Abstract: Methods and systems for compensating display panel operations providing a current from power circuitry over a first path between a display panel and the power circuitry are provided. A sensing current may be injected into the first path via a second path between the power circuitry and the first path. An equivalent series resistance (ESR) of the first path may be calculated using a third path and the sensing current. A processor may compensate for electrical fluctuations from the power circuitry to the display panel based at least in part on the measured ESR.

Abstract: An electronic device may be provided with an organic light-emitting diode display. The display may include row driver circuitry that provides an emission control signal at an output terminal to display pixels. The emission control signals may enable or disable light emission by the pixels. The row driver circuitry may include a bootstrapping capacitor that stores charge for boosting a gate signal at an intermediate node for a pull-up transistor above a power supply voltage. The row driver circuitry may include a pull-down transistor coupled to the intermediate node. The source terminal of the pull-down transistor may be coupled to the output terminal or an additional pull-down transistor may be stacked with the pull-down transistor to reduce leakage current. Charge pump circuitry may be coupled to the intermediate node to ensure that the intermediate node is maintained at a voltage above the power supply voltage.

Abstract: An electronic device may have a display with an array of pixels. The device may have an array of components such as an array of light sensors for capturing fingerprints of a user through an array of corresponding transparent windows in the display. A capacitive touch sensor, proximity sensor, force sensor, or other sensor may be used by control circuitry in the device to monitor for the presence of a user's finger over the array of light sensors. In response, the control circuitry can direct the display to illuminate a subset of the pixels, thereby illuminating the user's finger and causing reflected light from the finger to illuminate the array of light sensors for a fingerprint capture operation. The display may have display driver circuitry that facilitates the momentary illumination of the subset of pixels with uniform flash data while image data is displayed in other portions of the display.

Abstract: Aspects of the subject technology relate to electronic devices with displays. A display may include an array of display pixels and control circuitry for operating the display. In some scenarios, interference signals from other components of the electronic device or additional external devices can couple to the control circuitry for the display and cause distortions in displayed data. Display frames may be displayed by an electronic device display with a varying phase. The varying phase display frames may each include a distortion pattern that also varies from frame to frame due to the varying phase. The varying distortion patterns may average out or visibly cancel when viewed by a user such that no visible artifact of the interference signal is seen by the user. The varying phase can be actively tuned to the interference signal if desired.

Abstract: Aspects of the subject technology relate to electronic devices with displays. A display may include an array of display pixels and control circuitry for operating the display. In some scenarios, interference signals from other components of the electronic device or additional external devices can couple to the control circuitry for the display and cause distortions in displayed data. Display frames may be displayed by an electronic device display with a varying phase. The varying phase display frames may each include a distortion pattern that also varies from frame to frame due to the varying phase. The varying distortion patterns may average out or visibly cancel when viewed by a user such that no visible artifact of the interference signal is seen by the user. The varying phase can be actively tuned to the interference signal if desired.

Abstract: A display device may include a display having a pixels and a processor. The processor may receive image data, determine a digital offset value for a pixel based on a location of the pixel, such that the digital offset value compensates for one or more non-uniformity properties of the pixel. The processor may determine a scale factor associated with the pixel based on at least two of a luminance setting for the display, a driving mode of the display, and a gray level value for the pixel. The processor may then generate correction image data by applying the scale factor to the digital offset value, generate compensated image data based on the correction image data and the image data, and provide the compensated image data to the display.

Abstract: This application sets forth a circuit configuration for a light emitting diode (LED) or organic light emitting diode (OLED) display. The circuit configuration allows for the pulse-width modulation (PWM) of each emission signal sent to each line of the display. The PWM of each emission signal is accomplished using a gate-in-panel (GIP) controller of the display. The GIP controller uses an arrangement of shift register outputs and a programmable clock input to control an output of an inverter that provides the emission signal. The programmable clock input can be programmed according to a desired timing or duty cycle for the emission signal. In this way, by limiting the duty cycle of the emission signal, dimming and other display features can be exhibited by the LED or OLED display.

Abstract: Display panels and methods for operating a display panel are described. In an embodiment, the display panel includes a plurality of pixels arranged in rows and columns, a plurality of rows of emission control lines extending through the plurality of rows of pixels, and a global emission line coupled to the plurality of rows of emission control lines. Modes of operation of the display panel include global flash mode and low persistence mode.

Abstract: An electronic device may have a flexible display such as an organic light-emitting diode display. A strain sensing resistor may be formed on a bent tail portion of the flexible display to gather strain measurements. Resistance measurement circuitry in a display driver integrated circuit may make resistance measurements on the strain sensing resistor and a temperature compensation resistor to measure strain. A crack detection line may be formed from an elongated pair of traces that are coupled at their ends to form a loop. The crack detection line may run along a peripheral edge of the flexible display. Crack detection circuitry may monitor the resistance of the crack detection line to detect cracks. The crack detection circuitry may include switches that adjust the length of the crack detection line and thereby allow resistances to be measured for different segments of the line.

Abstract: An electronic device may be provided with an organic light-emitting diode display. The display may include row driver circuitry that provides an emission control signal at an output terminal to display pixels. The emission control signals may enable or disable light emission by the pixels. The row driver circuitry may include a bootstrapping capacitor that stores charge for boosting a gate signal at an intermediate node for a pull-up transistor above a power supply voltage. The row driver circuitry may include a pull-down transistor coupled to the intermediate node. The source terminal of the pull-down transistor may be coupled to the output terminal or an additional pull-down transistor may be stacked with the pull-down transistor to reduce leakage current. Charge pump circuitry may be coupled to the intermediate node to ensure that the intermediate node is maintained at a voltage above the power supply voltage.

Abstract: An electronic device may be provided with wireless circuitry and a display. A display driver integrated circuit in the display may have a spectrum analyzer circuit. An antenna may monitor for wireless signals. The display driver integrated circuit may use the spectrum analyzer circuit to analyze the wireless signals and determine whether there is a potential for visible display artifacts. In the presence of conditions that can lead to display artifacts, the display driver integrated circuit may adjust a gate driver control signal. Adjustments to the gate driver control signal may be made using adjustable signal dividers. The adjustments to the gate driver control signal eliminate the visible display artifacts.

Abstract: An electronic device comprises a display and a controller. The controller is configured to determine a change in a refresh rate of the display from a first frequency to a second frequency. The controller is also configured to selectively generate a control signal configured to control emission of a light emitting diode of a display pixel of the display based on the first frequency.

Abstract: A method for testing integrated circuit-to-substrate joints that electrically connect an IC to a substrate. An ammeter is coupled to a test node of the driver IC, while the test node is coupled to a current source, and a measured current output of the ammeter is recorded. A voltmeter is coupled to the test node while the test node is coupled to an end node of a group of dummy IC-to-substrate joints that are daisy chained; a first measured voltage output of the voltmeter is then recorded. The IC then couples the test node to another end node of the daisy chained dummy joints, and a second measured voltage output is recorded. A resistance or admittance value for the electrical connection of the IC to the substrate is then computed, using the first and second measured voltage outputs and the measured current output. Other embodiments are also described and claimed.

Abstract: This application sets forth a circuit configuration for a light emitting diode (LED) or organic light emitting diode (OLED) display. The circuit configuration allows for the pulse-width modulation (PWM) of each emission signal sent to each line of the display. The PWM of each emission signal is accomplished using a gate-in-panel (GIP) controller of the display. The GIP controller uses an arrangement of shift register outputs and a programmable clock input to control an output of an inverter that provides the emission signal. The programmable clock input can be programmed according to a desired timing or duty cycle for the emission signal. In this way, by limiting the duty cycle of the emission signal, dimming and other display features can be exhibited by the LED or OLED display.

Abstract: Systems and methods for efficiently generating display driver timing signals are provided. In one example, display driver circuitry of an electronic display may provide a negative voltage from a negative voltage supply to display control circuitry during a first period and may provide a positive voltage from a positive voltage supply to the display control circuitry during a second period. After providing the negative voltage during the first period but before providing the positive voltage during the second period, the display driver circuitry may precharge the capacitance of the display control circuitry to ground. In this way, the positive voltage supply substantially does not supply charge to raise the voltage on the capacitance of the display control circuitry from the negative voltage to ground.

Abstract: The present disclosure relates to devices and methods for reducing power consumption of a display. One electronic display includes a first switch coupled between a first gate of a first transistor and a second gate of a second transistor to selectively connect the first gate to the second gate. The display includes a second switch coupled between the second gate of the second transistor and a third gate of a third transistor to selectively connect the second gate to the third gate. The display also includes driving circuitry that controls the first switch to connect the first gate to the second gate to share a first charge between the first and second gates. The driving circuitry also controls the second switch to connect the second gate to the third gate to share a second charge between the second and third gates. Accordingly, power consumption of the display may be reduced.

Abstract: An electronic device may be provided with wireless circuitry and a display. A display driver integrated circuit in the display may have a spectrum analyzer circuit. An antenna may monitor for wireless signals. The display driver integrated circuit may use the spectrum analyzer circuit to analyze the wireless signals and determine whether there is a potential for visible display artifacts. In the presence of conditions that can lead to display artifacts, the display driver integrated circuit may adjust a gate driver control signal. Adjustments to the gate driver control signal may be made using adjustable signal dividers. The adjustments to the gate driver control signal eliminate the visible display artifacts.

Abstract: An electronic device may be provided with a housing such as a metal housing in which a display is mounted. Control circuitry in the electronic device such as a system-on-chip integrated circuit may produce image data. A display driver integrated circuit may receive the image data from the system-on-chip integrated circuit and may display the image data on the display. In the absence of electrostatic discharge, the display driver integrated circuit may operate normally and may generate a heartbeat signal. When disrupted due to electrostatic discharge, the display driver circuitry may cease production of the heartbeat signal. The system-on-chip integrated circuit can implement a watchdog timer. If the watchdog timer times out because the heartbeat signal is not received within a timeout period, the system-on-chip integrated circuit may reset the display.

Abstract: An electronic display includes a display panel. The display panel includes a pixel array and receives a supply voltage. The display panel also includes a panel driver configured to generate a gate line voltage. The panel driver also supplies the gate line voltage to the display panel based on a comparison between the gate line voltage and the supply voltage.

Abstract: Methods and devices employing mura prevention circuitry, are provided. In one example, a method may include supplying a first voltage pathway between a common electrode driver and a common electrode of an electronic display device and supplying a second voltage pathway between the common electrode driver and ground. Mura prevention circuitry may be supplied that activates the first voltage pathway when the electronic display device is turned on and an activation gate signal is provided from a gate corresponding to the common electrode driver. Further, the mura prevention circuitry may activate the second voltage pathway when the electronic display device is turned off or no activation gate signal is provided from the gate corresponding to the common electrode driver.