Display device
By introducing a waveform generation circuit into the power supply circuit and changing the operating frequency of the isolation voltage conversion circuit, the problem of high electromagnetic interference in the power supply circuit is solved, and the stable operation of the power supply circuit under different load conditions is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HISENSE VISUAL TECH CO LTD
- Filing Date
- 2021-09-13
- Publication Date
- 2026-06-05
Smart Images
Figure CN115811220B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, and more particularly to a display device. Background Technology
[0002] Currently, commonly used power supply circuits include power factor correction circuits and isolation voltage conversion circuits. The power factor correction circuit and isolation voltage conversion circuit process the external mains signal to obtain the power supply signal.
[0003] Typically, the isolation voltage conversion circuit in a power supply circuit performs voltage change processing at a fixed operating frequency. When operating at a fixed frequency, it is easy to generate harmonic noise with the same frequency as the operating frequency and higher-order harmonic noise with a frequency greater than the operating frequency in the conductive medium used for signal transmission, resulting in significant electromagnetic interference.
[0004] Therefore, there is a need to provide a power supply circuit to solve the problem of high electromagnetic interference in power supply circuits in related technologies. Summary of the Invention
[0005] This application provides a display device that solves the problem of high electromagnetic interference in power supply circuits in related technologies through the aforementioned power supply circuit.
[0006] Some embodiments of this application provide a display device, including a circuit board on which a power supply circuit is disposed;
[0007] The power supply circuit includes: a rectifier and filter circuit, a power factor correction circuit, an isolation voltage conversion circuit, and a waveform generation circuit; the power factor correction circuit is connected to the rectifier and filter circuit, the isolation voltage conversion circuit, and the waveform generation circuit, respectively.
[0008] The rectifier and filter circuit is used to rectify and filter the input power supply signal;
[0009] The power factor correction circuit is used to output a first supply voltage based on the signal collected from the output terminal of the power factor correction circuit and the adjustment signal generated by the waveform generation circuit.
[0010] The waveform generation circuit is used to provide an adjustment signal to the power factor correction circuit;
[0011] The isolated voltage conversion circuit is used to perform voltage conversion processing on the received first power supply voltage and output a second power supply voltage.
[0012] In some embodiments, the frequency value corresponding to the period of the adjustment signal generated by the waveform generation circuit cannot be higher than the loop bandwidth of the power factor correction circuit.
[0013] In some embodiments, the waveform generation circuit includes: a microcontroller unit, a digital-to-analog converter unit, and a third amplifier;
[0014] The output terminal of the microcontroller unit is connected to the input terminal of the digital-to-analog converter unit, and the output terminal of the digital-to-analog converter unit is connected to the non-inverting input terminal of the third amplifier; the output terminal of the third amplifier is connected to the inverting input terminal of the third amplifier, serving as the output terminal of the waveform generation circuit.
[0015] In some embodiments, the adjustment signal is a triangular wave signal.
[0016] In some embodiments, it further includes a main controller and a second controllable element;
[0017] The second controllable element is connected to both the waveform generation circuit and the main controller. The second controllable element is used to adjust the adjustment signal output by the waveform generation circuit according to the control signal sent by the main controller.
[0018] In some embodiments, the main controller detects the load size; based on a preset load threshold and the detected load size, when the load exceeds the preset load threshold, the main controller sends a first control signal to control the waveform generation circuit to stop outputting the adjustment signal;
[0019] When the load is not greater than the preset load threshold, the main controller sends a second control signal to control the waveform generation circuit to generate an output adjustment signal.
[0020] In some embodiments, the second controllable element includes an optocoupler; the input terminal of the optocoupler is connected to the motherboard, and the output terminal of the optocoupler is connected to the waveform generation circuit.
[0021] In some embodiments, the optocoupler includes a light-emitting diode and a photosensitive element;
[0022] The positive terminal of the light-emitting diode serves as the input terminal of the optocoupler and is connected to the main controller; the negative terminal of the light-emitting diode is grounded; the photosensitive element is coupled to the light-emitting diode; the output terminal of the photosensitive element serves as the output terminal of the optocoupler and is connected to the waveform generation circuit.
[0023] In some embodiments, the second controllable element includes a controllable switch;
[0024] One end of the controllable switch is connected to the power supply of the waveform generation circuit, the other end of the controllable switch is connected to the waveform generation circuit, and the control terminal of the controllable switch is connected to the main controller.
[0025] In some embodiments, the power factor correction circuit includes: a control unit, a first controllable element, an inductor, a diode, and a polarized capacitor;
[0026] The input terminal of the control unit serves as the second input terminal of the power factor correction circuit and is connected to the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit; the output terminal of the control unit is connected to the control terminal of the first controllable element.
[0027] One end of the inductor serves as the first input terminal of the power factor correction circuit and is connected to the power supply signal. The other end of the inductor is connected to the anode of the diode and the first terminal of the controllable element. The cathode of the diode is connected to the anode of the polarized capacitor and serves as the output terminal of the power factor correction circuit. The second terminal of the controllable element is connected to ground via the cathode of the polarized capacitor.
[0028] Some embodiments of this application provide a power supply circuit, including: a power factor correction circuit, an isolation voltage conversion circuit, and a waveform generation circuit;
[0029] The waveform generation circuit is used to provide an adjustment signal, which is a periodic signal;
[0030] The first input terminal of the power factor correction circuit is connected to the power supply signal, and the second input terminal of the power factor correction circuit is connected to the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit. The power factor correction circuit is used to correct the power supply signal according to the compensation signal and output a voltage signal. The compensation signal includes a composite signal of the signal output by the power factor correction circuit and the adjustment signal.
[0031] The isolated voltage conversion circuit is connected to the output terminal of the power factor correction circuit. The isolated voltage conversion circuit is used to perform voltage conversion processing on the received voltage signal and output a power supply signal.
[0032] In some embodiments, the power factor correction circuit includes: a control unit, a first controllable element, an inductor, a diode, and a polarized capacitor;
[0033] The input terminal of the control unit serves as the second input terminal of the power factor correction circuit and is connected to the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit; the output terminal of the control unit is connected to the control terminal of the first controllable element.
[0034] One end of the inductor serves as the first input terminal of the power factor correction circuit and is connected to the power supply signal. The other end of the inductor is connected to the positive terminal of the diode and the first terminal of the controllable element. The negative terminal of the diode is connected to the positive terminal of the polarized capacitor and serves as the output terminal of the power factor correction circuit. The second terminal of the controllable element is connected to the negative terminal of the polarized capacitor and grounded.
[0035] In some embodiments, the power supply circuit further includes: a first resistor, a second resistor, and a third resistor;
[0036] One end of the first resistor is connected to the output terminal of the power factor correction circuit, and the other end of the first resistor is connected to one end of the second resistor, one end of the third resistor, and the input terminal of the control unit; the other end of the second resistor is grounded; and the other end of the third resistor is connected to the waveform generation circuit.
[0037] In some embodiments, the waveform generation circuit includes: a first amplifier, a second amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a first capacitor;
[0038] The inverting input of the first amplifier is connected to a first reference signal, the non-inverting input of the first amplifier is connected to one end of the fifth resistor and one end of the sixth resistor, and the output of the first amplifier is connected to the other end of the fifth resistor and one end of the fourth resistor; the other end of the fourth resistor is connected to the inverting input of the second amplifier and one end of the first capacitor; the non-inverting input of the second amplifier is connected to a second reference signal, and the output of the second amplifier is connected to the other end of the first capacitor and the other end of the sixth resistor, serving as the output of the waveform generation circuit.
[0039] In some embodiments, the waveform generation circuit includes: a microcontroller unit, a digital-to-analog converter unit, and a third amplifier;
[0040] The output terminal of the microcontroller unit is connected to the input terminal of the digital-to-analog converter unit, and the output terminal of the digital-to-analog converter unit is connected to the non-inverting input terminal of the third amplifier; the output terminal of the third amplifier is connected to the inverting input terminal of the third amplifier, serving as the output terminal of the waveform generation circuit.
[0041] In some embodiments, the microcontroller unit and the digital-to-analog converter unit are integrated within a single chip; or, the microcontroller unit and the digital-to-analog converter unit are separated.
[0042] In some embodiments, the waveform generation circuit includes an integrator circuit and a fourth amplifier; the output terminal of the integrator circuit is connected to the non-inverting input terminal of the fourth amplifier, and the output terminal of the fourth amplifier is connected to the inverting input terminal of the fourth amplifier, serving as the output terminal of the waveform generation unit.
[0043] In some embodiments, the power supply circuit further includes: a second controllable element;
[0044] The second controllable element is connected to the waveform generation circuit and the motherboard. The second controllable element is used to adjust the adjustment signal output by the waveform generation circuit according to the control signal sent by the motherboard.
[0045] In some embodiments, the second controllable element includes an optocoupler; the input terminal of the optocoupler is connected to the motherboard, and the output terminal of the optocoupler is connected to the waveform generation circuit.
[0046] In some embodiments, the optocoupler includes a light-emitting diode and a photosensitive element;
[0047] The positive terminal of the light-emitting diode serves as the input terminal of the optocoupler and is connected to the motherboard; the negative terminal of the light-emitting diode is grounded; the photosensitive element is coupled to the light-emitting diode; the output terminal of the photosensitive element serves as the output terminal of the optocoupler and is connected to the waveform generation circuit.
[0048] In some embodiments, the second controllable element includes a controllable switch;
[0049] One end of the controllable switch is connected to the power supply of the waveform generation circuit, the other end of the controllable switch is connected to the waveform generation circuit, and the control terminal of the controllable switch is connected to the motherboard.
[0050] Some embodiments of this application provide a display device, including: a power supply circuit, a backlight element, a motherboard, and an audio output module as described in any of the first aspects;
[0051] The power supply circuit is connected to the backlight element, the motherboard, and the audio output module, and is used to provide power supply signals to the backlight element, the motherboard, and the audio output module.
[0052] The display device provided in this application includes a power supply circuit comprising: a power factor correction circuit, an isolation voltage conversion circuit, and a waveform generation circuit. The waveform generation circuit provides an adjustment signal. The first input terminal of the power factor correction circuit is connected to the power supply signal, and the second input terminal of the power factor correction circuit is connected to both the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit. The power factor correction circuit corrects the power supply signal based on a compensation signal and outputs a voltage signal. The compensation signal is a composite signal of the signal output by the power factor correction circuit and the adjustment signal. The isolation voltage conversion circuit is connected to the output terminal of the power factor correction circuit and performs voltage conversion processing on the received voltage signal to output a power supply signal. By providing the waveform generation circuit, the power factor correction circuit can continuously change the waveform of the voltage signal output by the circuit, thereby changing the operating frequency of the isolation voltage conversion circuit and reducing electromagnetic interference in the power supply circuit. Attached Figure Description
[0053] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0054] Figure 1 A schematic diagram of a power supply circuit provided in this application;
[0055] Figure 2 A schematic diagram of a power supply circuit provided in an embodiment of this application;
[0056] Figure 3 A schematic diagram of a power factor correction circuit provided in an embodiment of this application;
[0057] Figure 4 A schematic diagram illustrating the connection method between a power factor correction circuit and a waveform generation circuit provided in an embodiment of this application;
[0058] Figure 5 This is a schematic diagram of the structure of a waveform generation circuit provided in an embodiment of this application;
[0059] Figure 6 A waveform diagram illustrating the operating frequency of a power factor correction circuit and an isolation voltage conversion circuit provided in an embodiment of this application;
[0060] Figure 7 This is a schematic diagram of another waveform generation circuit provided in an embodiment of this application;
[0061] Figure 8 This is a schematic diagram of another power supply circuit provided in an embodiment of this application;
[0062] Figure 9This is a schematic diagram of another power supply circuit provided in an embodiment of this application;
[0063] Figure 10 This is a schematic diagram of the structure of the fourth power supply circuit provided in the embodiments of this application;
[0064] Figure 11 This is a schematic diagram of the structure of the fifth power supply circuit provided in the embodiments of this application;
[0065] Figure 12 This application provides a schematic diagram of a signal waveform change.
[0066] Figure 13 This is a schematic diagram of the structure of a display device provided in this application.
[0067] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0068] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application.
[0069] The following section describes the application scenarios involved in this application and the problems existing in the prior art.
[0070] Currently, power supply circuit designs typically include a power factor correction circuit and an isolation voltage conversion circuit. In some embodiments, a rectifier and filter circuit can be added before the power factor correction circuit to rectify and filter the input power supply signal before it is input to the power factor correction circuit. Figure 1 As shown, Figure 1This application provides a schematic diagram of a power supply circuit. Typically, isolation voltage conversion circuits operate at a fixed frequency. In this case, harmonic noise concentrated near the operating frequency is generated on the transmission medium, causing electromagnetic interference to the power supply circuit. The display device provided in this application aims to solve the above-mentioned technical problems in related technologies. The technical solution of this application and how it solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.
[0071] The display device provided in the following embodiments of this application includes a circuit board with a power supply circuit. Specific improvements are concentrated in the power supply circuit, which will be described in detail below. A main controller is located on the circuit board. Some display devices place the power supply circuit and the main controller on the power board and the main board respectively, while others place them on the same circuit board. This application does not limit the placement of these components.
[0072] Figure 2 This is a schematic diagram of a power supply circuit provided in an embodiment of this application. Figure 2 As shown, the power supply circuit includes: a power factor correction circuit, an isolation voltage conversion circuit, and a waveform generation circuit;
[0073] A waveform generation circuit is used to provide an adjustment signal, wherein the adjustment signal is a periodic signal. For example, the adjustment signal can be a triangular wave signal, a sine wave signal, a square wave signal, etc.
[0074] In some embodiments, in order to ensure the stability of the output voltage of the power factor correction circuit, a continuously varying periodic signal, such as a triangular wave signal, can be selected.
[0075] The first input terminal of the power factor correction circuit is connected to the power supply signal, and the second input terminal is connected to both the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit. The power factor correction circuit corrects the power supply signal based on a compensation signal, outputting a voltage signal. The compensation signal is a composite signal of the signal output from the power factor correction circuit and the adjustment signal. An isolation voltage converter circuit is connected to the output terminal of the power factor correction circuit. This circuit performs voltage conversion processing on the received voltage signal and outputs the power supply signal.
[0076] For example, in this embodiment, a waveform generation circuit is provided in the power supply circuit. The first input terminal of the power factor correction circuit in the power supply circuit is used to receive a power supply signal. This power supply signal can be a power supply signal from an external mains input or a power supply signal after rectification and filtering of the mains signal. The second input terminal of the power factor correction circuit is connected to the output terminal of the power factor correction unit and the output terminal of the waveform generation circuit. That is, the second input terminal of the power factor correction circuit can be used to receive a compensation signal synthesized from the signal collected from the output terminal of the power factor correction circuit and the adjustment signal generated by the waveform generation unit. Then, the power factor correction circuit can perform power factor correction processing on the power supply signal received at the first input terminal based on the compensation signal received at the second input terminal and output a voltage signal to the isolation voltage conversion circuit connected to the output terminal of the power factor correction circuit. After processing by the isolation voltage conversion circuit, the power supply signal is output.
[0077] In this embodiment, by connecting the waveform generation circuit to the second input terminal of the power factor correction circuit, an adjustment signal generated by the waveform generation circuit is introduced into the second input terminal of the power factor correction circuit. This allows the power factor correction circuit to perform power factor correction on the power supply signal at the first input terminal based on the adjustment signal and the compensation signal of the signal at the output terminal of the power factor correction circuit obtained by sampling. This causes a change in the amplitude of the waveform of the voltage signal output by the power factor correction circuit. Since the operating frequency of the isolation voltage conversion circuit is related to the voltage signal input to the isolation voltage conversion circuit, the voltage signal output by the isolation voltage conversion circuit, and the load connected to the output terminal, the change in the voltage signal output by the power factor correction circuit causes a change in the operating frequency of the isolation voltage conversion circuit. This solves the problem of large electromagnetic interference caused when the operating frequency of the isolation voltage conversion circuit is fixed.
[0078] In some embodiments, the maximum value of the voltage signal output by the power factor correction circuit after adjustment based on the synthesized signal must not exceed the voltage across the capacitor at the end connection of the power factor correction circuit and the required voltage of the isolation voltage conversion circuit connected to the power factor correction circuit (e.g., the operating voltage and turn-on voltage of each device in the isolation voltage conversion circuit). Furthermore, the minimum value of the voltage signal output by the power factor correction circuit after adjustment based on the synthesized signal must not cause undervoltage or other abnormalities in the isolation voltage conversion circuit, thereby ensuring the normal operation of the power supply circuit.
[0079] In some embodiments, the frequency value corresponding to the period of the adjustment signal generated by the waveform generation circuit cannot be higher than the loop bandwidth of the power factor correction circuit (e.g., 20Hz). This is to avoid the adjustment signal frequency affecting the correction effect of the power factor correction circuit and causing abnormal operation of the power factor correction circuit. Furthermore, the frequency cannot be too low, as a low frequency will affect the degree to which the electromagnetic compatibility of the power supply circuit is improved.
[0080] In some embodiments, Figure 3 A schematic diagram of a power factor correction circuit provided in an embodiment of this application is shown below. Figure 3 As shown, the power factor correction circuit includes: a control unit, a first controllable element, an inductor, a diode, and a polarized capacitor; wherein, the input terminal of the control unit serves as the second input terminal of the power factor correction circuit and is connected to the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit; the output terminal of the control unit is connected to the control terminal of the first controllable element; one end of the inductor serves as the first input terminal of the power factor correction circuit and is connected to the power supply signal, and the other end of the inductor is connected to the positive terminal of the diode and the first terminal of the controllable element; the negative terminal of the diode is connected to the positive terminal of the polarized capacitor and serves as the output terminal of the power factor correction circuit; the second terminal of the controllable element is connected to the negative terminal of the polarized capacitor and grounded. Figure 3 The component in the dashed box is a switching transistor, which is a type of component that can be selected as the first controllable element. In some embodiments, the first controllable element includes switching transistors such as MOSFETs and transistors.
[0081] For example, the control unit, based on a composite signal formed by the signal output from the output terminal of the power factor correction circuit connected to it and the adjustment signal output from the waveform generation circuit connected to it, controls the on and off frequency of the first controllable element by controlling the control terminal of the first controllable element, thereby performing power factor correction processing on the power supply signal input to the first input terminal of the power factor correction circuit, and thus obtaining the signal output by the power factor correction circuit. In some embodiments, the control unit may also be a PFC (Power Factor Correction) controller.
[0082] Based on the above embodiments, the waveform generation circuit and the control unit can be connected in the following manner. For example... Figure 4 As shown, Figure 4 This is a schematic diagram illustrating the connection between a power factor correction circuit and a waveform generation circuit, as provided in an embodiment of this application. Figure 3 Based on the structure shown, in this embodiment, the power supply circuit further includes: a first resistor R1, a second resistor R2, and a third resistor R3.
[0083] In this circuit, one end of the first resistor R1 is connected to the output terminal of the power factor correction circuit, and the other end of the first resistor R1 is connected to one end of the second resistor R2, one end of the third resistor R3, and the input terminal of the control unit. The other end of the second resistor R2 is grounded, and the other end of the third resistor R3 is connected to the waveform generation circuit. Thus, after voltage division by the three resistors, a composite compensation signal is generated at the connection of the first resistor R1, the second resistor R2, and the third resistor R3. The compensation signal can then be input to the input terminal of the control unit, so that the control unit controls the on and off frequencies of the first controllable element based on the compensation signal, thereby controlling the waveform of the voltage signal output by the power factor correction circuit, changing the operating frequency of the isolation voltage conversion circuit, and keeping the operating frequency in a variable state.
[0084] In some embodiments, the waveform generation circuit may also be selected from voltage sources, current sources, or variable resistors, etc. When the waveform generation circuit is any of the above components, it can be directly connected to... Figure 4 The other end of the third resistor R3 can also be removed, and the output terminal of this component can be directly connected to the connection point between the first resistor R1 and the second resistor R2 (i.e., Figure 4 (At the black dot in the middle).
[0085] Based on any of the above embodiments, the signal output by the waveform generation circuit can be a triangular wave signal. In this case, the waveform generation circuit may include: a first amplifier, a second amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a first capacitor. Figure 5 As shown, Figure 5 This is a schematic diagram of a waveform generation circuit provided in an embodiment of this application.
[0086] like Figure 5As shown in the diagram, the inverting input of the first amplifier is connected to the first reference signal (labeled VREF1). The non-inverting input of the first amplifier is connected to one end of the fifth resistor and one end of the sixth resistor. The output of the first amplifier is connected to the other end of the fifth resistor and one end of the fourth resistor. The other end of the fourth resistor is connected to the inverting input of the second amplifier and one end of the first capacitor. The non-inverting input of the second amplifier is connected to the second reference signal (labeled VREF2). The output of the second amplifier is connected to the other end of the first capacitor and the other end of the sixth resistor, serving as the output of the waveform generation circuit. The first amplifier can generate a square wave signal based on the first reference signal input at the inverting input and the signal received at the non-inverting input based on the sampling feedback from the fifth and sixth resistors. Then, the second amplifier integrates the square wave signal output by the first amplifier based on the second reference voltage received at the non-inverting input, the square wave signal output by the first amplifier, and the action of the first capacitor to generate a triangular wave signal. When the signal output by the waveform generation circuit is a triangular wave signal, the voltage waveform output by the power factor correction circuit will also be adjusted to a triangular wave waveform.
[0087] For example, Figure 6 This is a waveform diagram illustrating the operating frequency of a power factor correction circuit and an isolation voltage conversion circuit provided in this application embodiment. When the voltage change waveform output by the power factor correction circuit is a periodic triangular wave, the operating frequency of the isolation voltage conversion circuit will also exhibit a triangular wave curve as the output voltage changes. Furthermore, the period of the output voltage of the power factor correction circuit is the same as the period of the operating frequency of the isolation voltage conversion circuit, thereby solving the problem of electromagnetic interference generated when the isolation voltage conversion circuit operates at a fixed operating frequency.
[0088] In some embodiments, when the signal output by the waveform generation circuit is a triangular wave signal, the waveform generation circuit includes: a microcontroller unit, a digital-to-analog converter unit, and a third amplifier. For example... Figure 7 As shown, Figure 7 This is a schematic diagram of another waveform generation circuit provided in an embodiment of this application. In the figure, the output terminal of the microcontroller unit is connected to the input terminal of the digital-to-analog converter unit, the output terminal of the digital-to-analog converter unit is connected to the non-inverting input terminal of the third amplifier, and the output terminal of the third amplifier is connected to the inverting input terminal of the third amplifier, serving as the output terminal of the waveform generation circuit.
[0089] For example, in this embodiment, the microcontroller unit can be used to generate discrete adjustment signals, and then send the signals to a digital-to-analog converter unit connected to the microcontroller unit. The digital-to-analog converter unit can convert the discrete adjustment signals into continuous adjustment signals, that is, obtain an analog signal after digital-to-analog conversion. Then, the analog signal is input to the non-inverting input terminal of a third amplifier connected to the output terminal of the digital-to-analog converter unit, and the inverting input terminal of the third amplifier is connected to the output terminal of the third amplifier. Under the action of the third amplifier, the amplified adjustment signal (i.e., the adjustment signal generated by the waveform generation circuit) is output.
[0090] In some embodiments, based on the above embodiments, the microcontroller unit and the digital-to-analog converter unit are integrated within a single chip; or, the microcontroller unit and the digital-to-analog converter unit are separated.
[0091] In some embodiments, the waveform generation circuit includes an integrator circuit and a fourth amplifier; the output terminal of the integrator circuit is connected to the non-inverting input terminal of the fourth amplifier, and the output terminal of the fourth amplifier is connected to the inverting input terminal of the fourth amplifier, serving as the output terminal of the waveform generation unit.
[0092] For example, in this embodiment, the integrator circuit in the waveform generation circuit can be used to generate an adjustment signal, and the adjustment signal is input to the non-inverting input of the fourth amplifier connected to the output of the integrator circuit, and the inverting input of the fourth amplifier is connected to the output of the fourth amplifier. Under the action of the fourth amplifier, the amplified adjustment signal (i.e., the adjustment signal generated by the waveform generation circuit) is output.
[0093] In some embodiments, when the power supply circuit described above is applied to a display device, the waveform generation circuit can be directly connected to the main controller in the display device (e.g., the main controller can be placed on the main circuit board, referred to as the motherboard). The following description will use the motherboard as an example. Figure 8 As shown, Figure 8 This is a schematic diagram of another power supply circuit provided in an embodiment of this application. The diagram includes a rectifier and filter circuit, a power factor correction circuit, a waveform generation unit, and an isolation voltage conversion circuit.
[0094] The rectifier and filter circuit includes a rectifier bridge, capacitors, and inductors. The rectifier bridge rectifies the input signal, while the capacitors and inductors filter the signal. The isolation voltage circuit includes a control unit, switching elements, a transformer, diodes, and capacitors, used to transform the input voltage to obtain the desired value. For a detailed description of the power factor correction circuit and waveform generation unit, please refer to the above text; further details are omitted here.
[0095] Figure 8In the waveform generation circuit, there is an integrating circuit. The input terminal of the integrating circuit is connected to the motherboard in the display device. The integrating circuit in the waveform generation circuit integrates the square wave signal generated by the motherboard, and then amplifies it through the fourth amplifier to output the adjustment signal (i.e., the adjustment signal generated by the waveform generation circuit).
[0096] In some embodiments, Figure 9 This is a schematic diagram of another power supply circuit provided in an embodiment of this application. Figure 9 and Figure 8 In contrast, adding a second controllable component between the waveform generation circuit and the main board, such as... Figure 9 As shown, the power supply circuit also includes a second controllable element; wherein the second controllable element is connected to the waveform generation circuit and the motherboard, and the second controllable element is used to adjust the adjustment signal output by the waveform generation circuit according to the control signal sent by the motherboard.
[0097] For example, in this embodiment, the waveform generation circuit is connected to the motherboard via a second controllable element, and the second controllable element can control whether the waveform generation circuit outputs an adjustment signal based on the control signal generated by the motherboard. For instance, since the load connected to the isolation voltage conversion circuit and the operating frequency of the isolation voltage conversion circuit satisfy the relationship that the larger the load, the lower the operating frequency, the less electromagnetic interference is generated when the operating frequency is lower. Therefore, the adjustment signal output by the waveform generation circuit can be controlled based on the load size. For example, the motherboard in the display device can be used to detect the load size connected to the output terminal of the isolation voltage conversion circuit, and based on the detected load size and a preset load threshold, when the load is greater than the preset load threshold, the motherboard can send a first control signal to control the waveform generation circuit to stop outputting the adjustment signal. When the load is not greater than the preset load threshold, the motherboard can send a second control signal to control the waveform generation circuit to generate an output adjustment signal. Furthermore, through this embodiment, by setting the second controllable element, the adjustment signal output by the waveform generation circuit can be adjusted according to requirements or preset control conditions, thereby reducing the power consumption of the power supply circuit.
[0098] In some embodiments, in the actual circuit structure, the second controllable element includes an optocoupler, wherein the input end of the optocoupler is connected to the motherboard, and the output end of the optocoupler is connected to the waveform generation circuit.
[0099] For example, when the input terminal of the optocoupler is connected to the motherboard and the output terminal of the optocoupler is connected to the waveform generation circuit, the optocoupler can be used to output a signal to the waveform generation circuit when it receives a signal from the motherboard, and stop outputting when it does not receive a signal from the motherboard. For instance, when the motherboard detects that the load at the output terminal of the isolation voltage conversion circuit is not greater than a preset load threshold, it can generate a control signal, which is then sent to the waveform generation circuit connected to the output terminal of the optocoupler via the optocoupler connected to the motherboard, causing the waveform generation circuit to output. If the motherboard detects that the load at the output terminal of the isolation voltage conversion circuit is greater than the preset load threshold, and the input terminal of the optocoupler does not receive the control signal sent by the motherboard, the waveform generation circuit connected to the output terminal of the optocoupler stops outputting.
[0100] In addition, optocouplers can also serve as signal isolation devices, preventing interference between the signals at the input and output ends of the optocoupler.
[0101] Specifically, in the actual circuit connection process, the second controllable element includes an optocoupler, which comprises a light-emitting diode (LED) and a photosensitive element. The positive terminal of the LED serves as the input terminal of the optocoupler and is connected to the motherboard; the negative terminal of the LED is grounded; the photosensitive element is coupled to the LED; and the output terminal of the photosensitive element serves as the output terminal of the optocoupler and is connected to the waveform generation circuit. When a control signal is transmitted from the motherboard to the positive terminal of the LED in the optocoupler, the LED conducts and emits light. Due to the coupling between the photosensitive element and the LED, the photosensitive element conducts at this time and outputs the control signal through its output terminal.
[0102] For example, Figure 10 This is a schematic diagram of the fourth power supply circuit provided in an embodiment of this application. Figure 9 Based on this, the diagram includes a motherboard, an optocoupler, a waveform generation unit, a power factor correction circuit, an isolation voltage conversion circuit, and a filtering circuit. The waveform generation unit consists of an integrator circuit and an amplifier, with the integrator circuit composed of resistors and capacitors. The positive terminal of the LED in the optocoupler is connected to the motherboard, and the negative terminal of the LED is grounded. The phototransistor in the optocoupler is coupled to the LED. The first output terminal of the phototransistor is connected to the power supply through a resistor, and it is also connected to the input terminal of the integrator circuit in the waveform generation circuit. When the LED is turned on, the phototransistor can output a signal through its first output terminal.
[0103] The integrating circuit includes a resistor and a capacitor. One end of the resistor serves as the input terminal of the integrating circuit and is connected to the first output terminal of the phototransistor. The other end of the resistor is connected to the non-inverting input terminal of the amplifier and one end of the capacitor, while the other end of the capacitor is grounded. The inverting input terminal of the amplifier is connected to the output terminal of the amplifier, and the output terminal of the amplifier serves as the output terminal of the waveform generation circuit and is connected to the input terminal of the control unit in the power factor correction circuit.
[0104] In practical operation, the motherboard can generate a square wave signal when the load is not greater than a preset threshold (or when other conditions for activating the waveform generation circuit are met). After transmission through the optocoupler connected to the motherboard, the signal is transmitted to one end of the resistor in the integrating circuit connected to the first output terminal of the phototransistor in the optocoupler. After the action of the resistor and capacitor in the integrating circuit, the square wave signal is integrated into a triangular wave signal. Then, the triangular wave signal is input to the non-inverting input terminal of the power amplifier. After being amplified by the amplifier, it is output to the control unit in the power factor correction circuit. The control unit performs power correction on the power supply signal input to the first input terminal of the power factor correction circuit based on the combined signal of the received triangular wave signal and the signal fed back from the output terminal of the power factor correction circuit, and outputs the corrected signal.
[0105] In some embodiments, Figure 11 This is a schematic diagram of the fifth power supply circuit provided in an embodiment of this application. Figure 9 Based on the structure shown, the second controllable element includes a controllable switch; one end of the controllable switch is connected to the power supply VCC of the waveform generation circuit, the other end of the controllable switch is connected to the waveform generation circuit, and the control terminal of the controllable switch is connected to the motherboard. Specifically, the control terminal of the controllable switch can be used to receive control signals sent by the motherboard, and based on the control signals, turn on or off the power supply and the waveform generation circuit connected to both ends of the controllable switch.
[0106] For example, when the waveform generation circuit consists of a microcontroller unit, a digital-to-analog converter unit, and a third amplifier, one end of the controllable switch can be connected to the power supply terminal of the microcontroller unit, and the other end of the controllable switch can be connected to the power supply of the microcontroller unit. Then, the motherboard can output a control signal to the control terminal of the controllable switch to control whether the microcontroller unit is powered, that is, whether the waveform generation circuit outputs or stops outputting.
[0107] For example, when the waveform generation circuit includes a first amplifier, a second amplifier, a fourth resistor, a fifth resistor, a sixth resistor, and a first capacitor, one end of a controllable switch can be connected to the inverting input of the first amplifier, and the other end of the controllable switch can be connected to a voltage source that provides a reference signal to the inverting input of the first amplifier. Then, when the control terminal of the controllable switch is connected to the other end based on the control signal sent by the motherboard, the voltage source can provide a first reference voltage to the first amplifier, the first amplifier in the waveform generation circuit starts to work, and the waveform generation circuit can generate an adjustment signal.
[0108] In some embodiments, the following structure can be used to control the waveform of the modulation signal output by the waveform generation circuit.
[0109] In some embodiments, when the motherboard is connected to the input terminal of the waveform generation circuit, the motherboard is used to generate a third control signal based on the load and a first control strategy. The third control signal is used to control the amplitude change or period of the adjustment signal output by the waveform generation unit. The first control strategy is that the larger the load, the smaller the amplitude change and the larger the period of the periodic signal output by the waveform generation unit.
[0110] For example, when the waveform generation circuit includes an integrator (composed of resistors and capacitors) and a fourth amplifier, the motherboard can be connected to the input of the integrator. The integrator can integrate the square wave signal sent by the motherboard and output a triangular wave signal. After being amplified by the fourth amplifier connected to the integrator, the adjustment signal output by the waveform generation circuit is obtained. Furthermore, based on this, the motherboard can generate a square wave signal (i.e., a third control signal) according to the load and the first control strategy to control the amplitude change or period of the triangular wave signal obtained by the integrator. Figure 12 This is a schematic diagram of a signal waveform change provided in an embodiment of this application. The signal transmission change in the diagram is as follows: Figure 8Based on the circuit structure, the motherboard generates a periodic square wave signal. Each cycle consists of two duty cycle signals; the end of the first duty cycle signal (duration T1) marks the beginning of the second duty cycle signal (duration T2). After passing through an optocoupler, this signal is integrated by a resistor and capacitor circuit to generate a triangular wave, transforming the waveform from the left side of the diagram to the right side. To control the amplitude change of the output adjustment signal, the motherboard can determine the amplitude change of the waveform generation circuit's output signal by controlling the difference between the duty cycles of the two signals; the smaller the difference, the smaller the amplitude change. Alternatively, it can be determined by controlling the duration of each of the two duty cycle signals; the longer the sum of the durations of the two signals, the larger the period. Furthermore, the motherboard sends a third control signal, generated based on the load and the first control strategy, to the integrating circuit in the waveform generation circuit to change the amplitude change or period of the adjustment signal output by the waveform generation circuit.
[0111] In some embodiments, the adjustment signal output by the waveform generation circuit can also be a DC signal, a periodic signal with generalized periodicity, meaning the period of this generalized periodic signal can be infinite. When it is necessary to adjust the operating frequency of the isolation voltage converter circuit, the waveform generation circuit can be turned on to change the signal amplitude output by the power factor correction circuit, thereby changing the operating frequency of the isolation voltage converter circuit, so that the operating frequency of the isolation voltage converter circuit operates within a suitable range, improving electromagnetic compatibility issues.
[0112] In this embodiment, the adjustment signal output by the waveform generation circuit continuously adjusts the amplitude or period of the adjustment signal based on the size of the load connected to the output terminal of the isolation voltage conversion circuit. Since different loads will cause different operating frequencies of the isolation voltage conversion circuit, the amplitude and period of the adjustment signal are changed based on the load adaptability to improve the applicability of the power supply circuit.
[0113] Based on the above embodiments, when an optocoupler is provided between the motherboard and the input terminal of the waveform generation circuit, the waveform generation circuit can be controlled to output an adjustment signal when the motherboard sends a third control signal. When the motherboard does not send a third control signal, the waveform generation circuit stops outputting the adjustment signal. Furthermore, the optocoupler can achieve electrical isolation between its two ends to prevent interference. Alternatively, a control switch can be provided between the motherboard and the input terminal of the waveform generation circuit. The motherboard has a first output terminal and a second output terminal. The first output terminal can be connected to the control terminal of the control switch and is used to output a signal generated by the motherboard to control the on / off state of the control switch. The first terminal of the control switch is connected to the second output terminal of the motherboard, and the second terminal of the control switch is connected to the input terminal of the waveform generation circuit. When the motherboard controls the control switch to turn on, the first and second terminals of the control switch are connected, and the motherboard can output a third control signal through the second output terminal to cause the waveform generation circuit to generate an adjustment signal.
[0114] In some embodiments, when the motherboard is connected to the input terminal of the waveform generation circuit, the motherboard is used to generate a fourth control signal based on the load and the second control strategy. The fourth control signal is used to control the amplitude of the adjustment signal output by the waveform generation unit. The second control strategy is that the smaller the load, the higher the amplitude of the periodic signal output by the waveform generation unit.
[0115] For example, when the waveform generation circuit includes an integrator (composed of resistors and capacitors) and a fourth amplifier, the motherboard can be connected to the input of the integrator. The integrator integrates the square wave signal sent by the motherboard and outputs a triangular wave signal. This triangular wave signal is then amplified by the fourth amplifier connected to the integrator to obtain the adjustment signal output by the waveform generation circuit. Furthermore, since the operating frequency of the isolation voltage conversion circuit in the power supply circuit must be within a preset frequency range, if the input voltage of the isolation voltage conversion circuit is low, its operating frequency will exceed the preset frequency range, causing it to malfunction. When the load is small, the operating frequency of the isolation voltage conversion circuit is high. In this case, the amplitude of the adjustment signal output by the waveform generation circuit can be reduced, thereby reducing the overall amplitude of the signal output by the power factor correction circuit, so that the operating frequency of the isolation voltage conversion circuit falls within the preset frequency range. The motherboard can generate a periodic square wave signal for the fourth control signal, and each cycle consists of two duty cycle signals, with the end of the first duty cycle signal being the start of the second duty cycle signal. To control the amplitude of the output adjustment signal, when generating the fourth control signal, the sum of the two duty cycle signals in the fourth control signal can be adjusted based on the load and the second control strategy to adjust the DC component in the final generated triangular wave, thereby further adjusting the amplitude of the output triangular wave. The larger the sum of the duty cycles of the two duty cycle signals, the larger the DC component of the triangular wave, and consequently, the lower the overall amplitude of the triangular wave. Then, the waveform generation unit connected to the motherboard can obtain the adjustment signal by integrating and amplifying the fourth control signal.
[0116] In this embodiment, an adjustment signal is obtained at the input of the power factor adjustment circuit based on the fourth control signal generated by the motherboard. This not only solves the electromagnetic interference problem caused by the isolation voltage conversion circuit at a fixed operating frequency, but also adjusts the amplitude of the output adjustment signal based on the load adjustment of the fourth control signal, so that the isolation voltage conversion circuit can work within a preset frequency range and ensure that the isolation voltage conversion circuit can work normally.
[0117] Based on the above embodiments, when an optocoupler is provided between the motherboard and the input terminal of the waveform generation circuit, the motherboard can control the waveform generation circuit to output an adjustment signal when it sends a fourth control signal. When the motherboard does not send a fourth control signal, the waveform generation circuit stops outputting the adjustment signal. Furthermore, the optocoupler can achieve electrical isolation between its two ends to prevent interference. Alternatively, a switching element can be provided between the motherboard and the input terminal of the waveform generation circuit. The motherboard has a third output terminal and a fourth output terminal. The third output terminal can be connected to the control terminal of the switching element and is used to output a signal generated by the motherboard to control the switching element's on / off state. The first end of the switching element is connected to the fourth output terminal of the motherboard, and the second end of the switching element is connected to the input terminal of the waveform generation circuit. When the motherboard controls the switch to turn on, the first and second ends of the switching element are connected, and the motherboard can output a fourth control signal through the fourth output terminal to cause the waveform generation circuit to generate an adjustment signal.
[0118] In some embodiments, Figure 13 A schematic diagram of the structure of a display device provided in this application is shown below. Figure 13 As shown in the figure, the components include: the power supply circuit, backlight element, motherboard, and audio output module as described in any of the above embodiments.
[0119] The power supply circuit, connected to the backlight element, motherboard, and audio output module, provides power signals to these components. The power supply circuit can be located on a power board.
[0120] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.
[0121] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A display device, characterized in that, The device includes a circuit board on which a power supply circuit is provided; the power supply circuit includes: a rectifier and filter circuit, a power factor correction circuit, an isolation voltage conversion circuit, a waveform generation circuit, and a controller; The power factor correction circuit is connected to the rectifier filter circuit, the isolation voltage conversion circuit, and the waveform generation circuit, respectively. The rectifier and filter circuit is used to rectify and filter the input power supply signal; The power factor correction circuit is used to output a first supply voltage based on the signal collected from the output terminal of the power factor correction circuit and the adjustment signal generated by the waveform generation circuit. The waveform generation circuit is used to provide an adjustment signal to the power factor correction circuit; The isolation voltage conversion circuit is used to perform voltage conversion processing on the received first power supply voltage and output a second power supply voltage. The main controller is configured as follows: Detect the size of the load; Based on a preset load threshold and the detected load size, when the load is greater than the preset load threshold, the main controller sends a first control signal to control the waveform generation circuit to stop outputting the adjustment signal; when the load is not greater than the preset load threshold, the main controller sends a second control signal to control the waveform generation circuit to generate the output adjustment signal.
2. The display device according to claim 1, characterized in that, The frequency value corresponding to the period of the adjustment signal generated by the waveform generation circuit cannot be higher than the loop bandwidth of the power factor correction circuit.
3. The display device according to claim 1, characterized in that, The waveform generation circuit includes: a microcontroller unit, a digital-to-analog converter unit, and a third amplifier; The output terminal of the microcontroller unit is connected to the input terminal of the digital-to-analog converter unit, and the output terminal of the digital-to-analog converter unit is connected to the non-inverting input terminal of the third amplifier; the output terminal of the third amplifier is connected to the inverting input terminal of the third amplifier, serving as the output terminal of the waveform generation circuit.
4. The display device according to claim 1, characterized in that, The adjustment signal is a triangular wave signal.
5. The display device according to claim 1, characterized in that, It also includes a second controllable element; The second controllable element is connected to both the waveform generation circuit and the main controller. The second controllable element is used to adjust the adjustment signal output by the waveform generation circuit according to the control signal sent by the main controller.
6. The display device according to claim 5, characterized in that, The second controllable element includes an optocoupler; The input terminal of the optocoupler is connected to the motherboard, and the output terminal of the optocoupler is connected to the waveform generation circuit.
7. The display device according to claim 6, characterized in that, The optocoupler includes a light-emitting diode and a photosensitive element; The positive terminal of the light-emitting diode serves as the input terminal of the optocoupler and is connected to the main controller; the negative terminal of the light-emitting diode is grounded; the photosensitive element is coupled to the light-emitting diode; the output terminal of the photosensitive element serves as the output terminal of the optocoupler and is connected to the waveform generation circuit.
8. The display device according to claim 1, characterized in that, The power factor correction circuit includes: a control unit, a first controllable element, an inductor, a diode, and a polarized capacitor; The input terminal of the control unit serves as the second input terminal of the power factor correction circuit and is connected to the output terminal of the power factor correction circuit and the output terminal of the waveform generation circuit; the output terminal of the control unit is connected to the control terminal of the first controllable element. One end of the inductor serves as the first input terminal of the power factor correction circuit and is connected to the power supply signal. The other end of the inductor is connected to the positive terminal of the diode and the first terminal of the first controllable element. The negative terminal of the diode is connected to the positive terminal of the polarized capacitor and serves as the output terminal of the power factor correction circuit. The second terminal of the first controllable element is connected to the negative terminal of the polarized capacitor and grounded.