AM drive circuit and display screen

Abstract

The utility model discloses an AM drive circuit and a display screen, and the AM drive circuit comprises a control module which is used for outputting an AM drive signal; the driving module is used for driving a load according to the AM driving signal; the signal balance module is connected to the control module and the driving module, the signal balance module is used for increasing the AM driving signal by a first preset voltage and then outputting the AM driving signal to the driving module, and the first preset voltage is larger than or equal to the voltage difference between the ground voltage of the driving module and the ground voltage of the control module. According to the AM driving circuit provided by the invention, the AM driving signal output by the control module is boosted according to the first preset voltage through the signal balance module, and the boosted first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module and the ground voltage of the control module; the signal output by the control module can still be matched with the signal input requirement of the driving module, negative pressure of the driving signal is avoided, and load driving is safer and more reliable.

Description

Technical Field

[0001] The utility model relates to the field of circuit structures, in particular to an AM driving circuit and a display screen. Background Art

[0002] MiniLED is a new type of LED display technology. MiniLED screens make the LED lamp beads of the backlight module very small, integrate more LED lamp beads on the same screen, divide more backlight partitions, achieve more precise regional light adjustment, and effectively improve screen brightness and contrast. Many current MiniLED backlight products use AM drive (active matrix drive) mode, and output drive signals to the driver chip on the lamp board through the control board to drive the lamp beads on the lamp board. Because the wiring of the lamp board needs to pass through the power supply signal ground of the driver chip, the positive and negative poles of the lamp beads, etc., and is affected by factors such as the small spacing between the lamp beads, the ground signal network of the lamp board has impedance, resulting in the ground voltage of the driver chip module on the lamp board being raised relative to the ground voltage of the control board. The voltage of the drive signal output by the control board is negative relative to the ground voltage of the lamp board. Once the negative pressure exceeds the negative pressure resistance control requirements of the driver chip, it is easy to damage the driver chip, thereby burying the hidden danger of failure. Utility Model Content

[0003] The embodiment of the utility model provides an AM driving circuit to solve the problem that the load ground voltage of LED products is elevated, resulting in a negative voltage in the driving chip signal input.

[0004] In a first aspect, an embodiment of the utility model provides an AM driving circuit, which includes:

[0005] A control module, used for outputting an AM driving signal;

[0006] A driving module, used for driving a load according to the AM driving signal;

[0007] A signal balancing module, connected to the control module and the driving module, and configured to increase the AM driving signal by a first preset voltage and then output it to the driving module;

[0008] The first preset voltage is greater than or equal to a voltage difference between a ground voltage of the driving module and a ground voltage of the control module.

[0009] In the AM driving circuit provided in the embodiment of the utility model, the signal balancing module includes a voltage clamping unit and a voltage supply unit, the voltage clamping unit is connected to the control module and the driving module, and the voltage supply unit is connected to the voltage clamping unit; wherein the voltage supply unit is used to provide a reference voltage, and the voltage clamping unit is used to compare the voltage of the AM driving signal with the reference voltage, and clamp the voltage of the AM driving signal at different preset levels according to the comparison result.

[0010] In the AM driving circuit provided by an embodiment of the utility model, the voltage clamping unit includes a first clamping device, which is connected to the driving module, the voltage supply unit and the driving module; wherein the first clamping device is used to clamp the voltage of the AM driving signal at a preset high level when the AM driving signal is greater than or equal to the reference voltage.

[0011] In the AM driving circuit provided by an embodiment of the utility model, the voltage clamping unit also includes a second clamping device, and the second clamping device and the first clamping device are commonly connected to the control module, the driving module and the voltage supply unit; wherein the second clamping device is used to clamp the voltage of the AM driving signal at a preset low level when the AM driving signal is less than the reference voltage.

[0012] In the AM driving circuit provided in an embodiment of the utility model, the first clamping device and the second clamping device are both diodes, the anode of the first clamping device and the cathode of the second clamping device are commonly connected to the control module, and the cathode of the first clamping device and the anode of the second clamping device are commonly connected to the pressure supply unit and the driving module.

[0013] In the AM driving circuit provided in the embodiment of the utility model, the voltage supply unit includes a power supply and a first resistor, one end of the first resistor is connected to the power supply, and the other end is connected to the first clamping device, the second clamping device and the driving module.

[0014] In the AM driving circuit provided by the embodiment of the utility model, the voltage clamping unit includes a bidirectional diode, one end of the bidirectional diode is connected to the control module, and the other end of the bidirectional diode is connected to the voltage supply unit and the driving module.

[0015] In the AM driving circuit provided by the embodiment of the utility model, the AM driving circuit also includes a signal enhancer module, the signal balancing module also includes an overshoot suppression unit, the signal enhancer module is connected between the control module and the voltage clamping unit, and the overshoot suppression unit is connected to the voltage clamping unit, the voltage supply unit and the driving module; wherein the signal enhancer module is used to enhance the AM driving signal output by the control module and then output it to the voltage clamping unit, and the overshoot suppression unit is used to eliminate the overshoot of the enhanced AM driving signal.

[0016] In the AM driving circuit provided in an embodiment of the utility model, the overshoot suppression unit includes a first capacitor and a second resistor, one end of the second resistor is connected to the voltage clamping unit and the voltage supply unit, and the other end is connected to the driving module and one end of the first capacitor, and the other end of the first capacitor is grounded.

[0017] In a second aspect, an embodiment of the utility model provides a display screen, which includes any one of the AM driving circuits provided by the embodiments of the utility model.

[0018] The embodiment of the utility model provides an AM driving circuit and a display screen, wherein the AM driving circuit includes a control module, a driving module and a signal balancing module; the control module is used to output an AM driving signal; the driving module is used to drive a load according to the AM driving signal; the signal balancing module is connected to the control module and the driving module, and the signal balancing module is used to increase the AM driving signal by a first preset voltage and then output it to the driving module; wherein the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module and the ground voltage of the control module. The AM driving circuit provided in the present application uses a signal balancing module to increase the AM driving signal output by the control module according to the first preset voltage, and the increased first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module and the ground voltage of the control module. When the actual ground voltage of the driving module is raised, the signal output by the control module can still match the signal input requirement of the driving module, thereby avoiding negative pressure in the driving signal, and driving the load is safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1A structural block diagram of an AM driving circuit provided in an embodiment of the utility model;

[0021] Figure 2 A structural block diagram of an AM driving circuit provided by an embodiment of the utility model;

[0022] Figure 3 Another structural block diagram of the AM driving circuit provided by the embodiment of the utility model;

[0023] Figure 4 A circuit diagram of an AM driving circuit provided in an embodiment of the utility model;

[0024] Figure 5 A waveform diagram of an AM driving signal of an AM driving circuit provided in an embodiment of the utility model;

[0025] Figure 6 Another waveform diagram of the AM driving signal of the AM driving circuit provided in the embodiment of the utility model;

[0026] The reference numerals in the figures are:

[0027] 10. Control module; 20. Drive module; 30. Signal balance module; 31. Voltage clamping unit; 311. First clamping device; 312. Second clamping device; 32. Voltage supply unit; 33. Overshoot suppression unit; 40. Signal enhancer module. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] The directional terms mentioned in the present invention, such as "upper", "lower", "front", "back", "left", "right", "inner", "outer", "side", etc., are only for reference to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present invention, but not to limit the present invention. In addition, in the drawings, structures with similar or identical structures are represented by the same reference numerals.

[0030] Reference Figure 1 to Figure 1 to Figure 6 , please refer to Figure 1, which shows an embodiment of the AM driving circuit provided by the utility model. The structure and working principle of the AM driving circuit are described in detail below in conjunction with the drawings of the specification. The AM driving circuit includes a control module 10, a driving module 20 and a signal balancing module 30; the control module 10 is used to output an AM driving signal; the driving module 20 is used to drive a load according to the AM driving signal; the signal balancing module 30 is connected to the control module 10 and the driving module 20, and the signal balancing module 30 is used to increase the AM driving signal to a first preset voltage and then output it to the driving module 20; wherein the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module 20 and the ground voltage of the control module 10.

[0031] In the specific implementation, the AM driving circuit is mainly used to drive the backlight of the Mini LED screen. In other embodiments, the AM driving circuit can apply the driving circuit of other devices or circuits. The fundamental reason why the Mini LED screen can display the picture is the existence of the backlight module, and its backlight module is a module composed of many LED lamp beads that can emit white light. The backlight module is mainly driven by the driving module 20, that is, the backlight module of the Mini LED screen is a load driven by the driving module 20. Usually, a backlight module requires multiple driving modules 20 to drive. The driving mode of the Mini LED screen adopts the AM driving (active matrix driving) mode. The AM driving is mainly based on the glass substrate and uses TFT driving control to realize the single-zone regulation of the backlight module. The control module 10 is usually connected to multiple driving modules 20. The control module 10 outputs an AM driving signal to each driving module 20. After receiving the corresponding AM driving signal output by the control module 10, the corresponding driving module 20 can drive the backlight module of the Mini LED screen according to the AM driving signal. The essence of the AM driving signal is the high and low level pulses output by the control module 10. The control module 10 is specifically an IC such as a single-chip microcomputer, FPGA, or a module integrating these ICs. In practice, the backlight module of the Mini LED screen is connected to the driving module 20, and the two are usually integrated on a PCB light board. The various signal ends of the driving module 20 are connected to the corresponding signal ends of the backlight module of the Mini LED screen, and the power supply signal ground of the driving module 20 maintains a consistent ground voltage with the signal ground of the backlight module of the Mini LED screen. Affected by factors such as the small spacing between the LED lamp beads of the backlight module and the wiring, the ground signal network of the backlight module of the Mini LED screen inevitably has a certain amount of impedance, and the ground signal of the driving module 20 is connected and consistent with the ground signal of the backlight module. Due to the existence of impedance, when the Mini LED screen is working, the ground voltage of the driving module 20 is in a raised state relative to the ground voltage of the control board. If the signal output end of the control module 10 is directly connected to the signal input end of the driving module 20 in a traditional manner, the AM driving signal output by the control module 10 will not be lost after reaching the driving module 20. However, if the waveform of the AM driving signal is captured by referring to the ground signal of the driving module 20, the high and low levels of the AM driving signal are compared according to the actual high and low level standards of the driving module 20. The voltage of the AM driving signal will be weakened. The reason is that the difference between the ground voltage of the control module 10 and the ground voltage of the driving module 20 causes the voltage of the AM driving signal output by the control module 10 to be negative relative to the ground voltage of the lamp board.

[0032] In this embodiment, the control module 10 is connected to the driving module 20 through the signal balancing module 30, that is, the signal balancing module 30 is connected between the control module 10 and the driving module 20 as a module for transferring the AM driving signal. The signal balancing module 30 is mainly used to boost the AM driving signal output by the control module 10, so that the voltage of the AM driving signal is increased by a first preset voltage. In this embodiment, the ground voltage of the driving module 20 specifically refers to the ground voltage of the driving module 20 after it is raised when the Mini LED screen is working. For example, referring to Figure 5 and Figure 6 , Figure 5 FIG. 1 shows the waveform of the AM driving signal relative to the ground voltage of the control module 10. Figure 6 The waveform of the AM driving signal relative to the ground voltage of the driving module 20 is shown. The most ideal situation when the control module 10 drives the driving module 20 should be that the ground voltage of the driving module 20 should be consistent with the ground voltage of the control module 10 at 0V, but in fact, the ground voltage of the driving module 20 is raised by 0.25V, that is, the actual ground voltage of the driving module 20 is 0.25V if the ground voltage of the control module 10 is used as a reference. If the AM driving signal output by the control module 10 is a waveform with a high level of 3.3V and a low level of 0V, then the waveform of the AM driving signal is captured according to the actual ground voltage of the driving module 20 of 0.25V. At this time, the AM driving signal is a waveform with a high level of 3.05V and a low level of -0.25V if the actual ground voltage of the driving module 20 is used as a reference, and the low level is a negative voltage. The signal balancing module 30 increases the voltage of the AM driving signal output by the control module 10 by a first preset voltage, and the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module 20 and the ground voltage of the control module 10. For example, if the ground voltage of the control module 10 is 0V and the ground voltage of the driving module 20 is 0.3V, then the first preset voltage is 0.3V minus 0V, which equals 0.3V. Then the AM driving signal output by the control module 10 (such as Figure 4 The voltage of DIS1_M1, DIS2_M1) will be increased by 0.3V by the signal balancing module 30. Assuming that the high level of the AM driving signal is 3.3V and the low level is 0.3V, the high level of the AM driving signal output after the signal balancing module 30 is boosted is 3.6V and the low level is 0.6V. The signal balancing module 30 then boosts the AM driving signal (such as Figure 4As shown in FIG. 1 , the ground voltage of the driving module 20 is output to the driving module 20. Even if the ground voltage of the driving module 20 is raised compared to the ground voltage of the control module 10, since the voltage of the AM driving signal is equal to the negative pressure formed after the ground voltage of the driving module 20 is raised, the negative pressure formed after the ground voltage of the driving module 20 is raised is offset by the first preset voltage, so that the waveform of the AM driving signal output to the driving module 20 obtained by referring to the actual ground voltage standard of the driving module 20 is still consistent with the waveform of the AM driving signal output by the control module 10. The AM driving signal output by the control module 10 matches the signal input requirement of the driving module 20. The driving module 20 can drive the backlight module load according to the normal waveform, avoiding the problem of negative pressure of the driving signal relative to the input of the driving module 20, and the driving becomes safer and more reliable.

[0033] In this embodiment, the AM driving signal output by the control module is boosted according to a first preset voltage through a signal balancing module, and the boosted first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module and the ground voltage of the control module. When the actual ground voltage of the driving module is raised, the signal output by the control module can still match the signal input requirement of the driving module, thereby avoiding negative pressure in the driving signal and making the load driving safer and more reliable.

[0034] In one embodiment, referring to Figure 2 , the signal balancing module 30 includes a voltage clamping unit 31 and a voltage supply unit 32, the voltage clamping unit 31 is connected to the control module 10 and the driving module 20, and the voltage supply unit 32 is connected to the voltage clamping unit 31; wherein the voltage supply unit 32 is used to provide a reference voltage, and the voltage clamping unit 31 is used to compare the voltage of the AM driving signal with the magnitude of the reference voltage, and clamp the voltage of the AM driving signal at different preset levels according to the comparison result. In a specific implementation, the input end of the voltage clamping unit 31 is connected to the output end of the control module 10 for outputting the AM driving signal, and the output end of the voltage clamping unit 31 is connected to the input end of the voltage supply unit 32 and the driving module 20 for receiving the AM driving signal. The voltage supply unit 32 is mainly used to provide a reference voltage for the voltage clamping unit 31, and the voltage supply unit 32 can specifically be a voltage source, etc. The AM driving signal output by the control module 10 (such as Figure 4As shown in FIG. 2 , DIS1_M1 and DIS2_M1) will first enter the voltage clamping unit 31. The voltage clamping unit 31 mainly plays the role of clamping the voltage output to the driving module 20. The voltage clamping unit 31 compares the input AM driving signal with the reference voltage provided by the voltage supply unit 32, and clamps the input AM driving signal at different preset levels according to the comparison result. The preset level may include a preset high level and a preset low level. For example, if the reference voltage provided by the voltage supply unit 32 is 2.4V, if the high level voltage of the AM driving signal output to the voltage clamping unit 31 is greater than 2.4V, the voltage clamping unit 31 can clamp the high level voltage of the AM driving signal to a preset high level voltage value. On the contrary, if the low level voltage of the AM driving signal output to the voltage clamping unit 31 is less than 2.4V, the voltage clamping unit 31 can clamp the low level voltage of the AM driving signal to a preset low level voltage value. The specific voltage values ​​of different preset levels are determined by the reference voltage provided by the voltage supply unit 32. Therefore, by adjusting the voltage value of the reference voltage provided by the voltage supply unit 32, the voltage value of the AM driving signal when clamped at different preset levels can be adjusted.

[0035] Further, refer to Figure 2, the voltage clamping unit 31 includes a first clamping device 311, the first clamping device 311 is connected to the driving module 20, the voltage supply unit 32 and the driving module 20; wherein the first clamping device 311 is used to clamp the voltage of the AM driving signal at a preset high level when the AM driving signal is greater than or equal to the reference voltage. The voltage clamping unit 31 also includes a second clamping device 312, the second clamping device 312 and the first clamping device 311 are connected to the control module 10, the driving module 20 and the voltage supply unit 32; wherein the second clamping device 312 is used to clamp the voltage of the AM driving signal at a preset low level when the AM driving signal is less than the reference voltage. In a specific implementation, the voltage clamping unit 31 is composed of a first clamping device 311 and a second clamping device 312, and the first clamping device 311 and the second clamping device 312 can be diodes, or can also be devices with a clamping function. The first clamp device 311 and the second clamp device 312 are both connected to the output end of the AM drive signal of the control module 10, and the first clamp device 311 and the second clamp device 312 are also connected to the pressure supply unit 32 and the drive module 20. The pressure supply unit 32 provides the same reference voltage for the first clamp device 311 and the second clamp device 312, and the AM drive signal is simultaneously input and output to the first clamp device 311 and the second clamp device 312. The essence of the AM drive signal is a high and low level pulse. When the high level voltage of the AM drive signal is greater than or equal to the reference voltage, the first clamp device 311 clamps the voltage of the AM drive signal at a preset high level. When the low level voltage of the AM drive signal is less than the reference voltage, the second clamp device 312 clamps the voltage of the AM drive signal at a preset low level. The specific voltage values ​​of the preset high level and the preset low level are determined by the reference voltage provided by the voltage supply unit 32. By adjusting the voltage value of the reference voltage provided by the voltage supply unit 32, the voltage value of the AM drive signal when it is clamped at the preset high level by the first clamping device 311 can be adjusted, and the voltage value of the AM drive signal when it is clamped at the preset low level by the second clamping device 312 can be adjusted.

[0036] Furthermore, the first clamp device 311 and the second clamp device 312 are both diodes, the anode of the first clamp device 311 and the cathode of the second clamp device 312 are connected to the control module 10, and the cathode of the first clamp device 311 and the anode of the second clamp device 312 are connected to the pressure supply unit 32 and the driving module 20. In a specific implementation, the first clamp device 311 and the second clamp device 312 are both diodes with the same specification parameters, such as Figure 4As shown, the first clamping device 311 is a diode D1, and the second clamping device 312 is a diode D2. By connecting the anode of the diode D1 to the cathode of the diode D2, and the cathode of the diode D1 to the anode of the diode D2, the diode D1 and the diode D2 form a bidirectional conductive device. When the voltage of the AM drive signal is at a high level, its voltage is greater than or equal to the reference voltage, and the diode D1 of the first clamping device 311 is turned on. At this time, the high level of the AM drive signal is clamped, and the voltage is clamped at the reference voltage plus the forward conduction voltage drop of the diode D1, so that the AM drive signal output to the drive module 20 is higher than the voltage of the original AM drive signal by the forward conduction voltage drop of the diode D1; when the voltage of the AM drive signal is at a low level, its voltage is less than the reference voltage, and the diode D2 of the second clamping device 312 is turned on. At this time, the high level of the AM drive signal is clamped, and the voltage is clamped at the reference voltage minus the forward conduction voltage drop of the diode D2, so that the voltage of the AM drive signal output to the drive module 20 becomes the reference voltage minus the forward conduction voltage drop of the diode D2. In general, the high-level voltage and low-level voltage of the AM driving signal output by the control module 10 are both increased. Since the amplitude of the high level is much greater than the threshold of the digital logic that the high level is greater than 2.4V, the high level of the AM driving signal is increased without affecting the high-level signal input requirement of the driving module 20. The low-level voltage of the AM driving signal is determined by the power supply and the first resistor R1. The power supply is usually fixed at 3.3V. In this way, it is only necessary to select a suitable value for the first resistor R1 so that when the AM driving signal output by the control module 10 is at a low level, the low-level voltage of the AM driving signal minus the forward conduction voltage drop of the diode D2 is equal to the first preset voltage, and the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module 20 and the ground voltage of the control module 10. In this way, when the AM driving signal is at a low level, the minimum value of the low-level voltage of the AM driving signal output to the driving module 20 is greater than or equal to the voltage value of the ground voltage of the driving module 20 being raised. Even if the ground voltage of the driving module 20 is raised, the AM driving signal output to the driving module 20 will not have a negative voltage, thereby meeting the high and low level signal input requirements of the driving module 20.

[0037] Specifically, the diode is a Schottky diode. The Schottky diode has a low forward voltage drop, usually between several hundred millivolts and several hundred millivolts, can achieve low power consumption and high efficiency conduction characteristics, and has a fast recovery time, and can be quickly turned off when the forward voltage switches from a high level to a low level. When the input AM drive signal is at a high level, the voltage of the high level is greater than the reference voltage provided by the voltage supply unit 32, and one of the Schottky diodes is forward-conducted, clamping the high level of the AM drive signal at the voltage value of the sum of the reference voltage provided by the voltage supply unit 32 and the forward conduction tube voltage drop of the Schottky diode; when the input AM drive signal is at a low level, the voltage of the low level is less than the reference voltage provided by the voltage supply unit 32, and the other Schottky diode is turned on, and the low level of the AM drive signal is clamped at the voltage value of the difference between the reference voltage provided by the voltage supply unit 32 and the reverse conduction tube voltage drop of the Schottky diode. By adjusting the reference voltage provided by the pressure supply unit 32 to a first preset voltage, where the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module 20 and the ground voltage of the control module 10, a suitable AM ​​driving signal waveform can be obtained, and negative pressure will not appear at the input of the driving module 20.

[0038] In one embodiment, referring to Figure 4 , the pressure supply unit 32 includes a power supply and a first resistor R1, one end of the first resistor R1 is connected to the power supply, and the other end is connected to the first clamp device 311, the second clamp device 312 and the driving module 20. In a specific implementation, the power supply selection is the same as the power supply voltage of the control module 10, which is usually +3V. One end of the first resistor R1 is connected to the power supply, and the other end is connected to the first clamp device 311, the second clamp device 312 and the driving module 20. After the power supply passes through the voltage drop of the first resistor R1, the voltage at the other end of the first resistor R1 ( Figure 4 The voltage is formed at the point A shown in FIG. 3 ) and is provided as a reference voltage to the first clamp device 311 and the second clamp device 312. By setting the first resistor R1 at a suitable resistance value, reference voltages of different magnitudes can be adjusted and provided to the voltage clamp unit 31.

[0039] In one embodiment, the voltage clamping unit 31 includes a bidirectional diode, one end of which is connected to the control module 10, and the other end of which is connected to the voltage supply unit 32 and the driving module 20. In a specific implementation, the voltage clamping unit 31 adopts a bidirectional diode, which has a bidirectional conduction characteristic and can conduct current under both forward and reverse voltages. When the input AM driving signal is at a high level, the voltage of the high level is greater than the reference voltage provided by the voltage supply unit 32, the bidirectional diode is forward-conducted, and the high level of the AM driving signal is clamped at a corresponding voltage value, and the specific clamped voltage value is the sum of the reference voltage provided by the voltage supply unit 32 and the forward conducting tube voltage drop of the bidirectional diode; when the input AM driving signal is at a low level, the voltage of the low level is less than the reference voltage provided by the voltage supply unit 32, the bidirectional diode is reverse-conducted, and the low level of the AM driving signal is clamped at a corresponding voltage value, and the specific clamped voltage value is the difference between the reference voltage provided by the voltage supply unit 32 and the reverse conducting tube voltage drop of the bidirectional diode. By adjusting the reference voltage provided by the pressure supply unit 32 to a first preset voltage, where the first preset voltage is greater than or equal to the voltage difference between the ground voltage of the driving module 20 and the ground voltage of the control module 10, a suitable AM ​​driving signal waveform can be obtained, and negative pressure will not appear at the input of the driving module 20.

[0040] In one embodiment, referring to Figure 3, the AM driving circuit also includes a signal enhancer module 40, and the signal balancing module 30 also includes an overshoot suppression unit 33. The signal enhancer module 40 is connected between the control module 10 and the voltage clamping unit 31, and the overshoot suppression unit 33 is connected to the voltage clamping unit 31, the pressure supply unit 32 and the driving module 20; wherein the signal enhancer module 40 is used to enhance the signal of the AM driving signal output by the control module 10 and then output it to the voltage clamping unit 31, and the overshoot suppression unit 33 is used to eliminate the overshoot of the enhanced AM driving signal. In a specific implementation, the actual control module 10 is usually connected to the driving module 20 through an FFC wire, and there is a certain impedance due to the length of the wire and the PIN spacing of the wire. The AM driving signal output by the control module 10 will be attenuated to a certain extent during the transmission process. In this embodiment, in order to avoid the attenuation of the AM driving signal, the signal enhancer module 40 is connected between the control module 10 and the signal balancing module 30 to enhance the strength of the AM driving signal. The signal enhancer module 40 is a unit module for enhancing the signal strength, which is composed of an input end, an amplifier circuit and an output end. Here, the input end of the signal enhancer module 40 is connected to the control module 10, and the output end is connected to the voltage clamping unit 31. The principle of the signal enhancer module 40 is to use the amplifier circuit to increase the power or voltage of the input AM drive signal to the required output level. Here, the signal enhancer module 40 can adopt a type based on a current amplifier, and the current of the input signal is increased by controlling the current of the amplifier. The amplifier provides sufficient current to enhance the strength of the AM drive signal. Since the signal enhancer module 40 enhances the AM drive signal, the energy of the AM drive signal becomes relatively large, and sometimes the waveform of the AM drive signal will overshoot. Overshoot refers to the instantaneous rise and fall of the voltage when the AM drive signal is converted from a low level to a high level or from a high level to a low level. The energy generated by the overshoot will become noise and electromagnetic radiation, which will affect the system. In order to avoid overshoot in the waveform of the AM driving signal after being enhanced by the signal enhancer module 40, an overshoot suppression unit 33 is connected between the voltage clamping unit 31 and the driving module 20. The overshoot suppression unit 33 can absorb the overshoot electrical energy of the AM driving signal after the signal is enhanced by the signal enhancer module 40 and stabilize the AM driving signal, thereby eliminating the overshoot phenomenon.

[0041] Further, refer to Figure 4, the overshoot suppression unit 33 includes a first capacitor C1 and a second resistor R2, one end of the second resistor R2 is connected to the voltage clamping unit 31 and the voltage supply unit 32, and the other end is connected to the driving module 20 and one end of the first capacitor C1, and the other end of the first capacitor C1 is grounded. In a specific implementation, the overshoot suppression unit 33 uses the first capacitor C1 and the second resistor R2 to eliminate the overshoot of the AM driving signal enhanced by the signal enhancement module. One end of the second resistor R2 is connected to the voltage clamping unit 31 and the voltage supply unit 32, and the other end is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the ground. The second resistor R2 can consume part of the overshoot electric energy of the enhanced AM driving signal and convert it into the form of heat energy, and the first capacitor C1 absorbs the other part of the overshoot electric energy, so that the AM driving signal output to the driving module 20 has low noise and stable waveform, which is more in line with the signal input requirements of the driving module 20.

[0042] In one embodiment, a display screen is provided, which includes an AM driving circuit, and also includes components such as a liquid crystal panel and a backlight module. The AM driving circuit is mainly used to drive the light emitted by the backlight module. The backlight module is mainly composed of a plurality of LED lamp beads, and the AM driving circuit is specifically used to drive the LED lamp beads of the backlight module to emit light. The light emitted by the backlight module is processed by the polarizer, liquid crystal material and filter of the liquid crystal panel to obtain pixels of different colors and brightness, thereby completing the function of image display. Among them, the AM driving circuit in this embodiment can adopt any one of the AM driving circuits provided by the utility model. Since the specific structure and working principle of the AM driving circuit have been introduced in detail in the previous specification, they will not be repeated here for the sake of brevity of the specification.

[0043] The display screen in this embodiment adopts the AM driving circuit provided by the utility model, so the driving reliability of the backlight module is improved. When displaying pictures, the driving signal will not have negative pressure, and the display screen is safe to use and has a longer service life.

[0044] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An AM driving circuit, characterized in that: include: A control module, used for outputting an AM driving signal; A driving module, used for driving a load according to the AM driving signal; A signal balancing module, connected to the control module and the driving module, and configured to increase the AM driving signal by a first preset voltage and then output it to the driving module; The first preset voltage is greater than or equal to a voltage difference between a ground voltage of the driving module and a ground voltage of the control module.

2. The AM driving circuit according to claim 1, characterized in that: The signal balancing module comprises a voltage clamping unit and a voltage supply unit, wherein the voltage clamping unit is connected to the control module and the driving module, and the voltage supply unit is connected to the voltage clamping unit; The voltage supply unit is used to provide a reference voltage, and the voltage clamping unit is used to compare the voltage of the AM drive signal with the reference voltage, and clamp the voltage of the AM drive signal at different preset levels according to the comparison result.

3. The AM driving circuit according to claim 2, characterized in that: The voltage clamping unit includes a first clamping device, and the first clamping device is connected to the driving module, the voltage supply unit and the driving module; Wherein, the first clamping device is used to clamp the voltage of the AM driving signal at a preset high level when the AM driving signal is greater than or equal to the reference voltage.

4. The AM driving circuit according to claim 3, characterized in that: The voltage clamping unit further includes a second clamping device, and the second clamping device and the first clamping device are commonly connected to the control module, the driving module and the voltage supply unit; The second clamping device is used to clamp the voltage of the AM driving signal at a preset low level when the AM driving signal is less than the reference voltage.

5. The AM driving circuit according to claim 4, characterized in that: The first clamp device and the second clamp device are both diodes, the anode of the first clamp device and the cathode of the second clamp device are commonly connected to the control module, and the cathode of the first clamp device and the anode of the second clamp device are commonly connected to the pressure supply unit and the drive module.

6. The AM driving circuit according to claim 4, characterized in that: The pressure supply unit includes a power supply and a first resistor, one end of the first resistor is connected to the power supply, and the other end of the first resistor is connected to the first clamping device, the second clamping device and the driving module.

7. The AM driving circuit according to claim 2, characterized in that: The voltage clamping unit includes a bidirectional diode, one end of the bidirectional diode is connected to the control module, and the other end of the bidirectional diode is connected to the voltage supply unit and the driving module.

8. The AM driving circuit according to claim 2, characterized in that: The AM driving circuit further includes a signal enhancer module, the signal balancing module further includes an overshoot suppression unit, the signal enhancer module is connected between the control module and the voltage clamping unit, and the overshoot suppression unit is connected to the voltage clamping unit, the voltage supply unit and the driving module; The signal enhancer module is used to enhance the AM driving signal output by the control module and then output it to the voltage clamping unit, and the overshoot suppression unit is used to eliminate the overshoot of the enhanced AM driving signal.

9. The AM driving circuit according to claim 8, characterized in that: The overshoot suppression unit includes a first capacitor and a second resistor, one end of the second resistor is connected to the voltage clamping unit and the voltage supply unit, the other end is connected to the driving module and one end of the first capacitor, and the other end of the first capacitor is grounded.

10. A display screen, characterized in that: Comprising the AM driving circuit as described in any one of claims 1-9.

Images