Display driver having output correction function
Various embodiments disclose a display driver, wherein the display driver may be configured to detect a defective output buffer among output buffers and perform an output correction function for the defective output buffer.
1. A display driver comprising:
an output buffer configured to output a source signal corresponding to an input signal;
a dummy buffer configured to output a dummy source signal corresponding to the input signal;
a detection circuit configured to provide a control signal by detecting a state of the source signal; and
a switching circuit configured to select one of the source signal and the dummy source signal according to the control signal and output a selected signal as an output signal,
wherein the detection circuit is configured to select the source signal in response to a check signal that remains enabled during a preset test frame period and output the control signal when the check signal is disabled due to expiration of the preset test frame period.
2. The display driver according to claim 1 , wherein the output buffer receives the input signal having a level transition in a first frame in which an output of the source signal is activated, and
wherein the detection circuit provides the control signal for selecting the source signal when a level transition is in the source signal, and provides the control signal for selecting the dummy source signal when the level transition is not in the source signal.
3. The display driver according to claim 1 , wherein the detection circuit includes:
a comparator configured to receive the source signal corresponding to the input signal having a level transition during the preset test frame period and output a comparison signal obtained by comparing the source signal with a preset reference voltage;
a failure determination unit configured to provide an activated determination signal at a level transition time point of the comparison signal, and provide a deactivated determination signal when a level transition is not in the comparison signal; and
a control circuit configured to output the control signal for selecting the source signal in response to the activated determination signal and output the control signal for selecting the dummy source signal in response to the deactivated determination signal.
4. The display driver according to claim 3 , wherein the control circuit is configured to:
output the control signal for selecting the source signal in response to a check signal that remains enabled during the test frame period; and
when the check signal is disabled due to expiration of the test frame period, output the control signal for selecting the source signal in response to the activated determination signal, or output the control signal for selecting the dummy source signal in response to the deactivated determination signal.
5. The display driver according to claim 3 , further comprising:
a check switch that is turned on by a check signal that remains enabled during the test frame period and transmits the source signal to the comparator.
6. The display driver according to claim 1 , wherein the switching circuit includes:
a first switch configured to switch to output the source signal as the output signal according to a first switching signal included in the control signal; and
a second switch configured to switch to output the dummy source signal as the output signal according to a second switching signal included in the control signal, and
wherein the detection circuit provides the first switching signal for turning on the first switch and the second switching signal for turning off the second switch when the source signal has a level transition corresponding to the input signal during a preset test frame period, and provides the first switching signal for turning off the first switch and the second switching signal for turning on the second switch when the level transition is not in the source signal during the preset test frame period.