Voltage regulation method, terminal device, chip and storage medium

Abstract

Embodiments of the present application provide a voltage regulation method, a terminal device, a chip and a storage medium, and relate to the technical field of display, which can improve the problem of high power consumption of the display driving circuit of the terminal device. The voltage regulation method comprises: obtaining the highest gray scale of each color channel of a to-be-displayed image; determining the lowest working voltage required by the display driving circuit to display the highest gray scale of each color channel, so as to adjust the working voltage of the display circuit according to the content displayed; and determining the maximum value in the lowest working voltage required by the display driving circuit to display the highest gray scale of each color channel as the target working voltage of the display driving circuit. In this way, the target working voltage of the display driving circuit is determined according to the gray scale of the to-be-displayed image, which can ensure that each gray scale of each color channel of the to-be-displayed image can be normally displayed, and the power consumption of the display driving circuit is reduced when the highest gray scale of the to-be-displayed image is lower than the highest gray scale that can be displayed by the light-emitting device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a voltage adjusting method, a terminal device, a chip and a storage medium. BACKGROUND

[0002] Display or display screen is an output device that converts electrical signals into image signals, and is an important component of electronic devices such as computers, mobile phones and televisions. Currently, the most widely used displays are liquid crystal displays (LCD) and organic light-emitting diodes (OLED). The display principle of these two types of displays is based on the optical principle of combining multiple primary colors to form a pixel point. For example, each pixel point includes red (R), green (G), and blue (B) sub-pixels, which are referred to as RGB, or includes red (R), green (G), blue (B), and white (W) sub-pixels, which are referred to as RGBW. Different sub-pixels display different brightness or gray scales, and multiple primary colors mix to display different colors of pixel points.

[0003] Taking OLED as an example, the gray scale displayed by the OLED light-emitting unit under different sizes of driving current is different. The greater the current of the driving signal, the greater the gray scale displayed, and the smaller the current of the driving signal, the smaller the gray scale displayed. Therefore, the gray scale displayed by each color light-emitting unit can be adjusted by controlling the current size of the driving signal of the light-emitting unit or adjusting the duty cycle of the driving signal.

[0004] Currently, display components usually work in a fixed voltage mode, that is, the driving tube and the light-emitting device are connected in series between the power supply with a fixed voltage difference. However, the content displayed by the OLED light-emitting unit or other light-emitting units is dynamically changing, and not all display screens appear the highest gray scale. Therefore, the fixed voltage working mode makes the power consumption of the display component large. SUMMARY

[0005] Therefore, the present application provides a voltage adjusting method, a terminal device, a chip and a storage medium to improve the problem of high power consumption caused by the display driving circuit of the terminal device working in a fixed voltage mode.

[0006] In a first aspect, the present application provides a voltage regulating method applied to a processor of a terminal device, the terminal device further comprising a display component, the display component comprising a display driving circuit, the method comprising: obtaining a highest gray scale of each color channel of an image to be displayed, for example, if the image is displayed by the display driving circuit in an RGB mode, then the highest gray scales of red, green and blue channels are obtained, if the image is displayed by the display driving circuit in an RGBW mode, then the highest gray scales of red, green, blue and white channels are obtained; determining a lowest working voltage required by the display driving circuit for displaying the highest gray scale of each color channel; the working voltage of the display driving circuit mainly consists of a voltage division of a driving transistor and a voltage division of a light emitting device, when displaying the highest gray scale, the voltage division of the light emitting device reaches a highest state and the voltage division of the driving transistor reaches a lowest state, since the driving transistor works in a saturation region, therefore, the sum of the lowest saturation voltage of the driving transistor in the saturation region and the voltage division of the light emitting device when the voltage division of the light emitting device reaches the highest state is taken as the lowest working voltage of the display driving circuit, which can ensure that each gray scale can be normally displayed, the maximum value of the lowest working voltages required by the display driving circuit for displaying the highest gray scale of each color channel is determined as a target working voltage of the display driving circuit, so that it can be ensured that each gray scale of different color channels of the image to be displayed can be normally displayed, and the power consumption of the display driving circuit can be reduced when the gray scale of the image to be displayed is lower than the highest gray scale of the light emitting device.

[0007] In a possible implementation, the display driving circuit comprises a driving transistor and a light emitting device, the driving transistor is used to provide a driving current to the light emitting device, and the determining of the lowest working voltage required by the display driving circuit for displaying the highest gray scale of each color channel comprises: determining the driving current and the driving voltage required by the light emitting device for displaying the highest gray scale of each color channel according to a pre-stored corresponding relationship between the gray scale of the light emitting device and the driving current of each color channel and a pre-stored corresponding relationship between the driving current and the driving voltage; determining the lowest saturation voltage of the driving transistor when outputting the driving current according to a pre-stored corresponding relationship between the current and the voltage of the driving transistor; and determining the sum of the driving voltage and the lowest saturation voltage as the lowest working voltage required by the display channel for displaying the highest gray scale. The working voltage of the display driving circuit mainly consists of the voltage division of the driving transistor and the voltage division of the light emitting device, wherein the driving transistor works in a saturation region and the output current does not change with the voltage division, when the light emitting device displays the highest gray scale of a certain color channel, the driving voltage of the light emitting device reaches a maximum, and the sum of the driving voltage at this time and the lowest voltage of the driving transistor working in the saturation region when the driving voltage of the light emitting device reaches the maximum is taken as the lowest working voltage, which can guarantee that the light emitting device can display any gray scale of the color channel.

[0008] In a possible implementation, the lowest saturation voltage of the drive transistor when outputting the drive current is determined according to the pre-stored correspondence between the current and the voltage of the drive transistor, including: according to the pre-stored correspondence between the current and the voltage of the drive transistor, the lowest voltage corresponding to the drive current when the drive transistor works in the saturation region is determined as the lowest saturation voltage of the drive transistor.

[0009] In a possible implementation, the voltage adjustment method further includes: sending a control instruction to the display component, so that the display component adjusts the working voltage of the display driving circuit to the target working voltage.

[0010] In a possible implementation, the control instruction includes a voltage adjustment amount, and the voltage adjustment amount is a difference between the input voltage of the display driving circuit and the target working voltage, or the control instruction includes the target working voltage.

[0011] In a possible implementation, the voltage adjustment method further includes: determining a current variation of the drive transistor according to the voltage adjustment amount and the pre-stored correspondence between the current and the voltage of the drive transistor, the voltage adjustment amount being a difference between the input voltage of the display driving circuit and the target working voltage; determining a brightness compensation amount according to the current variation; and sending the brightness compensation amount to the display component. Since the drive transistor may not reach an ideal state, when the working voltage of the display driving circuit is adjusted, the voltage of the drive transistor is reduced to the lowest saturation voltage, which may cause the saturation current output by the drive transistor to decrease, that is, the drive current in the light-emitting interval is reduced, resulting in a decrease in the gray scale displayed by the light-emitting device. Therefore, the brightness of the light-emitting device is compensated according to the current variation of the drive transistor, so as to avoid a decrease in the displayed gray scale due to the drive transistor not reaching the ideal state.

[0012] In a possible implementation, the highest gray scale of each color channel of the to-be-displayed image is obtained by: obtaining the gray scale of each color channel of each pixel point of the to-be-displayed image; and taking the maximum value of the gray scales of the same color channel of all the pixel points of the to-be-displayed image as the highest gray scale of the color channel.

[0013] In a second aspect, an embodiment of the present application provides a terminal device, including: a display component and one or more processors, the processor being connected with the display component, the display component including a display driving circuit; and the processor being configured to execute computer program instructions to implement the voltage adjustment method according to any one of the implementations of the first aspect.

[0014] In a third aspect, an embodiment of the present application provides a chip, the chip being applied to a terminal device, and the chip including one or more processors, the processor being configured to execute computer program instructions to enable the terminal device to perform the voltage adjustment method according to any one of the implementations of the first aspect.

[0015] In a fourth aspect, embodiments of the present application also provide a computer readable storage medium storing a computer program, which, when executed by a processor, causes a terminal device to perform the voltage regulation method according to any one of the implementations of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structural schematic diagram of a terminal device provided by an embodiment of the present application;

[0017] Figure 2 A circuit diagram of a display driving circuit provided by an embodiment of the present application;

[0018] Figure 3 A schematic diagram of the relationship between the current and the voltage of a driving transistor provided by an embodiment of the present application;

[0019] Figure 4 A circuit diagram of another display driving circuit provided by an embodiment of the present application;

[0020] Figure 5 A schematic diagram of a terminal device provided by an embodiment of the present application;

[0021] Figure 6 A schematic diagram of another terminal device provided by an embodiment of the present application;

[0022] Figure 7 A schematic diagram of another terminal device provided by an embodiment of the present application;

[0023] Figure 8 A schematic diagram of a system architecture of a terminal device provided by an embodiment of the present application;

[0024] Figure 9 A flowchart of a voltage regulation method provided by an embodiment of the present application;

[0025] Figure 10 A flowchart of another voltage regulation method provided by an embodiment of the present application;

[0026] Figure 11 A flowchart of another voltage regulation method provided by an embodiment of the present application;

[0027] Figure 12 A gray scale histogram provided by an embodiment of the present application;

[0028] Figure 13 A flowchart of another voltage regulation method provided by an embodiment of the present application;

[0029] Figure 14A schematic diagram of the relationship between current and voltage of a red light-emitting device provided in an embodiment of the present application is shown in FIG. 1.

[0030] Figure 15 A schematic diagram of the relationship between current and voltage of a blue light-emitting device provided in an embodiment of the present application is shown in FIG. 2.

[0031] Figure 16 A schematic diagram of the relationship between current and voltage of a green light-emitting device provided in an embodiment of the present application is shown in FIG. 3.

[0032] Figure 17 A schematic diagram of the relationship between current and voltage of another driving transistor provided in an embodiment of the present application is shown in FIG. 4.

[0033] Figure 18 A flowchart of another voltage adjustment method provided in an embodiment of the present application is shown in FIG. 5. DETAILED DESCRIPTION

[0034] The embodiments of the present application are applied to a terminal device 100, and the terminal device 100 provided in the embodiments of the present application can be a mobile phone, a smart screen, a tablet computer, a wearable electronic device, a car machine, an augmented reality (AR) device, a virtual reality (VR) device, a notebook computer, a personal digital assistant (PDA), a projector, and the like. The embodiments of the present application do not limit the type of the terminal device 100.

[0035] The structure of a terminal device 100 applied in the embodiments of the present application is described below by taking a mobile phone as an example. Please refer to FIG. 6. Figure 1 The terminal device 100 can include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charge management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a loudspeaker 170A, a receiver 170B, a microphone 170C, a headset interface 170D, a sensor module 180, a key 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, and the like.

[0036] The sensor module 180 can include a pressure sensor, a gyro sensor, a barometric pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, and the like.

[0037] It can be understood that the structure illustrated in the embodiment does not constitute a specific limitation on the terminal device 100. In other embodiments, the terminal device 100 can include more or fewer components than illustrated, or combine certain components, or split certain components, or different component arrangements. The illustrated components can be implemented in hardware, software, or a combination of software and hardware.

[0038] The processor 110 can include one or more processing units, for example: the processor 110 can include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units can be independent devices or integrated into one or more processors.

[0039] The controller can be the nerve center and command center of the terminal device 100. The controller can generate operation control signals according to instruction operation codes and timing signals, and complete the control of fetching and executing instructions.

[0040] The memory can also be provided in the processor 110 for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. The memory can save instructions or data that the processor 110 has just used or repeatedly uses. If the processor 110 needs to use the instructions or data again, it can be directly called from the memory. This avoids repeated access and reduces the waiting time of the processor 110, thus improving the efficiency of the system.

[0041] In some embodiments, the processor 110 can include one or more interfaces. The interfaces can include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0042] It can be understood that the interface connection relationship between the modules shown in the embodiments is only illustrative and does not limit the structure of the terminal device 100. In other embodiments, the terminal device 100 can also use different interface connection manners or combinations of multiple interface connection manners.

[0043] The charging management module 140 is configured to receive charging input from a charger. The charger can be a wireless charger or a wired charger. The charging management module 140 can charge the battery 142 and also supply power to the terminal device through the power management module 141.

[0044] The power management module 141 is configured to connect the battery 142, the charging management module 140, and the processor 110. The power management module 141 receives input from the battery 142 and / or the charging management module 140 to supply power to the processor 110, the internal memory 121, the external memory, the display screen 194, the camera 193, and the wireless communication module 160, etc. In some embodiments, the power management module 141 and the charging management module 140 can also be arranged in the same device.

[0045] The wireless communication function of the terminal device 100 can be realized through the antenna 1, the antenna 2, the mobile communication module 150, the wireless communication module 160, the modem processor, and the baseband processor, etc. In some embodiments, the antenna 1 and the mobile communication module 150 of the terminal device 100 are coupled, and the antenna 2 and the wireless communication module 160 are coupled, so that the terminal device 100 can communicate with the network and other devices through wireless communication technology.

[0046] Antennas 1 and 2 are used for transmitting and receiving electromagnetic wave signals. Each antenna in terminal device 100 can be used to cover a single or multiple communication frequency bands. Different antennas can also be multiplexed to improve the utilization of antennas. For example, antenna 1 can be multiplexed as a diversity antenna for wireless local area networks. In some other embodiments, antennas can be used in combination with tuning switches.

[0047] Mobile communication module 150 can provide solutions for wireless communication including 2G / 3G / 4G / 5G, etc. applied on terminal device 100. Mobile communication module 150 can include at least one filter, switch, power amplifier, low noise amplifier (LNA), etc. Mobile communication module 150 can receive electromagnetic waves from antenna 1, and perform filtering, amplification, etc. on the received electromagnetic waves, and transmit the processed signals to a modem processor for demodulation.

[0048] Mobile communication module 150 can also amplify the signals modulated by the modem processor, and convert the signals into electromagnetic waves radiated out through antenna 1. In some embodiments, at least part of the functional modules of mobile communication module 150 can be arranged in processor 110. In some embodiments, at least part of the functional modules of mobile communication module 150 can be arranged in the same device as at least part of the modules of processor 110.

[0049] Wireless communication module 160 can provide solutions for wireless communication including WLAN (such as wireless fidelity (Wi-Fi) network), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR) technology, etc. applied on terminal device 100.

[0050] Wireless communication module 160 can be one or more devices integrated with at least one communication processing module. Wireless communication module 160 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering processing on the electromagnetic wave signals, and transmits the processed signals to processor 110. Wireless communication module 160 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification on the signals, and convert the signals into electromagnetic waves radiated out through antenna 2.

[0051] The terminal device 100 implements display functions through a GPU, a display screen 194, and an application processor, etc. The GPU is a microprocessor for image processing, connected to the display screen 194 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 110 can include one or more GPUs that execute program instructions to generate or change display information.

[0052] The display screen 194 is used to display images, videos, etc. The display screen 194 includes a display panel and a printed circuit board (PCB) on which a display driving circuit is disposed. The processor 110 can send data of an image to be displayed to the display screen, and the display driving circuit drives the image data to be displayed on the display panel.

[0053] In embodiments of the present application, the display panel can be an organic light emitting diode (OLED), an active matrix organic light emitting diode (AMOLED), or a micro light emitting diode (Micro LED), etc. In some possible implementations, the terminal device 100 can include one or more display screens 194, which can communicate with the processor 110 through a display serial interface (DIS) interface to implement display functions of the terminal device 100.

[0054] The terminal device 100 can implement a shooting function through an ISP, a camera 193, a video codec, a GPU, a display screen 194, and an application processor, etc. The ISP is used to process data fed back by the camera 193. The camera 193 is used to capture still images or videos. In some embodiments, the terminal device 100 can include one or N cameras 193, where N is a positive integer greater than 1.

[0055] The external memory interface 120 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the terminal device 100. The external memory card communicates with the processor 110 through the external memory interface 120 to implement a data storage function. For example, music, video, etc. files are saved in the external memory card.

[0056] The internal memory 121 can be used to store computer executable program codes, which include instructions. The processor 110 performs various functional applications and data processing of the terminal device 100 by running the instructions stored in the internal memory 121. For example, in the embodiments of the present application, the processor 110 can perform the instructions stored in the internal memory 121, and the internal memory 121 can include a program storage area and a data storage area.

[0057] The program storage area can store an operating system, at least one application program required by a function (such as a sound playing function, an image playing function, etc.), and the like. The data storage area can store data (such as audio data, a phone book, etc.) created during the use of the terminal device 100, and the like. In addition, the internal memory 121 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, a universal flash storage (UFS), and the like.

[0058] The terminal device 100 can realize audio functions such as music playing, recording, etc. through the audio module 170, the speaker 170A, the receiver 170B, the microphone 170C, the earphone interface 170D, the application processor, and the like.

[0059] The keys 190 include a power-on key, a volume key, and the like. The keys 190 can be mechanical keys. They can also be touch keys. The motor 191 can generate a vibration prompt. The motor 191 can be used for incoming call vibration prompt, and can also be used for touch vibration feedback. The indicator 192 can be an indicator light, which can be used to indicate a charging state, a power change, and can also be used to indicate a message, a missed call, a notification, and the like. The SIM card interface 195 is used to connect a SIM card. The SIM card can be inserted into or pulled out of the SIM card interface 195 to realize contact and separation with the terminal device 100. The terminal device 100 can support one or N SIM card interfaces, and N is a positive integer greater than 1. The SIM card interface 195 can support a Nano SIM card, a Micro SIM card, a SIM card, and the like.

[0060] It should be noted that, Figure 1 The structures shown are not sufficient to define the specific terminal device 100. In other embodiments of the present application, the terminal device 100 can include more or fewer components than those shown, or the terminal device 100 can include a combination of some of the components shown, or the terminal device 100 can include sub-components of some of the components shown, Figure 1 or the terminal device 100 can include Figure 1 or the terminal device 100 can include Figure 1 or the terminal device 100 can include sub-components of some of the components shown, Figure 1The illustrated components can be implemented in hardware, software, or a combination of both hardware and software.

[0061] The most widely used displays at present are liquid crystal display (LCD) and organic light emitting diode (OLED), and the display principle of these two types of displays is based on the optical principle of combining three primary colors to form a pixel point. Generally, each pixel point includes red, green, and blue sub-pixels, and this display principle is referred to as the red, green, and blue (RGB) mode. Each sub-pixel can display adjustable gray scale, and the combination of three different gray scale brightness primary colors can form a variety of different colors. The gray scale is to divide the brightness variation between the brightest and darkest of the three colors into several parts in order to facilitate the signal input corresponding to the screen brightness adjustment. For example, if the gray scale range of the red, green, and blue sub-pixels is 0-255, when the gray scale displayed by the red and green sub-pixels of a certain pixel point is 15, and the gray scale displayed by the blue sub-pixel is 0, the color mixed after the three colors displayed by the pixel point is yellow.

[0062] In some other embodiments, the display can also display images in other display modes, such as the red, green, blue, and white (RGBW) mode. The principle of the RGBW mode is the same as that of the RBG mode, that is, different gray scale light is displayed by the red, green, and blue sub-pixels or the red, green, blue, and white sub-pixels of each pixel point, and different colors are displayed after mixing. In the embodiments of the present application, the RGB mode is taken as an example for illustration.

[0063] The LCD itself cannot emit light and displays by emitting light from the backlight layer, while the OLED itself can emit light. Each pixel point includes three light emitting devices of red, green, and blue, and emits light when powered on and does not emit light when powered off. Therefore, there is no light leakage and pure black can be displayed. In addition, the greater the current, the greater the brightness of the light emitting device, and the smaller the current, the smaller the brightness of the light emitting device. By controlling the applied voltage or current of each light emitting device, the color ratio of the red, green, and blue sub-pixels can be controlled to control the color of each pixel point.

[0064] The LCD has a backlight layer, and all pixel points share the same backlight layer. Therefore, when the screen is turned on, the entire screen is turned on at the same time, and when the screen is turned off, the entire screen is turned off at the same time. The OLED does not have a backlight layer, and each pixel point is independently controlled. Therefore, unlike the LCD, the entire screen of the OLED does not need to be turned on or turned off as a whole, but a part of the pixel points can be turned on, and the remaining pixel points can be turned off without being powered on. Therefore, the power consumption of the OLED is lower than that of the LCD.

[0065] The driving mode of OLED can be divided into passive driving and active driving. The active driving OLED, i.e. active matrix organic light emitting diode (AMOLED), can emit light by driving transistor in a saturated state to generate driving current, which drives the OLED to emit light.

[0066] Figure 2 A display driving circuit provided by the embodiment of the present application comprises a transistor M1, a transistor M2, a capacitor C0 and a light emitting device D0. The gate of the transistor M1 is used to input a scanning signal Vscan, the source of the transistor M1 is used to input a data signal Vdata, and the drain of the transistor M1 is connected with the gate of the transistor M2. The gate of the transistor M2 is connected with one end of the capacitor C0, the source of the transistor M2 is connected with the other end of the capacitor C0, the drain of the transistor M2 is connected with the anode of the light emitting device D0, and the cathode of the light emitting device D0 is grounded. The transistor M1 is turned on when the gate is selected by the scanning signal Vscan, and the data signal Vdata is introduced from the source of the transistor M1. The transistor M2 generally works in a saturation region. Referring to Figure 3 , Figure 3 The current-voltage relationship curve of the transistor M2 is shown. The transistor M2 working in the saturation region, the current flowing through the source and the drain does not change with the voltage V DS of the drain and the source, but is determined by the gate-source voltage V GS , so that the transistor M2 can provide stable driving current for the light emitting device D0. The transistor M2 is generally also called a driving transistor.

[0067] wherein V GS = Vdata- VD0, VD0 is the opening voltage of the light emitting device D0, VDD is a stable voltage source connected with the source of the transistor M2, and used to provide energy required by the light emitting device D0 to emit light. The capacitor C0 is used to maintain the stability of the gate voltage of the transistor M2 in a display period of one frame of image.

[0068] In Figure 2 the display driving circuit shown, since VDD is a stable voltage source, the transistor M2 works in the saturation region. When V GS increases, the saturation current I D flowing through the source and the drain of the transistor M2 increases, the current of the light emitting device D0 increases, and the display gray scale increases. When V GS decreases, the saturation current I D flowing through the source and the drain of the transistor M2 decreases, the current of the light emitting device D0 decreases, and the display gray scale decreases. Therefore, by changing VGS The driving transistor M2 outputs different saturation currents so as to make the light emitting device DO have different brightness.

[0069] Figure 4 Another display driving circuit provided by the embodiment of the present application includes a light emitting device D1, transistors T1-T7, a capacitor C1, Figure 4 The display driving circuit shown includes 7 transistors and 1 capacitor, and is therefore also referred to as a 7T1C display driving circuit. The light emitting device D1 can be a light emitting device of any color, for example, a red, green, blue, white or other color light emitting device.

[0070] The first electrode of the transistor T4 is connected with the power supply VDD, and the first electrode plate of the capacitor C1 is also connected with the power supply VDD. The second electrode of the transistor T4 is connected with the first electrode of the transistor T2. The second electrode of the transistor T2 is connected with the first electrode of the transistor T3. The second electrode of the transistor T3 is connected with the anode of the light emitting device D1. The cathode of the light emitting device D1 is connected with the power supply VSS. The gate of the transistor T2 is connected with the second electrode plate of the capacitor C1. The gate of the transistor T3 and the gate of the transistor T4 are both connected with the control signal end (EM) for inputting the control signal. The second electrode plate of the capacitor C1 is also connected with the first electrode of the transistor T7. The second electrode of the transistor T7 is connected with the initialization signal end (INIT). The gate of the transistor T7 is connected with the initialization control end (Gn-1). The Gn-1 outputs the control signal to control the transistor T7 to be turned on after the end of one frame of image display, and the INIT is connected to complete the initialization. The first electrode of the transistor T5 is connected with the second electrode of the transistor T4. The second electrode of the transistor T5 is connected with the data signal end (DATA). The gate of the transistor T5 is connected with the display control end (Gn). The Gn is used to output the control signal to control the transistor T5 to be turned on, and the data of the image to be displayed is input from the DATA. The first electrode of the transistor T1 is connected with the gate of the transistor T2. The second electrode of the transistor T1 is connected with the second electrode of the transistor T2. The gate of the transistor T1 is connected with the Gn. The first electrode of the transistor T6 is connected with the INIT. The second electrode of the transistor T6 is connected with the second electrode of the transistor T3. The gate of the transistor T6 is connected with the Gn-1. The transistor can be a metal-oxide-semiconductor field effect transistor (MOSFET). The transistor is divided into two types of N (negative) type transistor and P (positive) type transistor. The transistor includes a first electrode, a second electrode and a gate. The conduction or turn-off of the transistor can be controlled by controlling the level of the input gate of the transistor. When the transistor is turned on, the first electrode and the second electrode are turned on to generate a conduction current. When the gate voltages of the transistors are different, the size of the conduction current generated between the first electrode and the second electrode is also different. When the transistor is turned off, the second electrode and the second electrode will not be turned on, and no current will be generated. In the embodiments of the present application, the gate of the transistor is also referred to as the control end, the first electrode is also referred to as the source, and the second electrode is also referred to as the drain. Alternatively, the gate is referred to as the control end, the first electrode is referred to as the drain, and the second electrode is referred to as the source. As can be seen, the first electrode and the second electrode can be interchangeable. Generally, the electrode from which the current flows out is referred to as the source, and the electrode into which the current flows is referred to as the drain. For example, if the current flows from the first electrode to the second electrode, the first electrode is the source and the second electrode is the drain.

[0071] In addition, the N-type transistor is turned on when the level of the control end is high, the first electrode and the second electrode are turned on, and a conduction current is generated between the first electrode and the second electrode; the N-type transistor is turned off when the level of the control end is low, the first electrode and the second electrode are not turned on, and no current is generated. The P-type transistor is turned on when the level of the control end is low, the first electrode and the second electrode are turned on, and a conduction current is generated; the P-type transistor is turned off when the level of the control end is high, the first electrode and the second electrode are not turned on, and no current is generated.

[0072] The working principle of the display driving circuit is briefly introduced as follows Figure 4 As shown in the figure, the working principle of the display driving circuit is briefly introduced as follows

[0073] Then, the Gn output control signal controls the transistor T1 to be turned on, and the data signal output by the DATA is transmitted to the second electrode plate of the capacitor C1 through the transistor T2 and the transistor T1, and the capacitor C1 is charged, which is equivalent to temporarily storing the data signal in the capacitor C1. Therefore, the capacitor C1 is also called a storage capacitor.

[0074] In the next step, the transistor T1 is turned off, and the light emitting device D1 starts to emit light. The brightness is controlled by the current flowing through the first electrode and the second electrode of the transistor T2. In the embodiment of the application, the current flows from the first electrode to the second electrode of the transistor T2, so the first electrode of the transistor T2 is the source electrode, the second electrode of the transistor T2 is the drain electrode, and the current flowing through the first electrode and the second electrode is also called the drain current I D In addition, since the transistor T2 works in the saturation region, the drain current in the saturation region is also called the saturation current. In the embodiment of the application, the transistor T2 works in the saturation region and is used to control the driving current of the light emitting device D1, so the transistor T2 is also called a driving transistor, and the current I D The gate voltage V G That is, the voltage of the second electrode plate of the capacitor C1 is controlled, and the voltage of the second electrode plate of the capacitor C1 is obtained by charging the second electrode plate of the capacitor C1 through the transistor T1 with the data signal in the previous step.

[0075] In this display period, the control signal output by the EM can control the transistor T3 and the transistor T4 to be turned on or turned off, and the duty cycle of the control signal output by the EM can be used to adjust the brightness or gray scale displayed by the light emitting device D1. By controlling the duty cycle of the control signal output by the EM, the display brightness can be adjusted. For example, the larger the duty cycle, the greater the display brightness, and the smaller the duty cycle, the smaller the display brightness.

[0076] In embodiments of the present application, the light emitting device described above can be a current-driven light emitting device including a light emitting diode (LED), a mini light emitting diode (mini LED), a micro light emitting diode (micro LED), an organic light emitting diode (OLED), a micro light emitting diode (Micro LED), a flexible organic light emitting diode (FOLED), etc.

[0077] The following is described by taking the light emitting device as an OLED.

[0078] The voltage drop after the transistor T4 and the transistor T3 are turned on is very low, so the sum of the voltage drops of the transistor T2 and the light emitting device D1 is approximately equal to the voltage difference between the power supply VDD and the power supply VSS. Figure 4 The display driving circuit shown is working in a fixed voltage driving mode, i.e., the voltage difference between the power supply VDD and the power supply VSS is fixed and unchangeable,

[0079] Since the transistor T2 works in the saturation region, the current flowing through the first and second electrodes does not decrease with the decrease of the voltage of the first and second electrodes of the transistor T2, so the light emitting device D1 can be provided with stable current to drive the light emitting device D1 to emit light. When the gate voltage of the transistor T2 increases, the saturation current flowing through the first and second electrodes of the transistor T2 increases, the current of the light emitting device D1 increases, and the gray scale of the display increases; when the gate voltage of the transistor T2 decreases, the saturation current flowing through the first and second electrodes of the transistor T2 decreases, the current of the light emitting device D1 decreases, and the gray scale of the display decreases, so different saturation currents are output by driving the transistor T2 with different gate voltages to make the light emitting device D1 display different brightness.

[0080] When the current of the light emitting device D1 decreases and the displayed gray scale or brightness is low, the voltage drop on the light emitting device D1 decreases, so the voltage drop of the transistor T2 increases. Since the transistor T2 works in the saturation region, the current flowing through the first and second electrodes does not increase with the increase of the voltage of the first and second electrodes of the transistor T2, so the light emitting device D1 can be provided with stable current to drive the light emitting device D1 to emit light; similarly, when the current of the light emitting device D1 increases and the displayed gray scale or brightness is high, the voltage drop on the light emitting device D1 increases, so the voltage drop of the transistor T2 decreases.

[0081] For the power supply VDD and the power supply VSS, the voltage difference between them needs to be guaranteed to be within a range that ensures that the transistor T2 does not work in the linear region at any brightness. When the transistor T2 works in the linear region, the current flowing through the first electrode and the second electrode of the transistor T2 is not proportional to the gate voltage, so the driving current flowing through the light emitting device D1 cannot be adjusted by adjusting the gate voltage of the transistor T2. When the transistor T2 works in the saturation region, the current flowing through the first electrode and the second electrode of the transistor T2 is proportional to the gate voltage of the transistor T2, so the highest gray scale and the lowest gray scale and each gray scale therebetween can be displayed by the light emitting device D1 by adjusting the gate voltage of the transistor T2.

[0082] However, the content displayed by the display assembly is dynamically changing, and is not fixed, that is, not all images to be displayed will have the highest gray scale. For example, when a movie with a main scene at night is played, the brightness of the night scene is low, and the gray scale of all images displayed may be low. In this case, the display driving circuit still works in the fixed voltage mode, which results in a large power consumption waste.

[0083] Therefore, the embodiments of the present application provide a voltage adjustment method for adjusting the working voltage of a display driving circuit according to the gray scale of an image to be displayed, so as to save power consumption.

[0084] In a possible implementation, referring to Figure 5 The voltage adjustment method provided by the embodiments of the present application can be applied to a television, for example, can be applied to a smart screen. By the method provided by the embodiments of the present application, the lowest working voltage corresponding to the highest gray scale of each color channel of an image displayed by the smart screen can be determined, the maximum value of the lowest working voltage corresponding to the highest gray scale of each color channel is taken as the target working voltage, so that the power consumption of the television can be reduced while ensuring that all gray scales of each color channel can be displayed.

[0085] In a possible implementation, referring to Figure 6 The voltage adjustment method provided by the embodiments of the present application can be applied to a computer display, for example, as shown in Figure 6 By the method provided by the embodiments of the present application, the lowest working voltage corresponding to the highest gray scale of each color channel of an image displayed by the display can be determined, and the maximum value of the lowest working voltage corresponding to the highest gray scale of all color channels is determined as the target voltage, so that the power consumption of the display can be reduced while ensuring that all gray scales of each color channel can be displayed.

[0086] In a possible implementation, the voltage adjustment method provided by the embodiments of the present application can be applied to a mobile phone, for example, as shown inFigure 7 As shown, by the method provided in the embodiments of the present application, the maximum working voltage corresponding to the highest gray scale of each color channel can be determined according to the highest gray scale of each color channel of the image displayed by the mobile phone, and the maximum value of the minimum working voltage corresponding to the highest gray scale of each color channel is determined as the target voltage, so that the power consumption of the mobile phone display screen can be reduced while ensuring that all gray scales of each color channel can be displayed.

[0087] The above is an example of the application scenario of the embodiments of the present application, and does not limit the application scenario of the embodiments of the present application. The method provided by the embodiments of the present application can be applied to any terminal device that displays through a display driving circuit.

[0088] For example, referring to Figure 8 , Figure 8 A schematic diagram of a system architecture of a terminal device provided by the embodiments of the present application is shown. The terminal device can be Figure 1 The terminal device 100 shown, or can also be Figures 5 to 7 Any terminal device shown, for example, referring to Figure 8 , the terminal device 200 can include a processor 210, a display component 230 and a display serial interface 250.

[0089] The processor 210 includes a display buffer module 211, a gray scale statistics module 213, a voltage calculation module 215 and a brightness compensation calculation module 217. For example, the display component 230 can include a display panel and a printed circuit board (PCB), and the PCB is provided with a display driving circuit. For example, the display driving circuit can be Figure 4 The display driving circuit shown or other display driving circuit, the display component drives the image data to be displayed on the display panel through the display driving circuit.

[0090] For example, the processor 210 provided by the embodiments of the present application can be a central processing unit (CPU) in the terminal device 200, a graphics processing unit (GPU) or other processor for video or image display.

[0091] For example, the display panel can use LED, miniLED, micro LED, OLED, MicroLED, FOLED and other light emitting devices.

[0092] For example, the above-mentioned gray scale statistics module 213, voltage calculation module 215 and brightness compensation calculation module 217 can be integrated on a system on chip (SOC) of the terminal device 200.

[0093] The display buffer module 211 is configured to store image or video data. The display buffer module 211 can send the image or video data to be displayed to the display component 230 through the display serial interface 250 for display. The display component 230 displays the image to be displayed frame by frame. After the end of a display period, the display component 230 can send a synchronization signal to the processor 210 through the display serial interface 250 to inform the processor 210 to send the next frame of the image to be displayed.

[0094] The gray scale statistics module 213 is configured to determine the maximum gray scale of each color channel of the image to be displayed. The maximum gray scale refers to the maximum value of the gray scale corresponding to each pixel point of a color channel of the image to be displayed. Generally, the gray scale ranges from 0 to 255, and the higher the gray scale, the greater the brightness. Each pixel point includes multiple color channels, and thus the gray scale statistics module 213 can determine the maximum gray scale corresponding to each color channel. The voltage calculation module 215 is configured to determine the minimum operating voltage corresponding to the maximum gray scale of each color channel according to the maximum gray scale corresponding to each color channel. The maximum value of the minimum operating voltage corresponding to each color channel is determined as the target operating voltage. Then, the voltage adjustment amount can be determined according to the target operating voltage and the input voltage of the display driving circuit. The processor 210 sends a control instruction to the display component 230 through the display serial interface 250 to adjust the operating voltage of the display driving circuit to the target operating voltage when the display component 230 displays the image to be displayed.

[0095] The control instruction can include the target operating voltage or the voltage adjustment amount determined according to the difference between the target operating voltage and the input voltage of the display driving circuit. The display component 230 adjusts the power supply voltage of the display driving circuit according to the voltage adjustment amount, so that the voltage difference between the power supply VDD and the power supply VSS reaches the target operating voltage, thereby reducing the power consumption of the display driving circuit.

[0096] In addition, the processor 210 further includes a brightness compensation calculation module 217. The brightness compensation calculation module 217 is configured to calculate a brightness compensation value. In an ideal state, when the driving transistor of the display driving circuit operates in the saturation region, the current flowing through the first electrode and the second electrode of the driving transistor remains constant when the voltage between the first electrode and the second electrode changes. However, the driving transistor cannot reach the ideal state, and the slope of the output characteristic curve of the driving transistor is not 0. Therefore, when the voltage decreases, the saturation current of the driving transistor slightly decreases, which causes the gray scale displayed by the light emitting device to decrease. Therefore, the brightness needs to be compensated to compensate for the loss of gray scale caused by the slope of the output characteristic curve of the driving transistor being not 0.

[0097] Exemplarily, the luminance compensation calculation module 217 can determine the current variation according to the output characteristic curve of the driving transistor, i.e. the corresponding relationship between the output current and the voltage of the driving transistor. For example, when the voltage between the first electrode and the second electrode of the driving transistor is backed from V1 to V2, the current is reduced from I1 to I2, and the difference between the current I1 and the current I2 is the current variation, which will cause the luminance of the light emitting device to decrease, and thus the luminance of the light emitting device needs to be compensated.

[0098] Exemplarily, the current variation herein can be determined as the luminance compensation amount, and the luminance compensation amount is sent to the display component 230 through 250. The display component compensates the luminance of the light emitting device according to the luminance compensation amount, i.e. the current variation of the light emitting device, for example, the duty cycle of the control signal output by the EM terminal of the display driving circuit can be increased.

[0099] Of course, if the driving transistor can reach the ideal state, the slope of the output characteristic curve is 0, then there is no need for luminance compensation, and there is no need to set the luminance compensation calculation module 217.

[0100] Figure 9 A flowchart of the voltage adjustment method provided by the embodiment of the application is shown. The voltage adjustment method provided by the embodiment of the application is applied to a processor of a terminal device. The terminal device further includes a display component, and the display component includes a display driving circuit. The following drawings will introduce the voltage adjustment method provided by the embodiment of the application in detail. Please refer to Figure 9 The voltage adjustment method provided by the embodiment of the application includes:

[0101] S310: Obtain the highest gray scale of each color channel of the image to be displayed.

[0102] S330: Determine the lowest working voltage required by the display driving circuit to display the highest gray scale of each color channel.

[0103] S350: Determine the maximum value in the lowest working voltage required by the display driving circuit to display the highest gray scale of each color channel as the target working voltage of the display driving circuit.

[0104] The conventional display driving circuit works in a fixed voltage mode. Its working voltage can ensure that the lowest gray scale to the highest gray scale can be displayed on each pixel point. For example, if the lowest gray scale is 0 and the highest gray scale is 255, the working voltage of the display driving circuit can make the display driving circuit corresponding to any color of light emitting device can drive the light emitting device to display the gray scale of 0-255.

[0105] Generally, the operating voltage of the display driving circuit is maintained at a high voltage level to ensure that all gray scales can be displayed, but the display content is dynamically changing, for example, the gray scale of the previous frame image is high, and the gray scale of the next frame image is low, and it is possible that the highest gray scale of each pixel point on the image is lower than the highest gray scale that can be displayed by the light emitting device, for example, the highest gray scale that can be displayed by the light emitting device is 255, but the highest gray scale of all pixel points on the image is 200, and the operating voltage of the display driving circuit is still based on the highest gray scale 255, which will cause power waste. Therefore, the scheme provided in the embodiments of the present application first acquires the highest gray scale of each color channel of the to-be-displayed image, and determines the operating voltage of the display driving circuit according to the highest gray scale of each color channel of the to-be-displayed image.

[0106] In addition, because the current-voltage curves of light emitting devices of different colors are different, the corresponding relationship between the gray scale and the driving voltage of light emitting devices of different colors is also different, for example, the required driving voltage of the red light emitting device when displaying the highest gray scale is lower than the required driving voltage of the blue light emitting device when displaying the highest gray scale, and therefore, the scheme provided in the embodiments of the present application first determines the lowest operating voltage required by the display driving circuit to display the highest gray scale of each color channel according to the highest gray scale of each color channel of the to-be-displayed image, and here, each color channel refers to the color channel of the light emitting device, for example, if the image is displayed by the display in RGB mode, then here, the three channels of red, green and blue are referred to, and if the image is displayed by the display in RGBW mode, then here, the four channels of red, green, blue and white are referred to.

[0107] After determining the lowest operating voltage required by the display driving circuit to display the highest gray scale of each color channel, the maximum value in the lowest operating voltage required by the display driving circuit to display the highest gray scale of each color channel is determined as the target operating voltage of the display driving circuit. Because the display driving circuit of each pixel point of the display panel adopts the same input voltage as the operating voltage, for example Figure 4 In the display driving circuit shown, the input voltage of the power supply VDD and the power supply VSS is used as the operating voltage, in order to avoid the situation that part of the display driving circuit cannot normally display because the operating voltage is too low, and therefore, the maximum value in the lowest operating voltage required by each color channel to display the highest gray scale is determined as the target operating voltage of the display driving circuit.

[0108] For example, taking the RGB mode as an example, the highest gray scale of the red channel of the to-be-displayed image is R1, the highest gray scale of the green channel is G1, and the highest gray scale of the blue channel is B1, the lowest operating voltage of the display driving circuit of the red light emitting device when displaying R1 is V R1 , the lowest operating voltage of the display driving circuit of the green light emitting device when displaying G1 is V G1 , and the lowest operating voltage of the display driving circuit of the blue light emitting device when displaying B1 is VB1 The maximum value among V R1 , V G1 and V B1 is determined as the target working voltage of the display driving circuit, so that all gray scales of each color channel of the image to be displayed can be displayed.

[0109] The voltage adjustment method provided by the embodiment of the present application can adjust the working voltage of the display driving circuit according to the gray scale of the image to be displayed. First, the highest gray scale of each color channel of the image to be displayed is determined, and the lowest working voltage required by the display driving circuit to display the highest gray scale of each color channel is determined. Then, the maximum value of the lowest working voltage required by each color channel is taken as the target working voltage of the display driving circuit. In this way, the maximum value of the lowest working voltage required by the highest gray scale of different color channels is taken as the target working voltage of the display driving circuit, which can ensure that all gray scales of the image to be displayed can be normally displayed. On the other hand, the working voltage of the display driving circuit is adjusted according to the gray scale of the image to be displayed, so that the power consumption of the display driving circuit can be reduced when displaying an image with a low gray scale.

[0110] In a possible implementation, the processor is connected with the display component through a display serial interface. After determining the target working voltage of the display driving circuit corresponding to the image to be displayed, the processor sends a control instruction to the display component to adjust the working voltage of the display driving circuit to the target working voltage. Figure 10 The method further includes:

[0111] S360: sending a control instruction to the display component to adjust the working voltage of the display driving circuit to display the image to be displayed to the target working voltage.

[0112] In a possible implementation, the display driving circuit is powered by a power supply VDD and a power supply VSS. The voltage difference between the power supply VDD and the power supply VSS is the working voltage of the display driving circuit.

[0113] The voltage adjustment method provided by the embodiment of the present application can adjust the working voltage of the display driving circuit according to the gray scale of the image to be displayed. Therefore, the processor sends a control instruction to the display component, and the display component adjusts the working voltage of the display driving circuit to the target working voltage according to the control instruction sent by the processor when displaying the corresponding image, so as to reduce the power consumption.

[0114] In a possible implementation, the control instruction sent by the processor can include a voltage adjustment amount, which is the difference between the input voltage of the display driving circuit and the target working voltage.

[0115] In some embodiments, the input voltage of the display driving circuit includes a power supply VDD and a power supply VSS. Since the power supply VDD is a reference voltage commonly used by multiple sub-circuits in the display assembly, including the display driving circuit, the power supply VDD is generally not adjusted. Therefore, when adjusting the operating voltage of the display driving circuit, the voltage of the power supply VSS can be adjusted.

[0116] For example, the power supply VDD is +9V and the power supply VSS is -3V, that is, the operating voltage of the display driving circuit is 12V. If the target operating voltage of the display driving circuit is determined to be 9V according to the gray scale of the image to be displayed, the voltage adjustment amount is 3V. When adjusting the power supply VSS, since the voltage of the power supply VSS is -3V, the voltage of the power supply VSS after adjustment is 0V. Based on the voltage of the power supply VDD being +9V and the voltage of the power supply VSS being 0V, the voltage of the display driving circuit is adjusted to 9V. As a result, the operating voltage is reduced, and the power consumption of the display driving circuit can also be reduced.

[0117] Of course, in some other possible implementations, the control instruction sent by the processor to the display assembly can include a target operating voltage, and the display assembly can adjust the operating voltage of the display driving circuit to the target operating voltage according to the control instruction sent by the processor.

[0118] For example, referring to Figure 11 , there are various ways to obtain the highest gray scale of each color channel of the image to be displayed. For example, S310 can include:

[0119] S310-1: Obtain the gray scale of each color channel of each pixel point of the image to be displayed.

[0120] S310-2: Take the maximum value of the gray scale of the same color channel of all pixel points of the image to be displayed as the highest gray scale of the channel.

[0121] The image to be displayed is composed of multiple pixel points. The gray scale of each color sub-pixel of each pixel point of the image to be displayed can be traversed, and then the maximum value of the gray scale of all sub-pixels of each color is taken as the highest gray scale of the color channel. For example, taking RGB as an example, the maximum value of the gray scale of the red sub-pixel of all pixel points is taken as the highest gray scale of the red channel, the maximum value of the gray scale of the green sub-pixel of all pixel points is taken as the highest gray scale of the green channel, and the maximum value of the gray scale of the blue sub-pixel of all pixel points is taken as the highest gray scale of the blue channel. Thus, the highest gray scales of the red channel, the green channel, and the blue channel are determined.

[0122] In some other possible implementations, the highest gray scale of each color channel can also be determined according to the gray scale histogram of each color of the image to be displayed, as Figure 12 shown in Figure 12A gray scale histogram of a color channel is shown, the horizontal axis represents the gray scale, and the vertical axis represents the number of pixels, according to Figure 12 It can be seen that the highest gray scale of this color channel of the image is 125.

[0123] Alternatively, the highest gray scale of each color channel of the to-be-displayed image can also be determined by pre-processing the to-be-displayed image by a graphics processing unit (GPU), a video decoder, a video processing unit (VPU), etc.

[0124] After obtaining the highest gray scale of each color channel of the to-be-displayed image, the lowest operating voltage required by the display driving circuit to display the highest gray scale of each color channel is determined. For example, refer to Figure 13 , step S330 includes:

[0125] S330-1: According to the pre-stored corresponding relationship between the gray scale of each color of the light emitting device and the driving current, and the corresponding relationship between the driving current and the driving voltage, the driving current and the driving voltage required by the light emitting device to display the highest gray scale of each color channel are determined.

[0126] The foregoing examples have mentioned that the current-voltage relationship curves of light emitting devices of different colors are different. Then, the embodiments of the present application take an OLED display in RGB mode as an example for illustration, in combination with Figures 14 to 16 , Figure 14 The V-I characteristic curve of the red OLED is shown, Figure 15 The V-I characteristic curve of the blue OLED is shown, Figure 16 The V-I characteristic curve of the green OLED is shown.

[0127] The light emitting device provided by the embodiments of the present application is a current-driven light emitting device, that is, the gray scale displayed by the light emitting device is positively correlated with the driving current. When the driving current is maximum, the highest gray scale is displayed, and when the driving current is minimum, the lowest gray scale is displayed. Refer to Figure 14 , the driving current of the red OLED reaches maximum when the driving voltage is about 5V, and the highest gray scale is displayed. However, it should be noted that the highest gray scale referred to here refers to the highest gray scale that can be displayed by the light emitting device, and not the highest gray scale of the to-be-displayed image. For example, the highest gray scale that can be displayed by the red OLED is 255, and in combination with Figure 14 , the red OLED displays the highest gray scale 255 when the driving voltage is about 5V, and in combination with Figure 15 , the blue OLED displays the highest gray scale 255 when the driving voltage is close to 5V, and in combination with Figure 16, the green OLED can only display the highest gray scale 255 when the driving voltage is more than 6V. Therefore, in the case of displaying the same gray scale (for example, 255), the driving current or driving voltage required by different light emitting devices is different. If the driving voltage is about 5V, the red OLED and the blue OLED can display the highest gray scale, but the green OLED cannot display the highest gray scale due to the low driving voltage. Therefore, the lowest working voltage of the light emitting device of each color channel needs to be determined according to the highest gray scale of each color channel, and the maximum value is taken as the target working voltage of the whole display driving circuit.

[0128] It has been mentioned in the foregoing examples that the working voltage of the display driving circuit is composed of the sum of the voltage on the light emitting device and the driving transistor. Therefore, first, after obtaining the highest gray scale of each color channel of the image to be displayed, the driving current and driving voltage required by the light emitting device to display the highest gray scale of each color channel are determined.

[0129] For example, the driving current and driving voltage required by the light emitting device to display the highest gray scale of each color channel can be determined according to the pre-stored corresponding relationship between the gray scale and the driving current and the corresponding relationship between the driving current and the driving voltage.

[0130] For example, in a possible implementation, the corresponding relationship between the gray scale displayed by the light emitting device and the driving current and the corresponding relationship between the driving current and the driving voltage can be stored in the form of a table. After obtaining the highest gray scale of each color channel of the image to be displayed, the driving current and driving voltage required by the light emitting device to display the highest gray scale of each color channel can be obtained by looking up the table.

[0131] Taking the OLED as an example, the corresponding relationship between the gray scale and the driving current of different color OLEDs is determined after the production of the OLED, and the relationship between the driving current and the voltage of different color OLEDs, or the V-I characteristic, is also determined. For example, in a possible implementation, the corresponding relationship between the gray scale displayed by the red OLED and the driving current and the driving voltage can be stored in the form of Table 1. If the highest gray scale of the red channel of the image to be displayed is 200, the driving current and driving voltage of the red light emitting device when the gray scale is 200 can be determined according to the corresponding relationship between the gray scale and the driving current and the corresponding relationship between the driving current and the driving voltage shown in Table 1.

[0132] Table 1

[0133]

[0134] The correspondence relationship between the gray scale of the OLED and the working parameters such as the driving current and the driving voltage can also be stored in other forms, and the embodiments of the present application do not limit this. After obtaining the highest gray scale of each color channel of the to-be-displayed image, the driving current and the driving voltage required by the light-emitting device to display the highest gray scale of each color channel are determined respectively.

[0135] S330-3: According to the correspondence relationship between the current and the voltage of the driving transistor stored in advance, the minimum saturation voltage of the driving transistor when outputting the driving current is determined.

[0136] S330-5: The sum of the driving voltage required by the light-emitting device to display the highest gray scale of each color channel and the minimum saturation voltage is determined as the minimum working voltage required to display the highest gray scale of the channel.

[0137] The foregoing examples have mentioned that the driving transistor works in the saturation region, so as to output a stable saturation current as the driving current of the light-emitting device.

[0138] In combination with the current-voltage relationship curve of the driving transistor working in the saturation region shown in the foregoing examples, Figure 3 When the driving transistor works in the saturation region, the drain current I D does not change with the drain-source voltage V DS , and does not change. The drain current I D only changes with the gate-source voltage V GS of the driving transistor. That is, in the case where the driving current of the light-emitting device is maintained stable and unchanged, the voltage division on the driving transistor can be increased or decreased, as long as the driving transistor still works in the saturation region, and the change of the voltage division on the driving transistor will not affect the working of the light-emitting device.

[0139] Since the driving transistor and the light-emitting device are connected in series between the power supply VDD and the power supply VSS, when the voltage division of the light-emitting device increases, the voltage division on the driving transistor decreases. Taking the red OLED as an example, when the light-emitting device displays the highest gray scale of the red channel of the to-be-displayed image, the driving voltage of the light-emitting device reaches the maximum, and the voltage division of the driving transistor is the minimum. When the gray scale displayed by the light-emitting device decreases, the driving voltage of the light-emitting device will decrease, and the voltage division of the driving transistor will increase. As long as it is ensured that the driving transistor still works in the saturation region when the light-emitting device displays the highest gray scale of the red channel of the to-be-displayed image, that is, the voltage division of the driving transistor is the minimum, the driving transistor can work in the saturation region in the case where the light-emitting device displays any gray scale of the red channel of any to-be-displayed image.

[0140] In other words, as long as the driving transistor can work in the saturation region when the light emitting device displays the highest gray scale, the driving transistor will keep working in the saturation region when the light emitting device displays any gray scale. In order to reduce the power consumption of the display driving circuit, the lowest saturation voltage of the driving transistor when outputting the driving current required by the light emitting device to display the highest gray scale of each color channel is determined.

[0141] For example, in the embodiment of the present application, the lowest saturation voltage refers to the lowest voltage of the driving transistor when working in the saturation region and outputting the driving current required by the light emitting device to display the highest gray scale. For example, in combination with the above example Figure 17 For example, if the driving current required by the light emitting device to display the highest gray scale is 100 mA, when the drain-source voltage of the driving transistor is V4, the drain current output by the driving transistor is 100 mA, and the light emitting device can display the highest gray scale; when the drain-source voltage of the driving transistor is V3, because the driving transistor works in the saturation region, the drain current does not change or changes very little when the drain-source voltage decreases, the drain current output by the driving transistor is still 100 mA, and the light emitting device can still display the highest gray scale. In the case that the light emitting device displays the highest gray scale, the driving current and the driving voltage remain unchanged, and the power consumption does not change, but the source-drain voltage of the driving transistor can be V3 or V4, and V4>V3. It can be imagined that in the case that the output current remains unchanged, the greater the voltage, the greater the power consumption of the driving transistor. Therefore, in order to reduce the power consumption, the voltage drop of the driving transistor is reduced to the lowest voltage in the saturation region when the light emitting device displays the highest gray scale, that is, the lowest saturation voltage proposed in the embodiment of the present application. In this way, the driving current of the light emitting device remains unchanged, the driving voltage remains unchanged, the voltage drop of the driving transistor is reduced to the lowest saturation voltage, the sum of the driving voltage of the light emitting device and the lowest saturation voltage of the driving transistor, that is, the working voltage of the display driving circuit, reaches the lowest state. The sum of the driving voltage of the light emitting device and the lowest saturation voltage of the driving transistor when the driving current required by the light emitting device to display the highest gray scale of the red, green and blue channels is determined as the target working voltage of the display driving circuit. In this way, in the case that the gray scale of the image to be displayed is low, the target working voltage of the display driving circuit will also be low, and the power consumption of the display driving circuit can be reduced.

[0142] In addition, because the adjustment of the working voltage of the display driving circuit has little effect on the current of the light emitting device, and in general, the adjustment speed can reach more than 60 frames per second, the problem of display flicker will not occur.

[0143] For example, taking the OLED display in RGB mode as an example, after determining the lowest saturation voltage of the driving transistor when outputting the driving current required for the display to display the highest gray scale of each color channel, the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the red channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the red channel; the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the green channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the green channel; and the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the blue channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the blue channel.

[0144] In addition, since the highest gray scale of each color channel of the image to be displayed can be different, for example, the image to be displayed is overall yellowish, so the highest gray scale of the red and green channels can be higher, and the highest gray scale of the blue channel can be lower, for example, the highest gray scale of the red channel is 255, the highest gray scale of the green channel is 255, and the highest gray scale of the blue channel is 10; if the image to be displayed is overall grayish, the highest gray scales of the red, green, and blue channels can be close, for example, all are 123; and the foregoing examples have mentioned that the corresponding relationship of the gray scale-current-voltage of the light-emitting devices of different colors is different. All the light-emitting devices share the same working voltage, so when selecting the target working voltage, the maximum value of the lowest working voltage required for the highest gray scale of each color channel should be determined as the target working voltage of the display driving circuit, and the working voltage of the color channel with the highest gray scale cannot be selected as the target working voltage.

[0145] For example, in combination with Figures 14 to 16 For example, taking the OLED display in RGB mode as an example, after determining the lowest saturation voltage of the driving transistor when outputting the driving current required for the display to display the highest gray scale of each color channel, the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the red channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the red channel; the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the green channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the green channel; and the sum of the driving voltage of the light-emitting device when displaying the highest gray scale of the blue channel and the lowest saturation voltage of the driving transistor is determined as the lowest working voltage required for the display driving circuit to display the highest gray scale of the blue channel.

[0146] Since the minimum operating voltage required for the green light emitting device to display the blue gray scale 240 is greater than the minimum operating voltage required for the red light emitting device to display the gray scale 255, if the minimum operating voltage required for the red light emitting device to display the gray scale 255 is taken as the target operating voltage, the green light emitting device cannot display the green gray scale 240. Therefore, in the embodiment of the present application, after the minimum operating voltage required for the display driving circuit to display the highest gray scale of each color channel is determined, the maximum value of the minimum operating voltage required for each color channel to display the highest gray scale is determined as the target operating voltage of the display driving circuit, so that each gray scale of each color channel of the image to be displayed can be normally displayed.

[0147] In an ideal state, when the driving transistor works in the saturation region, the drain current does not change when the drain-source voltage changes. If the horizontal axis represents the drain-source voltage and the vertical axis represents the drain current in the current-voltage relationship curve diagram, the drain current curve of the transistor in the saturation region should be parallel to the horizontal axis in an ideal case.

[0148] However, in some cases, the driving transistor cannot reach the ideal state, and the curve of the drain current has a certain slope. Therefore, when the drain-source voltage of the driving transistor is adjusted to the minimum saturation voltage, the drain current may change, that is, the driving current of the light emitting device changes, which may cause abnormal display of the gray scale of the light emitting device. For example, if the drain current of the driving transistor decreases, the driving current of the light emitting device decreases, and the gray scale displayed by the light emitting device also decreases.

[0149] Therefore, in the case where the driving transistor cannot reach the ideal state, the brightness of the light emitting device needs to be compensated. Since the drain current of the driving transistor decreases when the drain-source voltage of the driving transistor is adjusted to the minimum saturation voltage, the driving current of the light emitting device decreases, and the gray scale loss caused by the decrease of the driving current of the light emitting device needs to be compensated.

[0150] It should be understood that, in some possible implementations, the processor sends a control instruction to the display component to adjust the operating voltage of the display driving circuit to the target operating voltage. Here, the voltage adjustment amount is mainly caused by the setting of the drain-source voltage of the driving transistor to the minimum saturation voltage. Generally, the driving current and the driving voltage of the light emitting device do not change when the operating voltage of the display driving circuit is adjusted, but the drain current output by the driving transistor decreases when the drain-source voltage of the driving transistor is adjusted to the minimum saturation voltage. The brightness compensation can also be considered as compensation for the gray scale loss of the light emitting device caused by the decrease of the drain current output by the driving transistor.

[0151] For example, referring to Figure 18The voltage adjusting method provided by the embodiments of the present application further comprises:

[0152] S370: determining a current variation of the driving transistor according to the voltage adjustment and the pre-stored corresponding relationship between the current and the voltage of the driving transistor.

[0153] S380: determining a brightness compensation according to the current variation of the driving transistor.

[0154] In the foregoing example, in order to reduce the power consumption, the voltage of the driving transistor is adjusted to the lowest saturation voltage, but the driving transistor may not reach the ideal state, so that the reduction of the voltage of the driving transistor will cause the output current to also be reduced. In a possible implementation, the current variation of the driving transistor can be determined according to the voltage variation of the driving transistor and the pre-stored corresponding relationship between the current and the voltage of the driving transistor, wherein the voltage adjustment is the difference between the input voltage of the display driving circuit and the target working voltage. Since the target working voltage of the display driving circuit is mainly the variation caused by the adjustment of the drain-source voltage of the driving transistor to the lowest saturation voltage, the adjustment of the working voltage of the display driving circuit can be approximately equal to the variation of the drain-source voltage of the driving transistor. Therefore, based on the voltage adjustment and the pre-stored corresponding relationship between the current and the voltage of the driving transistor, the current variation ΔI of the driving transistor can be determined.

[0155] For example, the driving transistor is a PMOS transistor, and the voltage adjustment is the difference between the input voltage of the display driving circuit and the target working voltage. Figure 17 When the voltage of the driving transistor is reduced from V1 to V2, the output current of the driving transistor is reduced from I1 to I2, and the current variation ΔI is I1-I2.

[0156] In a possible implementation, after the voltage variation of the driving transistor is determined, the current variation can be calculated according to the slope of the current-voltage curve of the driving transistor.

[0157] For example, the slope of the current-voltage curve of the driving transistor is k, and the voltage adjustment is ΔV, so that ΔI=k*ΔV.

[0158] After the current variation of the driving transistor is determined, the brightness compensation is determined according to the current variation of the driving transistor. In a possible implementation, the current variation can be determined as the brightness compensation, and in other possible implementations, the current variation can also be converted into the brightness compensation according to a set rule.

[0159] For example, the display assembly performs the brightness compensation by controlling the duty cycle of the EM signal of the display driving circuit. For example, the current of the driving transistor is reduced by 5%, so that when the brightness compensation is performed, the display assembly can increase the duty cycle of the EM signal by 5%.

[0160] After the luminance compensation amount is determined, the voltage adjustment method further includes:

[0161] S390: sending the luminance compensation amount to the display component.

[0162] In an example, the luminance compensation amount is sent to the display component, and the display component compensates the luminance displayed by the light emitting device according to the luminance compensation amount.

[0163] In the above examples, the display mode is the RGM mode, and thus the highest gray scale of the red, green, and blue channels of the image to be displayed is determined first, and then the lowest working voltage required by the display driving circuit to display the highest gray scale of each color is determined, and the maximum value of the lowest working voltage corresponding to each color is taken as the target working voltage. The working voltage of the display driving circuit is adjusted by the target working voltage when displaying the image to be displayed. In this way, when the highest gray scale of the image to be displayed is lower than the highest gray scale that can be displayed by the light emitting device, the power consumption of the display driving circuit can be reduced, and the power consumption of the entire display screen or display component is reduced. In some other possible implementations, the display component can also display in other modes, such as the RGBW mode. Thus, the target working voltage of the display driving circuit needs to be determined according to the highest gray scale of the red, green, blue, and white channels of the display image, or the display component can also display in another mode, which is not limited in the embodiments of the present application.

[0164] The embodiments of the present application also provide a chip, which is applied to a terminal device, for example, can be applied to Figure 1 , or Figures 5 to 8 any terminal device shown in the present application, wherein the chip includes one or more processors, and the processor is used to execute computer program instructions, so that the terminal device executes the voltage adjustment method provided by the foregoing embodiments of the present application.

[0165] The embodiments of the present application also provide a computer readable storage medium, which stores a computer program, and the computer program is executed by the processor of the terminal device, so that the terminal device executes the voltage adjustment method provided by the foregoing embodiments of the present application.

[0166] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A voltage regulation method, characterized in that, A processor applied to a terminal device, the terminal device further comprising a display component, the display component including a display driving circuit, the display driving circuit including a driving transistor and a light-emitting device, the driving transistor being used to provide driving current to the light-emitting device, the method comprising: Obtain the highest grayscale value for each color channel of the image to be displayed; Determine the minimum operating voltage required for the display driver circuit to display the highest grayscale for each of the color channels; The maximum value among the minimum operating voltages required for the display driving circuit to display the highest grayscale of each of the color channels is determined as the target operating voltage of the display driving circuit; Wherein, determining the minimum operating voltage required for the display driving circuit to display the highest grayscale for each of the color channels includes: Based on the pre-stored correspondence between the grayscale and driving current of the light-emitting device for each color, and the correspondence between driving current and driving voltage, determine the driving current and driving voltage required for the light-emitting device to display the highest grayscale of each color channel. Based on the pre-stored correspondence between the current and voltage of the driving transistor, determine the minimum saturation voltage at which the driving transistor outputs the driving current; The sum of the driving voltage and the lowest saturation voltage required for the light-emitting device to display the highest grayscale of each color channel is determined as the minimum operating voltage required to display the highest grayscale of the color channel; The step of determining the minimum saturation voltage of the driving transistor when it outputs the driving current, based on a pre-stored correspondence between the current and voltage of the driving transistor, includes: Based on the pre-stored correspondence between the current and voltage of the driving transistor, when the driving transistor is operating in the saturation region, the lowest voltage corresponding to the driving current is determined as the lowest saturation voltage of the driving transistor.

2. The voltage regulation method according to claim 1, characterized in that, The method further includes: A control command is sent to the display component to adjust the operating voltage of the display driving circuit for displaying the image to be displayed to the target operating voltage.

3. The voltage regulation method according to claim 2, characterized in that, The control command includes a voltage adjustment amount, which is the difference between the input voltage of the display driving circuit and the target operating voltage; or, the control command includes the target operating voltage.

4. The voltage regulation method according to any one of claims 1 to 3, characterized in that, The method further includes: The change in current of the driving transistor is determined based on the voltage adjustment amount and the pre-stored correspondence between the current and voltage of the driving transistor; the voltage adjustment amount is the difference between the input voltage of the display driving circuit and the target operating voltage. The brightness compensation amount is determined based on the current change. The brightness compensation amount is sent to the display component.

5. The voltage regulation method according to claim 1, characterized in that, The process of obtaining the highest grayscale of each color channel of the image to be displayed includes: Obtain the grayscale of each color channel for each pixel in the image to be displayed; The maximum gray level of the same color channel of all pixels in the image to be displayed is taken as the highest gray level of that channel.

6. A terminal device, characterized in that, include: A display component and one or more processors, the processors being connected to the display component, the display component including a display driving circuit; The processor is used to execute computer program instructions to implement the voltage regulation method as described in any one of claims 1 to 5.

7. A chip, characterized in that, The chip is applied to a terminal device, and the chip includes one or more processors, the processors being configured to execute computer program instructions to cause the terminal device to perform the voltage regulation method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, causes a terminal device to perform the method as described in any one of claims 1 to 5.

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