Common voltage source integrated circuit for liquid crystal display device
View Patent ↗A common voltage source IC device includes an operational amplifier, a push-pull circuit receiving an output signal from the operational amplifier and outputting a common voltage to a common voltage terminal; an inverting resistor connected to an inverting input of the operational amplifier; a feedback resistor connected to the common voltage terminal and the inverting input; a capacitor connected to the common voltage terminal and the inverting input; a first switching resistor connected to the inverting input and a first switching transistor, the first switching transistor connected to the common voltage terminal; a driving resistor receiving a drive voltage and connected to a non-inverting input of the operational amplifier; a variable resistor connected to the non-inverting input and a ground source; and a second switching resistor connected to the non-inverting input and a second switching transistor, the second switching transistor connected to the ground source.
1. A common voltage source IC device, comprising:
an operational amplifier including an inverting input and a non-inverting input;
a push-pull circuit receiving an output signal from the operational amplifier and outputting a common voltage to a common voltage terminal;
an inverting resistor receiving a control signal and connected to the inverting input;
a feedback resistor connected to the common voltage terminal and the inverting input;
a capacitor connected to the common voltage terminal and the inverting input;
a first switching resistor connected to the inverting input and a first switching transistor, the first switching transistor receiving a first switching signal and connected to the common voltage terminal;
a driving resistor receiving a drive voltage and connected to the non-inverting input;
a variable resistor connected to the non-inverting input and a ground source; and
a second switching resistor connected to the non-inverting input and a second switching transistor, the second switching transistor receiving a second switching signal and connected to the ground source.
2. The device according to claim 1 , wherein the operational amplifier is an inverting amplifier.
3. The device according to claim 1 , wherein the push-pull circuit includes at least one transistor.
4. The device according to claim 1 , wherein the push-pull circuit receives the drive voltage and connects to the ground source.
5. The device according to claim 1 , wherein the control signal includes a square wave.
6. The device according to claim 1 , wherein the control signal has a half period of about 16.7 ms.
7. The device according to claim 1 , wherein the first switching signal changes at about the same time as the control signal is rising.
8. The device according to claim 1 , wherein the second switching signal changes at about the same time as the control signal is falling.
9. The device according to claim 1 , wherein the feedback resistor, the capacitor and the first switching resistor are parallel to one another.
10. The device according to claim 1 , wherein the first and second switching transistors have polarities different from each other.
11. A common voltage source IC device, comprising:
an operational amplifier including an inverting input and a non-inverting input;
a push-pull circuit receiving an output signal from the operational amplifier and outputting a common voltage to a common voltage terminal;
an inverting resistor receiving a control signal and connected to the inverting input;
a capacitor connected to the common voltage terminal and the inverting input;
a feedback resistor and a first switching resistor connected serially to each other between the common voltage terminal and the inverting input;
a first switching transistor connected in parallel with the first switching resistor, the first switching transistor receiving a first switching signal and connected to the common voltage terminal;
a driving resistor receiving–a drive voltage and connected to the non-inverting input;
a variable resistor connected to the non-inverting input and a ground source; and
a second switching resistor connected to the non-inverting input and a second switching transistor, the second switching transistor receiving a second switching signal and connected to the ground source.
12. The device according to claim 11 , wherein the operational amplifier includes an inverting amplifier.
13. The device according to claim 11 , wherein the push-pull circuit has at least one transistor.
14. The device according to claim 11 , wherein the push-pull circuit receives the drive voltage and is connected to the ground source.
15. The device according to claim 11 , wherein the control signal includes a square wave.
16. The device according to claim 11 , wherein the control signal has a half period of about 16.7 ms.
17. The device according to claim 11 , wherein the first switching signal changes at about the same time as the control signal is rising.
18. The device according to claim 11 , wherein the second switching signal changes at about the same time as the control signal is falling.
19. The device according to claim 11 , wherein the capacitor, the feedback resistor and first switching resistor are connected in parallel.
20. The device according to claim 11 , wherein the first and second switching transistors have polarities different from each other.
21. A common voltage source IC device, comprising:
an operational amplifier including an inverting input and a non-inverting input;
a push-pull circuit receiving an output signal from the operational amplifier and outputting a common voltage to a common voltage terminal;
an inverting resistor receiving a control signal and connected to the inverting input;
a feedback resistor connected to the common voltage terminal and the inverting input;
a capacitor connected to the common voltage terminal and the inverting input;
a first switching resistor receiving a drive voltage and connected to a first switching transistor, the first switching transistor receiving a first switching signal and connected to the non-inverting input;
a driving resistor receiving the drive voltage and connected to the non-inverting input;
a variable resistor connected to the non-inverting input and a ground source; and
a second switching resistor connected to the non-inverting input and a second switching transistor, the second switching transistor receiving a second switching signal and connected to the ground source.
22. The device according to claim 21 , wherein the operational amplifier includes an inverting amplifier.
23. The device according to claim 21 , wherein the push-pull circuit has at least one transistor.
24. The device according to claim 21 , wherein the push-pull circuit receives the drive voltage and connects to the ground source.
25. The device according to claim 21 , wherein the control signal includes a square wave.
26. The device according to claim 21 , wherein the control signal has a half period of about 16.7 ms.
27. The device according to claim 21 , wherein the first switching signal changes at about the same time as the control signal is rising.
28. The device according to claim 21 , wherein the second switching signal changes at about the same time as the control signal is falling.
29. The device according to claim 21 , wherein the capacitor and the feedback resistor are connected in parallel to each other.
30. The device according to claim 22 , wherein the first and second switching transistors have the same polarity.