Apparatus and method for driving display panels for reducing power consumption of grayscale voltage generator

1. A display panel driver comprising:

a grayscale voltage generator configured to develop a set of different grayscale voltages corresponding to grayscale levels of pixels within a display panel; and

a plurality of grayscale selector driver circuits each of which is responsive to pixel data to select one of said grayscale voltages, and to provide a drive voltage corresponding to said selected one of said grayscale voltages for a selected pixel within said display panel, said grayscale selector driver circuits each comprising an amplifier and first and second switches, said first switch connecting an output of said amplifier to said selected pixel within said display panel, and said second switch connecting said one of said grayscale voltages to said selected pixel within said display panel,

wherein said grayscale voltage generator is allowed to output said set of grayscale voltages during a first period within a horizontal period, and prohibited from outputting said set of grayscale voltages during a second period within said horizontal period,

wherein said grayscale voltage generator includes:

first serially-connected resistors for generating different voltages through voltage dividing;

a set of amplifiers receiving said different voltages, respectively, and developing a set of bias voltages through voltage follower operation;

second serially-connected resistors receiving said bias voltages on nodes thereof and developing said set of grayscale voltages through voltage dividing;

a third switch for feeding a power supply voltage to said first serially-connected resistors, and

wherein said grayscale voltage generator stops outputting said set of grayscale voltages through turning off said third switch, and placing outputs of said amplifiers into a high-impedance state.

2. The display panel driver according to claim 1 , further comprising:

a gamma control circuit controlling said grayscale voltage generator,

wherein said gamma control circuit is responsive to an externally-provided standby signal asynchronous with said horizontal period to prohibit said grayscale voltage generator from outputting said set of grayscale voltages; and

wherein said gamma control circuit controls initiation and termination of said first period.

3. The display panel driver according to claim 1 , further comprising:

a gamma control circuit controlling said grayscale voltage generator,

wherein each of said grayscale selector driver circuits stops providing said drive voltage at a certain timing within said horizontal period, and

wherein said gamma control circuit prohibits said grayscale voltage generator from outputting said set of grayscale voltages simultaneously with or just after said certain timing.

4. The display panel driver according to claim 1 , wherein said grayscale voltage generator additionally includes a set of output switches connected between said second serially-connected resistors and said grayscale selector driver circuit.

5. The display panel driver according to claim 4 , wherein said output switches are turned off before said grayscale voltage generator stops developing said grayscale voltages.

6. The display panel driver according to claim 4 , wherein said output switches are turned off after each of said grayscale selector driver circuits stops providing said drive voltage for said display panel.

7. The display panel driver according to claim 1 , further comprising:

a dummy load circuit including a capacitive element;

a dummy grayscale selector driver circuit design to select one of said grayscale voltages, and to provide a drive voltage corresponding to said selected one of said grayscale voltages for said dummy load circuit; and

a voltage comparator receiving an output measured voltage developed across said capacitive element and selected one(s) of said set of grayscale voltages from said grayscale voltage generators,

wherein said voltage comparator compares said output measured voltage with a reference voltage generated from said set of grayscale voltages to develop a comparison result signal, and

wherein said grayscale voltage generators stops developing said set of grayscale voltages in response to said comparison result signal.

8. The display panel driver according to claim 1 , wherein a duration of said first period within said horizontal period is the same for all values of said grayscale voltages of said set of different grayscale voltages.

9. The display panel driver according to claim 1 , wherein said second period within said horizontal period occurs sequentially after said first period within said horizontal period.