Source driving chip, display device and bias current adjusting method thereof

Abstract

The invention provides a source electrode driving chip, a display device and a bias current adjusting method of the display device. The source electrode driving chip comprises an equalizer, a clock and data recovery circuit and a bias current adjusting circuit, the input end of the equalizer is configured to receive differential signals, the clock and data recovery circuit is electrically connected with the output end of the equalizer, and the input end of the bias current adjusting circuit is electrically connected with the output end of the equalizer; the output end of the bias current adjusting circuit is electrically connected with the clock and data recovery circuit, and the bias current adjusting circuit is configured to detect the swing variation of the differential signal and adjust the target bias current output to the clock and data recovery circuit according to the swing variation. Linkage adjustment of the differential signal swing and the bias current is realized through the bias current adjustment circuit, the anti-interference capability of the source electrode driving chip is improved, the power consumption is optimized, and the manufacturing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a source driver chip, a display device, and a method for adjusting the bias current thereon. Background Technology

[0002] In display devices, the timing controller and the source driver chip transmit data via differential signals, which are differential signals embedded in the clock signal. During signal transmission, the differential signals are susceptible to external interference, leading to a deterioration in signal transmission quality.

[0003] With advancements in semiconductor manufacturing technology, the process node for timing controllers has been upgraded from 55 nanometers to 22 nanometers or lower, resulting in a corresponding reduction in the core voltage of the timing controller. Since the sum of the differential signal swing voltage and the common-mode voltage of the differential signal is limited by the core voltage, the swing adjustment range of the differential signal output by the timing controller is restricted, leading to lower anti-interference capabilities in the display device.

[0004] Therefore, it is necessary to propose a new technical solution to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a source driver chip, a display device, and a method for adjusting the bias current thereto, in order to solve the technical problem of low anti-interference capability of display devices in the prior art.

[0006] This application provides a source driver chip, comprising: an equalizer, the input of which is configured to receive a differential signal; a clock and data recovery circuit electrically connected to the output of the equalizer; and a bias current adjustment circuit, the input of which is electrically connected to the output of the equalizer, and the output of which is electrically connected to the clock and data recovery circuit; wherein the bias current adjustment circuit is configured to detect the swing change of the differential signal and adjust the target bias current output to the clock and data recovery circuit according to the swing change.

[0007] In the aforementioned source driver chip, the bias current adjustment circuit is configured to superimpose the bias current increment corresponding to the swing change with a preset bias current value to obtain the target bias current.

[0008] In the aforementioned source driver chip, when the swing change is zero, the target bias current is equal to the preset bias current value.

[0009] In the aforementioned source driver chip, when the swing change is greater than zero, the target bias current is greater than the preset bias current value.

[0010] In the aforementioned source driver chip, the bias current adjustment circuit is configured to increase the target bias current when the swing of the differential signal increases, and to restore the target bias current to a preset bias current value when the swing of the differential signal returns to the default swing value.

[0011] In the aforementioned source driver chip, the bias current adjustment circuit includes: a first constant current source configured to provide a preset bias current value; a second constant current source configured to provide the bias current increment; a transistor, the gate of which is electrically connected to a control signal input terminal, one of the source and drain of which is electrically connected to the first and second constant current sources, and the other of the source and drain of which is electrically connected to a target bias current output terminal; and a sampling resistor electrically connected between the other of the source and drain of which is the transistor and a ground terminal.

[0012] This application also provides a display device, comprising: a timing controller configured to output a differential signal; and the aforementioned source driver chip, electrically connected to the timing controller, for receiving the differential signal.

[0013] In the aforementioned display device, the timing controller is configured to adjust the swing of the differential signal when the differential signal is detected to be out of lock.

[0014] In the aforementioned display device, the source driver chip is configured to feed back a lockout indication signal to the timing controller after receiving the differential signal indicating a lockout state.

[0015] This application also provides a method for adjusting the bias current of a source driver chip, comprising: an equalizer receiving a differential signal; a bias current adjustment circuit detecting the swing change of the differential signal; the bias current adjustment circuit adjusting a target bias current according to the swing change; and the bias current adjustment circuit outputting the target bias current to a clock and data recovery circuit.

[0016] In the above-mentioned bias current adjustment method for the source driver chip, the bias current adjustment circuit adjusts the target bias current according to the swing change, which includes: the bias current adjustment circuit superimposing the bias current increment corresponding to the swing change with a preset bias current value to obtain the target bias current.

[0017] In the above-mentioned bias current adjustment method for the source driver chip, when the swing change is zero, the target bias current is equal to the preset bias current value.

[0018] In the above-mentioned bias current adjustment method for the source driver chip, when the swing change is greater than zero, the target bias current is greater than the preset bias current value.

[0019] In the above-mentioned bias current adjustment method for the source driver chip, the bias current adjustment circuit adjusts the target bias current according to the swing change, including: the bias current adjustment circuit increases the target bias current when the swing of the differential signal increases; the bias current adjustment circuit restores the target bias current to a preset bias current value when the swing of the differential signal recovers to the default swing value.

[0020] In the above-mentioned bias current adjustment method for the source driver chip, adjusting the target bias current according to the swing change includes: the transistor receiving a preset bias current value provided by a first constant current source and the bias current increment provided by a second constant current source; the transistor superimposing the preset bias current value and the bias current increment to obtain the target bias current.

[0021] This application also provides a method for adjusting the bias current of a display device, comprising: a timing controller outputting a differential signal to a source driver chip; the source driver chip receiving the differential signal; the source driver chip detecting the swing change of the differential signal; the source driver chip adjusting a target bias current according to the swing change; and the source driver chip outputting the target bias current to a clock and data recovery circuit.

[0022] The bias current adjustment method for the above-mentioned display device further includes: the source driver chip detecting whether the differential signal is out of lock; when the differential signal is detected to be out of lock, the timing controller adjusting the swing of the differential signal.

[0023] In the above-mentioned bias current adjustment method for the display device, the source driver chip detecting whether the differential signal is out of lock includes: after receiving the differential signal in an out-of-lock state, the source driver chip feeds back an out-of-lock indication signal to the timing controller.

[0024] In the above-mentioned bias current adjustment method for the display device, the source driver chip adjusts the target bias current according to the swing change, which includes: the source driver chip superimposing the bias current increment corresponding to the swing change with a preset bias current value to obtain the target bias current.

[0025] In the above-mentioned bias current adjustment method for the display device, the source driver chip adjusting the target bias current according to the swing change includes: the source driver chip increasing the target bias current when the swing of the differential signal increases; and the source driver chip restoring the target bias current to a preset bias current value when the swing of the differential signal returns to the default swing value.

[0026] The source driver chip, display device, and bias current adjustment method provided in the embodiments of this application provide a bias current adjustment circuit in the source driver chip. The input terminal of the bias current adjustment circuit is electrically connected to the output terminal of the equalizer, and the output terminal of the bias current adjustment circuit is electrically connected to the clock and data recovery circuit. The bias current adjustment circuit detects the swing change of the differential signal and adjusts the target bias current output to the clock and data recovery circuit according to the swing change. When the differential signal is subjected to external interference during transmission, the timing controller triggers the automatic swing adjustment function, increasing the swing of the differential signal until the swing change is greater than zero. The bias current adjustment circuit detects this swing change and adds the corresponding increase in bias current to a preset bias current value to obtain a target bias current greater than the preset bias current value. This target bias current is then output to the clock and data recovery circuit. Driven by the larger target bias current, the clock and data recovery circuit's driving capability is enhanced, improving its ability to recover the differential signal. This improves the source driver chip's anti-interference capability against differential signals, thereby enhancing the anti-interference performance of the display device during mobile terminal anti-interference testing or consumer use. After the external interference disappears, the differential signal swing returns to its default value, with zero swing change. The bias current adjustment circuit then restores the target bias current to the preset bias current value, preventing the clock and data recovery circuit from continuously operating in high-current mode and reducing the power consumption of the source driver chip.

[0027] The technical solution provided in this application achieves coordinated adjustment of the differential signal swing and the bias current of the clock and data recovery circuit through a bias current adjustment circuit. When the differential signal is interfered with, the bias current is adaptively increased; after the interference disappears, the bias current is adaptively restored, thereby improving anti-interference capability while optimizing power consumption. Due to the improved anti-interference capability of the source driver chip, the display device's reliance on absorbing materials is reduced during mobile terminal anti-interference testing or consumer use, thus reducing the amount of absorbing materials used and lowering the manufacturing cost of the display device.

[0028] The technical solution provided by the embodiments of this application addresses the technical problem that the core voltage decreases and the differential signal swing adjustment range is limited due to the advancement of the timing controller process node. By adding a bias current adjustment circuit on the source driver chip side, the signal recovery capability is enhanced from the receiving end, making up for the deficiency of the limited swing adjustment range at the transmitting end, and improving the overall anti-interference performance of the display device. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a display device provided in an embodiment of this application.

[0030] Figure 2 This is a circuit diagram of the source driver chip provided in an embodiment of this application.

[0031] Figure 3 yes Figure 1 The display device shown or Figure 2 The diagram shows a differential signal in a source driver chip.

[0032] Figure 4 yes Figure 2 The circuit diagram shown is of the bias current adjustment circuit in the source driver chip. Detailed Implementation

[0033] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0034] The terms “first,” “second,” and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms “multiple,” and similar words mean two or more, unless otherwise expressly specified.

[0035] The technical solutions of different embodiments of this application can be combined with each other.

[0036] The display device provided in the embodiments of this application may be, for example, a liquid crystal display device or an organic light-emitting diode display device. The following description will use a liquid crystal display device as the example display device.

[0037] like Figure 1 As shown, the liquid crystal display device includes a timing controller, a gate driving circuit, a source driving chip, a gate line (SCAN), a data line (DATA), and pixel units (PX). The timing controller is electrically connected to the source driving chip, and transmits a differential signal to the source driving chip, such as... Figure 3As shown. The gate drive circuit is electrically connected to the gate line SCAN, and outputs a gate scan signal to the gate line SCAN. The source drive chip is electrically connected to the data line DATA, and outputs a data signal to the data line DATA. The pixel unit PX is located at the intersection of the gate line SCAN and the data line DATA. The pixel unit PX receives the gate scan signal and the data signal to realize image display.

[0038] In display devices, the timing controller and the source driver chip transmit data via differential signals. These differential signals are embedded clock signals and are point-to-point (P2P) differential signals. During mobile terminal anti-interference testing or consumer use, the differential signals are susceptible to external electromagnetic interference during transmission from the timing controller to the source driver chip. When the differential signal is interfered with, a lost-lock status flag signal carried in the differential signal indicates a lost-lock state. Upon receiving this lost-lock status differential signal, the source driver chip sends a lost-lock indication signal back to the timing controller. Upon detecting the lost-lock indication signal, the timing controller triggers an automatic swing adjustment function, increasing the swing of the differential signal to improve its anti-interference capability. After the differential signal is no longer interfered with, the timing controller restores the swing of the differential signal to its default value.

[0039] With advancements in semiconductor manufacturing technology, the process node for timing controllers has been reduced from 55 nanometers to 22 nanometers or lower, resulting in a corresponding decrease in the core voltage of the timing controller. The sum of the differential signal swing voltage and the differential signal common-mode voltage is less than or equal to the core voltage of the timing controller. This reduction in the core voltage limits the range of differential signal swing adjustment, thus limiting the ability to improve the anti-interference capability of the display device during mobile terminal anti-interference testing or consumer use by adjusting the differential signal swing.

[0040] like Figure 2 As shown, an embodiment of this application provides a source driver chip, which includes an equalizer, a clock and data recovery circuit, and a bias current adjustment circuit. The input of the equalizer is configured to receive a differential signal. The equalizer performs equalization processing on the received differential signal to compensate for distortion during transmission. The clock and data recovery circuit is electrically connected to the output of the equalizer and recovers the clock and data signals from the differential signal output by the equalizer. The input of the bias current adjustment circuit is electrically connected to the output of the equalizer, and the output of the bias current adjustment circuit is electrically connected to the clock and data recovery circuit. The bias current adjustment circuit detects the swing change ΔSwing of the differential signal and adjusts the target bias current output to the clock and data recovery circuit according to the swing change ΔSwing.

[0041] The bias current adjustment circuit continuously monitors the amplitude change ΔSwing of the differential signal. It detects the current amplitude value of the differential signal and compares it with the default amplitude value to obtain the amplitude change ΔSwing. When the differential signal is not subjected to external interference during transmission, the current amplitude value equals the default amplitude value, and the amplitude change ΔSwing is zero. When the differential signal is subjected to external interference during transmission, the timing controller triggers the automatic amplitude adjustment function, increasing the amplitude of the differential signal. The current amplitude value of the differential signal then exceeds the default amplitude value, and the amplitude change ΔSwing is greater than zero.

[0042] The bias current adjustment circuit adjusts the target bias current based on the swing change ΔSwing. The bias current adjustment circuit then adjusts the bias current increment I corresponding to the swing change ΔSwing. Bias_△Swing With the preset bias current value I Bias_Default The target bias current is obtained by superimposing the results. When the swing change ΔSwing is zero, the bias current increment I... Bias_△Swing The target bias current is zero, and the target bias current is equal to the preset bias current value I. Bias_Default When the swing change ΔSwing is greater than zero, the bias current increment I Bias_△Swing The target bias current is greater than zero and equal to the preset bias current value I. Bias_Default With bias current increment I Bias_△Swing The sum of these values ​​indicates that the target bias current is greater than the preset bias current value I. Bias_Default The bias current adjustment circuit increases the target bias current when the amplitude of the differential signal increases. The circuit increases the bias current according to the magnitude of the increase in the differential signal amplitude. When the amplitude of the differential signal returns to the default amplitude value, the circuit restores the target bias current to the preset bias current value I. Bias_Default .

[0043] The target bias current is used to bias the clock and data recovery circuit, which operates under the drive of this current. The anti-interference capability of the clock and data recovery circuit in the source driver chip increases with the increase of the target bias current. A larger target bias current results in a stronger driving capability of the clock and data recovery circuit, a stronger recovery capability for differential signals, and a stronger anti-interference capability for differential signals from the source driver chip. However, the power consumption of the source driver chip also increases accordingly. When the differential signal is subjected to external interference during transmission, the swing change ΔSwing is greater than zero, and the target bias current is greater than the preset bias current value I. Bias_DefaultUnder the influence of a larger target bias current, the clock and data recovery circuits exhibit enhanced driving capability and improved differential signal recovery, while the source driver chip's anti-interference capability for differential signals is enhanced. After external interference disappears, the differential signal swing returns to its default value, the swing change ΔSwing becomes zero, and the target bias current returns to the preset bias current value I. Bias_Default The clock and data recovery circuit operates at a preset bias current value I. Bias_Default It operates under the drive of the source driver chip, avoiding continuous operation of the clock and data recovery circuits in high current mode, thus reducing the power consumption of the source driver chip.

[0044] In one embodiment, such as Figure 4 As shown, the bias current adjustment circuit includes a first constant current source, a second constant current source, a transistor M1, and a sampling resistor R. The first constant current source is configured to provide a preset bias current value I. Bias_Default The second constant current source is configured to provide the bias current increment I. Bias_△Swing The gate of transistor M1 is electrically connected to the control signal input terminal Vin. One of the sources and drains of transistor M1 is electrically connected to the first and second constant current sources. The other of the sources and drains of transistor M1 is electrically connected to the target bias current output terminal Vout. The sampling resistor R is electrically connected between the other of the sources and drains of transistor M1 and the ground terminal.

[0045] Transistor M1 is a field-effect transistor. The gate of transistor M1 is electrically connected to the control signal input terminal Vin, which receives the differential signal output from the equalizer. The control signal originates from the equalizer's output terminal. A first constant current source and a second constant current source are connected in parallel. The output terminals of the first and second constant current sources are electrically connected to one of the source and drain terminals of transistor M1, providing a total bias current to either the source or drain of transistor M1. The source of transistor M1 is electrically connected to ground through a sampling resistor R. The target bias current output terminal Vout is electrically connected to the source of transistor M1. Vout is also electrically connected to the other end of the sampling resistor R opposite to the end electrically connected to ground. The target bias current output terminal Vout outputs the target bias current to the clock and data recovery circuit from the connection point between the source of transistor M1 and the other end of the sampling resistor R opposite to the end electrically connected to ground.

[0046] The preset bias current value I provided by the first constant current source Bias_Default The bias current increment I provided by the second constant current source is a constant value. Bias_△Swing Adjustments are made based on the amplitude change ΔSwing of the differential signal. When the amplitude change ΔSwing of the differential signal is zero, the bias current increment I provided by the second constant current source... Bias_△SwingWhen the current is zero, the total bias current received by either the source or drain of transistor M1 is equal to the preset bias current value I provided by the first constant current source. Bias_Default The target bias current output at the target bias current output terminal Vout is equal to the preset bias current value I. Bias_Default When the amplitude change ΔSwing of the differential signal is greater than zero, the bias current increment I provided by the second constant current source... Bias_△Swing If the bias current is greater than zero, the total bias current received by either the source or drain of transistor M1 is equal to the preset bias current value I provided by the first constant current source. Bias_Default With the bias current increment I provided by the second constant current source Bias_△Swing The sum of these values ​​means that the target bias current output at the target bias current output terminal Vout is equal to the preset bias current value I. Bias_Default With bias current increment I Bias_△Swing sum.

[0047] The sampling resistor R is used to detect the current flowing through transistor M1. The voltage across the sampling resistor R is proportional to the current flowing through transistor M1. By detecting the voltage across the sampling resistor R, the current flowing through transistor M1 is obtained, thus obtaining the target bias current. The sampling resistor R is also used for source / drain degradation negative feedback. The bias current adjustment circuit adjusts the bias current increment I provided by the second constant current source according to the voltage across the sampling resistor R. Bias_△Swing This enables closed-loop control of the target bias current.

[0048] In one embodiment, the bias current adjustment circuit further includes a comparator and a control logic circuit. The first input terminal of the comparator is electrically connected to the other end of the sampling resistor R opposite to the end electrically connected to ground. The second input terminal of the comparator receives a reference voltage, and the output terminal of the comparator is electrically connected to the input terminal of the control logic circuit. The comparator compares the voltage across the sampling resistor R with the reference voltage and outputs the comparison result to the control logic circuit. The control logic circuit adjusts the bias current increment I provided by the second constant current source according to the comparison result. Bias_△Swing When the voltage across the sampling resistor R is less than the reference voltage, the control logic circuit controls the second constant current source to increase the bias current increment I. Bias_△Swing When the voltage across the sampling resistor R is greater than the reference voltage, the control logic circuit controls the second constant current source to reduce the bias current increment I. Bias_△Swing When the voltage across the sampling resistor R equals the reference voltage, the control logic circuit controls the second constant current source to maintain the bias current increment I. Bias_△Swing constant.

[0049] In one embodiment, the bias current adjustment circuit further includes a swing detection circuit. The input of the swing detection circuit is electrically connected to the output of the equalizer, and the output of the swing detection circuit is electrically connected to the input of the control logic circuit. The swing detection circuit detects the current swing value of the differential signal, compares the current swing value with a default swing value to obtain the swing change ΔSwing, and outputs the swing change ΔSwing to the control logic circuit. The control logic circuit generates a control signal based on the swing change ΔSwing, and outputs the control signal to a second constant current source. The second constant current source adjusts the bias current increment I according to the control signal. Bias_△Swing The swing detection circuit includes a peak detector and a subtractor. The peak detector detects the peak voltage of the differential signal to obtain the current swing value. The subtractor subtracts the current swing value from the default swing value to obtain the swing change ΔSwing.

[0050] In one embodiment, the response time of the bias current adjustment circuit is less than or equal to 10 microseconds. After detecting a change in the swing of the differential signal, the bias current adjustment circuit adjusts the target bias current within 10 microseconds, achieving a rapid response to changes in the differential signal swing and promptly improving the anti-interference capability of the clock and data recovery circuits. The shorter the response time of the bias current adjustment circuit, the faster the source driver chip responds to external interference, and the better the anti-interference performance of the source driver chip.

[0051] In one embodiment, the preset bias current value I Bias_Default The range is from 1 mA to 5 mA, for example, 1 mA, 1.5 mA, 2 mA, 2.5 mA, 3 mA, 3.5 mA, 4 mA, 4.5 mA, and 5 mA. Bias current increment I Bias_△Swing The range is from 0 mA to 5 mA, for example, 0 mA, 0.5 mA, 1 mA, 1.5 mA, 2 mA, 2.5 mA, 3 mA, 3.5 mA, 4 mA, 4.5 mA, and 5 mA. The target bias current ranges from 1 mA to 10 mA, for example, 1 mA, 2 mA, 3 mA, 4 mA, 5 mA, 6 mA, 7 mA, 8 mA, 9 mA, and 10 mA. When the differential signal is not disturbed, the target bias current is equal to the preset bias current value I. Bias_Default When the differential signal is disturbed, the target bias current is equal to the preset bias current value I. Bias_Default With bias current increment I Bias_△Swing sum.

[0052] In one embodiment, the swing change ΔSwing is related to the bias current increment I. Bias_△Swing The relationship between them is linear. The bias current adjustment circuit calculates the bias current increment I based on the swing change ΔSwing and a preset proportionality coefficient. Bias_△Swing Bias current increment IBias_△Swing It equals the product of the change in swing amplitude ΔSwing and the proportionality constant. The proportionality constant ranges from 0.1 mA / mV to 1 mA / mV, for example, 0.1 mA / mV, 0.2 mA / mV, 0.3 mA / mV, 0.4 mA / mV, 0.5 mA / mV, 0.6 mA / mV, 0.7 mA / mV, 0.8 mA / mV, 0.9 mA / mV, and 1 mA / mV.

[0053] In one embodiment, the swing change ΔSwing is related to the bias current increment I. Bias_△Swing The relationship between them is non-linear. The bias current adjustment circuit looks up the corresponding bias current increment I in a preset lookup table based on the swing change ΔSwing. Bias_△Swing The lookup table stores the bias current increment I corresponding to different swing amplitude changes ΔSwing. Bias_△Swing The mapping relationship is used to determine the bias current increment I by the bias current adjustment circuit based on the lookup table. Bias_△Swing This enables precise control of the target bias current.

[0054] In one embodiment, the bias current adjustment circuit further includes a temperature compensation circuit. The temperature compensation circuit detects the operating temperature of the source driver chip and adjusts the preset bias current value I according to the operating temperature. Bias_Default and bias current increment I Bias_△Swing This compensates for the effect of temperature changes on the bias current. The temperature compensation circuit includes a temperature sensor and a compensation logic circuit. The temperature sensor detects the operating temperature of the source driver chip, and the compensation logic circuit generates a temperature compensation coefficient based on the operating temperature. The compensation logic circuit then applies a preset bias current value I. Bias_Default and bias current increment I Bias_△Swing Multiply each value by the temperature compensation coefficient to obtain the preset bias current value and the bias current increment after temperature compensation.

[0055] Embodiments of this application also provide a display device, which includes a timing controller and the source driver chip described in the above embodiments. The display device is a liquid crystal display device or an organic light-emitting diode display device. The timing controller is configured to output a differential signal, and the source driver chip is electrically connected to the timing controller, receiving the differential signal output by the timing controller. The timing controller is configured to adjust the swing of the differential signal when a differential signal loss is detected, and the source driver chip is configured to feed back a loss-of-lock indication signal to the timing controller after receiving the differential signal in the loss-of-lock state.

[0056] The timing controller and the source driver chip transmit data via differential signals. These differential signals are embedded in the clock signal and are point-to-point differential signals, each carrying a lock-out status flag. When the differential signal is not affected by external interference during transmission, the lock-out status flag indicates a locked state. Upon receiving the locked differential signal, the source driver chip sends a lock indication signal back to the timing controller, which maintains the differential signal swing at its default value. When the differential signal is affected by external interference during transmission, the lock-out status flag indicates a locked state. Upon receiving the locked differential signal, the source driver chip sends a lock-out indication signal back to the timing controller. Upon detecting the lock-out indication signal, the timing controller triggers an automatic swing adjustment function, increasing the differential signal swing.

[0057] The bias current adjustment circuit in the source driver chip continuously monitors the swing change ΔSwing of the differential signal. When the swing of the differential signal increases, the swing change ΔSwing becomes greater than zero. The bias current adjustment circuit then increases the target bias current output to the clock and data recovery circuit. Driven by a larger target bias current, the clock and data recovery circuit exhibits enhanced driving capability and improved recovery capability of the differential signal, thus enhancing the source driver chip's anti-interference capability for the differential signal. After external interference disappears, the swing of the differential signal returns to its default value, and the swing change ΔSwing becomes zero. The bias current adjustment circuit then restores the target bias current to the preset bias current value I. Bias_Default This reduces the power consumption of the source driver chip.

[0058] In one embodiment, the display device further includes an absorbing material layer. The absorbing material layer is disposed near the differential signal transmission path between the timing controller and the source driver chip. The absorbing material layer absorbs external electromagnetic interference, reducing its impact on the differential signal. Because the bias current adjustment circuit in the source driver chip improves the chip's anti-interference capability against differential signals, the thickness of the absorbing material layer is reduced, the amount of absorbing material used is decreased, and the manufacturing cost of the display device is lowered.

[0059] In one embodiment, the core voltage of the timing controller ranges from 0.8 volts to 1.2 volts, for example, 0.8 volts, 0.85 volts, 0.9 volts, 0.95 volts, 1.0 volts, 1.05 volts, 1.1 volts, 1.15 volts, and 1.2 volts. The default swing value of the differential signal ranges from 200 millivolts to 600 millivolts, for example, 200 millivolts, 250 millivolts, 300 millivolts, 350 millivolts, 400 millivolts, 450 millivolts, 500 millivolts, 550 millivolts, and 600 millivolts. The common-mode voltage of the differential signal ranges from 0.4 volts to 0.8 volts, for example, 0.4 volts, 0.45 volts, 0.5 volts, 0.55 volts, 0.6 volts, 0.65 volts, 0.7 volts, 0.75 volts, and 0.8 volts. The sum of the differential signal swing voltage and the differential signal common-mode voltage is less than or equal to the core voltage of the timing controller.

[0060] In one embodiment, after the timing controller triggers the automatic swing adjustment function, the swing of the differential signal increases to 1.2 to 2 times the default swing value, for example, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2 times the default swing value. The timing controller adjusts the increase in the swing of the differential signal according to the duration and frequency of the unlock indication signal; the longer the duration of the unlock indication signal or the higher the unlock frequency, the greater the increase in the swing of the differential signal.

[0061] An embodiment of this application also provides a bias current adjustment method for a source driver chip. The method includes the following steps: an equalizer receives a differential signal, a bias current adjustment circuit detects the swing change ΔSwing of the differential signal, the bias current adjustment circuit adjusts the target bias current according to the swing change ΔSwing, and the bias current adjustment circuit outputs the target bias current to the clock and data recovery circuit.

[0062] In the process of the equalizer receiving differential signals, the input terminal of the equalizer receives the differential signal output by the timing controller. The differential signal is a differential signal embedded in the clock and is a point-to-point differential signal. The equalizer performs equalization processing on the received differential signal to compensate for the distortion of the differential signal during transmission. The equalizer outputs the equalized differential signal to the clock and data recovery circuit and the bias current adjustment circuit.

[0063] In the step of detecting the amplitude change ΔSwing of the differential signal by the bias current adjustment circuit, the bias current adjustment circuit continuously detects the amplitude change ΔSwing of the differential signal. The bias current adjustment circuit detects the current amplitude value of the differential signal and compares the current amplitude value with the default amplitude value to obtain the amplitude change ΔSwing. When the current amplitude value of the differential signal is equal to the default amplitude value, the amplitude change ΔSwing is zero; when the current amplitude value of the differential signal is greater than the default amplitude value, the amplitude change ΔSwing is greater than zero.

[0064] In the step of adjusting the target bias current according to the swing change ΔSwing, the bias current adjustment circuit adjusts the bias current increment I corresponding to the swing change ΔSwing. Bias_△Swing With the preset bias current value I Bias_Default The target bias current is obtained by superimposing the values. The bias current adjustment circuit increases the bias current according to the increase in the swing of the differential signal. When the swing change ΔSwing is zero, the target bias current equals the preset bias current value I. Bias_Default When the swing amplitude change ΔSwing is greater than zero, the target bias current is greater than the preset bias current value I. Bias_Default The bias current adjustment circuit increases the target bias current when the swing of the differential signal increases, and restores the target bias current to the preset bias current value I when the swing of the differential signal returns to the default swing value. Bias_Default .

[0065] In the step where the bias current adjustment circuit outputs the target bias current to the clock and data recovery circuit, the bias current adjustment circuit outputs the target bias current to the clock and data recovery circuit through the target bias current output terminal Vout. The target bias current is used to bias the clock and data recovery circuit. Driven by the target bias current, the clock and data recovery circuit recovers the clock signal and data signal from the differential signal output by the equalizer. The anti-interference capability of the clock and data recovery circuit of the source driver chip increases with the increase of the target bias current.

[0066] In one embodiment, the step of the bias current adjustment circuit adjusting the target bias current according to the swing change ΔSwing includes: transistor M1 receiving a preset bias current value I provided by the first constant current source. Bias_Default The bias current increment I provided by the second constant current source Bias_△Swing Transistor M1 will set the preset bias current value I Bias_Default With bias current increment I Bias_△SwingThe target bias current is obtained by superimposing the signals. Transistor M1 is a field-effect transistor, and its gate receives a control signal from the output of the equalizer. A first constant current source and a second constant current source are connected in parallel. The outputs of the first and second constant current sources are electrically connected to one of the source and drain terminals of transistor M1. One of the source and drain terminals of transistor M1 receives a preset bias current value I provided by the first constant current source. Bias_Default The bias current increment I provided by the second constant current source Bias_△Swing The source of transistor M1 is electrically connected to the ground terminal through the sampling resistor R, and the source of transistor M1 outputs the target bias current to the clock and data recovery circuit.

[0067] In one embodiment, the method further includes: a bias current adjustment circuit adjusting the bias current increment I based on the voltage across the sampling resistor R. Bias_△Swing The bias current adjustment circuit detects the voltage across the sampling resistor R, compares the voltage across R with a reference voltage, and adjusts the bias current increment I provided by the second constant current source based on the comparison result. Bias_△Swing When the voltage across the sampling resistor R is less than the reference voltage, the bias current adjustment circuit controls the second constant current source to increase the bias current increment I. Bias_△Swing When the voltage across the sampling resistor R is greater than the reference voltage, the bias current adjustment circuit controls the second constant current source to reduce the bias current increment I. Bias_△Swing When the voltage across the sampling resistor R equals the reference voltage, the bias current adjustment circuit controls the second constant current source to maintain the bias current increment I. Bias_△Swing constant.

[0068] In one embodiment, the method further includes: a bias current adjustment circuit adjusting a preset bias current value I according to the operating temperature of the source driver chip. Bias_Default and bias current increment I Bias_△Swing The bias current adjustment circuit detects the operating temperature of the source driver chip, generates a temperature compensation coefficient based on the operating temperature, and adjusts the preset bias current value I. Bias_Default and bias current increment I Bias_△Swing Multiply by the temperature compensation coefficient to obtain the preset bias current value and the bias current increment after temperature compensation, thus compensating for the effect of temperature change on the bias current.

[0069] An embodiment of this application also provides a method for adjusting the bias current of a display device. The method includes the following steps: a timing controller outputs a differential signal to a source driver chip; the source driver chip receives the differential signal; the source driver chip detects the swing change ΔSwing of the differential signal; the source driver chip adjusts the target bias current according to the swing change ΔSwing; and the source driver chip outputs the target bias current to a clock and data recovery circuit.

[0070] In the step of the timing controller outputting a differential signal to the source driver chip, the differential signal output by the timing controller is a differential signal embedded in the clock, and the differential signal is a point-to-point differential signal. The process node of the timing controller is less than or equal to 22 nanometers, and the core voltage of the timing controller is less than the sum of the swing voltage of the differential signal and the common-mode voltage of the differential signal.

[0071] In one embodiment, the method further includes: the source driver chip detecting whether the differential signal is unlocked; and when the differential signal is detected to be unlocked, the timing controller adjusting the swing of the differential signal. The step of the source driver chip detecting whether the differential signal is unlocked includes: the source driver chip detecting an unlock status flag signal carried in the differential signal; when the unlock status flag signal indicates an unlock status, the source driver chip determining that the differential signal is unlocked; after receiving the unlocked differential signal, the source driver chip feeding back an unlock indication signal to the timing controller; and after receiving the unlock indication signal, the timing controller triggers an automatic swing adjustment function to increase the swing of the differential signal.

[0072] The steps for the source driver chip to adjust the target bias current according to the swing change ΔSwing include: the source driver chip adjusting the bias current increment I corresponding to the swing change ΔSwing. Bias_△Swing With the preset bias current value I Bias_Default The target bias current is obtained by superimposing the values. The source driver chip increases the bias current according to the amplitude increase of the differential signal. The source driver chip increases the target bias current when the amplitude of the differential signal increases, and restores the target bias current to the preset bias current value I when the amplitude of the differential signal returns to the default amplitude value. Bias_Default The target bias current is used to bias the clock and data recovery circuit. The anti-interference capability of the clock and data recovery circuit of the source driver chip increases with the increase of the target bias current.

[0073] In one embodiment, the method further includes: a timing controller adjusting the amplitude increase of the differential signal based on the duration and frequency of the unlock indication signal. The timing controller detects the duration and frequency of the unlock indication signal; the longer the duration or the higher the frequency, the larger the amplitude increase of the differential signal. When the duration of the unlock indication signal is less than a first preset time threshold and the frequency is less than a first preset frequency threshold, the timing controller increases the amplitude of the differential signal to 1.2 to 1.5 times the default amplitude value. When the duration of the unlock indication signal is greater than or equal to the first preset time threshold or the frequency is greater than or equal to the first preset frequency threshold, the timing controller increases the amplitude of the differential signal to 1.5 to 2 times the default amplitude value.

[0074] In one embodiment, the method further includes: the source driver chip adjusting the bias current increment I based on the voltage across the sampling resistor R. Bias_△Swing The source driver chip detects the voltage across the sampling resistor R, compares the voltage across R with a reference voltage, and adjusts the bias current increment I based on the comparison result. Bias_△Swing This enables closed-loop control of the target bias current.

[0075] In one embodiment, the method further includes: the source driver chip adjusting a preset bias current value I according to the operating temperature. Bias_Default and bias current increment I Bias_△Swing The source driver chip detects the operating temperature and generates a temperature compensation coefficient based on it. The source driver chip then applies a preset bias current value I. Bias_Default and bias current increment I Bias_△Swing Multiply by the temperature compensation coefficient to obtain the preset bias current value and the bias current increment after temperature compensation, thereby compensating for the influence of temperature changes on the bias current and improving the anti-interference performance of the source driver chip at different operating temperatures.

[0076] Through the above technical solutions, the source driver chip, display device and bias current adjustment method provided in the embodiments of this application realize the linkage adjustment of the differential signal swing and the bias current of the clock and data recovery circuit through the bias current adjustment circuit. When the differential signal is interfered with, the bias current is adaptively increased, and the bias current is adaptively restored after the interference disappears. While improving the anti-interference capability of the source driver chip, the power consumption is optimized, the anti-interference performance of the display device is improved during the anti-interference test of the mobile terminal or during the use by consumers, the amount of absorbing material used is reduced, and the manufacturing cost of the display device is reduced.

[0077] The embodiments of this application have been described in detail above. The content of this specification should not be construed as limiting the scope of protection of this application.

Claims

1. A source driving chip, characterized in that, The equalizer is configured to receive a differential signal at an input thereof. A clock and data recovery circuit is electrically connected to an output of the equalizer. A bias current adjustment circuit is electrically connected to the output of the equalizer and to the clock and data recovery circuit. The bias current adjustment circuit is configured to detect a swing variation of the differential signal and adjust a target bias current output to the clock and data recovery circuit according to the swing variation. The bias current adjustment circuit is configured to superimpose a bias current increment corresponding to the swing variation on a preset bias current value to obtain the target bias current. When the swing variation is zero, the target bias current is equal to the preset bias current value.

2. The source driving chip according to claim 1, wherein, When the swing variation is greater than zero, the target bias current is greater than the preset bias current value.

3. The source driving chip according to claim 2, wherein, The bias current adjustment circuit is configured to increase the target bias current when the swing of the differential signal increases and restore the target bias current to the preset bias current value when the swing of the differential signal returns to a default swing value.

4. The source driving chip according to claim 2, wherein, The bias current adjustment circuit includes:

5. The source driving chip according to claim 1, wherein, A first constant current source configured to provide a preset bias current value; 6. The source driving chip according to claim 1, wherein, A second constant current source configured to provide the bias current increment; A transistor having a gate electrically connected to a control signal input, one of a source and a drain of the transistor electrically connected to the first constant current source and the second constant current source, and the other of the source and the drain of the transistor electrically connected to a target bias current output; A sampling resistor electrically connected between the other of the source and the drain of the transistor and a ground terminal. The timing controller is configured to output a differential signal. The source drive chip according to any one of claims 1-6 is electrically connected to the timing controller and configured to receive the differential signal.

7. A display device, characterized by comprising: The timing controller is configured to adjust a swing of the differential signal when a loss of lock of the differential signal is detected. The source drive chip is configured to feed back a loss of lock indication signal to the timing controller after receiving the differential signal in a loss of lock state. An equalizer receives a differential signal. A bias current adjustment circuit detects a swing variation of the differential signal.

8. The display device according to claim 7, wherein The bias current adjustment circuit adjusts a target bias current according to the swing variation.

9. The display device according to claim 8, wherein The bias current adjustment circuit outputs the target bias current to a clock and data recovery circuit.

10. A method for adjusting a bias current of a source driving chip, characterized in that, The bias current adjustment circuit adjusts a target bias current according to the swing variation includes: The bias current adjustment circuit superimposes a bias current increment corresponding to the swing variation on a preset bias current value to obtain the target bias current. When the swing variation is zero, the target bias current is equal to the preset bias current value. When the swing variation is greater than zero, the target bias current is greater than the preset bias current value. ​ 11. The method of claim 10, wherein the bias current of the source driving chip is adjusted by adjusting the bias current of the first bias current source. ​ ​ 12. The method of claim 11, wherein the bias current of the source driving chip is adjusted by adjusting the bias current of the first bias current source. ​ 13. The method of claim 11, wherein the bias current of the source driving chip is adjusted by adjusting the bias current of the first bias current source. ​ 14. The method of claim 10, wherein the bias current of the source driving chip is adjusted by adjusting the bias current of the source driving chip. The bias current adjustment circuit adjusts a target bias current according to the swing change amount, and the adjusting the target bias current according to the swing change amount comprises: The bias current adjustment circuit increases the target bias current when the swing of the differential signal increases; The bias current adjustment circuit restores the target bias current to a preset bias current value when the swing of the differential signal returns to a default swing value.

15. The method of claim 10, wherein the bias current of the source driving chip is adjusted by adjusting the bias current of the source driving chip. The adjusting the target bias current according to the swing change amount comprises: The transistor receives a preset bias current value provided by a first constant current source and the bias current increment provided by a second constant current source; The transistor superimposes the preset bias current value and the bias current increment to obtain the target bias current.

16. A bias current adjustment method of a display device, characterized by, Comprise: The timing controller outputs a differential signal to a source drive chip; The source drive chip receives the differential signal; The source drive chip detects a swing change amount of the differential signal; The source drive chip adjusts a target bias current according to the swing change amount; The source drive chip outputs the target bias current to a clock and data recovery circuit.

17. The bias current adjusting method of a display device according to claim 16, wherein Further comprise: The source drive chip detects whether the differential signal is out of lock; When it is detected that the differential signal is out of lock, the timing controller adjusts the swing of the differential signal.

18. The bias current adjusting method of a display device according to claim 17, wherein The source drive chip detects whether the differential signal is out of lock comprises: The source drive chip feeds back an out-of-lock indication signal to the timing controller after receiving the differential signal in the out-of-lock state.

19. The bias current adjusting method of a display device according to claim 16, wherein The source drive chip adjusts a target bias current according to the swing change amount comprises: The source drive chip superimposes a bias current increment corresponding to the swing change amount and a preset bias current value to obtain the target bias current.

20. The bias current adjusting method of a display device according to claim 16, wherein The source drive chip adjusts a target bias current according to the swing change amount comprises: The source drive chip increases the target bias current when the swing of the differential signal increases; The source drive chip restores the target bias current to a preset bias current value when the swing of the differential signal returns to a default swing value.

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