RRAM circuit and method

1. A memory circuit comprising:

a bias voltage generator comprising a first current path, the first current path comprising a node and a current source configured to output a first current at the node, wherein the bias voltage generator is configured to output a bias voltage from the node based on a voltage difference generated from conduction of the first current in the first current path;

a drive circuit configured to receive the bias voltage and output a drive voltage having a voltage level based on the bias voltage; and

a resistive random-access memory (RRAM) device configured to conduct a second current responsive to the drive voltage.

2. The memory circuit of claim 1 , wherein the current source is configured to generate the first current having a predetermined current level based on a compliance current of the RRAM device.

3. The memory circuit of claim 1 , further comprising a second current path configured to conduct the second current, wherein

the RRAM device is included in the second current path,

the first current path comprises a path segment having a resistance value based on a portion of the second current path between the drive circuit and the RRAM device, and

the voltage difference is based on the resistance value.

4. The memory circuit of claim 1 , further comprising a second current path configured to conduct the second current, wherein

the RRAM device is included in the second current path,

the first current path comprises a path segment having a resistance value based on a portion of the second current path between the RRAM device and a reference node, and

the voltage difference is based on the resistance value.

5. The memory circuit of claim 1 , wherein

the RRAM device comprises a resistive layer configured to conduct the second current,

the first current path comprises a resistive device having a resistance value based on the resistive layer, and

the voltage difference is based on the resistance value.

6. The memory circuit of claim 5 , wherein

the resistive layer is capable of having a high resistance state (HRS) and a low resistance state (LRS), and

the resistance value is based on the LRS.

7. The memory circuit of claim 1 , wherein

the RRAM device comprises a selection transistor configured to conduct the second current,

the first current path comprises a transistor configured to generate the voltage difference by conducting the first current, and

the memory circuit is configured to generate a selection transistor voltage difference having a value corresponding to a value of the voltage difference.

8. The memory circuit of claim 7 , wherein

the selection transistor is configured to conduct the second current responsive to an activation voltage, and

the transistor in the first current path is configured to conduct the first current responsive to the activation voltage.

9. The memory circuit of claim 8 , wherein the bias voltage generator comprises an amplifier configured to generate the activation voltage based on a resistance value of a resistive device.

10. A memory circuit comprising:

an activation voltage generator configured to generate an activation voltage based on a resistance value of a resistive device;

a first transistor configured to conduct a first current from a current source responsive to the activation voltage, thereby generating a voltage difference; and

an array of resistive random-access memory (RRAM) devices, each RRAM device comprising a selection transistor,

wherein the selection transistor of each RRAM device comprises a gate configured to receive the activation voltage and is thereby configured to generate a selection transistor voltage difference responsive to the activation voltage, the selection transistor voltage difference having a value corresponding to a value of the voltage difference.

11. The memory circuit of claim 10 , wherein the resistive device is a first resistive device of a voltage divider in parallel with a conductive path of the first transistor.

12. The memory circuit of claim 10 , wherein the activation voltage generator comprises a second transistor configured to control a second current through the resistive device.

13. The memory circuit of claim 12 , wherein the activation voltage generator is configured to bias a gate of the second transistor responsive to a value of a reference voltage.

14. The memory circuit of claim 10 , wherein the resistive device is configured to receive a second current from another current source, the first current and the second current having a same current level.

15. The memory circuit of claim 10 , wherein the resistive device comprises a polycrystalline silicon material.

16. The memory circuit of claim 10 , further comprising an amplifier configured to

receive a target value of the voltage difference from the activation voltage generator, and

output the activation voltage to the first transistor and the selection transistor of each RRAM device.

17. A method of performing a write operation on a resistive random-access memory (RRAM) device, the method comprising:

generating a first current using a current source in a first current path;

conducting the first current in the first current path to generate a voltage difference;

including the voltage difference in a bias voltage output from a node in the first current path;

generating a drive voltage from the bias voltage; and

applying the drive voltage to the RRAM device.

18. The method of claim 17 , wherein the conducting the first current in the first current path comprises generating the voltage difference across a path segment having a resistance value based on a portion of a second current path that includes the RRAM device.

19. The method of claim 17 , wherein the conducting the first current in the first current path comprises generating the voltage difference across a transistor having a conductance level based on an activation voltage.

20. The method of claim 19 , further comprising:

generating the activation voltage based on a resistance value of a resistive device; and

applying the activation voltage to the RRAM device.