Dummy load control circuit, power panel and terminal equipment

Abstract

The invention discloses a dummy load control circuit, a power panel and terminal equipment. The dummy load control circuit comprises an energy storage module, a voltage sampling module, a switch control module and an access control module, the energy storage module is connected to the circuit power supply end; the voltage sampling module is used for generating a first control signal when the sampling voltage is greater than or equal to a preset voltage threshold; the switch control module is used for being switched off during power-off or responding to the first control signal and generating a second control signal based on working voltage conduction during standby; and the access control module is used for responding to disconnection of the second control signal, electrically disconnecting the dummy load from the output end of the power panel, and electrically connecting the dummy load with the output end of the power panel based on connection of the energy storage voltage or the working voltage when the switch control module is disconnected. According to the invention, the dummy load is automatically switched according to the on-load of the output end of the power panel, and the access of the dummy load is maintained during power-off so as to discharge the electric energy stored by the capacitor at the output end, thereby improving the safety and reliability.

Description

Technical Field

[0001] This application relates to the field of power supply technology, specifically to a dummy load control circuit, a power supply board, and a terminal device. Background Technology

[0002] With the increasing application of power supply products, for power supplies with multiple outputs, dummy loads are usually introduced into the output branches without feedback to avoid high output voltage. At the same time, the problem of increased standby power consumption after introducing dummy loads is solved by controlling the connection and disconnection of dummy loads with external signals.

[0003] However, the use of external signals to control dummy loads in related technologies has significant limitations. Furthermore, if the external signal fails to synchronize when the power is off, the energy stored in the capacitor at the power output terminal may short-circuit to the power board or cause electric shock. Summary of the Invention

[0004] In view of the above problems, this application provides a dummy load control circuit, a power supply board, and a terminal device to solve the above technical problems.

[0005] In a first aspect, this application provides a dummy load control circuit, which includes an energy storage module, a voltage sampling module, a switching control module, and an access control module, wherein:

[0006] Energy storage module, connected to the circuit power supply terminal;

[0007] The voltage sampling module is connected to the output terminal of the power board. It is used to sample the output voltage of the power board to obtain the sampled voltage, and generates a first control signal when the sampled voltage is greater than or equal to a preset voltage threshold.

[0008] The switch control module is connected to the voltage sampling module and the circuit power supply terminal. It is used to disconnect when the power is off or when the first control signal is received, and to turn on based on the working voltage provided by the circuit power supply terminal in standby mode to generate a second control signal.

[0009] The access control module is connected to the switch control module, the circuit power supply terminal, the energy storage module, and the dummy load. It is used to disconnect in response to the second control signal to electrically disconnect the dummy load from the power board output terminal, and to connect the dummy load to the power board output terminal based on the energy storage voltage provided by the energy storage module or the working voltage provided by the circuit power supply terminal when the switch control module is disconnected.

[0010] In one possible implementation of this application, the voltage sampling module includes a first voltage divider unit and a comparison unit;

[0011] One end of the first voltage divider unit is connected to the output terminal of the power board, and the other end is connected to the ground terminal. The first voltage divider node of the first voltage divider unit is connected to the comparator unit to output the sampled voltage.

[0012] The first end of the comparison unit is connected to the switch control module, the second end of the comparison unit is connected to the ground terminal, and the reference end of the comparison unit is connected to the first voltage divider node of the first voltage divider unit to receive the sampling voltage. The comparison unit is used to control the electrical conduction between the switch control module and the ground terminal when the sampling voltage is greater than or equal to a preset voltage threshold to generate a first control signal.

[0013] In one possible implementation of this application, the first voltage divider unit includes a first resistor circuit and a second resistor circuit. One end of the first resistor circuit is connected to the output terminal of the power supply board, and the other end is connected to one end of the second resistor circuit. The other end of the second resistor circuit is connected to the ground terminal, and the connection node of the first resistor circuit and the second resistor circuit is connected to the reference terminal of the comparison unit.

[0014] In one possible implementation of this application, the comparison unit includes a Zener diode, and the preset voltage threshold is equal to the turn-on voltage of the Zener diode.

[0015] In one possible implementation of this application, the switch control module includes a first switch unit, a second voltage divider unit, and a second switch unit;

[0016] One end of the first switching unit is connected to the circuit power supply terminal, and the other end is connected to one end of the second voltage divider unit. The other end of the second voltage divider unit is connected to the ground terminal. The second voltage divider node of the second voltage divider unit is connected to the control terminal of the second switching unit. The first end of the second switching unit is connected to the control module, and the second end of the second switching unit is connected to the ground terminal.

[0017] The first switching unit is used to be turned on when in standby or when powered on, and to be turned off when powered off;

[0018] The second voltage divider unit is used to generate a first drive signal based on the working voltage and output it to the second switching unit when the first switching unit is turned on.

[0019] The second switching unit is used to control the electrical connection between the access control module and the ground terminal in response to the first driving signal to generate a second control signal, and to control the electrical disconnection between the access control module and the ground terminal when the first switching unit is disconnected or when the first control signal is received.

[0020] In one possible implementation of this application, the first switching unit includes an optocoupler photodetector, and an optocoupler light emitter adapted to the optocoupler photodetector is disposed on the power board to emit light in standby or power-on mode.

[0021] In one possible implementation of this application, the access control module includes a third voltage divider unit and a third switching unit;

[0022] One end of the third voltage divider unit is connected to the energy storage module and the circuit power supply terminal, and the other end is connected to the ground terminal. The third voltage divider node of the third voltage divider unit is connected to the control terminal of the third switching unit. The first end of the third switching unit is connected to the dummy load, and the second end of the third switching unit is connected to the ground terminal.

[0023] The third voltage divider unit is used to generate a second drive signal based on the energy storage voltage or the operating voltage and output it to the third switching unit.

[0024] The third switching unit is used to control the electrical connection between the dummy load and the ground terminal in response to the second drive signal, so as to make the dummy load and the power board output terminal electrically connected, and to control the electrical disconnect between the dummy load and the ground terminal when the second control signal is received, so as to make the dummy load and the power board output terminal electrically disconnected.

[0025] In one possible implementation of this application, the energy storage module includes an energy storage capacitor with one end connected to a ground terminal and the other end connected to a circuit power supply terminal.

[0026] Secondly, this application also provides a power board, which includes a power board body, a dummy load, and a dummy load control circuit as described in the first aspect.

[0027] Thirdly, this application also provides a terminal device, which includes a device body and a dummy load control circuit, such as the one in the first aspect, or a power board, disposed on the device body.

[0028] From the above, it can be concluded that this application has the following beneficial effects:

[0029] In this application, the output voltage of the power board is sampled by a voltage sampling module, and a first control signal is generated and output to the switch control module when the sampled voltage is greater than or equal to a preset voltage threshold. The switch control module disconnects when powered down or when it receives the first control signal, so that the access control module can be turned on based on the energy storage voltage provided by the energy storage module or the working voltage provided by the circuit power supply terminal, so that the dummy load is electrically connected to the output terminal of the power board, that is, the dummy load is connected to the power circuit, which limits the drift of the output voltage or discharges the electrical energy stored in the capacitor at the output terminal of the power board, thereby improving safety and reliability.

[0030] Furthermore, the switch control module can also generate a second control signal and output it to the access control module when the circuit power supply terminal is turned on during standby. This causes the access control module to disconnect in response to the second control signal, electrically disconnecting the dummy load from the power board output terminal. In other words, the dummy load is not connected to the power circuit, thereby reducing standby power consumption. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the dummy load control circuit provided in the embodiments of this application;

[0033] Figure 2 This is a schematic diagram of the voltage sampling module provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the circuit principle of the dummy load control circuit provided in the embodiments of this application;

[0035] Figure 4 This is a schematic diagram of the switch control module provided in the embodiments of this application;

[0036] Figure 5 This is a schematic diagram of the access control module provided in the embodiments of this application. Detailed Implementation

[0037] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0038] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0039] In the embodiments of this application, it should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0040] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0041] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0042] Furthermore, in the embodiments of this application, "multiple" refers to two or more. Therefore, in the embodiments of this application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two, or more. For example, including at least one means including one, two, or more, and is not limited to which ones are included. For example, including at least one of A, B, and C, then it could include A, B, C, A and B, A and C, B and C, or A and B and C.

[0043] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0044] In the embodiments of this application, the first terminal / first end of each transistor is one of the source and the drain, and the second terminal / second end of each transistor is the other of the source and the drain. Since the source and drain of a transistor can be structurally symmetrical, they can be structurally indistinguishable. That is, the first terminal / first end and the second terminal / second end of the transistor in the embodiments of this application can be structurally indistinguishable. For example, when the transistor is a P-type transistor, the first terminal / first end is the source, and the second terminal / second end is the drain; for example, when the transistor is an N-type transistor, the first terminal / first end is the drain, and the second terminal / second end is the source.

[0045] In the circuit structure provided by the embodiments of this application, nodes such as the first node and the second node do not represent actual existing components, but rather represent the junction points of related couplings in the circuit diagram. In other words, these nodes are equivalent to the junction points of related couplings in the circuit diagram.

[0046] Before introducing the dummy load control circuit, power board, and terminal device of this application, we will first introduce the relevant background information of the embodiments of this application.

[0047] For power supplies with multiple outputs, when the output is heavily loaded, the output voltage of the output branch without feedback will inevitably drift, possibly even exceeding the withstand voltage of the output filter capacitor, causing damage to the filter capacitor. To solve this problem, related technologies usually introduce a dummy load into the output branch without feedback to limit the output voltage. However, introducing a dummy load will increase standby power consumption.

[0048] To address this, current terminal devices use external signals to control the connection and disconnection of dummy loads in their motherboard power supply. This means that dummy loads are removed during standby and connected during normal operation, thus limiting voltage spikes under heavy loads and reducing standby power consumption under light loads.

[0049] However, in some application scenarios, it is not possible to switch dummy loads using external signals. Furthermore, if the external signal fails to synchronize when the power is off, the electrical energy stored in the capacitor at the power output terminal may short-circuit to the power board through other media or cause electric shock, posing a safety hazard.

[0050] Based on this, embodiments of this application provide a dummy load control circuit, a power board, and a terminal device. The dummy load control circuit detects the output voltage of the power board to achieve automatic switching of the dummy load, thereby limiting the output voltage drift under heavy load, reducing standby power consumption under light load, and maintaining the dummy load connection when powered off to discharge the energy stored in the output capacitor, thereby improving safety and reliability.

[0051] The dummy load control circuit, power board, and terminal equipment provided in this application will be described in detail below.

[0052] First, this application provides a dummy load control circuit, which can be used in a power board or a terminal device that integrates the power board. The terminal device can be an electronic device such as a television, monitor, or large display screen.

[0053] Please see Figure 1 , Figure 1 This is a schematic diagram of a dummy load control circuit provided in an embodiment of this application. The dummy load control circuit 100 may include an energy storage module 110, a voltage sampling module 120, a switch control module 130, and an access control module 140.

[0054] The energy storage module 110 can be connected to the circuit power supply terminal; the voltage sampling module 120 can be connected to the power board output terminal to sample the output voltage of the power board (not shown in the figure) to obtain a sampled voltage, and generate a first control signal when the sampled voltage is greater than or equal to a preset voltage threshold; the switch control module 130 can be connected to the voltage sampling module 120 and the circuit power supply terminal to disconnect when powered down or when the first control signal is received, and to conduct based on the working voltage provided by the circuit power supply terminal in standby mode to generate a second control signal; the access control module 140 can be connected to the switch control module 130, the circuit power supply terminal, the energy storage module 110 and the dummy load 150 to disconnect in response to the second control signal to electrically disconnect the dummy load 150 from the power board output terminal, and to conduct based on the energy storage voltage provided by the energy storage module 110 or the working voltage provided by the circuit power supply terminal when the switch control module 130 is disconnected to electrically connect the dummy load 150 to the power board output terminal.

[0055] A power supply board can be a multi-output power module, with different output branches connected to different components to provide power. For example, in the case of an LED display, each output branch of the power supply board can be connected to a corresponding LED, thus powering and driving the LED to emit light. Furthermore, to ensure stable power supply, one or more capacitors, such as filter capacitors, can be connected to the output terminal of each output branch to improve the stability of the output voltage.

[0056] For output branches without feedback branches, in addition to connecting the components to be powered, the corresponding power board output terminal can also be connected to a dummy load 150, which is used to limit the voltage drift of the output branch.

[0057] In this embodiment, the power board can also supply power to the unit modules in the dummy load control circuit 100. Therefore, the power supply terminal of this circuit can be a voltage output terminal of the power board. For example, the power board can process the mains power through a series of processes such as rectification, filtering, step-down, and voltage regulation to generate an operating voltage suitable for each unit module in the dummy load control circuit 100, and provide it to each unit module in the dummy load control circuit 100 through the power supply terminal of this circuit.

[0058] The energy storage module 110 is connected to the circuit power supply terminal. Therefore, when the power board is connected to the power supply, such as by connecting to mains power, the circuit power supply terminal can provide the operating voltage to charge the energy storage module 110, which corresponds to the standby or power-on state of the device. In other words, the energy storage module 110 can be charged using the operating voltage output from the circuit power supply terminal when in standby or power-on state.

[0059] When the power is off, the power board is de-energized, so there is no working voltage output at the power supply end of the circuit. The energy storage module 110 stops charging and can discharge to the outside. That is, at this time, the energy storage module 110 can be used as a power supply end to supply power to each unit module in the dummy load control circuit 100.

[0060] The voltage sampling module 120 is connected to the output terminal of the power board. Therefore, when there is an output voltage at the output terminal of the power board, the voltage sampling module 120 can sample the output voltage to obtain the sampled voltage. It can be understood that there is an output voltage at the output terminal of the power board during standby or power-on, but there is no output voltage at the output terminal of the power board when power-off.

[0061] In this embodiment, the voltage sampling module 120 can generate a first control signal and output it to the switch control module 130 when the sampled voltage is greater than or equal to a preset voltage threshold. When the power board output is lightly loaded, i.e., when the device is in standby mode, the output voltage of the power board output is small, and the corresponding sampled voltage is also small. At this time, the voltage sampling module 120 will not generate the first control signal. However, when the power board output is heavily loaded, the output voltage of the power board output is large, and the corresponding sampled voltage is also large. Once the sampled voltage is greater than or equal to the preset voltage threshold, the voltage sampling module 120 generates the first control signal and outputs it to the switch control module 130.

[0062] The switch control module 130 is connected to the voltage sampling module 120, the circuit power supply terminal, and the access control module 140. When the device is in standby mode, the switch control module 130 can turn on based on the working voltage provided by the circuit power supply terminal and generate a second control signal to be output to the access control module 140. When the device is powered off or receives the first control signal, the switch control module 130 is turned off and no second control signal is generated to the access control module 140.

[0063] The access control module 140 is connected to the dummy load 150 and is used to control whether the dummy load 150 is connected to the power board output. When the access control module 140 receives the second control signal, it can determine that the device is in standby mode. In order to reduce standby power consumption, the dummy load 150 needs to be disconnected. Therefore, the access control module 140 can respond to the second control signal to disconnect, thereby breaking the circuit in the branch where the dummy load 150 is located, electrically disconnecting the dummy load 150 from the power board output, so that the dummy load 150 is not connected to the power circuit.

[0064] When the access control module 140 does not receive the second control signal, it can be determined that the switch control module 130 is disconnected. Correspondingly, either the device is powered down or the power board output is reloaded. If the device is powered down, the access control module 140 can conduct based on the energy storage voltage provided by the energy storage module 110. At this time, the branch containing the dummy load 150 is connected, and the dummy load 150 is electrically connected to the power board output. Thus, the dummy load 150 is connected to the power circuit to discharge the energy stored in the capacitor (not shown in the figure) connected to the power board output. If the power board output is reloaded, the access control module 140 can conduct based on the operating voltage provided by the circuit power supply. At this time, the branch containing the dummy load 150 is also connected, and the dummy load 150 is electrically connected to the power board output. Thus, the dummy load 150 is connected to the power circuit, limiting the output voltage drift of the power board output.

[0065] In this embodiment, the voltage sampling module 120 samples the output voltage of the power board, and generates a first control signal when the sampled voltage is greater than or equal to a preset voltage threshold. The first control signal is then output to the switch control module 130. The switch control module 130 disconnects when powered down or when it receives the first control signal, so that the access control module 140 can be turned on based on the energy storage voltage provided by the energy storage module 110 or the working voltage provided by the circuit power supply terminal. This enables the dummy load 150 to be electrically connected to the output terminal of the power board, that is, the dummy load 150 is connected to the power circuit, which limits the rise of the output voltage or discharges the energy stored in the capacitor at the output terminal of the power board, thereby improving safety and reliability.

[0066] Furthermore, the switch control module 130 can also generate a second control signal and output it to the access control module 140 when the circuit power supply terminal is turned on during standby, so that the access control module 140 disconnects in response to the second control signal, electrically disconnecting the dummy load 150 from the power board output terminal, that is, the dummy load 150 is not connected to the power circuit, thereby reducing standby power consumption.

[0067] Next, continue with Figure 1 The unit modules shown are described in detail, as well as the specific implementation methods that may be used in practical applications.

[0068] like Figure 2As shown, in some embodiments of this application, the voltage sampling module 120 may include a first voltage divider unit 1201 and a comparison unit 1202; one end of the first voltage divider unit 1201 is connected to the output terminal of the power board, and the other end is connected to the ground terminal GND. The first voltage divider node V1 of the first voltage divider unit 1201 is connected to the comparison unit 1202 to output the sampling voltage; the first end of the comparison unit 1202 is connected to the switch control module 130, the second end of the comparison unit 1202 is connected to the ground terminal GND, and the reference end of the comparison unit 1202 is connected to the first voltage divider node V1 of the first voltage divider unit 1201 to receive the sampling voltage; the comparison unit 1202 may be used to control the switch control module 130 to electrically conduct with the ground terminal GND when the sampling voltage is greater than or equal to a preset voltage threshold, so as to generate a first control signal.

[0069] In this embodiment, the first voltage divider unit 1201 can be any existing voltage divider circuit, such as a resistor voltage divider circuit. The first voltage divider unit 1201 can sample the output voltage at the power board output terminal, and the sampled voltage is output from the first voltage divider node V1 to the reference terminal of the comparison unit 1202.

[0070] After receiving the sampled voltage, the comparison unit 1202 compares it with a preset voltage threshold. If the sampled voltage is greater than or equal to the preset voltage threshold, the comparison unit 1202 is turned on, electrically connecting the switch control module 130 to the ground terminal GND, pulling the switch control module 130 low to ground. This results in a low-level first control signal, which is then output to the switch control module 130. Conversely, when there is no output voltage at the power board output or the sampled voltage at the first voltage divider node is less than the preset voltage threshold, the comparison unit 1202 is not turned on, and therefore no low-level signal (i.e., no first control signal) is output to the switch control module 130.

[0071] Please continue reading. Figure 2 In some embodiments of this application, the first voltage divider unit 1201 may include a first resistor circuit and a second resistor circuit. One end of the first resistor circuit is connected to the output terminal of the power board, and the other end is connected to one end of the second resistor circuit. The other end of the second resistor circuit is connected to the ground terminal GND. The connection node of the first resistor circuit and the second resistor circuit, that is, the first voltage divider node V1, is connected to the reference terminal of the comparison unit 1202.

[0072] In this embodiment of the application, the first resistor circuit and the second resistor circuit may each include one or more series resistors. The output voltage is sampled by voltage division through series resistors. It is understood that the number and type of resistors in series in the first resistor circuit and the second resistor circuit can be selected according to the actual application scenario, and are not limited here.

[0073] like Figure 3As shown, as an example, the first resistor circuit includes a second resistor R2 and a third resistor R3 connected in series, and the second resistor circuit includes a fourth resistor R4. The second resistor R2, the third resistor R3 and the fourth resistor R4 are connected in series to divide the output voltage LED+ at the power board output terminal. The calculation formula for the sampling voltage of the first voltage divider node V1 is (R4 / R2+R3+R4)*LED+.

[0074] In this embodiment, the output voltage LED+ at the power board output terminal is sampled by a series resistor voltage divider. This method has a simple structure, high reliability, and low component cost, resulting in a low overall cost.

[0075] Please continue reading. Figure 3 In some embodiments of this application, the comparison unit 1202 may include a Zener diode U1, and a preset voltage threshold is equal to the turn-on voltage of the Zener diode U1.

[0076] In this embodiment, the reference terminal of the Zener diode U1 is connected to the first voltage divider node V1, the cathode of the Zener diode U1 is connected to the switch control module 130, and the anode of the Zener diode U1 is connected to the ground terminal GND. When the sampling voltage of the first voltage divider node V1 is greater than or equal to the turn-on voltage of the Zener diode U1, the Zener diode U1 is turned on, pulling the switch control module 130 low to ground, that is, outputting a low-level signal, i.e., the first control signal, to the switch control module 130.

[0077] It is understood that in some other embodiments, the comparison unit 1202 may also use any existing comparator chip, which can be determined according to the actual application scenario, and is not limited here.

[0078] In this embodiment, the output voltage LED+ at the power board output terminal is sampled by using a Zener diode U1 combined with a series resistor for voltage division, in order to control the switching of the dummy load 150. Compared with the sampling of output current in related technologies, this method achieves higher accuracy and is simpler and faster.

[0079] like Figure 4As shown, in some embodiments of this application, the switch control module 130 includes a first switch unit 1301, a second voltage divider unit 1302, and a second switch unit 1303. One end of the first switch unit 1301 is connected to the circuit power supply terminal, and the other end is connected to one end of the second voltage divider unit 1302. The other end of the second voltage divider unit 1302 is connected to the ground terminal GND. The second voltage divider node V2 of the second voltage divider unit 1302 is connected to the control terminal of the second switch unit 1303. The first end of the second switch unit 1303 is connected to the access control module 140, and the second end of the second switch unit 1303 is connected to the ground terminal GND. ND; The first switching unit 1301 can be turned on in standby or power-on mode, and turned off when power-off; The second voltage divider unit 1302 can be used to generate a first drive signal based on the working voltage and output it to the second switching unit 1303 when the first switching unit 1301 is turned on; The second switching unit 1303 can be used to control the electrical connection between the access control module 140 and the ground terminal GND in response to the first drive signal to generate a second control signal, and to control the electrical disconnection between the access control module 140 and the ground terminal GND when the first switching unit 1301 is turned off or receives the first control signal.

[0080] In this embodiment of the application, the first switch unit 1301 can be turned on when the device is in standby or powered on, that is, when the power board is powered on, the first switch unit 1301 is turned on, and when the device is powered off, that is, when the power board is powered off, the first switch unit 1301 is turned off.

[0081] When the first switching unit 1301 is turned on, the second voltage divider unit 1302 can divide the operating voltage provided by the circuit power supply terminal, thereby generating a first drive signal at the second voltage divider node V2 and outputting it to the second switching unit 1303. The second switching unit 1303 can respond to the first drive signal to electrically connect the access control module 140 and the ground terminal GND, pulling the access control module 140 low to ground, that is, the generated second control signal is a low-level signal, and outputting the low-level signal to the access control module 140.

[0082] If the device is powered off, the first switch unit 1301 will be disconnected. Then, there will be no first drive signal output to the second switch unit 1303 at the second voltage divider node V2. In this case, the second switch unit 1303 will be disconnected, which will electrically disconnect the connection control module 140 from the ground terminal GND.

[0083] Alternatively, when the power board output is under heavy load, the second switching unit 1303 can also disconnect in response to the first control signal from the voltage sampling module 120, thereby electrically disconnecting the access control module 140 from the ground terminal GND.

[0084] In this embodiment, the second voltage divider unit 1302 can also be a resistor voltage divider circuit. As an example, the second voltage divider unit 1302 may include a third resistor circuit and a fourth resistor circuit, such as... Figure 3 As shown, the third resistor circuit includes a fifth resistor R5 and a sixth resistor R6, and the fourth resistor circuit includes a seventh resistor R7. The fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 are connected in series to divide the +12V working voltage from the circuit power supply terminal, thereby generating the first drive signal at the second voltage divider node V2, which is the voltage divided by the seventh resistor R7, and outputting it to the second switching unit 1303.

[0085] It is understood that the +12V operating voltage is only one example of this application. The magnitude of the operating voltage provided by the circuit power supply terminal can be determined according to the actual application scenario, and is not limited here.

[0086] In this embodiment, the second switching unit 1303 can be any existing controllable switching transistor, including but not limited to transistors, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), etc. The specific type can be selected according to the actual application scenario, and no limitation is made here.

[0087] like Figure 3 As shown, as an example, the second switching unit 1303 uses an N-type first MOS transistor Q1. The gate of the first MOS transistor Q1 is connected to the second voltage divider node V2, the source is connected to the ground terminal GND, and the drain is connected to the access control module 140.

[0088] When the first switching unit 1301 is turned on, the first MOSFET Q1 can respond to the first drive signal and pull the access control module 140 low to ground, that is, output a low-level signal, namely the second control signal, to the access control module 140.

[0089] When the first switching unit 1301 is turned off, the gate of the first MOSFET Q1 is pulled low to ground, and the first MOSFET Q1 is not turned on; or, when the Zener diode U1 is turned on, the gate of the first MOSFET Q1 is also pulled low to ground, and the first MOSFET Q1 is not turned on.

[0090] Understandable, although Figure 3 The cathode of the Zener diode U1 is connected at the connection node V4 of the fifth resistor R5 and the sixth resistor R6. However, in some other examples, the gate of the first MOSFET Q1 can also be connected to the cathode of the Zener diode U1 to receive the first control signal.

[0091] Please continue reading. Figure 3 In some embodiments of this application, the first switching unit 1301 may include an optocoupler photodetector PC2B, and an optocoupler emitter (not shown in the figure) adapted to the optocoupler photodetector PC2B is disposed on the power board to emit light in standby or power-on mode.

[0092] In this embodiment of the application, an optocoupler emitter is provided on the power board. When the power board is powered on, that is, in standby or power-on mode, the optocoupler emitter emits light, thereby driving the optocoupler receiver PC2B to conduct. When the power board is powered off, the optocoupler emitter does not emit light, thereby disconnecting the optocoupler receiver PC2B.

[0093] By cooperating with the optocoupler receiver PC2B and the optocoupler emitter on the power board, the status of the power board can be detected, thereby enabling precise control of the conduction or disconnection of the first MOSFET Q1, and thus controlling the dummy load 150.

[0094] like Figure 5 As shown, in some embodiments of this application, the access control module 140 may include a third voltage divider unit 1401 and a third switch unit 1402; one end of the third voltage divider unit 1401 is connected to the energy storage module 110 and the circuit power supply terminal, and the other end is connected to the ground terminal GND. The third voltage divider node V3 of the third voltage divider unit 1401 is connected to the control terminal of the third switch unit 1402. The first end of the third switch unit 1402 is connected to the dummy load 150, and the second end of the third switch unit 1402 is connected to the ground terminal GND. The third voltage divider unit 1401 may be used to generate a second drive signal based on the energy storage voltage or the operating voltage and output it to the third switch unit 1402. The third switch unit 1402 may be used to control the dummy load 150 to be electrically connected to the ground terminal GND in response to the second drive signal, so that the dummy load 150 is electrically connected to the power board output terminal, and to control the dummy load 150 to be electrically disconnected from the ground terminal GND when receiving the second control signal, so that the dummy load 150 is electrically disconnected from the power board output terminal.

[0095] In this embodiment of the application, the third voltage divider unit 1401 can also be a resistor voltage divider circuit. As an example, the third voltage divider unit 1401 may include a fifth resistor circuit and a sixth resistor circuit, such as... Figure 3 As shown, the fifth resistor circuit includes an eighth resistor R8 and a ninth resistor R9, and the sixth resistor circuit includes a tenth resistor R10. The eighth resistor R8, the ninth resistor R9 and the tenth resistor R10 are connected in series to divide the +12V working voltage from the circuit power supply terminal, thereby generating a second drive signal at the third voltage divider node V3, which is the voltage divided by the tenth resistor R10, and outputting it to the third switching unit 1402.

[0096] The third switching unit 1402 can also use any existing controllable switching transistor, including but not limited to transistors, MOSFETs, IGBTs, etc. The specific choice can be made according to the actual application scenario, and no limitation is made here.

[0097] like Figure 3 As shown, as an example, the third switching unit 1402 uses an N-type second MOS transistor Q2. The gate of the second MOS transistor Q2 is connected to the third voltage divider node V3, the source is connected to the ground terminal GND, and the drain is connected to the first resistor R1, which is also the dummy load 150.

[0098] In this embodiment, when the device is in standby mode, the first MOSFET Q1 is turned on, pulling the gate of the second MOSFET Q2 to ground, thereby turning off the second MOSFET Q2. The branch where the first resistor R1, i.e. the dummy load 150, is located is disconnected, thus electrically disconnected from the power board output terminal. The first resistor R1, i.e. the dummy load 150, is not connected to the power circuit.

[0099] When the power board output is under heavy load, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in series to divide the +12V working voltage provided by the power supply terminal of the circuit. The second drive signal is generated at the third voltage divider node V3 and output to the second MOSFET Q2. The second MOSFET Q2 is turned on, and the first resistor R1, i.e. the dummy load 150, is electrically connected to the power board output terminal. The first resistor R1, i.e. the dummy load 150, is connected to the power circuit.

[0100] When the power board is powered off, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in series to divide the energy storage voltage provided by the energy storage module 110. That is, the energy storage module 110 can maintain the +12V voltage for a period of time after the power board is powered off. During this period, the third voltage divider node V3 will also generate a second drive signal output to the second MOSFET Q2, driving the second MOSFET Q2 to conduct. The first resistor R1, i.e., the dummy load 150, maintains electrical connection with the output terminal of the power board and is connected to the power circuit to quickly discharge the energy stored in the capacitor at the output terminal of the power board.

[0101] Understandable, although Figure 3 In this example, the drain of the first MOSFET Q1 is connected to node V8 of the eighth resistor R8 and the ninth resistor R9. However, in some other examples, the gate of the second MOSFET Q2 can also be connected to the drain of the first MOSFET Q1 to access the second control signal.

[0102] Please continue reading. Figure 3 In some embodiments of this application, the energy storage module 110 may include an energy storage capacitor E1 with one end connected to the ground terminal GND and the other end connected to the circuit power supply terminal.

[0103] In this embodiment, the energy storage capacitor E1 can be any existing electrolytic capacitor. By connecting the energy storage capacitor E1 to the power supply terminal of the circuit, the electrical energy provided by the power supply terminal of the circuit can be stored. When the power is off, the second MOSFET Q2 is kept on, so that the dummy load 150 is always in the power circuit, and the capacitor connected to the output terminal of the power board can be discharged, thereby improving power safety, preventing accidental electric shock, and avoiding circuit damage.

[0104] like Figure 3 As shown in the embodiment of this application, a diode D1 is also connected between the circuit power supply terminal and the energy storage capacitor E1 to prevent the energy storage capacitor E1 from supplying power to the circuit power supply terminal in reverse.

[0105] The first capacitor C1 connected to the Zener diode U1, the second capacitor C2 connected to the first MOSFET Q1, and the third capacitor C3 connected to the second MOSFET Q2 can be used to filter out interference signals and improve stability.

[0106] Understandable. Figure 3 The first resistor R1 representing the dummy load 150 is only one example of this application. In other application scenarios, the dummy load 150 may also include multiple resistors, which may be connected in series and / or in parallel, without limitation here.

[0107] The following is combined Figure 3 The working principle of the dummy load control circuit provided in the embodiments of this application will be explained.

[0108] When the power board is in standby mode, the output voltage LED+ is low because the load connected to the power board output is very small. The sampling voltage at the first voltage divider node V1 is less than the turn-on voltage of the Zener diode U1, so the Zener diode U1 is not conducting. Simultaneously, since the power board is in standby mode, the circuit outputs a +12V operating voltage, and the optocoupler on the power board emits light, driving the optocoupler receiver PC2B to conduct. The fifth resistor R5, the sixth resistor R6, and the seventh resistor R7 are connected in series to divide the +12V operating voltage. A first drive signal is generated at the second voltage divider node V2 and output to the first MOSFET Q1, turning on the first MOSFET Q1. Because the first MOSFET Q1 is conducting, it pulls the gate of the second MOSFET Q2 low, preventing the second MOSFET Q2 from conducting. Therefore, the first resistor R1 (dummy load 150) is electrically disconnected from the power board output, and the first resistor R1 (dummy load 150) is not connected to the power circuit, thus not affecting standby power consumption.

[0109] When the power board output is under heavy load, the output voltage LED+ increases. When the sampling voltage at the first voltage divider node V1 is greater than or equal to the turn-on voltage of the Zener diode U1, the Zener diode U1 turns on, pulling the gate of the first MOSFET Q1 low and turning off the first MOSFET Q1. At this time, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in series to divide the +12V operating voltage from the circuit power supply terminal, thereby generating a second drive signal at the third voltage divider node V3 and outputting it to the second MOSFET Q2, driving the second MOSFET Q2 to turn on, so that the first resistor R1 (dummy load 150) is electrically connected to the power board output terminal. The first resistor R1 (dummy load 150) is connected to the power circuit, limiting the output voltage LED+ at the power board output terminal from drifting.

[0110] When the power board is powered off, the optocoupler on the power board stops emitting light, the optocoupler receiver PC2B turns off, and thus the first MOSFET Q1 turns off. At this time, due to the presence of the energy storage capacitor E1, the +12V operating voltage can be maintained for a period of time. During this period, the energy storage voltage provided by the energy storage capacitor E1 is divided by the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10. At the third voltage divider node V3, a second drive signal is generated to drive the second MOSFET Q2 to conduct, so that the first resistor R1 (dummy load 150) is electrically connected to the output terminal of the power board. The first resistor R1 (dummy load 150) is connected in the power circuit to quickly discharge the energy in the capacitor at the output terminal of the power board, so as to prevent the energy in the capacitor from short-circuiting to the power board through other media, causing circuit damage, and preventing accidental electric shock, thereby improving safety.

[0111] Based on the dummy load control circuit in the above embodiments, this application also provides a power board, which may include a power board body, a dummy load, and such as Figures 1 to 5 The corresponding dummy load control circuit in any embodiment.

[0112] Since the power board includes the present application, as described in this application Figures 1 to 5 Corresponding to the dummy load control circuit in any embodiment, the present application can be implemented as described above. Figures 1 to 5 For all the beneficial effects that the dummy load control circuit can achieve in any embodiment, please refer to the preceding description, which will not be repeated here.

[0113] Based on the above embodiments, this application also provides a terminal device, which may include a device body and a component disposed on the device body, such as... Figures 1 to 5 This corresponds to the dummy load control circuit or power supply board in any embodiment.

[0114] The terminal device can be an electronic device such as a television, monitor, or large display screen.

[0115] Because the terminal device includes the present application, as described in this application Figures 1 to 5 Corresponding to the dummy load control circuit in any embodiment, the present application can be implemented as described above. Figures 1 to 5 For all the beneficial effects that the dummy load control circuit can achieve in any embodiment, please refer to the preceding description, which will not be repeated here.

[0116] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A dummy load control circuit, characterized in that, include: Energy storage module, connected to the circuit power supply terminal; A voltage sampling module is connected to the output terminal of the power board to sample the output voltage of the power board to obtain a sampled voltage, and generates a first control signal when the sampled voltage is greater than or equal to a preset voltage threshold. A switch control module, connected to the voltage sampling module and the circuit power supply terminal, is used to disconnect when power is off or when the first control signal is received, and to turn on based on the working voltage provided by the circuit power supply terminal in standby mode to generate a second control signal; An access control module is connected to the switch control module, the circuit power supply terminal, the energy storage module, and the dummy load. It is used to disconnect in response to the second control signal, so that the dummy load is electrically disconnected from the power board output terminal, and when the switch control module is disconnected, it is turned on based on the energy storage voltage provided by the energy storage module or the working voltage provided by the circuit power supply terminal, so that the dummy load is electrically connected to the power board output terminal.

2. The dummy load control circuit according to claim 1, characterized in that, The voltage sampling module includes a first voltage divider unit and a comparison unit; One end of the first voltage divider unit is connected to the output terminal of the power board, and the other end is connected to the ground terminal. The first voltage divider node of the first voltage divider unit is connected to the comparator unit to output the sampled voltage. The first end of the comparison unit is connected to the switch control module, the second end of the comparison unit is connected to the ground terminal, and the reference end of the comparison unit is connected to the first voltage divider node of the first voltage divider unit to access the sampling voltage. The comparison unit is used to control the switch control module to be electrically connected to the ground terminal when the sampling voltage is greater than or equal to the preset voltage threshold to generate the first control signal.

3. The dummy load control circuit according to claim 2, characterized in that, The first voltage divider unit includes a first resistor circuit and a second resistor circuit. One end of the first resistor circuit is connected to the output terminal of the power board, and the other end is connected to one end of the second resistor circuit. The other end of the second resistor circuit is connected to the ground terminal. The connection node of the first resistor circuit and the second resistor circuit is connected to the reference terminal of the comparison unit.

4. The dummy load control circuit according to claim 2, characterized in that, The comparison unit includes a Zener diode, and the preset voltage threshold is equal to the turn-on voltage of the Zener diode.

5. The dummy load control circuit according to claim 1, characterized in that, The switch control module includes a first switch unit, a second voltage divider unit, and a second switch unit. One end of the first switching unit is connected to the power supply terminal of the circuit, and the other end is connected to one end of the second voltage divider unit. The other end of the second voltage divider unit is connected to the ground terminal. The second voltage divider node of the second voltage divider unit is connected to the control terminal of the second switching unit. The first end of the second switching unit is connected to the access control module, and the second end of the second switching unit is connected to the ground terminal. The first switching unit is configured to be turned on during standby or power-on, and to be turned off during power-off; The second voltage divider unit is used to generate a first drive signal based on the operating voltage and output it to the second switching unit when the first switching unit is turned on; The second switching unit is configured to control the electrical connection between the access control module and the ground terminal in response to the first driving signal to generate the second control signal, and to control the electrical disconnection between the access control module and the ground terminal when the first switching unit is disconnected or when the first control signal is received.

6. The dummy load control circuit according to claim 5, characterized in that, The first switching unit includes an optocoupler light receiver, and an optocoupler light emitter adapted to the optocoupler light receiver is disposed on the power board to emit light in standby or power-on mode.

7. The dummy load control circuit according to claim 1, characterized in that, The access control module includes a third voltage divider unit and a third switch unit; One end of the third voltage divider unit is connected to the energy storage module and the circuit power supply terminal, and the other end is connected to the ground terminal. The third voltage divider node of the third voltage divider unit is connected to the control terminal of the third switch unit. The first end of the third switch unit is connected to the dummy load, and the second end of the third switch unit is connected to the ground terminal. The third voltage divider unit is used to generate a second drive signal based on the energy storage voltage or the operating voltage and output it to the third switching unit; The third switching unit is configured to control the dummy load to be electrically connected to the ground terminal in response to the second drive signal, so as to make the dummy load electrically connected to the output terminal of the power board, and to control the dummy load to be electrically disconnected from the ground terminal when receiving the second control signal, so as to make the dummy load electrically disconnected from the output terminal of the power board.

8. The dummy load control circuit according to claim 1, characterized in that, The energy storage module includes an energy storage capacitor with one end connected to the ground terminal and the other end connected to the power supply terminal of the circuit.

9. A power supply board, characterized in that, It includes a power board body, a dummy load, and a dummy load control circuit as described in any one of claims 1-8.

10. A terminal device, characterized in that, It includes a device body and a dummy load control circuit as described in any one of claims 1-8 or a power supply board as described in claim 9, disposed on the device body.

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