Current mirror circuit, driving circuit using the same, and method of driving the circuit

1. A current mirror circuit, comprising:

a first transistor having a first terminal electrically connected to a voltage source and having a gate terminal and a second terminal that are electrically connected to each other;

a second transistor having a first terminal electrically connected to the voltage source and having a gate terminal electrically connected to the gate terminal of the first transistor; and

a compensator adapted to compensate for a threshold voltage of each of the first transistor and the second transistor, wherein the compensator is coupled with each of the first transistor and the second transistor,

wherein the first transistor and the second transistor each serve as a diode when a first control signal is applied, and

wherein the compensator comprises:

a first capacitor and a second capacitor, each of which is electronically connected between the gate terminal of the first transistor and the gate terminal of the second transistor, wherein a common terminal of the first capacitor is connected to a common terminal of the second capacitor;

a third transistor provided between the common terminals of the first and second capacitors and the voltage source and configured to be turned on when the first control signal is supplied; and

a fourth transistor connected between the gate terminal and the second terminal of the second transistor and configured to be turned on when the first control signal is supplied.

2. The current mirror circuit of claim 1 , wherein the threshold voltage of the first transistor is stored in the first capacitor and the threshold voltage of the second transistor is stored in the second capacitor when the first control signal is supplied.

3. The current mirror circuit of claim 1 , further comprising:

a fifth transistor electrically connected to the second terminal of the first transistor and configured to be turned on by a second control signal; and

a sixth transistor electrically connected to the second terminal of the second transistor and configured to be turned on by the second control signal.

4. The current mirror circuit of claim 3 , further comprising a control signal generator coupled with the fifth transistor and the sixth transistor and configured to supply the second control signal after supplying the first control signal, and separately coupled with the third transistor and the fourth transistor, wherein the control signal generator is configured to apply the second control signal to both the fifth transistor and the sixth transistor after supplying the first control signal to both the third transistor and the second transistor.

5. The current mirror circuit of claim 3 , further comprising a current controller connected to the fifth transistor to control an amount of current that flows from the first transistor via the fifth transistor.

6. A current mirror circuit, comprising:

a first transistor; a second transistor, wherein the first transistor and the second transistor are connected to form a current mirror circuit and each serves as a diode when a first control signal is applied; and

a compensator coupled with the current mirror circuit to compensate for a threshold voltage of the first transistor and for a threshold voltage of the second transistor,

wherein the compensator comprises:

a first capacitor and a second capacitor, each of which is electronically connected between the gate terminal of the first transistor and the gate terminal of the second transistor, wherein a common terminal of the first capacitor is connected to a common terminal of the second capacitor;

a third transistor provided between the common terminals of the first and second capacitors and the voltage source and configured to be turned on when the first control signal is supplied; and

a fourth transistor connected between the gate terminal and the second terminal of the second transistor and configured to be turned on when the first control signal is supplied.

7. A driving circuit, comprising:

a bias unit to supply a first bias current; and

a driver coupled with the bias unit and driven when the first bias current is supplied,

wherein the bias unit comprises;

a first transistor having a first terminal electrically connected to a voltage source and having a gate terminal and a second terminal that are electrically connected to each other;

a second transistor having a first terminal electrically connected to the voltage source and having a gate terminal electrically connected to the gate terminal of the first transistor; and

a compensator adapted to compensate for a threshold voltage of the first transistor and a threshold voltage of the second transistor, wherein the compensator is coupled with each of the first transistor and the second transistor,

wherein the first transistor and the second transistor each serve as a diode when a first control signal is applied, and

wherein the compensator comprises:

a first capacitor and a second capacitor, each of which is electrically connected between the gate terminal of the first transistor and the gate terminal of the second transistor, wherein a common terminal of the first capacitor is connected to a common terminal of the second capacitor;

a third transistor electrically connected between the common terminals of the first and second capacitors and the voltage source and configured to be turned on when the first control signal is supplied; and

a fourth transistor electrically connected between the gate terminal and the second terminal of the second transistor and configured to be turned on when the first control signal is supplied.

8. The driving circuit of claim 7 , wherein the threshold voltage of the first transistor is stored in the first capacitor and the threshold voltage of the second transistor is stored in the second capacitor when the first control signal is supplied.

9. The driving circuit of claim 8 , further comprising:

a fifth transistor electrically connected to the second terminal of the first transistor wherein the fifth transistor is configured to be turned on by a second control signal and to provide a current path so that a predetermined first current flows from the first transistor; and

a sixth transistor electrically connected between the second terminal of the second transistor and the driver wherein the sixth transistor is configured to be turned on by the second control signal and to supply to the driver a first bias current that corresponds to the first current.

10. The driving circuit of claim 9 , wherein the first control signal and the second control signal are supplied sequentially.

11. The driving circuit of claim 9 , wherein the bias unit further comprises an output unit for supplying a second bias current to the driver.

12. The driving circuit of claim 11 , wherein the output unit comprises;

a seventh transistor electrically connected to the first transistor by a current mirror circuit;

an eighth transistor electrically connected between the second terminal and the gate terminal of the seventh transistor and configured to be turned on when the first control signal is supplied;

a third capacitor electrically connected between the gate terminal of the seventh transistor and the first capacitor; and

a ninth transistor electrically connected between the driver and the second terminal of the seventh transistor and configured to be turned on when the second control signal is supplied.

13. The driving circuit of claim 12 , wherein the output unit further comprises:

a tenth transistor electrically connected between the voltage source and the third capacitor and configured to be turned on when the first control signal is supplied; and

an eleventh transistor electrically connected between the third capacitor and the first capacitor and configured to be turned on when the second control signal is supplied.

14. A method of driving a current mirror circuit, the method comprising the steps of:

compensating for a threshold voltage of each of a first transistor and a second transistor that are electrically connected in the form of a current mirror circuit;

supplying a first current via the first transistor through which electric current flows so that the first transistor serves as a diode; and

supplying a second current via the second transistor such that a value of the second current equals, or approximately equals, a value of the first current,

wherein the first transistor and the second transistor each serve as a diode when a first control signal is applied, and

wherein the compensator comprises:

a first capacitor and a second capacitor, each of which is electrically connected between the gate terminal of the first transistor and the gate terminal of the second transistor, wherein a common terminal of the first capacitor is connected to a common terminal of the second capacitor;

a third transistor electrically connected between the common terminals of the first and second capacitors and the voltage source and configured to be turned on when the first control signal is supplied; and

a fourth transistor electrically connected between the gate terminal and the second terminal of the second transistor and configured to be turned on when the first control signal is supplied.

15. The method of claim 14 , wherein the step of compensating for the threshold voltages comprises the steps of:

storing the threshold voltage of the first transistor in the first capacitor that is electrically connected to the gate terminal of the first transistor; and

storing the threshold voltage of the second transistor in the second capacitor that is electrically connected to the gate terminal of the second transistor.

16. The method of claim 14 , further comprising the step of controlling the amount of the first current via a current controller that is electrically connected to the first transistor.