Variable resistance memory devices and methods of programming variable resistance memory devices

1. A variable resistance memory device comprising:

a variable resistance memory cell;

a by-pass circuit configured to electrically by-pass a programming pulse supplied to the variable resistance memory cell after a resistive state of the variable resistance memory cell has changed in response to the programming pulse,

wherein the by-pass circuit comprises a delay circuit and a by-pass switch, and wherein the delay circuit receives the programming pulse and outputs a corresponding delayed signal which controls the by-pass switch to by-pass a current flow into the variable resistance memory cell.

2. The variable resistance memory device of claim 1 , wherein the by-pass switch is a transistor electrically connected in parallel with the variable resistance memory cell.

3. The variable resistance memory device of claim 1 , further comprising a current limiting element which limits a cell current magnitude of the variable resistance memory cell.

4. The variable resistance memory device of claim 1 , wherein the variable resistance memory cell comprises at least one transition metal oxide (TMO).

5. A variable resistance memory device comprising:

a variable resistance memory cell;

a by-pass circuit configured to electrically by-pass a programming pulse supplied to the variable resistance memory cell after a resistive state of the variable resistance memory cell has changed in response to the programming pulse,

wherein the by-pass circuit comprises a voltage sensor and a by-pass switch, and wherein the voltage sensor senses a voltage drop of the variable resistance memory cell, and is responsive to the voltage drop to control the by-pass switch to by-pass a current flow into the variable resistance memory cell.

6. The variable resistance memory device of claim 5 , wherein the voltage sensor is an inverter.

7. The variable resistance memory device of claim 5 , wherein the by-pass switch is a transistor electrically connected in parallel with the variable resistance memory cell.

8. A variable resistance memory device, comprising:

a variable resistance memory cell array comprising a plurality of variable resistance memory cells electrically connected between a plurality of bit lines and a plurality of words lines;

a current limiting circuit which limits a cell current magnitude of the variable resistance memory cells;

a by-pass circuit configured to electrically by-pass the variable resistance memory cells while a programming pulse is supplied to the variable resistance memory cells after a resistive state of the variable resistance memory cells has changed in response to the programming pulse, wherein a portion of the programming pulse electrically by-passes the variable resistance memory cells through the by-pass circuit,

wherein the current limiting circuit comprises a current limiting transistor connected between a programming pulse terminal and the plurality of bit lines,

wherein the variable resistance memory device further comprises a decoder circuit connected between current limiting transistor and the plurality of bit lines, and

wherein the by-pass circuit comprises a delay circuit and a by-pass switch, and wherein the delay circuit receives the programming pulse and outputs a corresponding delayed signal which controls the by-pass switch to by-pass a current flow into the variable resistance memory cell.

9. The variable resistance memory device of claim 8 , wherein the by-pass switch is a transistor connected between a reference voltage and a connection node between the decoder circuit and the current limiting transistor.

10. A variable resistance memory device, comprising:

a variable resistance memory cell array comprising a plurality of variable resistance memory cells electrically connected between a plurality of bit lines and a plurality of words lines;

a current limiting circuit which limits a cell current magnitude of the variable resistance memory cells;

a by-pass circuit configured to electrically by-pass the variable resistance memory cells while a programming pulse is supplied to the variable resistance memory cells after a resistive state of the variable resistance memory cells has changed in response to the programming pulse, wherein a portion of the programming pulse electrically by-passes the variable resistance memory cells through the by-pass circuit,

wherein the current limiting circuit comprises a current limiting transistor connected between a programming pulse terminal and the plurality of bit lines,

wherein the variable resistance memory device further comprises a decoder circuit connected between current limiting transistor and the plurality of bit lines, and

wherein the by-pass circuit comprises a voltage sensor and a by-pass switch, and wherein the voltage sensor senses a voltage drop of the variable resistance memory cells, and is responsive to the voltage drop to control the by-pass switch to by-pass a current flow into the variable resistance memory cells.

11. The variable resistance memory device of claim 10 , wherein the by-pass is a transistor connected between a reference voltage and a connection node between the decoder circuit and the current limiting transistor.

12. A variable resistance memory device, comprising:

a variable resistance memory cell array comprising a plurality of variable resistance memory cells electrically connected between a plurality of bit lines and a plurality of words lines;

a current limiting circuit which limits a cell current magnitude of the variable resistance memory cells;

a by-pass circuit configured to electrically by-pass the variable resistance memory cells while a programming pulse is supplied to the variable resistance memory cells after a resistive state of the variable resistance memory cells has changed in response to the programming pulse, wherein a portion of the programming pulse electrically by-passes the variable resistance memory cells through the by-pass circuit,

wherein the current limiting circuit comprises a plurality of current limiting transistors respectively connected between a programming pulse terminal and the respective plurality of bit lines,

wherein the variable resistance memory device further comprises a decoder circuit connected to the plurality of bit lines opposite the plurality of current limiting transistors, and

wherein the by-pass circuit comprises a delay circuit and a by-pass switch, and wherein the delay circuit receives the programming pulse and outputs a corresponding delayed signal which controls the by-pass switch to by-pass a current flow into the variable resistance memory cells.

13. The variable resistance memory device of claim 12 , wherein the by-pass switch is a transistor connected between a reference voltage and the decoder circuit.

14. A variable resistance memory device, comprising:

a variable resistance memory cell array comprising a plurality of variable resistance memory cells electrically connected between a plurality of bit lines and a plurality of words lines;

a current limiting circuit which limits a cell current magnitude of the variable resistance memory cells;

a by-pass circuit configured to electrically by-pass the variable resistance memory cells while a programming pulse is supplied to the variable resistance memory cells after a resistive state of the variable resistance memory cells has changed in response to the programming pulse, wherein a portion of the programming pulse electrically by-passes the variable resistance memory cells through the by-pass circuit,

wherein the current limiting circuit comprises a plurality of current limiting transistors respectively connected between a programming pulse terminal and the respective plurality of bit lines,

wherein the variable resistance memory device further comprises a decoder circuit connected to the plurality of bit lines opposite the plurality of current limiting transistors, and

wherein the by-pass circuit comprises a voltage sensor and a by-pass switch, and wherein the voltage sensor senses a voltage drop of the variable resistance memory cells, and is responsive to the voltage drop to control the by-pass switch to by-pass a current flow into the variable resistance memory cells.

15. The variable resistance memory device of claim 14 , wherein the by-pass switch is a transistor connected between a reference voltage and the decoder circuit.