Electronic device and operating method of electronic device

1. An operating method of an electronic device, the method comprising:

receiving input data;

selecting a program voltage pattern corresponding to the input data from among a plurality of program voltage patterns for storing the input data in a memristor array circuit; and

storing the input data in the memristor array circuit based on the selected program voltage pattern,

wherein each of the plurality of program voltage patterns includes a plurality of voltage pulses in which a pulse magnitude gradually increases over time, and

wherein a first voltage difference between adjacent voltage pulses in a first program voltage pattern of the plurality of program voltage patterns is different from a second voltage difference of adjacent voltage pulses in a second program voltage pattern of the plurality of program voltage patterns.

2. The method of claim 1 , wherein the selecting of the program voltage pattern includes:

when the input data have a first value, selecting the first program voltage pattern; and

when the input data have a second value, selecting the second program voltage pattern.

3. The method of claim 2 , wherein, when the input data have the first value, a corresponding cell of the memristor array circuit is programmed to a high resistance state (HRS), and

wherein, when the input data have the second value, the corresponding cell of the memristor array circuit is programmed to a low resistance state (LRS).

4. The method of claim 3 , wherein the first voltage difference of adjacent voltage pulses in the first program voltage pattern is greater than the second voltage difference of adjacent voltage pulses in the second program voltage pattern.

5. The method of claim 3 , wherein a number of voltage pulses included in the first program voltage pattern is less than a number of voltage pulses included in the second program voltage pattern.

6. The method of claim 1 , wherein, depending on values stored in two adjacent memristor cells in a same row of the memristor array circuit, a value stored in the two adjacent memristor cells is a value of “1”, “0”, or “−1”.

7. The method of claim 6 , wherein, when all the two memristor cells are programmed to an HRS, the value stored in the two memristor cells is “0”,

wherein, when a memristor cell placed on one side from among the two memristor cells is programmed to an LRS and a memristor cell placed on an opposite side from among the two memristor cells is programmed to the HRS, the value stored in the two memristor cells is “1”, and

wherein, when the memristor cell placed on the one side from among the two memristor cells is programmed to the HRS and the memristor cell placed on the opposite side from among the two memristor cells is programmed to the LRS, the value stored in the two memristor cells is “−1”.

8. The method of claim 7 , wherein the two memristor cells store at least a portion of a synaptic weight of a neural network.

9. The method of claim 1 , wherein the selecting of the program voltage pattern includes:

selecting the program voltage pattern based on the input data and an input of a user.

10. The method of claim 1 , wherein the operating mode is determined as one of a high-accuracy operating mode and a low-accuracy operating mode, depending on a quality of service (QoS) required with regard to the electronic device.

11. The method of claim 10 , wherein a first voltage difference of consecutive voltage pulses in a program voltage pattern selected in the low-accuracy operating mode from among the plurality of program voltage patterns is greater than a second voltage difference of consecutive voltage pulses in a program voltage pattern selected in the high-accuracy operating mode from among the plurality of program voltage patterns.

12. An electronic device comprising:

a memristor array circuit; and

a memristor array controlling circuit configured to store input data in the memristor array circuit depending on a program voltage pattern, which is selected to correspond to the input data, from among a plurality of program voltage patterns for storing the input data in the memristor array circuit,

wherein each of the plurality of program voltage patterns includes a plurality of voltage pulses in which a pulse magnitude gradually increases over time, and

wherein a first voltage difference between adjacent voltage pulses in a first program voltage pattern of the plurality of program voltage patterns is different from a second voltage difference of adjacent voltage pulses in a second program voltage pattern of the plurality of program voltage patterns.

13. The electronic device of claim 12 , wherein the memristor array controlling circuit selects one of a plurality of program schemes and selects a program voltage pattern corresponding to the input data from among program voltage patterns belonging to the selected program scheme.

14. The electronic device of claim 13 , wherein at least one of a scheme of programming a memristor cell of the memristor array circuit to a high resistance state (HRS) and a scheme of programming the memristor cell to a low resistance state (LRS) is different among the plurality of program schemes.

15. The electronic device of claim 12 , wherein the memristor array controlling circuit adjusts a fine level of the selected program voltage pattern.

16. The electronic device of claim 12 , wherein, after the input data are stored in the memristor array circuit, the memristor array controlling circuit calculates second input data and at least a portion of the input data stored in the memristor array circuit.

17. The electronic device of claim 16 , wherein the memristor array controlling circuit calculates a result of the calculation as third input data and at least another portion of the input data stored in the memristor array circuit.

18. An electronic device comprising:

a memory device configured to store data;

a processor configured to use the memory device as a working memory; and

a neural network system configured to perform learning or inference by using the data stored in the memory device depending on a request of the processor,

wherein the neural network system includes:

a memristor array circuit; and

a memristor array controlling circuit configured to store input data in the memristor array circuit depending on a program voltage pattern, which is selected to correspond to the input data, from among a plurality of program voltage patterns for storing the input data in the memristor array circuit,

wherein each of the plurality of program voltage patterns includes a plurality of voltage pulses in which a pulse magnitude gradually increases over time, and

wherein a first voltage difference between adjacent voltage pulses in a first program voltage pattern of the plurality of program voltage patterns is different from a second voltage difference of adjacent voltage pulses in a second program voltage pattern of the plurality of program voltage patterns.