Storage element for controlling a logic circuit, and a logic device having an array of such storage elements
View Patent ↗The present invention is a storage element for controlling a logic circuit and a logic device having a plurality of storage elements. The storage element has a first and a second non-volatile memory cells connected in series at an output node. Each of the first and second non-volatile memory cells is for storing a state opposite to the other. A demultiplexer has an input, a switched input and two outputs. The output node is connected to the input of the demultiplexer. One of the outputs is used to control the logic circuit. The other output is connected to a bit line which is connected to a sense amplifier. Finally, the switched input receives a switch signal and outputs the signal from the output node to either the one output or the other output.
1. A storage element for controlling a logic circuit, said storage element comprising:
a first floating gate flash memory transistor of a first conductivity type, said first floating gate flash memory transistor having a first region and a spaced apart second region, each region being of a second conductivity type with a channel region of the first conductivity type therebetween; a floating gate is spaced apart from a first portion of the channel region and is adjacent to the first region; a coupling gate is over the floating gate and is capacitively coupled thereto; a control gate is adjacent to and spaced apart from the floating gate and the coupling gate, said control gate is spaced apart from another portion of the channel region and has a portion adjacent to the second region; an erase gate is over the first region and is spaced apart therefrom and spaced apart from the floating gate and the coupling gate;
a second floating gate flash memory transistor of the first conductivity type, said second floating gate flash memory transistor has a first region and a spaced apart second region, each region being of the second conductivity type with a channel region of the first conductivity type therebetween; a floating gate is spaced apart from a first portion of the channel region and adjacent to the first region; a coupling gate is over the floating gate and is capacitively coupled thereto; a control gate is adjacent to and spaced apart from the floating gate and the coupling gate, said control gate is spaced apart from another portion of the channel region and has a portion adjacent to the second region; an erase gate is over the first region and is spaced apart therefrom and spaced apart from the floating gate and the coupling gate;
wherein the second region of the first floating gate flash memory transistor is electrically connected to the second region of the second floating gate flash memory transistor, and provides a storage output; and
a switch having an input, two outputs, and a switch input for receiving the storage output at the input, and for supplying a signal to one of the two outputs in response to the switch input, wherein said one output being coupled to the logic circuit.
2. The storage element of claim 1 wherein the switch comprises two MOS transistors of the first conductivity type.
3. The storage element of claim 1 wherein the other output is connected to a sense amplifier.
4. The storage element of claim 1 wherein said first conductivity is N type.
5. The storage element of claim 1 wherein said first conductivity is P type.
6. A storage cell for controlling a logic circuit, said storage cell comprising:
a first and a second non-volatile memory cells of the same type connected in series at a first node wherein said first non-volatile memory cell is for being programmed in a first conduction state and said second non-volatile memory cell is for being programmed in a conduction second state, opposite said first conduction state; and
a switch having an input, two outputs and a switch input; said input connected to the first node; one of said two outputs coupled to the logic circuit; another of the outputs coupled to a sense amplifier for sensing the state of the first or second non-volatile memory cells; and the switch input for receiving a switch signal to connect the first node to the one output or to the another output.
7. The storage cell of claim 6 wherein each of the first and second non-volatile memory cells is a floating gate memory transistor.
8. The storage cell of claim 6 wherein each of the first and second non-volatile memory cells is a phase changing memory cell.
9. The storage cell of claim 6 wherein each of the first and second non-volatile memory cells is a SONOS memory cell.
10. The storage cell of claim 6 wherein said switch comprises two MOS transistors of the same conductivity type.
11. The storage cell of claim 10 wherein each of said MOS transistors of said switch are P type.
12. The storage cell of claim 6 wherein said switch comprises two transmission gates.
13. A programmable logic device comprising:
a plurality of storage elements arranged in an array comprising at least one row and a plurality of columns;
each storage element comprising a first and a second non-volatile memory cells of the same type connected in series at a first node wherein said first non-volatile memory cell is for being programmed in a first conduction state and said second non-volatile memory cell is for being programmed in a second conduction state, opposite said first conduction state;
each storage element having an associated switch, each switch having an input, two outputs and a switch input; said input of a switch connected to the first node of an associated storage element; one of said two outputs coupled to a sense amplifier for sensing the state of the first or second non-volatile memory cells; and a switch input for receiving a switch signal to connect the first node to the one output or to another output;
a plurality of logic elements arranged in an array comprising at least one row and a plurality of columns, with each logic element substantially aligned with a storage element in the column direction; and
each logic element having an input coupled to the another output of the associated storage element.
14. The logic device of claim 13 wherein said input of each logic element is connected to the another output of the associated storage element in the column direction.
15. The logic device of claim 13 wherein each storage element comprises:
a first floating gate flash memory transistor of a first conductivity type, said first floating gate flash memory transistor having a first region and a spaced apart second region, each region being of a second conductivity type with a channel region of the first conductivity type therebetween; a floating gate is spaced apart from a first portion of the channel region and adjacent to the first region; a coupling gate is over the floating gate and is capacitively coupled thereto; a control gate is adjacent to and spaced apart from the floating gate and the control gate, said control gate is spaced apart from another portion of the channel region and having a portion adjacent to the second region; an erase gate is over the first region and is spaced apart therefrom and spaced apart from the floating gate and the coupling gate;
a second floating gate flash memory transistor of the first conductivity type, said second floating gate flash memory transistor having a first region and a spaced apart second region, each region being of the second conductivity type with a channel region of the first conductivity type therebetween; a floating gate is spaced apart from a first portion of the channel region and adjacent to the first region; a coupling gate is over the floating gate and is capacitively coupled thereto; a control gate is adjacent to and spaced apart from the floating gate and the control gate, said control gate is spaced apart from another portion of the channel region and having a portion adjacent to the second region; an erase gate is over the first region and is spaced apart therefrom and spaced apart from the floating gate and the coupling gate; and
wherein the second region of the first floating gate flash memory transistor is electrically connected to the second region of the second floating gate flash memory transistor, and provides the first node.
16. The logic device of claim 15 wherein the switch comprises two MOS transistors of the first conductivity type.
17. The logic device of claim 15 wherein the other output is connected to a sense amplifier.
18. The logic device of claim 15 wherein the plurality of logic elements are AND circuits.
19. The logic device of claim 15 wherein the plurality of logic elements are OR circuits.
20. The logic device of claim 15 wherein the plurality of logic elements are Look Up Table circuits.
21. The logic device of claim 15 wherein the plurality of logic elements are switches.
22. The logic device of claim 15 wherein said plurality of storage elements include a plurality of spaced apart arrays of storage elements, each array having at least one row and a plurality columns of storage elements; and
wherein said plurality of logic elements include a plurality of spaced apart arrays of logic elements, each array having at least one row and a plurality columns of logic elements; and
wherein each array of logic elements is between each array of storage elements.
23. The logic device of claim 15 wherein said plurality of storage elements include a plurality of spaced apart arrays of storage elements, each array having at least one row and a plurality columns of storage elements; and
wherein said plurality of logic elements include a plurality of spaced apart arrays of logic elements, each array having at least one row and a plurality columns of logic elements; and
wherein each array of logic elements is between each array of storage elements.
24. The logic device of claim 23 further comprising a plurality of bit lines, each bit line crossing a plurality of arrays of storage elements and a plurality of arrays of logic elements and connecting to the one output of each storage element in a column direction, with the sense amplifier connected to each bit line.
25. The logic device of claim 23 further comprising a plurality of word lines, a first word line extending in the row direction connecting the coupling gate of said first floating gate flash memory transistors in the same row, a second word line extending in the row direction connecting the coupling gate of said second floating gate flash memory transistors in the same row; a third word line extending in the row direction connecting the control gate of said first floating gate flash memory transistors in the same row; and a fourth word line extending in the row direction connecting the control gate of said second floating gate flash memory transistors in the same row.
26. The logic device of claim 23 further comprising a plurality of erase lines, each extending in the row direction connecting the erase gate of said first and second floating gate flash memory transistor.
27. The logic device of claim 25 , wherein a method of operation of the logic device comprises controlling the voltage applied to the first word line and the second word line to minimize the leakage current of the storage element.