# US 2022/0044640 A1 · Data driver and display device including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0044640 A1 - Document ID: US20220044640A1 - Status: Published application - Kind: A1 - Application number: 17/197,550 - Filed: 2021-03-10 - Published: 2022-02-10 - Earliest claimed: 2020-08-10 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: Seong Joo LEE; Oh Jo KWON; Ji Woong KIM; Hyung Gun MA; Jun Yong SONG; Sang Hyun HEO - Web page: https://patentgrep.com/patent/US20220044640A1 ## CPC - G09G 3/3275: Details of drivers for data electrodes - G09G 3/3266: Details of drivers for scan electrodes - G09G 2310/0243: Details of the generation of driving signals - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - G09G 2310/0289: Details of voltage level shifters arranged for use in a driving circuit - G09G 2310/0291: Details of output amplifiers or buffers arranged for use in a driving circuit - G09G 2310/0294: Details of sampling or holding circuits arranged for use in a driver for data electrodes - G09G 2310/066: Waveforms comprising a gently increasing or decreasing portion, e.g. ramp - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A data driver includes: a signal generator which includes a staircase waveform gray voltage signal generator which generate a plurality of staircase waveform gray voltage signals using a lowest gamma reference voltage, a highest gamma reference voltage, and a plurality of gamma voltages having a magnitude between the lowest gamma reference voltage and the highest gamma reference voltage; and a channel driver which includes a decoder which output one staircase waveform gray voltage signal selected from the staircase waveform gray voltage signals, an output circuit which output a gray voltage corresponding to the selected staircase waveform gray voltage signal, and a reset unit which supplies one of the gamma voltages to the output circuit as a reset voltage. ## Claims ### Claim 1 A data driver comprising: a signal generator which includes a staircase waveform gray voltage signal generator which generates a plurality of staircase waveform gray voltage signals using a lowest gamma reference voltage, a highest gamma reference voltage, and a plurality of gamma voltages having a magnitude between the lowest gamma reference voltage and the highest gamma reference voltage; and a channel driver which includes a decoder which outputs one staircase waveform gray voltage signal selected from the staircase waveform gray voltage signals, an output circuit which outputs a gray voltage corresponding to the selected staircase waveform gray voltage signal, and a reset unit which supplies one of the gamma voltages to the output circuit as a reset voltage. ### Claim 2 (depends on 1) The data driver of claim 1, wherein the decoder selects one staircase waveform gray voltage signal from the plurality of staircase waveform gray voltage signals every horizontal period. ### Claim 3 (depends on 2) The data driver of claim 2, wherein the reset voltage is the one gamma voltage of the plurality of gamma voltages, which corresponds to an intermediate value between a final gray voltage of one staircase waveform gray voltage signal selected in a previous horizontal period and an initial gray voltage of one staircase waveform gray voltage signal selected in a current horizontal period. ### Claim 4 (depends on 3) The data driver of claim 3, wherein the reset unit detects the one staircase waveform gray voltage signal selected in the previous horizontal period and the one staircase waveform gray voltage signal selected in the current horizontal period using upper bits of image data supplied to the decoder. ### Claim 5 (depends on 2) The data driver of claim 2, wherein the reset unit supplies the reset voltage to the output circuit every horizontal period and supplies the reset voltage to the output circuit before the one staircase waveform gray voltage signal selected by the decoder is supplied to the output circuit. ### Claim 6 (depends on 1) The data driver of claim 1, wherein each of the plurality of staircase waveform gray voltage signals increases stepwise with a plurality of gray voltage levels every horizontal period. ### Claim 7 (depends on 1) The data driver of claim 1, wherein each of the plurality of staircase waveform gray voltage signals alternately increases and decreases stepwise with a plurality of gray voltages every other horizontal period. ### Claim 8 (depends on 1) The data driver of claim 1, wherein the signal generator further includes a pulse width modulation (PWM) signal generation circuit which generates a plurality of PWM signals according to a digital code generated based on an oscillation signal, wherein the PWM signal generation circuit includes: an oscillator which generates the oscillation signal; a frequency divider which divides a frequency of the oscillation signal at a constant division ratio and generates an oscillation signal having the divided frequency; a code generator which counts the oscillation signal having the divided frequency and generates the digital code as a result of the count; and a PWM signal generator which generates the plurality of PWM signals in response to the digital code. ### Claim 9 (depends on 8) The data driver of claim 8, wherein the channel driver further includes a switching signal generation circuit which generates a plurality of switching signals using any one PWM signal selected from the plurality of PWM signals in response to lower bits, wherein the switching signal generation circuit includes: a selection circuit which outputs the one PWM signal selected from the plurality of PWM signals in response to the lower bits of image data; and a level shifter which generates the plurality of switching signals by shifting a level of the one PWM signal output from the selection circuit. ### Claim 10 (depends on 9) The data driver of claim 9, wherein the output circuit includes: a capacitor and a plurality of switches which perform a sampling/holding operation on the gray voltage corresponding to the selected staircase waveform gray voltage signal in response to the plurality of switching signals; and an operational amplifier which amplifies a voltage held in the capacitor through the sampling/holding operation. ### Claim 11 (depends on 10) The data driver of claim 10, wherein the operational amplifier includes a first input terminal which receives a reference voltage, a second input terminal connected to a first terminal of the capacitor, and an output terminal, the capacitor includes a second terminal connected to a first node, and the plurality of switches includes a first switch positioned between the reset unit and the first node, a second switch positioned between the second input terminal of the operational amplifier and the output terminal of the operational amplifier, and a third switch positioned between an output terminal of the decoder and the first node, and a fourth switch positioned between the output terminal of the operational amplifier and the first node. ### Claim 12 (depends on 11) The data driver of claim 11, wherein the first switch is turned on before the third switch is turned on and then the first switch is turned off after the third switch is turned. ### Claim 13 A display device comprising: a pixel unit which includes a plurality of pixels connected to data lines; and a data driver which supplies data signals to the data lines, wherein the data driver includes a signal generator which includes a staircase waveform gray voltage signal generation which generates a plurality of staircase waveform gray voltage signals using a lowest gamma reference voltage, a highest gamma reference voltage, and a plurality of gamma voltages having a magnitude between the lowest gamma reference voltage and the highest gamma reference voltage, and a channel driver which includes a decoder which outputs one staircase waveform gray voltage signal selected from the staircase waveform gray voltage signals, an output circuit which outputs a gray voltage corresponding to the selected staircase waveform gray voltage signals to the data line as a data signal, and a reset unit which supplies one of the gamma voltages to the output circuit as a reset voltage. ### Claim 14 (depends on 13) The display device of claim 13, wherein the decoder selects one staircase waveform gray voltage signal from the plurality of staircase waveform gray voltage signals every horizontal period. ### Claim 15 (depends on 14) The display device of claim 14, wherein the reset voltage is the one gamma voltage of the plurality of gamma voltages, which corresponds to an intermediate value of a final gray voltage of one staircase waveform gray voltage signal selected in a previous horizontal period and an initial gray voltage of one staircase waveform gray voltage signal selected in a current horizontal period. ### Claim 16 (depends on 15) The display device of claim 15, wherein the reset unit detects the one staircase waveform gray voltage signal selected in the previous horizontal period and the one staircase waveform gray voltage signal selected in the current horizontal period using upper bits of image data supplied to the decoder. ### Claim 17 (depends on 14) The display device of claim 14, wherein the reset unit supplies the reset voltage to the output circuit every horizontal period and supplies the reset voltage to the output circuit before the one staircase waveform gray voltage signal selected by the decoder is supplied to the output circuit. ### Claim 18 (depends on 13) The display device of claim 13, wherein each of the plurality of staircase waveform gray voltage signals increases stepwise with a plurality of gray voltage levels every horizontal period. ### Claim 19 (depends on 13) The display device of claim 13, further comprising a gamma reference voltage supply unit which supplies the lowest gamma reference voltage, the highest gamma reference voltage, and the plurality of gamma voltages to the data driver. ### Claim 20 A display device comprising: a pixel unit which includes pixels connected to a plurality of scan lines and a plurality of data lines; a data driver which supplies one staircase waveform gray voltage signal selected from a plurality of staircase waveform gray voltage signals to the pixel unit through the data line every horizontal period; and a scan driver which sequentially supplies scan signals to the pixel unit through the scan lines every horizontal period, wherein the data driver outputs a reset voltage between a previous horizontal period and a current horizontal period.