Gray-scale current generating circuit, display device using the same, and display panel and driving method thereof

A display device comprising:

• a display unit comprising a plurality of data lines for transmitting a data current, a plurality of scan lines for transmitting a selection signal, and a plurality of pixel areas defined by the data lines and the scan lines;
• a first shift register for sequentially delaying a first signal for as much as a first period and generating a plurality of second signals;
• a first latch for latching a plurality of grayscale data in synchronization with the second signals and outputting the latched grayscale data;
• a grayscale current generator for receiving the plurality of the grayscale data and outputting the data current corresponding to the grayscale data;
• and
• an output unit for applying the data current output by the grayscale current generator to the plurality of data lines,
• wherein the grayscale current generator comprises a bias current generator for generating a plurality of bias currents and a plurality of digital/analog (D/A) converters for using the plurality of bias currents, and
• wherein the plurality of D/A converters comprise a plurality of current sample/hold circuits for respectively sampling/holding the plurality of bias currents and outputting the bias currents in response to each bit of at least one of the plurality of grayscale data.

A display panel comprising:

• a display unit comprising a plurality of pixels for displaying an image in response to an applied data current;
• a first current generator for generating a plurality of first currents, the first currents being different from each other;
• and
• a plurality of current sample/hold circuits, each of the plurality of current sample/hold circuits being for storing a first voltage corresponding to a respective one of the first currents, and outputting a second current corresponding to the first voltage in response to applied grayscale data.

A grayscale current generating circuit for converting a digital grayscale data into a grayscale current and outputting the grayscale current, the grayscale current generating circuit comprising:

• a first current generator for outputting a plurality of first currents, the first currents being different from each other;
• a plurality of current sample/hold circuits for respectively sampling/holding the first currents and outputting the sampled/held first currents in response to each bit of the grayscale data;
• and
• a current summing unit for adding up the first currents sampled/held by the plurality of current sample/hold circuits, wherein the added up first currents are applied as the grayscale current.

A driving method of a display panel comprising a plurality of pixel circuits for displaying an image in response to an applied data current, the driving method comprising:

• generating a plurality of first currents, the first currents being different from each other;
• sampling the first currents and storing a plurality of the first voltages corresponding to the first currents;
• sampling/holding a plurality of second currents corresponding to the plurality of the first voltages in response to grayscale data;
• adding up the second currents;
• and
• outputting the added-up second currents as the data current.

A display device comprising:

• a display unit comprising a plurality of data lines for transmitting a data current, a plurality of scan lines for transmitting a selection signal, and a plurality of pixel areas defined by the data lines and the scan lines;
• a data driver for transforming a plurality of grayscale data into the data current and applying the data current to the data lines;
• and
• a scan driver for sequentially applying the selection signal to the plurality of scan lines,
• wherein the data driver comprises:
• a plurality of digital/analog (D/A) converter groups for receiving a plurality of first currents, the first currents being different from each other, the plurality of D/A converter groups being for outputting the data current corresponding to the grayscale data;
• and
• wherein the plurality of D/A converter groups comprise a first D/A converter for receiving the first currents and outputting the data current corresponding to the grayscale data, and a second D/A converter for receiving a first voltage corresponding to the first currents and outputting the data current corresponding to the grayscale data.

A display device comprising:

• a display unit comprising a plurality of data lines for transmitting a data current, a plurality of scan lines for transmitting a selection signal, and a plurality of pixel areas defined by the data lines and the scan lines;
• a first shift register for sequentially delaying a first signal for as much as a first period and generating a plurality of second signals;
• a first latch for latching a plurality of the grayscale data in synchronization with the second signals and outputting the latched grayscale data;
• a grayscale current generator for receiving the plurality of the grayscale data and outputting the data current corresponding to the grayscale data;
• an output unit for applying the data current output by the grayscale current generator to the plurality of the data lines;
• wherein the grayscale current generator comprises a bias current generator for generating a plurality of bias currents and a plurality of digital/analog (D/A) converter groups for sequentially using the plurality of the bias currents and outputting the data current corresponding to the grayscale data;
• and
• wherein a D/A converter group of the D/A converter groups comprises a first D/A converter for receiving the bias currents and outputting the data current corresponding to the grayscale data, and a second D/A converter for receiving a first voltage corresponding to the bias currents and outputting the data current corresponding to the grayscale data

A display panel comprising:

• a display unit comprising a plurality of pixels for displaying an image in response to an applied data current;
• a first current generator for generating a plurality of first currents, the first currents being different from each other;
• a plurality of first current sample/hold circuits for respectively storing a first voltage corresponding to the first currents, and respectively outputting a second current corresponding to the first voltage in response to a first grayscale data;
• and
• a plurality of second current sample/hold circuits for copying the first currents, storing a second voltage corresponding to the first currents, and outputting a third current corresponding to the second voltage in response to a second grayscale data.

A grayscale current generating circuit for transforming a plurality of digital grayscale data comprising first and second grayscale data into first and second grayscale currents and outputting the first and second grayscale currents comprising:

• a first current generator for outputting a plurality of first currents, the first currents being different from each other;
• a plurality of first current sample/hold circuits for respectively sampling/holding the first currents and outputting a second current corresponding to the sampled/held first currents in response to each bit of the first grayscale data;
• and
• a plurality of second current sample/hold circuits for copying the first currents and outputting a third current corresponding to the copied first currents in response to each bit of the second grayscale data.

A display panel driving method, for driving a display panel comprising a plurality of pixel circuits for displaying an image in response to an applied data current, comprising:

• a) sampling a plurality of first currents, the first currents being different from each other, and storing a plurality of first voltages respectively corresponding to the first currents;
• b) copying the first currents and storing a plurality of second voltages respectively corresponding to the first currents;
• c) outputting a plurality of second currents respectively corresponding to the first voltages in response to a first grayscale data representing a grayscale of a first pixel among the plurality of the pixels;
• d) outputting a plurality of third currents respectively corresponding to the second voltages in response to a second grayscale data representing a grayscale of a second pixel among the plurality of the pixels;
• and
• e) applying the second and third currents respectively to the first and second pixels.