rows of memory cells in a semiconductor substrate;
forming a first column multiplexor and a sense amplifier in the substrate;
coupling the first column multiplexor to bitlines of the primary memory cell array;
coupling a sense amplifier to the first column multiplexor and to the reference current generator memory cell array;
forming, a first current to voltage convertor and a second current to voltage convertor in the sense amplifier;
forming a comparator in the sense amplifier;
coupling the first and second current to voltage convertors to the comparator; and
coupling the reference current generator memory cell array to the second current to voltage convertor.
6. The method of claim 5 , further comprising:
coupling first column multiplexor to the first and second current to voltage convertors of the sense amplifier.
7. The method of claim 5 , further comprising simultaneously forming of the primary memory cell array and forming of the reference current generator memory cell array.
8. The method of claim 5 , further comprising:
forming a second column multiplexor;
coupling the second column multiplexor to the plurality of rows of the reference current generator memory cell array;
forming a current mirror; and
coupling the current mirror to the second column multiplexor.
9. A device, comprising:
a substrate; and
a primary memory array in the substrate, the primary memory array including:
a plurality of rows of memory cells;
a first column multiplexor coupled to the plurality of rows of memory cells, the first column multiplexor including;
a plurality of rows of bitline selection transistors;
a plurality of group selection transistors coupled to the plurality of rows of bitline selection transistors; and
a plurality of group selection transistors coupled to the plurality of group selection transistors; and
a sense amplifier coupled to the plurality of mode selection transistors of the first column multiplexor, the sense amplifier including
a reference current generator memory array in the substrate.
10. The device of claim 9 wherein the first column multiplexor includes a column decoder that includes:
a first level shifter coupled between a enable signal and a first one of the plurality of mode selection transistors;
a second level shifter coupled between an inverse of the enable signal and coupled to a second one of the plurality of mode selection transistors; and
a third level shifter coupled to a third one of the plurality of mode selection transistors.
11. The device of claim 10 wherein the first column multiplexor includes a column decoder that includes:
a plurality of inverters;
a plurality of address bits coupled to the plurality of inverters; and
a plurality of level shifters coupled to the plurality of address bits and the plurality of inventers.
12. The device of claim 11 wherein the column decoder includes a plurality of AND gates coupled to the plurality of level shifters and an exclusive OR gate coupled to ones of the plurality of AND gates.
13. The device of claim 12 wherein the plurality of address bits includes a first address bit coupled to a first one of the plurality of inverters and a second address bit coupled to a second one of the plurality of inverters.
14. The device of claim 1 , wherein the sense amplifier further includes:
a comparator, the first and second current to voltage convertors are coupled to the comparator.
15. The device of claim 4 , wherein the reference current generator memory cell array is coupled to the second current to voltage convertor by a transistor switch, wherein a gate of the transistor switch is controlled by the first one of the plurality of mode selection transistors.
16. The device of claim 15 , wherein an inverter is coupled between the gate of the transistor switch and the first one of the plurality of mode selection transistors, the inverter turns off the transistor switch when the first one of the plurality of mode selection transistors is turned on.
17. The method of claim 5 , further coupling the reference current generator memory cell array to the second current to voltage convertor by a transistor switch, wherein the transistor switch is controlled by one of a plurality of mode selection transistors.
18. The method of claim 17 , further coupling an inverter between the transistor switch and the one of the plurality of mode selection transistors, wherein the inverter turning off the transistor switch when the one of the plurality of mode selection transistors is turned on.