Power amplifier, driving chip, display device

Abstract

The application provides a power amplifier, a driving chip and a display device, the power amplifier comprising: an operational amplifier unit, a voltage regulating unit, a common voltage feedback signal input end, a common voltage signal input end and a signal output end; wherein the positive polarity input end of the operational amplifier unit is connected with the common voltage signal input end, the negative polarity input end of the operational amplifier unit is connected with the common voltage feedback signal input end through the voltage regulating unit, and the output end of the operational amplifier unit is connected with the signal output end; by arranging the voltage regulating unit in front of the negative polarity input end of the operational amplifier unit, the voltage of the common voltage feedback signal input by the common voltage feedback signal input end is limited, so that the problem that the display device is over-temperature protected and flickers due to the large voltage ripple of the common voltage feedback signal under some special heavy load pictures is solved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically to a power amplifier, a driver chip, and a display device. Background Technology

[0002] In LCD products, to avoid liquid crystal polarization, a polarity reversal method is usually used to drive the liquid crystal. This polarity reversal driving method requires an intermediate reference voltage (CV). COM ), typically around 8V, data voltage (V Date ) and CV COM The voltage difference is the driving voltage applied across the liquid crystal, V. Date The typical range is 0–16V, when V Date When the voltage is less than 8V, it is a negative polarity drive; when V... Date A voltage greater than 8V results in positive polarity drive. The polarity is continuously switched, thus achieving a polarity reversal drive mechanism. The CV (coulomb-coil) process... COM Widely distributed within the panel, easily affected by V Date Signal coupling (following V) Date (voltage change), therefore, as Figure 1 As shown, the current design addresses the crosstalk issue by using the in-plane feedback reference voltage (CV). COM_FB It is connected to the negative input of the amplifier. Currently, this application is used in certain heavy-load scenes (such as vertical stripe scenes), where CV... COM_FB When the ripple exceeds 4V, the amplifier's output current is stretched to its limit, causing distortion. The highest measured output current is 3.2A (specification <1.3A). According to the formula ΔP=∫i rms 2 As can be seen from dt*R, the continuous output of large current will trigger the over-temperature protection circuit to start over-temperature protection (OTP). At the same time, the reference voltage fed back in the plane is amplified by the amplifier, so that the output voltage Vout has a maximum value of 11.04V and a minimum value of 3.2V, causing the screen to flicker.

[0003] Therefore, existing technologies have shortcomings that urgently need to be addressed. Summary of the Invention

[0004] This invention provides a power amplifier, a driver chip, and a display device, which can solve the problems of over-temperature protection and screen flickering caused by large voltage ripple in the common voltage feedback signal under certain special heavy load conditions in existing display devices.

[0005] To solve the above problems, the technical solution provided by the present invention is as follows:

[0006] This invention provides a power amplifier, comprising: an operational amplifier unit, a voltage regulation unit, a common voltage feedback signal input terminal, a common voltage signal input terminal, and a signal output terminal;

[0007] The positive input terminal of the operational amplifier unit is connected to the common voltage signal input terminal, the negative input terminal of the operational amplifier unit is connected to the common voltage feedback signal input terminal through the voltage adjustment unit, and the output terminal of the operational amplifier unit is connected to the signal output terminal.

[0008] The voltage regulation unit is used to control the voltage of the common voltage feedback signal input to the common voltage feedback signal input terminal within a preset threshold, and input it to the negative polarity input terminal of the operational amplifier unit.

[0009] Optionally, in some embodiments of the present invention, the voltage regulation unit includes a first diode and a second diode, the first diode and the second diode are connected in parallel, and the cathode of the first diode and the anode of the second diode are connected together to the common voltage feedback signal input terminal, and the cathode of the first diode and the anode of the second diode are connected together to the negative polarity input terminal of the operational amplifier unit, and the anode of the first diode and the cathode of the second diode are connected together to the common voltage signal input terminal.

[0010] Optionally, in some embodiments of the present invention, the power amplifier further includes a first resistor, a second resistor, and a third resistor;

[0011] The output terminal of the operational amplifier unit is connected to the negative input terminal of the operational amplifier unit through the first resistor, the first diode and the second diode are connected to the negative input terminal of the operational amplifier unit through the second resistor, and the output terminal of the operational amplifier unit is also connected to the signal output terminal through the third resistor.

[0012] Optionally, in some embodiments of the present invention, the power amplifier further includes a first capacitor and a second capacitor;

[0013] The first diode and the second diode are connected to the common voltage feedback signal input terminal through the first capacitor;

[0014] One end of the second capacitor is grounded, and the other end is connected to the first capacitor and the common voltage feedback signal input terminal, respectively.

[0015] Optionally, in some embodiments of the present invention, the reference voltage of the common voltage signal is input to the common voltage signal input terminal, and the preset threshold is equal to the reference voltage ± the voltage drop of the first diode or the second diode.

[0016] Optionally, in some embodiments of the present invention, the voltage drop of the first diode and the voltage drop of the second diode are equal.

[0017] This invention provides a driver chip, including an over-temperature protection circuit and a power amplifier as described above; wherein the signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit.

[0018] This invention provides a display device, including a display panel and a driver chip as described above, wherein the driver chip is bonded to the display panel.

[0019] This invention provides a display device, including a display panel. The display panel includes an over-temperature protection circuit and a power amplifier as described above. The signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit.

[0020] Optionally, in some embodiments of the present invention, the display panel includes a display area and a non-display area. The display area includes a common voltage signal line, and the non-display area includes a common voltage feedback trace and a common voltage transmission trace. The common voltage signal line is connected to the common voltage feedback signal input terminal of the power amplifier via the common voltage feedback trace, and the output terminal of the over-temperature protection circuit is connected to the common voltage signal line via the common voltage transmission trace.

[0021] The beneficial effects of the present invention are as follows: The power amplifier, driver chip, and display device provided by the present invention, by setting a voltage regulation unit between the negative polarity input terminal of the operational amplifier unit and the common voltage feedback signal input terminal, limit the voltage of the common voltage feedback signal input to the common voltage feedback signal input terminal, so that the output voltage and current of the common voltage feedback signal after amplification by the amplifier are reduced, thereby solving the problem of over-temperature protection and screen flicker caused by the large voltage ripple of the common voltage feedback signal under certain special heavy load screen conditions. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is the circuit diagram of an existing power amplifier;

[0024] Figure 2 It is the in-plane feedback CV of the display panel. COM_FB Waveform diagram;

[0025] Figure 3 This is a circuit diagram of a power amplifier provided in an embodiment of the present invention;

[0026] Figure 4 yes Figure 3 CV after adjustment by the voltage regulation unit of the medium power amplifier COM_FB Waveform diagram;

[0027] Figure 5 The waveform diagram is obtained by using the power amplifier provided in the embodiment of the present invention under heavy load conditions. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. In the present invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0029] Please see Figure 3 , Figure 3 This is a circuit diagram of a power amplifier provided in an embodiment of the present invention. The power amplifier can be applied in a display device to receive a common voltage feedback signal from within the display panel, and is also connected to an over-temperature protection circuit on the display panel, so that the signal output from its output terminal is transmitted to the display panel via the over-temperature protection circuit. The power amplifier includes: an operational amplifier unit OP, a voltage regulation unit S1, a common voltage feedback signal input terminal in-put_1, a common voltage signal input terminal in-put_2, and a signal output terminal out-put.

[0030] The operational amplifier unit OP has its positive input terminal connected to the common voltage signal input terminal in-put_2, and its negative input terminal connected to the common voltage feedback signal input terminal in-put_1 via the voltage adjustment unit S1. The output terminal of the operational amplifier unit OP is connected to the signal output terminal out-put. The common voltage feedback signal input terminal in-put_1 receives the common voltage feedback signal fed back from within the display panel, and the common voltage signal input terminal in-put_2 receives the common voltage signal. The signal output by the operational amplifier unit OP is transmitted to the over-temperature protection circuit via the signal output terminal out-put.

[0031] The voltage regulation unit S1 is used to adjust the voltage CV of the common voltage feedback signal input to the common voltage feedback signal input terminal in-put_1. COM_FB It is controlled within a preset threshold and input to the negative polarity input terminal of the operational amplifier unit OP.

[0032] To reduce the voltage ripple of the common voltage feedback signal, this embodiment of the invention includes a voltage adjustment unit S1 located between the negative input terminal of the operational amplifier unit OP and the common voltage feedback signal input terminal in-put_1. The voltage adjustment unit S1 can limit the voltage of the common voltage feedback signal input to the common voltage feedback signal input terminal in-put_1, thereby reducing the voltage CV of the common voltage feedback signal. COM_FB By controlling the voltage and current within a preset threshold, the voltage feedback signal is amplified by the operational amplifier (OP) unit, resulting in a reduction in output voltage and current. This solves the problem of over-temperature protection and screen flickering caused by large voltage ripple in the common voltage feedback signal under certain special heavy load conditions.

[0033] In view of this, the present invention achieves the above objective by setting a voltage regulation unit S1 between the negative polarity input terminal of the operational amplifier unit OP and the common voltage feedback signal input terminal in-put_1. The specific solution is described below.

[0034] Please see Figure 3 The voltage regulation unit S1 includes a first diode D1 and a second diode D2. The first diode D1 and the second diode D2 are connected in parallel. The cathode of the first diode D1 and the anode of the second diode D2 are connected to the common voltage feedback signal input terminal in-put_1. The cathode of the first diode D1 and the anode of the second diode D2 are connected to the negative input terminal of the operational amplifier unit OP. The anode of the first diode D1 and the cathode of the second diode D2 are connected to the common voltage signal input terminal in-put_2.

[0035] Furthermore, the power amplifier also includes a first resistor R1, a second resistor R2, and a third resistor R3. The output terminal of the operational amplifier unit OP is connected to the negative input terminal of the operational amplifier unit OP through the first resistor R1. The first diode D1 and the second diode D2 are connected to the negative input terminal of the operational amplifier unit OP through the second resistor R2. The output terminal of the operational amplifier unit OP is also connected to the signal output terminal (output) through the third resistor R3. The first resistor R1, the second resistor R2, and the third resistor R3 are used for current limiting, which can reduce the current output by the signal output terminal (output) and prevent the signal output terminal from continuously outputting a large current that triggers over-temperature protection.

[0036] Furthermore, the power amplifier also includes a first capacitor C1 and a second capacitor C2. The first diode D1 and the second diode D2 are connected to the common voltage feedback signal input terminal in-put_1 via the first capacitor C1. The first capacitor C1 is used to charge the first diode D1 and the second diode D2. One end of the second capacitor C2 is grounded, and the other end is connected to both the first capacitor C1 and the common voltage feedback signal input terminal in-put_1.

[0037] In this embodiment of the invention, the voltage of the common voltage signal input at the common voltage signal input terminal in-put_2 is the reference voltage CV. COM The preset threshold is equal to the reference voltage ± the voltage drop across the first diode or the second diode.

[0038] Furthermore, the first diode D1 and the second diode D2 are made of the same material, and the voltage drop of the first diode D1 and the voltage drop of the second diode D2 are equal.

[0039] The principle of voltage limiting of the input common voltage feedback signal by the voltage regulation unit is explained below. Diodes have unidirectional conduction characteristics. Connecting two diodes in reverse parallel can form a clamping circuit. The clamping circuit can forcibly clamp the signal to a certain potential, achieving voltage limiting. When the cathode voltage of the diode is greater than the anode voltage, the diode is cut off; when the anode voltage is greater than the cathode voltage, the diode conducts. After conduction, the voltage across the diode is limited to its diode voltage drop.

[0040] Combination Figure 3 and Figure 4 As shown, this embodiment uses a diode voltage drop of approximately 0.4V as an example, meaning the voltage across the diode is clamped at 0.4V. When the voltage CV input to the common voltage feedback signal input terminal in-put_1...COM_FB Greater than the reference voltage CV COM When the first diode D1 is turned off, the second diode D2 is turned on, and the second diode D2 will convert the input CV... COM_FB Potential clamping at CV COM At +0.4V, that is, the anode voltage of the second diode D2 is CV. COM +0.4V. When the voltage CV input to the common voltage feedback signal input terminal in-put_1 is... COM_FB Less than the reference voltage -CV COM When the first diode D1 is turned on, the second diode D2 is turned off, and the first diode D1 will convert the input CV. COM_FB Potential clamping at CV COM At -0.4V, that is, the cathode voltage of the first diode D1 is CV. COM -0.4V. This clamps the voltage signal input to the common voltage feedback signal input terminal in-put_1 to ±0.4V, achieving voltage limiting of the common voltage feedback signal. This avoids screen flickering caused by a large voltage difference output by the operational amplifier unit OP. It also limits the current output to the signal output terminal out-put to <1.3A, preventing continuous high current output from triggering the over-temperature protection circuit.

[0041] Please see Figure 5 , Figure 5 This is a waveform diagram detected under heavy load using the power amplifier provided in this embodiment of the invention. The voltage CV of the in-plane feedback common voltage feedback signal is shown. COM_FB After passing through the power amplifier, the output voltage CV COM_out and current I_ out All decreased significantly.

[0042] This invention also provides a driver chip, which includes an over-temperature protection circuit and a power amplifier as described above. The signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit.

[0043] This invention also provides a display device, which includes a display panel and a driver chip as described above, wherein the driver chip is bonded to the display panel.

[0044] This invention also provides a display device, which includes a display panel. The display panel includes an over-temperature protection circuit and the aforementioned power amplifier. The signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit. The display panel includes a display area and a non-display area. The display area includes a common voltage signal line, and the non-display area includes a common voltage feedback trace and a common voltage transmission trace. The common voltage signal line is connected to the common voltage feedback signal input terminal of the power amplifier via the common voltage feedback trace, and the output terminal of the over-temperature protection circuit is connected to the common voltage signal line via the common voltage transmission trace.

[0045] The power amplifier, driver chip, and display device provided by this invention solve the problem of over-temperature protection and screen flicker caused by large voltage ripple in the common voltage feedback signal input terminal under certain special heavy load screen conditions. By setting a voltage regulation unit between the negative input terminal of the operational amplifier unit and the common voltage feedback signal input terminal, the voltage of the common voltage feedback signal input terminal is limited, so that the output voltage and current of the common voltage feedback signal after amplification by the amplifier are reduced.

[0046] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A driver chip, characterized in that, Includes over-temperature protection circuitry and power amplifier; The power amplifier includes: an operational amplifier unit, a voltage regulation unit, a common voltage feedback signal input terminal, a common voltage signal input terminal, and a signal output terminal; The positive input terminal of the operational amplifier unit is connected to the common voltage signal input terminal, the negative input terminal of the operational amplifier unit is connected to the common voltage feedback signal input terminal through the voltage adjustment unit, and the output terminal of the operational amplifier unit is connected to the signal output terminal. The voltage regulation unit is used to control the voltage of the common voltage feedback signal input to the common voltage feedback signal input terminal within a preset threshold, and input it to the negative polarity input terminal of the operational amplifier unit, so that the voltage and current output after the common voltage feedback signal is amplified by the operational amplifier unit are reduced. The signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit, and the output terminal of the over-temperature protection circuit is connected to the common voltage signal line via a common voltage transmission line.

2. The driver chip according to claim 1, characterized in that, The voltage regulation unit includes a first diode and a second diode, which are connected in parallel. The cathode of the first diode and the anode of the second diode are both connected to the common voltage feedback signal input terminal. The cathode of the first diode and the anode of the second diode are both connected to the negative polarity input terminal of the operational amplifier unit. The anode of the first diode and the cathode of the second diode are both connected to the common voltage signal input terminal.

3. The driver chip according to claim 2, characterized in that, The power amplifier also includes a first resistor, a second resistor, and a third resistor; The output terminal of the operational amplifier unit is connected to the negative input terminal of the operational amplifier unit through the first resistor, the first diode and the second diode are connected to the negative input terminal of the operational amplifier unit through the second resistor, and the output terminal of the operational amplifier unit is also connected to the signal output terminal through the third resistor.

4. The driver chip according to claim 3, characterized in that, The power amplifier also includes a first capacitor and a second capacitor; The first diode and the second diode are connected to the common voltage feedback signal input terminal through the first capacitor; One end of the second capacitor is grounded, and the other end is connected to the first capacitor and the common voltage feedback signal input terminal, respectively.

5. The driver chip according to claim 2, characterized in that, The common voltage signal input terminal inputs the reference voltage of the common voltage signal, and the preset threshold is equal to the reference voltage ± the voltage drop of the first diode or the second diode.

6. The driver chip according to claim 5, characterized in that, The voltage drop across the first diode is equal to the voltage drop across the second diode.

7. A power amplifier, characterized in that, Based on the driver chip according to any one of claims 1 to 6, the power amplifier includes: an operational amplifier unit, a voltage regulation unit, a common voltage feedback signal input terminal, a common voltage signal input terminal, and a signal output terminal; The positive input terminal of the operational amplifier unit is connected to the common voltage signal input terminal, the negative input terminal of the operational amplifier unit is connected to the common voltage feedback signal input terminal through the voltage adjustment unit, and the output terminal of the operational amplifier unit is connected to the signal output terminal. The voltage regulation unit is used to control the voltage of the common voltage feedback signal input to the common voltage feedback signal input terminal within a preset threshold, and input it to the negative polarity input terminal of the operational amplifier unit.

8. A display device, characterized in that, It includes a display panel and a driver chip as described in any one of claims 1 to 6, wherein the driver chip is bonded to the display panel.

9. A display device, characterized in that, The device includes a display panel, which includes an over-temperature protection circuit and a power amplifier as described in claim 7, wherein the signal output terminal of the power amplifier is connected to the input terminal of the over-temperature protection circuit.

10. The display device according to claim 9, characterized in that, The display panel includes a display area and a non-display area. The display area includes a common voltage signal line, and the non-display area includes a common voltage feedback line and a common voltage transmission line. The common voltage signal line is connected to the common voltage feedback signal input terminal of the power amplifier via the common voltage feedback line, and the output terminal of the over-temperature protection circuit is connected to the common voltage signal line via the common voltage transmission line.

Images