Systems and methods for generating reference voltages

1. A system for generating reference voltages comprising:

an integrated reference voltage generating circuit comprising:

a resistor circuit comprising a plurality of resistors coupled in series;

a first switch controlled by a first control signal and coupled between a first end of the resistor circuit and a first power source;

a second switch controlled by the first control signal and coupled between the first end of the resistor circuit and a second power source;

a third switch controlled by a second control signal and coupled between a second end of the resistor circuit and the first power source;

a fourth switch controlled by the second control signal and coupled between the second end of the resistor circuit and the second power source;

a first resistor coupled between the first end of the resistor circuit and the first switch;

a second resistor coupled between the first end of the resistor circuit and the second switch;

a third resistor coupled between the second end of the resistor circuit and the third switch;

a fourth resistor coupled between the second end of the resistor circuit and the fourth switch; and

a control circuit for generating the first and second control signals;

wherein the first and the second ends of the resistor circuit are coupled to the first voltage source respectively via the first and the third switches in a power-saving mode.

2. The system of claim 1 further comprising the first and second sources; and

wherein the first and the second power sources are voltage sources, the first power source having a voltage level lower than that of the second power source.

3. The system of claim 1 further comprising the first and second power sources;

and wherein the first power source is a positive voltage source and the second power source is a negative voltage source.

4. The system of claim 1 wherein the first and third switches are N-type transistors and the second and the fourth switches are P-type transistors.

5. The system of claim 1 further comprising:

a fifth switch having a first end coupled to the first end of the resistor circuit, and a second end coupled to the first and second resistors; and

a sixth switch having a first end coupled to the second end of the resistor circuit, and a second end coupled to the third and fourth resistors.

6. A system for generating reference voltages comprising:

an integrated reference voltage generating circuit comprising:

a resistor circuit comprising a plurality of resistors coupled in series;

a first switch controlled by a first control signal and coupled between a first end of the resistor circuit and a first power source;

a second switch controlled by the first control signal and coupled between the first end of the resistor circuit and a second power source;

a third switch controlled by a second control signal and coupled between a second end of the resistor circuit and the first power source;

a fourth switch controlled by the second control signal and coupled between the second end of the resistor circuit and the second power source;

a first resistor coupled between the first end of the resistor circuit and the first switch;

a second resistor coupled between the first end of the resistor circuit and the second switch;

a third resistor coupled between the second end of the resistor circuit and the third switch;

a fourth resistor coupled between the second end of the resistor circuit and the fourth switch;

a control circuit for generating the first and second control signals;

a multiplexer for selecting from input data obtained in different operating modes as output data of the system;

a digital-to-analog controller coupled to the multiplexer and the integrated reference voltage generating circuit for processing input data of an image displayed with full gradation; and

a control module for sending signals to the integrated reference voltage generating circuit and the multiplexer based on an operating mode of the system, wherein the system is operative to display images;

wherein the first and the second ends of the resistor circuit are coupled to the first power source respectively via the first and the third switches in a power-saving mode.

7. The system of claim 6 wherein the multiplexer selects from input data displayed with full gradation, in a partial display mode or in an 8-color mode as output data of the system.

8. The system of claim 6 further comprising a buffer coupled between the digital-to-analog controller and the multiplexer.

9. The system of claim 8 further comprising a timing controller coupled between the buffer, the control module and the integrated reference voltage generating circuit.

10. The system of claim 6 , wherein the system comprises a pixel display device and the reference voltage generator circuit is incorporated therein.

11. The system of claim 10 , wherein the pixel display is an active matrix liquid crystal display.