MEMRISTIVE CROSS-BAR ARRAY FOR DETERMINING A DOT PRODUCT

• US 20170316827A1
• Filed: 10/23/2014
• Published: 11/02/2017
• Est. Priority Date: 10/23/2014
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Inventors: GE, Ning, YANG, Jianhua, STRACHAN, John Paul, HU, Miao
• Granted Patent: US 10,008,264 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 17/11 for solving equations , e.g. nonlinear equations, general mathematical optimization problems optimization specially adapted for a specific administrative, business or logistic context G06Q10/04
• CPC Class Codes: G06F 17/16 Matrix or vector computation , e.g. matrix-matrix or matrix-vector multiplication, matrix factorization matrix transposition G06F7/78
• CPC Class Codes: G06G 7/16 for multiplication or division G06G7/19 and G06G7/24 take precedence; measuring electric power G01R21/00
• CPC Class Codes: G11C 13/0007 comprising metal oxide memory material, e.g. perovskites
• CPC Class Codes: G11C 13/0023 Address circuits or decoders
• CPC Class Codes: G11C 13/0026 Bit-line or column circuits
• CPC Class Codes: G11C 13/0028 Word-line or row circuits
• CPC Class Codes: G11C 13/004 Reading or sensing circuits or methods
• CPC Class Codes: G11C 13/0069 Writing or programming circuits or methods
• CPC Class Codes: G11C 2213/15 Current-voltage curve
• CPC Class Codes: G11C 2213/77 Array wherein the memory element being directly connected to the bit lines and word lines without any access device being used
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A method of obtaining a dot product includes applying a number of first voltages to a corresponding number of row lines within a memristive cross-bar array to change the resistive values of a corresponding number of memristors located a junctions between the row lines and a number of column lines. The first voltages define a corresponding number of values within a matrix, respectively. The method further includes applying a number of second voltages to a corresponding number of the row lines within the memristive cross-bar array. The second voltages define a corresponding number of vector values. The method further includes collecting the output currents from the column lines. The collected output currents define the dot product.

Claims

1. A memristive cross-bar array for determining a dot product, comprising:

a number of row lines;

a number of column lines intersecting the row lines to form a number of junctions;

a number of resistive memory elements coupled between the row lines and the column lines at the junctions, the resistive memory elements to;

receive a number of programming signals at the resistive memory devices, the programming signals defining a number of values within a matrix; and

receive a number of vector signals at the resistive memory devices, the vector signals defining a number of vector values to be applied to the resistive memory devices; and

a current collection line to collect all currents output from the resistive memory devices through their respective column lines, the collected currents equaling a dot product of the matrix values and the vector values.

2. The memristive cross-bar array of claim 1, further comprising a number of circuits connected to each row line to apply a reference voltage to each resistive memory device.

3. The memristive cross-bar array of claim 2, in which the circuits shift the operation region of the memristive cross-bar array, in which the shift of the operation region is based on the ratio of a voltage of a voltage input into the circuits and a voltage of a reference voltage input into the circuits.

4. The memristive cross-bar array of claim 3, in which the ratio comprises voltages such that the reference voltage is equal to a maximum voltage of the input voltage divided by two.

5. The memristive cross-bar array of claim 2, in which the circuits are negative feedback operational amplifiers.

6. The memristive cross-bar array of claim 1, in which the calculation of all the sums and the products of the dot product are performed simultaneously by the memristive cross-bar array.

7. The memristive cross-bar array of claim 1, in which the memristor cross-bar array is used as an accelerator in connection with a secondary computer program such that the output of the memristive cross-bar array is coupled to a processing device as input for the secondary computer program.

15. The memristive cross-bar array of claim 1, in which the processor inputs the output of the memristive cross-bar array to a secondary computer program.

8. A method of obtaining a dot product comprising:

applying a number of first voltages to a corresponding number of row lines within a memristive cross-bar array to change the resistive values of a corresponding number of memristors located a junctions between the row lines and a number of column lines, the first voltages defining a corresponding number of values within a matrix, respectively;

applying a number of second voltages to a corresponding number of the row lines within the memristive cross-bar array, the second voltages defining a corresponding number of vector values; and

collecting the output currents from the column lines, the collected output currents defining the dot product.

9. The method of claim 8, further comprising applying an initial voltage to each resistive memory device to set the resistive memory devices to an initial resistance.

10. The method of claim 9, in which the amplifiers are negative feedback operational amplifiers.

11. The method of claim 9, further comprising shifting the operation region of the memristive cross-bar array, in which the shift of the operation region is based on a ratio of a voltage value of a voltage input into the amplifiers and a voltage value of a reference voltage input into the amplifiers.

12. The method of claim 11, in which the ratio comprises voltages such that the reference voltage is equal to a maximum voltage of the input voltage divided by two.

13. A computing device for determining a dot product, comprising:

a processor, and

memristor cross-bar array coupled to the processor, the memristor cross-bar array comprising;

a number of row lines;

a number of column lines intersecting the row lines to form a number of junctions;

a number of memristor devices coupled between the row lines and the column lines at the junctions, the memristor devices to;

receive a number of programming signals at the memristor devices, the programming signals defining a number of values within a matrix; and

receive a number of vector signals at the memristor devices, the vector signals defining a number of vector values to be applied to the memristor devices; and

a number of circuits connected to each row line to apply a reference voltage to each resistive memory device to set the resistive memory devices to an initial resistance,

in which the circuits shift the operation region of the memristive cross-bar array based on the ratio of a voltage of a voltage input into the circuits and a voltage of a reference voltage input into the amplifiers.

14. The computing device of claim 13, in which the memristor cross-bar array further comprises a current collection line to collect all currents output from the resistive memory devices through their respective column lines, the collected current equaling a dot product of the matrix values and the vector values.