# US 8,570,251 B2 · DC-DC converter, organic electroluminescent display device including the same, and method of driving the organic electroluminescent display device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,251 B2 - Document ID: US8570251B2 - Status: Granted - Kind: B2 - Application number: 12/984,943 - Filed: 2011-01-05 - Published: 2011-11-10 - Granted: 2013-10-29 - Earliest claimed: 2010-05-06 - Assignees: Samsung Display Co., Ltd. - Applicants: Sung Cheon Park - Inventors: Sung Cheon Park - Web page: https://patentgrep.com/patent/US8570251B2 ## CPC - G09G 3/3208: organic, e.g. using organic light-emitting diodes [OLED] - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0842: forming a memory circuit, e.g. a dynamic memory with one capacitor - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2320/0238: Improving the black level - 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 In order to adjust a black level by using a power supply voltage, an organic electroluminescent display device includes: a plurality of scan lines arranged in a row direction; a plurality of data lines arranged in a column direction; a plurality of pixels formed at intersections between the plurality of scan lines and the plurality of data lines; and a direct current (DC)-DC converter to supply a power supply voltage to the plurality of pixels, wherein the DC-DC converter includes a set resistor, and to convert a reference voltage selected according to a set voltage determined by the set resistor into a power supply voltage and to supply the power supply voltage to the plurality of pixels. ## Claims ### Claim 1 An organic electroluminescent display device comprising: a plurality of scan lines arranged in a row direction; a plurality of data lines arranged in a column direction; a plurality of pixels formed at intersections between the plurality of scan lines and the plurality of data lines; and a direct current (DC)-DC converter to supply a power supply voltage to the plurality of pixels, wherein the DC-DC converter comprises a set resistor, and is configured to convert one reference voltage selected according to a set voltage determined by the set resistor into a power supply voltage and is configured to supply the power supply voltage to the plurality of pixels, wherein the DC-DC converter further comprises: a reference voltage generating unit configured to generate a plurality of reference voltages; a reference voltage selecting unit configured to select the one reference voltage from among the plurality of reference voltages according to the set voltage determined by the set resistor; and a power supply voltage generating unit configured to convert the selected one reference voltage into the power supply voltage to be supplied to the plurality of pixels. ### Claim 2 (depends on 1) The organic electroluminescent display device of claim 1, wherein the set resistor is exchangeable, and has a resistance that is variable. ### Claim 3 (depends on 1) The organic electroluminescent display device of claim 1, wherein the set resistor is located separate from the reference voltage generating unit, the reference voltage selecting unit, and the power supply voltage generating unit. ### Claim 4 (depends on 1) The organic electroluminescent display device of claim 1, wherein the reference voltage selecting unit comprises: a comparing unit configured to compare the set voltage with a comparative voltage; and a selecting unit configured to select the one reference voltage from among the plurality of reference voltages according to a result of the comparison performed by the comparing unit. ### Claim 5 (depends on 4) The organic electroluminescent display device of claim 4, wherein the comparing unit comprises at least one comparator comprising a first terminal to which the set voltage is applied and a second terminal to which the comparative voltage is applied, and the comparing unit is configured to output an output value by comparing the set voltage with the comparative voltage. ### Claim 6 (depends on 5) The organic electroluminescent display device of claim 5, wherein the selecting unit is configured to select the one reference voltage according to the output value of the at least one comparing unit. ### Claim 7 A DC-DC converter comprising: a set resistor; a reference voltage generating unit to generate a plurality of reference voltages; a reference voltage selecting unit to select one reference voltage from among the plurality of reference voltages according to a set voltage determined by the set resistor; and a power supply voltage generating unit to convert the selected reference voltage into a power supply voltage to be supplied to a plurality of pixels. ### Claim 8 (depends on 7) The DC-DC converter of claim 7, wherein the set resistor is exchangeable, and has a resistance that is variable. ### Claim 9 (depends on 7) The DC-DC converter of claim 7, wherein the set resister is located separate from the reference voltage generating unit, the reference voltage selecting unit, and the power supply voltage generating unit. ### Claim 10 (depends on 7) The DC-DC converter of claim 7, wherein the reference voltage selecting unit comprises: a comparing unit to compare the set voltage with a comparative voltage; and a selecting unit to select the one reference voltage from among the plurality of reference voltages according to a result of the comparison performed by the comparing unit. ### Claim 11 (depends on 10) The DC-DC converter of claim 10, wherein the comparing unit comprises at least one comparator comprising a first terminal to which the set voltage is applied and a second terminal to which the comparative voltage is applied, and to the comparing unit outputs an output value by comparing the set voltage with the comparative voltage. ### Claim 12 (depends on 11) The DC-DC converter of claim 11, wherein the selecting unit selects the one reference voltage according to the output value of the at least one comparator. ### Claim 13 A method of driving an organic electroluminescent display device comprising a plurality of scan lines arranged in a row direction, a plurality of data lines arranged in a column direction, a plurality of pixels formed at intersections between the plurality of scan lines and the plurality of data lines, and a DC-DC converter for supplying a power supply voltage to the plurality of pixels, the method comprising: receiving a set voltage determined by a set resistor; selecting one reference voltage from among a plurality of reference voltages according to the set voltage; and converting the selected reference voltage into a power supply voltage and supplying the power supply voltage to the plurality of pixels. ### Claim 14 (depends on 13) The method of claim 13, wherein the set resistor is exchangeable, and has a resistance that is variable. ### Claim 15 (depends on 13) The method of claim 13, wherein the set resistor is located separate from other elements of the DC-DC converter. ### Claim 16 A method of driving a DC-DC converter for supplying a power supply voltage to a plurality of pixels, the method comprising: receiving a set voltage determined by a set resistor; selecting one reference voltage from among a plurality of reference voltages according to the set voltage; and converting the selected reference voltage into a power supply voltage and supplying the power supply voltage to the plurality of pixels. ### Claim 17 (depends on 16) The method of claim 16, wherein the set resistor is exchangeable, and has a resistance that is variable. ### Claim 18 (depends on 16) The method of claim 16, wherein the set resistor is located separate from other elements of the DC-DC converter. ### Claim 19 (depends on 13) The method of claim 13, wherein the selecting of the one reference voltage further comprises comparing the set voltage with a comparative voltage. ### Claim 20 (depends on 16) The method of claim 16, wherein the selecting of the one reference voltage further comprises comparing the set voltage with a comparative voltage.