Configurable liquid crystal display driver system
Embodiments of the invention relate to a configurable LCD driver system having a plurality of configurable LCD drivers. Each LCD driver may be configured as a common or segment driver by selecting a drive voltage from an appropriate set of drive voltages associated with a common or segment driver in accordance with certain parameters, such as whether a user may configure the LCD driver as a common driver or segment driver, a multiplex ratio, and/or bias ratio of an LCD panel. The drive time and drive strength associated with the LCD driver may also be configurable. The selected drive voltage may be provided to a drive buffer to output an LCD drive voltage waveform for driving one or more segments or pixels in an LCD panel. A memory may store appropriate display data for both the segment and common drivers to control the output drive capability of the LCD driver.
1. An apparatus to configure a plurality of liquid crystal display (LCD) driver outputs, comprising:
a reference voltage generator comprising a plurality of outputs, wherein the reference voltage generator is configured to generate one of a plurality of reference voltages at each of the plurality of outputs;
a configuration block to configure each LCD driver output as one of a common driver associated with a first subset of the reference voltages or a segment driver associated with a second subset of the reference voltages according to a driver configuration state;
a plurality of switches comprising, for each voltage in the subset of voltages, two or more switches each configured to select the voltage from one of the plurality of outputs of the reference voltage generator, wherein the configuration block is further configured to control the plurality of switches to connect each of the plurality of LCD driver outputs to at least one selected voltage of the plurality of outputs of the reference voltage generator, and wherein the number of voltages included in the first subset of the reference voltages and the number of voltages included in the second subset of the reference voltages depend on a drive bias; and
a driver block configured to select a drive voltage generated from the subset of reference voltages according to display data stored in a memory and generates an LCD drive voltage waveform from the plurality of reference voltages to drive one or more LCD segments or pixels.
2. The apparatus of claim 1 , where the LCD drive voltage waveform is one of a common signal when the LCD driver output is configured as a common driver or a segment signal when the LCD driver output is configured as a segment driver.
3. The apparatus of claim 1 , where the configuration block comprises a control signal generator to generate signals according to at least one of the multiplex ratio, the drive bias, and the driver configuration state, where the driver configuration state indicates at least one of a drive time, a drive strength, a drive mode, and whether the LCD driver output is configured as one of a common driver or a segment driver.
4. The apparatus of claim 3 , where each LCD driver output includes a plurality of switches to select the drive voltage from the subset of reference voltages in response to the signals generated by the control signal generator.
5. The apparatus of claim 4 , where each LCD driver output includes a drive buffer to generate an LCD drive voltage waveform from the selected drive voltage responsive to the signals generated by the control signal generator.
6. The apparatus of claim 5 , where the driver buffer includes:
a high-drive buffer to drive the LCD drive voltage waveform to a threshold level; and
a low-drive buffer to modify the LCD drive voltage waveform to approximate the selected drive voltage, and to compensate a leakage associated with the LCD segments or pixels so as to maintain a constant voltage level at the LCD segments or pixels.
7. The apparatus of claim 1 , where the memory stores display data associated with both common drivers and segment drivers.
8. A method to configure a plurality of liquid crystal display (LCD) driver outputs, comprising:
generating one of a plurality of reference voltages at each of a plurality of outputs of a reference voltage generator;
configuring each LCD driver output as one of a common driver associated with a first subset of the reference voltages or a segment driver associated with a second subset of the reference voltages according to a driver configuration state, wherein said configuring comprises controlling a plurality of switches each coupling one of the plurality of LCD driver outputs to at least one of the plurality of outputs of the voltage reference generator to select a subset of reference voltages from the plurality of reference voltages by, for each voltage in the subset of reference voltages, selecting one of the plurality of reference voltages by connecting the LCD driver output to one of the plurality of outputs of the reference voltage generator and disconnecting the LCD driver output from another of the plurality of outputs of the reference voltage generator, and wherein the number of voltages included in the first subset of the reference voltages and the number of voltages included in the second subset of the reference voltages depend on a drive bias;
selecting a drive voltage from the subset of reference voltages in response to display data stored in a memory; and
generating a plurality of LCD drive voltage waveforms from the subset of reference voltages to drive one or more LCD segments or pixels.
9. The method of claim 8 , includes generating control signals in accordance with at least one of the multiplex ratio, the drive bias, and the driver configuration state, where the driver configuration state indicates at least one of a drive time, a drive strength, a drive mode, and whether the LCD driver output is configured as a common driver output or a segment driver output.
10. The method of claim 9 , where generating the plurality of LCD drive voltage waveforms from the subset of reference voltages includes generating the plurality of LCD drive voltage waveforms according to the driver configuration state.
11. The method of claim 8 , includes:
driving an LCD drive voltage waveform to a threshold level during a high-drive mode;
modifying the LCD drive voltage waveform to approximate the selected drive voltage during a low-drive mode; and
compensating any leakage associated with the LCD segments or pixels to provide a constant voltage level during the low-drive mode.
12. The method of claim 8 , includes storing data for both common drivers and segment drivers in the memory.
13. A system to configure a plurality of liquid crystal display (LCD) driver outputs, comprising:
means for generating one of a plurality of reference voltages at each of a plurality of reference voltage outputs;
means for configuring each LCD driver output as one of a common driver associated with a first subset of the reference voltages or a segment driver associated with a second subset of the reference voltages according to a driver output configuration state by controlling a plurality of switches each coupling one of the plurality of LCD driver outputs to at least one of the plurality of reference voltage outputs to select a subset of reference voltages from the plurality of reference voltages by, for each voltage in the subset of reference voltages, selecting one of the plurality of reference voltages by connecting the LCD driver output to one of the plurality of outputs of the reference voltage generator and disconnecting the LCD driver output from another of the plurality of outputs of the reference voltage generator, wherein the number of voltages included in the first subset of the reference voltages and the number of voltages included in the second subset of the reference voltages depend on a drive bias;
means for selecting a drive voltage from the subset of reference voltages in response to display data stored in a memory; and
means for generating a plurality of LCD drive voltage waveforms from the subset of reference voltages to drive one or more LCD segments or pixels.
14. The system of claim 13 , includes means for generating control signals in accordance with at least one of the multiplex ratio, the drive bias, and the driver configuration state, where the driver configuration state indicates at least one of a drive time, a drive strength, a drive mode, and whether the LCD driver output is configured as a common driver or a segment driver.
15. The system of claim 14 , includes means for selecting a drive voltage from the subset of reference voltages according to the driver configuration state and generating an LCD drive voltage waveform from the selected drive voltage.
16. The system of claim 15 , includes:
means for driving an LCD drive voltage waveform to a threshold level during a high-drive mode;
means for modifying the LCD drive voltage waveform to approximate the selected drive voltage during a low-drive mode; and
means for compensating any leakage associated with the LCD segments or pixels to provide a constant voltage level during the low-drive mode.
17. The system of claim 13 , includes means for storing display data for both common drivers and segment drivers in a memory.