Amplifying circuit and analog digital conversion circuit with the same

1. An analog to digital converting device, comprising:

a first digital conversion (ADC) circuit configured to receive an analog signal and convert a part of the analog signal into a first digital signal having a first predetermined number of bits;

a first multiplying digital to analog converting (MDAC) circuit configured to amplify a difference between a first converted signal converted as an analog value from the first digital signal and the analog signal;

a second ADC circuit configured to convert a signal amplified by the first MDAC circuit into a second digital signal having a second predetermined number of bits;

a second MDAC circuit configured to amplify a difference between a second converted signal converted as an analog value from the second digital signal and the signal outputted from the first MDAC circuit;

a third ADC circuit configured to convert a signal amplified by the second MDAC circuit into a third digital signal having a third predetermined number of bits; and

a common amplifying circuit shared by the first MDAC circuit and the second MDAC circuit, wherein the common amplifying circuit consumes a different amount of current according to which MDAC circuit the common amplifying circuit operates with.

2. The analog to digital converting device as recited in claim 1 , wherein the common amplifying circuit includes:

a first amplifying unit configured to amplify an inputted signal; and

a second amplifying unit configured to amplify an output of the first amplifying unit.

3. The analog to digital converting device as recited in claim 2 , wherein the first amplifying unit includes:

a load part including a first current path configured to provide a first current amount and a second current path configured to provide a second current amount;

a first input part configured to receive a difference between the first converted signal and the analog signal and to amplify the difference by controlling a current amount delivered from the load part;

a second input part configured to receive a difference between the second converted signal and the signal outputted from the first MDAC circuit and to amplify the difference by controlling a current amount delivered from the load part; and

a constant current part configured to output a constant current delivered from one of the first input part and the second input part into one of a third current path, a fourth current path, and both the third and the fourth current paths.

4. The analog to digital converting device as recited in claim 3 , wherein the first input part includes:

a first transistor configured to receive at a gate the difference between the first converted signal and the analog signal; and

a first switching unit connected to the first transistor in series and turned on in response to a first switching signal, and

wherein the second input part includes:

a second transistor, connected to the first transistor in parallel, configured to receive at a gate the difference between the second converted signal and the signal outputted from the first MDAC circuit; and

a second switching unit, connected to the second transistor in series, turned on in response to a second switching signal having an opposite phase of the first switching signal.

5. The analog to digital converting device as recited in claim 4 , wherein the first switching signal and the second switching signal, even though having the opposite phase, have different activation periods which are partially overlapped by a predetermined period.

6. The analog to digital converting device as recited in claim 3 , wherein the load part includes:

a first transistor configured to deliver current flowed through the first current path; and

a second and a third transistor, connected to each other in series and to the first transistor in parallel, configured to deliver current flowed through the second current path when selectively turned on by a switching signal.

7. The analog to digital converting device as recited in claim 6 , wherein the constant current part includes:

a fourth transistor configured to deliver current to the third current path; and

a fifth and a sixth transistors, connected to each other in series and to the fourth transistor in parallel, configured to deliver current to the fourth current path when selectively turned on by an inverted signal of the switching signal.

8. The analog to digital converting device as recited in claim 6 , wherein the constant current provided through the first current path is substantially similar to a constant current outputted to the third current path, and the constant current provided through the second current path is substantially similar to a constant current outputted to the fourth current path.

9. The analog to digital converting device as recited in claim 6 , wherein 85% and 15% amounts of predetermined operation current are respectively delivered through the first current path and the second current path.

10. The analog to digital converting device as recited in claim 6 , wherein 85% and 15% amounts of predetermined operation current are respectively outputted through the third current path and the fourth current path.

11. The analog to digital converting device as recited in claim 2 , wherein the second amplifying unit includes:

a load part including a first current path configured to provide a first current amount and a second current path configured to provide a second current amount;

an input part configured to receive the output of the first amplifying unit and amplify the output by controlling a current amount delivered from the load part; and

a constant current part configured to output an constant current delivered from the input part into one of a third current path and a fourth current path.

12. The analog to digital converting device as recited in claim 11 , wherein the load part includes:

a first transistor configured to deliver current flowed through the first current path; and

a second and a third transistors, connected to each other in series and to the first transistor in parallel, configured to deliver current flowed through the second current path when selectively turned on by a switching signal.

13. The analog to digital converting device as recited in claim 12 , wherein the constant current part includes:

a fourth transistor configured to deliver current to the third current path; and

a fifth and a sixth transistors, connected to each other in series and to the fourth transistor in parallel, configured to deliver current to the fourth current path when selectively turned on by an inverted signal of the switching signal.

14. The analog to digital converting device as recited in claim 1 , wherein the common amplifying circuit includes:

a load part including a first current path configured to provide a first current amount and a second current path configured to provide a second current amount;

a first input part configured to receive a difference between the first converted signal and the analog signal and to amplify the difference by controlling a current amount delivered from the load part;

a second input part configured to receive a difference between the second converted signal and the signal outputted from the first MDAC circuit and to amplify the difference by controlling a current amount delivered from the load part; and

a constant current part configured to output an constant current delivered from one of the first input part and the second input part into one of a third current path, a fourth current path, and both the third and the fourth current paths.

15. The analog to digital converting device as recited in claim 14 , wherein the first input part includes:

a first transistor configured to receive at a gate the difference between the first converted signal and the analog signal; and

a first switching unit connected to the first transistor in series and turned on in response to a first switching signal, and

wherein the second input part includes:

a second transistor, connected to the first transistor in parallel, configured to receive at a gate the difference between the second converted signal and the signal outputted from the first MDAC circuit; and

a second switching unit, connected to the second transistor in series, turned on in response to a second switching signal having an opposite phase of the first switching signal.

16. The analog to digital converting device as recited in claim 14 , wherein the first switching signal and the second switching signal, even though having the opposite phase, have different activation periods which are partially overlapped by a predetermined period.

17. The analog to digital converting device as recited in claim 14 , wherein the load part includes:

a first transistor configured to deliver current flowed through the first current path; and

a second and a third transistors, connected to each other in series and to the first transistor in parallel, configured to deliver current flowed through the second current path when selectively turned on by a switching signal.

18. The analog to digital converting device as recited in claim 17 , wherein the constant current part includes:

a fourth transistor configured to deliver current to the third current path; and

a fifth and a sixth transistors, connected to each other in series and to the fourth transistor in parallel, configured to deliver current to the fourth current path when selectively turned on by an inverted signal of the switching signal.

19. The analog to digital converting device as recited in claim 18 , wherein the constant current provided through the first current path is substantially similar to a constant current outputted to the third current path, and the constant current provided through the second current path is substantially similar to a constant current outputted to the fourth current path.

20. The analog to digital converting device as recited in claim 19 , wherein 85% and 15% amounts of predetermined operation current are respectively delivered through the first current path and the second current path.

21. The analog to digital converting device as recited in claim 19 , wherein 85% and 15% amounts of predetermined operation current are respectively outputted through the third current path and the fourth current path.

22. The analog to digital converting device as recited in claim 1 , wherein the first to the third predetermined bits are the same number of bits.

23. An amplifying device, comprising:

a first load part including a first current path configured to provide a first current amount and a second current path configured to provide a second current amount;

a first input part configured to receive a first analog signal and to amplify the first analog signal by controlling a current amount delivered from the first load part;

a second input part configured to receive a second analog signal and to amplify the second analog signal by controlling a current amount delivered from the first load part; and

a constant current part configured to output an constant current delivered from one of the first input part and the second input part into one of a third current path, a fourth current path, and both the third and the fourth current paths.

24. The amplifying device as recited in claim 23 , further comprising:

a second load part including a fifth current path configured to provide a fifth current amount and a sixth current path configured to provide a sixth current amount;

a third input part configured to receive a signal delivered from one of the first input part and the second input part and to amplify the signal by controlling a current amount delivered from the second load part; and

a constant current part configured to output an constant current, delivered from the third input part, into one of a seventh current path, a eighth current path, and both the seventh and the eighth current paths.