Backlight constant current control circuit and television

Abstract

The present invention proposes a backlight constant current control circuit, which relates to the field of electronic display and power supply technology, including: a power management module, a mainboard module and a voltage conversion module respectively connected to the power management module, a constant current drive module connected to the voltage conversion module, the power management module is also connected to the power supply, and the constant current drive module is also connected to the mainboard module and the backlight module; the power management module converts the output voltage of the power supply into a first power supply voltage and a second power supply voltage; the voltage conversion module converts the first power supply voltage into a backlight module voltage; the mainboard module works according to the second power supply voltage to generate a backlight drive signal; the constant current drive module outputs the backlight module voltage to the backlight module when receiving the backlight drive signal. The present invention forms a TV split box system through the power management module and the mainboard module, simplifies the structure of the backlight constant current control circuit on the traditional TV screen, and realizes a slim design on the TV screen.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic display and power supply, and in particular to a backlight constant current control circuit and a television. Background Art

[0002] In the related technologies, LED (Light-emitting Diode) TVs are increasingly developing towards larger sizes and ultra-thinness. At the same time, with the rapid development and popularization of Mini-LED technology, multi-zone constant current has become the backlight control method of Mini-LED TVs. The traditional backlight constant current control circuit adopts a control structure of a box power supply and a constant current board. The structure of the box power supply in the traditional backlight constant current control circuit is complex, which makes the structure of the traditional backlight constant current control circuit complex, making it difficult to make the overall thickness of the TV extremely thin. Summary of the invention

[0003] The main purpose of the present invention is to provide a backlight constant current control circuit and a television set, aiming to solve the technical problem of the complex structure of the traditional backlight constant current control circuit.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a backlight constant current control circuit, the backlight constant current control circuit is connected to a power supply and a backlight module respectively, and the backlight constant current control circuit comprises: a power management module, a voltage conversion module and a mainboard module respectively connected to the power management module, a constant current drive module connected to the voltage conversion module, the power management module is also connected to the power supply, and the constant current drive module is also connected to the mainboard module and the backlight module;

[0006] A power management module, used for converting the output voltage of the power supply into a first power supply voltage and a second power supply voltage;

[0007] A voltage conversion module, used for converting the first power supply voltage into a backlight module voltage;

[0008] A mainboard module, used to operate according to the second power supply voltage, generate a backlight driving signal, and send the backlight driving signal to the constant current driving module;

[0009] The constant current driving module is used to output the backlight module voltage to the backlight module when receiving the backlight driving signal.

[0010] Optionally, the power management module includes a DC conversion unit, a first power conversion unit and a second power conversion unit respectively connected to the DC conversion unit;

[0011] A DC conversion unit, used for converting the output voltage of the power supply into a DC voltage;

[0012] A first power conversion unit, used for converting a DC voltage into a first power supply voltage;

[0013] The second power conversion unit is used to convert the DC voltage into a second power supply voltage.

[0014] Optionally, the voltage conversion module includes a resonant filter unit and a feedback voltage stabilizing unit, the input end of the resonant filter unit is respectively connected to the output end of the power management module and the feedback voltage stabilizing unit, the output end is respectively connected to the constant current driving module and the input end of the feedback voltage stabilizing unit, and the input end of the feedback voltage stabilizing unit is also connected to the constant current driving module;

[0015] The constant current driving module is also used to receive the first feedback voltage of the backlight module to generate a feedback signal;

[0016] A feedback voltage stabilizing unit, used for outputting a second feedback voltage according to the backlight module voltage and the feedback signal;

[0017] The resonance filtering unit is used to perform resonance processing, voltage transformation processing and rectification and filtering processing on the first power supply voltage in sequence according to the second feedback voltage to obtain the backlight module voltage.

[0018] Optionally, the resonance filtering unit includes a first LLC resonance circuit, a voltage transformation circuit and a first rectification and filtering circuit;

[0019] The first LLC resonant circuit includes a field effect transistor Q1, a field effect transistor Q2 and a resonant controller U1;

[0020] The drain of the field effect transistor Q1 is respectively connected to the power management module and the positive electrode of the filter capacitor C1, the negative electrode of the filter capacitor C1 is grounded, the gate of the field effect transistor Q1 is connected to the first pin of the resonant controller U1 through the resistor R1, the source is respectively connected to the second pin of the resonant controller U1, the drain of the field effect transistor Q2 and the transformer circuit, the gate of the field effect transistor Q2 is connected to the third pin of the resonant controller U1 through the resistor R2, the source is connected to the transformer circuit through the capacitor C2 and is grounded, the fourth pin of the resonant controller U1 is connected to the transformer circuit through the capacitor C3, the fifth pin of the resonant controller U1 is respectively connected to the positive electrode of the filter capacitor C4 and the negative electrode of the diode D1, the negative electrode of the filter capacitor C4 is grounded, the positive electrode of the diode D1 is connected to the transformer circuit, and the sixth pin of the resonant controller U1 is connected to the feedback voltage stabilization unit.

[0021] Optionally, the voltage transformation circuit includes a transformer T1;

[0022] The first input terminal of the transformer T1 is connected to the source of the field effect transistor Q1, the second input terminal is respectively connected to one end of the capacitor C2 close to the transformer T1 and one end of the capacitor C3 close to the transformer T1, the third input terminal is connected to the positive electrode of the diode D1, the fourth input terminal is grounded, and the output terminals are respectively connected to the first rectifier and filter circuit.

[0023] Optionally, the first rectifying and filtering circuit includes a diode D2, a diode D3, a diode D4 and a diode D5;

[0024] The positive electrode of the diode D2 is connected to the first output terminal of the transformer T1, the positive electrode of the diode D3 is connected to the second output terminal of the transformer T1, the negative electrode of the diode D2 is connected to the negative electrode of the diode D3, and is respectively connected to the positive electrode of the filter capacitor C5, the feedback voltage stabilizing unit and the backlight module, the first grounding terminal of the transformer T1 is connected to the negative electrode of the filter capacitor C5, and is grounded, the positive electrode of the diode D4 is connected to the third output terminal of the transformer T1, the positive electrode of the diode D5 is connected to the fourth output terminal of the transformer T1, the negative electrode of the diode D4 is connected to the negative electrode of the diode D5, and is respectively connected to the positive electrode of the filter capacitor C6 and the constant current driving module, and the second grounding terminal of the transformer T1 is connected to the negative electrode of the filter capacitor C6, and is grounded.

[0025] Optionally, the constant current driving module includes a DC power supply unit, a micro control unit and a backlight control unit respectively connected to the DC power supply unit, the DC power supply unit is connected to the voltage conversion module, the micro control unit is also respectively connected to the backlight control unit and the mainboard module, and the backlight control unit is connected to the backlight module;

[0026] The voltage conversion module is further used to convert the first power supply voltage into a constant current driving voltage;

[0027] A DC power supply unit, configured to convert the constant current driving voltage into a third power supply voltage and a fourth power supply voltage when receiving an enable signal sent by the mainboard module, so as to supply power to the micro control unit and the backlight control unit respectively;

[0028] A micro control unit, used to work according to the third power supply voltage, analyze the backlight driving signal, and output a micro control signal;

[0029] The backlight control unit is used to work according to the fourth power supply voltage and output the backlight module voltage to the backlight module when receiving the micro control signal.

[0030] Optionally, the backlight constant current control circuit further includes a logic board module connected to the main board module;

[0031] The mainboard module is also used to generate low voltage differential signals;

[0032] The logic board module is used to perform timing control on low voltage differential signals, output row and column drive signals, and control the operation of the LCD screen.

[0033] Optionally, the backlight constant current control circuit further includes a sound module connected to the mainboard module;

[0034] The power management module is also used to convert the output voltage of the power supply into the voltage of the mainboard amplifier;

[0035] The mainboard module is also used to output a sound control signal according to the mainboard power amplifier voltage to control the operation of the sound module.

[0036] In a second aspect, the present invention further provides a television set, comprising:

[0037] A backlight constant current control circuit as described in any one of the above items;

[0038] The backlight module and the liquid crystal screen are respectively connected to the backlight constant current control circuit.

[0039] The present invention provides a backlight constant current control circuit. First, the output voltage of a power supply is converted into a first power supply voltage through a voltage management module, and the first power supply voltage is converted into a backlight module voltage to the backlight module through a voltage conversion module. Secondly, the output voltage of the power supply is converted into a second power supply voltage to supply power to a mainboard module through a power management module. The mainboard module works according to the second power supply voltage to generate a backlight drive signal. Finally, the backlight module voltage is output to the backlight module according to the backlight drive signal through a constant current drive module to make the backlight module work. The power management module and the mainboard module constitute a split box system of a television, and the voltage conversion module and the constant current drive module constitute an on-screen system of the television. By arranging the power management module in the split box system of the television, the structure of the box power supply in the traditional backlight constant current control circuit and the connection line between the split box system and the on-screen system are simplified, the problem of complex structure of the traditional backlight constant current control circuit is solved, and a slim shape design on the television screen is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0041] Figure 1 It is a connection diagram of the first embodiment of the backlight constant current control circuit of the present invention;

[0042] Figure 2 This is a connection diagram of the power management module of the first embodiment of the backlight constant current control circuit of the present invention;

[0043] Figure 3 This is a connection diagram of a voltage conversion module of a second embodiment of a backlight constant current control circuit of the present invention;

[0044] Figure 4 It is a circuit principle diagram of the second embodiment of the backlight constant current control circuit of the present invention;

[0045] Figure 5 FIG. 4 is a connection diagram of a third embodiment of a backlight constant current control circuit according to the present invention.

[0046] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0049] In the present invention, the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a device or system including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a device or system. In the absence of more restrictions, an element defined by the sentence "comprising..." does not exclude the presence of other identical elements in the device or system including the element.

[0050] In addition, in the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0051] In the present invention, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and they themselves have no specific meaning. Therefore, "module", "component" or "unit" can be used in a mixed manner. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0052] In the existing technology, LED TVs are increasingly developing towards larger sizes and ultra-thinness. At the same time, with the rapid development and popularization of Mini-LED technology, multi-zone constant current has become the backlight control method for Mini-LED TVs. However, there are still some problems in the slimming of large-size Mini-LED TVs:

[0053] 1. If the traditional power supply and constant current control architecture is used, it is difficult to achieve an extremely thin overall thickness of the TV, because the key components such as the power supply and constant current, mainboard, and speakers are assembled on the screen. When the AC 100-240V input, the key power devices such as the power supply EMI (electromagnetic interference) circuit, rectifier bridge, and PFC (power factor correction) circuit, when the AC 100V input, due to thermal design considerations, the common-mode inductance of the power supply, the rectifier bridge, and the PFC inductance are relatively large. When the power board, constant current board (or light board), mainboard, and speakers are assembled on the screen, the thickness of the whole machine is greatly increased, making it difficult to design the whole machine to be slim.

[0054] 2. Large-size Mini-LED TVs use Localdimming backlight control with hundreds or thousands of partitions. The module backlight power is large and the partition voltage is low (generally 12V-36V). If the "box power supply plus constant current board" method is adopted, the transmission current of the backlight part is large, which is not conducive to the appearance design of the whole machine, thus affecting the slim appearance connection design of high-end machines. Taking a 75-inch Mini-LED TV with a partition voltage of 36V as an example, the current of the connection line between the split box power supply and the constant current board is at least 7A (if 12V partition is used, the same backlight module, the transmission line carries a larger current), and a larger transmission line is required, which is not conducive to the design of the split TV.

[0055] 3. Since the power of the large-size Mini-LED TV backlight module is relatively large, if the constant current system adopts the traditional buck or boost method, the thermal design of the buck or boost circuit is extremely difficult and the cost is very high.

[0056] In summary, because the structure of the box power supply in the traditional backlight constant current control circuit is complicated, the structure of the traditional backlight constant current control circuit is complicated, which makes it difficult to achieve an extremely thin overall thickness of the TV.

[0057] In view of the technical problem of the complex structure of the traditional backlight constant current control circuit, the present invention provides a backlight constant current control circuit, and the overall idea is as follows:

[0058] The backlight constant current control circuit is connected to the power supply and the backlight module respectively, and the backlight constant current control circuit includes: a power management module, a mainboard module and a voltage conversion module respectively connected to the power management module, and a constant current drive module connected to the voltage conversion module. The power management module is also connected to the power supply, and the constant current drive module is also connected to the mainboard module and the backlight module; the power management module is used to convert the output voltage of the power supply into a first power supply voltage and a second power supply voltage; the voltage conversion module is used to convert the first power supply voltage into a backlight module voltage; the mainboard module is used to work according to the second power supply voltage and generate a backlight drive signal; the constant current drive module is used to output the backlight module voltage to the backlight module according to the backlight drive signal.

[0059] The present invention provides a backlight constant current control circuit. First, the output voltage of a power supply is converted into a first power supply voltage through a voltage management module, and the first power supply voltage is converted into a backlight module voltage to the backlight module through a voltage conversion module. Secondly, the output voltage of the power supply is converted into a second power supply voltage to power a mainboard through a power management module, and a mainboard module works according to the second power supply voltage to generate a backlight drive signal. Finally, the backlight module voltage is output to the backlight module according to the backlight drive signal through a constant current drive module to make the backlight module work. The power management module and the mainboard module constitute a split box system of a television, and the voltage conversion module, the constant current drive module and the backlight module constitute an on-screen system of the television. By arranging the power management module in the split box system of the television, the structure of the box power supply in the traditional backlight constant current control circuit and the connection line between the split box system and the on-screen system are simplified, the problem of complex structure of the traditional backlight constant current control circuit is solved, and a slim shape design on the television screen is realized.

[0060] The structured query language injection detection method of the present invention is described in detail below with reference to the accompanying drawings and specific implementations.

[0061] Embodiment 1

[0062] Reference Figure 1 , this embodiment provides a backlight constant current control circuit 1000, the backlight constant current control circuit 1000 is connected to the power supply 2000 and the backlight module 3000 respectively, and the backlight constant current control circuit 1000 includes: a power management module 100, a voltage conversion module 200 and a mainboard module 400 respectively connected to the power management module 100, and a constant current driving module 300 connected to the voltage conversion module 200, the power management module 100 is also connected to the power supply 2000, and the constant current driving module 300 is also connected to the mainboard module 400 and the backlight module 3000;

[0063] The power management module 100 is used to convert the output voltage of the power supply into a first power supply voltage and a second power supply voltage;

[0064] The voltage conversion module 200 is used to convert the first power supply voltage into a backlight module voltage;

[0065] The mainboard module 400 is used to operate according to the second power supply voltage and generate a backlight driving signal;

[0066] The constant current driving module 300 is used to output the backlight module voltage to the backlight module according to the backlight driving signal.

[0067] In this embodiment, the mainboard module 400 can be the mainboard system of the LCD TV, and the power supply can be a 100-240V or 220V AC power supply; the first power supply voltage can be a 200-400V high-voltage output, and the second power supply voltage can be a +12V low-voltage output to power the mainboard system; the backlight module voltage is generally a 12V-36V low-voltage output to power the backlight module 3000; the backlight drive signal can be a serial signal SPI, which is used to control the constant current drive module 300, so that the constant current drive module 300 controls the backlight module voltage according to the serial signal SPI to connect to the backlight module 3000, and controls the backlight module 3000 to work.

[0068] In a specific implementation, after the TV is turned on, the output voltage of the power supply is converted into a first power supply voltage through the voltage management module 100 and output to the voltage conversion module 200, and the first power supply voltage is converted into a backlight module voltage through the voltage conversion module 200 and output to the backlight module to provide a working voltage for the backlight module 3000, and then the output voltage of the power supply is converted into a second power supply voltage through the power management module 100 and output to the mainboard module 400 to power the mainboard module 400, and the mainboard module 400 starts to work and generates a backlight drive signal to the constant current drive module 300, and finally, the backlight module voltage is output to the backlight module 300 according to the backlight drive signal through the constant current drive module 300, so that the backlight module 3000 works.

[0069] Specifically, Figure 2As shown, the power management module 100 includes a DC conversion unit 110, a first power conversion unit 120 and a second power conversion unit 130 respectively connected to the DC conversion unit 110;

[0070] A DC conversion unit 110, used to convert the output voltage of the power supply into a DC voltage;

[0071] A first power conversion unit 120, configured to convert a DC voltage into a first power supply voltage;

[0072] The second power conversion unit 130 is used to convert the DC voltage into a second power supply voltage.

[0073] In this embodiment, Figure 2 As shown, the DC conversion unit 110 includes an EMI circuit 111 (filter circuit), a rectifier bridge 112 and a PFC circuit 113 (power factor correction circuit): the EMI circuit 111 is arranged between the AC power input line and the rectifier bridge 112, and is used to filter out voltage transients and high-frequency interference in the city power grid, and also prevent the high-frequency interference generated by the switch tube in the switching power supply from being transmitted to the city power grid, forming high-frequency interference to other electrical appliances; the rectifier bridge 112 converts AC power into DC power; the PFC circuit 113 continuously adjusts the input current waveform through an appropriate control circuit to make it close to a sine wave and keep it in phase with the input grid voltage, thereby greatly improving the power factor, reducing the grid load, increasing the output power, and significantly reducing the pollution of the power adapter to the grid.

[0074] like Figure 2 As shown, the first power conversion unit 120 includes a second LLC resonant circuit 121, a main transformer 122, a second rectifier and filter circuit 123, and a second feedback voltage stabilization circuit 124 connected in sequence, the second LLC resonant circuit 121 is connected to the DC conversion unit 110, the second rectifier and filter circuit 123 is connected to the voltage conversion module 124, the second LLC resonant circuit 121, the main transformer 122 and the second rectifier and filter circuit 123 are connected in sequence to perform resonance processing, voltage transformation processing and rectification and filtering processing on the DC voltage to obtain a first power supply voltage; the second feedback voltage stabilization circuit 123 is also connected to the second LLC resonant circuit 121, and is used to output a first adjustment voltage according to the first power supply voltage, adjust the first power supply voltage output by the first power conversion unit, and ensure that the first power supply voltage is output stably. For example, taking the module power of a 75-inch Mini-LED TV of 300W as an example, if the voltage of the light strip (or light panel) is 36V, the traditional transmission line current is 8.33A. However, if the first power supply voltage in this embodiment is 400V, the connection line current is only 0.75A, and the volume of the connection line can be greatly reduced.

[0075] like Figure 2As shown, the second power conversion unit 130 includes a third LLC resonant circuit 131, an auxiliary transformer 132, a third rectifier filter circuit 133 and a third feedback voltage stabilizing circuit 135 connected in sequence, the third LLC resonant circuit 131 is connected to the DC conversion unit 110, the third rectifier filter circuit 133 is connected to the mainboard module 400, the third LLC resonant circuit 131, the auxiliary transformer 132, and the third rectifier filter circuit 133 are connected in sequence to perform resonance processing, voltage transformation processing and rectification and filtering processing on the DC voltage to obtain a second power supply voltage; the third feedback voltage stabilizing circuit 135 is also connected to the third LLC resonant circuit 131, and is used to output a second adjustment voltage according to the second power supply voltage, adjust the second power supply voltage output by the second power conversion unit 130, and ensure that the second power supply voltage is output stably. The second LLC resonant circuit 121 is also connected to the third LLC resonant circuit 131 and the auxiliary transformer 132 respectively.

[0076] In this embodiment, the second LLC resonant circuit 121 and the third LLC resonant circuit 131 can be the same LLC resonant circuit, the second rectifier and filter circuit 123 and the third rectifier and filter circuit 133 can be the same rectifier and filter circuit, and the second feedback voltage stabilization circuit 124 and the third feedback voltage stabilization circuit 135 can be the same feedback voltage stabilization circuit.

[0077] In a specific implementation, after the TV is turned on, the output voltage of the power supply is converted into a DC voltage through the DC conversion unit 110 and output to the first power conversion unit 120. The DC voltage is converted into a first power supply voltage through the first power conversion unit 120 and output to the voltage conversion module 200. The DC voltage is also converted into a second power supply voltage through the second power conversion unit 130 to power the mainboard module 400.

[0078] The present embodiment provides a backlight constant current control circuit, which is composed of a power management module and a mainboard module to form a split box system of a television, and a voltage conversion module, a constant current drive module and a backlight module to form an on-screen system of the television. By setting the power management module in the split box system of the television, key power devices such as the EMI circuit, the rectifier bridge and the PFC circuit are set in the power management module of the split box system, thereby simplifying the structure of the traditional backlight constant current control circuit. The power management module is used to first convert the output voltage of the power supply, and then transferred to the constant current drive module through the voltage conversion module, thereby simplifying the connection line between the voltage conversion module and the constant current drive module. The height of the split box system does not affect the thickness of the entire machine on the screen. Therefore, the problem of complex structure of the traditional backlight constant current control circuit is solved, and a slim design on the TV screen is achieved.

[0079] This embodiment also sets a feedback voltage stabilization circuit in the first power conversion unit and the second power conversion unit to adjust the output voltage of the first power conversion unit and the second power conversion unit, thereby ensuring the stability of the output voltage of the first power conversion unit and the second power conversion unit.

[0080] Embodiment 2

[0081] Further, see Figure 3 This embodiment provides a second embodiment of a backlight constant current control circuit. Based on the above embodiment 1, the voltage conversion module 200 includes a resonant filter unit 210 and a feedback voltage stabilizing unit 220. The input end of the resonant filter unit 210 is respectively connected to the output end of the power management module 100 and the feedback voltage stabilizing unit 220, and the output end is respectively connected to the input end of the constant current driving module 300 and the feedback voltage stabilizing unit 220. The input end of the feedback voltage stabilizing unit 220 is also connected to the constant current driving module 300.

[0082] The constant current driving module 300 is further used to generate a feedback signal according to the first feedback voltage of the backlight module 3000;

[0083] The feedback voltage stabilizing unit 220 is used to output a second feedback voltage according to the backlight module voltage and the feedback signal;

[0084] The resonance filtering unit 210 is used to perform resonance processing, voltage transformation processing and rectification and filtering processing on the first power supply voltage in sequence according to the second feedback voltage, so as to convert the first power supply voltage into a backlight module voltage.

[0085] In this embodiment, Figure 3 As shown, the resonance filtering unit 210 may include a first LLC resonance circuit 211, a voltage conversion circuit 212 and a first rectification and filtering circuit 213. The first LLC resonance circuit 211 is connected to the power management module 100. The first LLC resonance circuit 211, the voltage conversion circuit 212 and the first rectification and filtering circuit 213 are connected in sequence. The first power supply voltage output by the power management module 100 is subjected to resonance processing, voltage conversion processing and rectification and filtering processing to obtain a backlight module voltage. The first rectification and filtering circuit 213 is connected to the constant current driving module 300 to transfer the backlight module voltage to the backlight module 3000 to provide a working voltage for the backlight module 3000. The feedback voltage stabilizing unit 220 is respectively connected to the first rectification and filtering circuit 213, the constant current driving module 300 and the first LLC resonance circuit 211. According to the backlight module voltage and the feedback signal of the constant current driving module 300, the second feedback voltage is output to adjust the backlight module voltage output by the resonance filtering unit 210.

[0086] In a specific implementation, after the TV is turned on, the first power supply voltage is subjected to resonance processing, voltage transformation processing and rectification and filtering processing in sequence through the resonance filter unit 210, and the first power supply voltage is converted into a backlight module voltage to provide a working voltage for the backlight module 3000, and a feedback signal is obtained from the constant current drive module 300 through the feedback voltage stabilization unit 220, and the backlight module voltage is collected from the resonance filter unit 210, and the backlight module voltage output by the resonance filter unit 210 is adjusted according to the backlight module voltage and the feedback signal to ensure the stability of the backlight module voltage, adjust the voltage difference between the light strips (or light panels) of the backlight module partitions, and reduce the temperature rise of the constant current drive module 300.

[0087] Specifically, Figure 4 As shown, the resonance filtering unit 210 includes a first LLC resonance circuit 211, a voltage transformation circuit 212 and a first rectification and filtering circuit 213;

[0088] The first LLC resonant circuit 211 includes a field effect transistor Q1, a field effect transistor Q2 and a resonant controller U1;

[0089] The drain of the field effect transistor Q1 is respectively connected to the power management module 100 and the positive electrode of the filter capacitor C1, the negative electrode of the filter capacitor C1 is grounded, the gate of the field effect transistor Q1 is connected to the first pin HO of the resonant controller U1 through the resistor R1, the source is respectively connected to the second pin HB of the resonant controller U1, the drain of the field effect transistor Q2 and the transformer circuit 212, the gate of the field effect transistor Q2 is connected to the third pin LO of the resonant controller U1 through the resistor R2, the source is connected to the transformer circuit 212 through the capacitor C2 and is grounded, the fourth pin CS of the resonant controller U1 is connected to the transformer circuit 212 through the capacitor C3, the fifth pin VCC of the resonant controller U1 is respectively connected to the positive electrode of the filter capacitor C4 and the negative electrode of the diode D1, the negative electrode of the filter capacitor C4 is grounded, the positive electrode of the diode D1 is connected to the transformer circuit 212, and the sixth pin FB of the resonant controller U1 is connected to the feedback voltage stabilization unit 220.

[0090] In this embodiment, Figure 4 As shown, the backlight module voltages Vled1+, Vled2+...Vledn+ correspond to the first feedback voltages Vled1-, Vled2-...Vledn-, respectively, representing the positive and negative poles of the partitioned light strips (or light panels) of the backlight module, indicating that the backlight module is divided into n partitions.

[0091] In a specific implementation, after the TV is turned on, the drain of the field effect transistor Q1 is connected to the power management module 100 and the positive electrode of the filter capacitor C1 respectively, the negative electrode of the filter capacitor C1 is grounded, and the first power supply voltage is received from the power management module 100. The gate of the field effect transistor Q1 is connected to the first pin HO of the resonance controller U1 through the resistor R1, and the source is connected to the second pin HB of the resonance controller U1, the drain of the field effect transistor Q2 and the transformer circuit respectively. The field effect transistor Q1 receives the high drive signal output by the first pin HO of the resonance controller U1, is turned on according to the high drive signal, and is connected to the first power supply voltage; the gate of the field effect transistor Q2 is connected to the third pin LO of the resonance controller U1 through the resistor R2, the source is connected to the transformer circuit through the capacitor C2, and is grounded, and the field effect transistor Q2 receives the resonance control The third pin LO of the resonant controller U1 outputs a low driving signal, and is turned on according to the low driving signal. The fourth pin CS of the resonant controller U1 is connected to the transformer circuit through the capacitor C3 to realize the soft start of the resonant controller U1. The fifth pin VCC of the resonant controller U1 is respectively connected to the positive electrode of the filter capacitor C4 and the negative electrode of the diode D1 to provide the working voltage of the resonant controller U1. The negative electrode of the filter capacitor C4 is grounded, and the positive electrode of the diode D1 is connected to the transformer circuit. The sixth pin FB of the resonant controller U1 is connected to the feedback voltage stabilizing unit 220. The resonant controller U1 adjusts the backlight module voltage Vledn+ according to the signal output by the feedback voltage stabilizing unit 220; the first power supply voltage is resonated through the field effect transistor Q1, the field effect transistor Q2 and the resonant controller U1 and then output to the transformer circuit.

[0092] Specifically, the voltage transformation circuit 212 includes a transformer T1;

[0093] The first input terminal 1 of the transformer T1 is connected to the source of the field effect transistor Q1, the second input terminal 2 is respectively connected to one end of the capacitor C2 close to the transformer and one end of the capacitor C3 close to the transformer, the third input terminal 3 is connected to the positive electrode of the diode D1, the fourth input terminal 4 is grounded, and the output terminals are respectively connected to the first rectifier and filter circuit 213.

[0094] In a specific implementation, after the TV is turned on, the first input terminal 1 of the transformer T1 is connected to the source of the field effect transistor Q1, the second input terminal 2 is respectively connected to one end of the capacitor C2 close to the transformer and one end of the capacitor C3 close to the transformer, the third input terminal 3 is connected to the positive electrode of the diode D1, the fourth input terminal 4 is grounded, and the output terminals are respectively connected to the first rectifier and filter circuit 213, and the first supply voltage is transformed by the transformer T1 and output to the first sorting and filtering circuit 213.

[0095] Specifically, the first rectifying and filtering circuit 213 includes a diode D2, a diode D3, a diode D4 and a diode D5;

[0096] The positive electrode of the diode D2 is connected to the first output terminal 5 of the transformer T1, the positive electrode of the diode D3 is connected to the second output terminal 6 of the transformer T1, the negative electrode of the diode D2 is connected to the negative electrode of the diode D3, and is respectively connected to the positive electrode of the filter capacitor C5, the feedback voltage stabilizing unit and the backlight module, the first grounding terminal 7 of the transformer T1 is connected to the negative electrode of the filter capacitor C5 and is grounded, the positive electrode of the diode D4 is connected to the third output terminal 8 of the transformer T1, the positive electrode of the diode D5 is connected to the fourth output terminal 9 of the transformer T1, the negative electrode of the diode D4 is connected to the negative electrode of the diode D5, and is respectively connected to the positive electrode of the filter capacitor C6 and the constant current driving module, and the second grounding terminal 10 of the transformer T1 is connected to the negative electrode of the filter capacitor C6 and is grounded.

[0097] In this embodiment, Figure 4 As shown, the feedback voltage stabilization unit 220 may be a first feedback voltage stabilization circuit 221 , and the first feedback voltage stabilization circuit 221 may be the same feedback voltage stabilization circuit as the second feedback voltage stabilization circuit 124 and the third feedback voltage stabilization circuit 135 .

[0098] In a specific implementation, the positive electrode of the diode D2 is connected to the first output terminal 5 of the transformer T1, the positive electrode of the diode D3 is connected to the second output terminal 6 of the transformer T1, the negative electrode of the diode D2 is connected to the negative electrode of the diode D3, and is respectively connected to the positive electrode of the filter capacitor C5, the first feedback voltage stabilization circuit and the backlight module, the first ground terminal 7 of the transformer T1 is connected to the negative electrode of the filter capacitor C5, and is grounded, the first power supply voltage after the voltage transformation is rectified and filtered, the backlight module voltage is output, and the working voltage of the backlight module is provided; the positive electrode of the diode D4 is connected to the third output terminal 8 of the transformer T1, the positive electrode of the diode D5 is connected to the fourth output terminal 9 of the transformer T1, the negative electrode of the diode D4 is connected to the negative electrode of the diode D5, and is respectively connected to the positive electrode of the filter capacitor C6 and the constant current drive module, the second ground terminal 10 of the transformer T1 is connected to the negative electrode of the filter capacitor C6, and is grounded, the first power supply voltage after the voltage transformation is rectified and filtered, and the constant current drive voltage is output. Specifically, the first feedback voltage stabilizing circuit 221 outputs a second feedback voltage to adjust the backlight module voltage output by the resonant filter unit according to the backlight module voltage and the feedback signal of the constant current driving module, thereby ensuring the stability of the output backlight module voltage and adjusting the voltage difference between the backlight module partition light strips (or light panels) to reduce the temperature rise of the constant current control chip.

[0099] Specifically, the constant current driving module 300 includes a DC power supply unit 310, a micro control unit 320 and a backlight control unit 330 respectively connected to the DC power supply unit 310, the DC power supply unit 310 is connected to the voltage conversion module 200, the micro control unit 320 is also respectively connected to the backlight control unit 330 and the mainboard module 400, and the backlight control unit 330 is connected to the backlight module 3000;

[0100] The voltage conversion module 200 is further used to convert the first supply voltage into a constant current driving voltage;

[0101] The DC power supply unit 310 is used to convert the constant current driving voltage into a third power supply voltage and a fourth power supply voltage when receiving an enable signal sent by the mainboard module, so as to supply power to the micro control unit 320 and the backlight control unit 330 respectively;

[0102] The micro control unit 320 is used to work according to the third power supply voltage, analyze the backlight driving signal, and output a micro control signal;

[0103] The backlight control unit 330 is used to work according to the fourth power supply voltage, and output the backlight module voltage to the backlight module when receiving the micro control signal.

[0104] In this embodiment, the micro control signal can be a micro control signal output by the micro control unit 320 after parsing and software algorithm of the serial signal SPI output by the main board module 400, which can be used to control the light bar (or light board) of the backlight module and the current of the partition, thereby realizing the partition dimming function of the backlight module of the entire TV screen. Figure 4 As shown, the feedback signal of the constant current driving module 300 may be a feedback signal output by the backlight control unit 330 .

[0105] In a specific implementation, after the TV is turned on, the first power supply voltage is converted into a constant current driving voltage through the voltage conversion module 200. After receiving the constant current driving voltage and the enable signal from the mainboard module 400 through the DC power supply unit 310, the constant current driving voltage is converted into a third power supply voltage and a fourth power supply voltage to provide working voltages for the micro control unit 320 and the backlight control unit 330 respectively. Then, the micro control unit 320 outputs a micro control signal according to the third power supply voltage and the backlight driving signal output by the mainboard module 400. Finally, the backlight control unit 330 works according to the fourth power supply voltage. When the micro control signal is received, the backlight module voltage is controlled to be connected to the backlight module to control the operation of the backlight module. In addition, the backlight control unit 330 outputs a feedback signal to the feedback voltage stabilizing unit so that the feedback voltage stabilizing unit outputs a second feedback voltage according to the feedback signal and the backlight module voltage.

[0106] The present embodiment provides a backlight constant current control circuit, which converts a first power supply voltage into a backlight module voltage and a constant current driving voltage through a resonant filtering unit, and controls the backlight module voltage to be directly connected to the backlight module according to the constant current driving voltage and the backlight driving signal output by the mainboard module through a constant current driving module, thereby controlling the operation of the backlight module and realizing direct-drive partitioned constant current driving of the backlight module.

[0107] This embodiment also sets a feedback voltage stabilization unit in the voltage conversion module to obtain the feedback signal output by the backlight module voltage and the constant current driving module, adjusts the output backlight module voltage, ensures the stability of the output backlight module voltage, and reduces the temperature rise of the constant current control chip.

[0108] Embodiment 3

[0109] Further, see Figure 5 , this embodiment provides a third embodiment of a backlight constant current control circuit 1000. Based on any one of the above embodiments 1 to 2, the backlight constant current control circuit 1000 further includes a logic board module 500 connected to the main board module 400;

[0110] The mainboard module 400 is also used to generate a low voltage differential signal LVDS;

[0111] The logic board module 500 is used to perform timing control on the low voltage differential signal LVDS, output row and column driving signals, and control the operation of the liquid crystal screen.

[0112] In this embodiment, the LCD screen can be a Mini-LED LCD display screen, and the logic board module 500 can be a T-CON board (timing control circuit, Timing Controller). The T-CON board can control the timing of the low-voltage differential signal LVDS sent by the main board module 400 on the logic board and convert it into the row and column driving signals required by the LCD screen glass substrate to drive the LCD screen to display images.

[0113] In a specific implementation, after the TV is turned on, the mainboard module 400 outputs a low voltage differential signal LVDS according to the second power supply voltage, and the logic board module 500 outputs row and column drive signals according to the low voltage differential signal LVDS to drive the LCD screen to display images.

[0114] Specifically, Figure 5 As shown, the backlight constant current control circuit 1000 also includes a sound module 600 connected to the mainboard module 400;

[0115] The power management module 100 is also used to convert the output voltage of the power supply into the mainboard power amplifier voltage;

[0116] The mainboard module 400 is also used to output a sound control signal according to the mainboard power amplifier voltage to control the operation of the sound module 600.

[0117] In this embodiment, the sound module 600 may be an external speaker, such as Figure 2As shown, the second power conversion unit 130 also includes a fourth rectifier and filter circuit 134, which is connected to the auxiliary transformer 132 and the mainboard module 400 respectively, and the DC voltage is resonated, transformed and rectified and filtered in sequence through the third LLC resonant circuit 131, the auxiliary transformer 132 and the fourth rectifier and filter circuit 134 to obtain the mainboard power amplifier voltage. Among them, the second rectifier and filter circuit 123, the third rectifier and filter circuit 133 and the fourth rectifier and filter circuit 134 can be the same rectifier and filter circuit.

[0118] In a specific implementation, after the TV is turned on, the output voltage of the power supply 2000 is converted into a mainboard amplifier voltage through the power management module 100 to power the sound module 600, and the mainboard module 400 outputs a sound control signal according to the second power supply voltage to control the sound module 600 to make sound.

[0119] This embodiment proposes a backlight constant current control circuit, which simplifies the structure of the traditional backlight constant current control circuit and the connection lines between the split box system and the on-screen system by placing the sound module of the TV in a split box system, thereby solving the problem of the complex structure of the traditional backlight constant current control circuit and realizing a slim design on the TV screen.

[0120] Embodiment 4

[0121] Based on the above embodiment, this embodiment provides a television set, which may include:

[0122] The backlight constant current control circuit 1000 of the above embodiment;

[0123] The backlight module 3000 and the liquid crystal screen are connected to the backlight constant current control circuit 1000 respectively.

[0124] In a specific implementation, the television is connected to the power supply 2000. After the television is turned on, the output voltage of the power supply is converted into a first power supply voltage through the power management module 100 and output to the voltage conversion module 200. The first power supply voltage is converted into a backlight module voltage through the voltage conversion module 200 to provide a power supply voltage for the backlight module 3000. A backlight drive signal is also output to the constant current drive module 300 through the mainboard module 400. The backlight module voltage is connected to the backlight module 3000 according to the backlight drive signal through the constant current drive module 300 to make the backlight module 300 work; the output voltage of the power supply is converted into a second power supply voltage through the power management module 100 and output to the mainboard module 400. The mainboard module 400 outputs a low voltage differential signal according to the second power supply voltage. The logic board module 500 outputs row and column drive signals according to the low voltage differential signal to drive the LCD screen to display an image.

[0125] In this embodiment, the specific structure of the backlight constant current control circuit refers to the above embodiment. Since this embodiment adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0126] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A backlight constant current control circuit, the backlight constant current control circuit is connected to a power supply and a backlight module respectively, characterized in that: The backlight constant current control circuit comprises: a power management module, a voltage conversion module and a mainboard module respectively connected to the power management module, a constant current drive module connected to the voltage conversion module, the power management module is also connected to the power supply, and the constant current drive module is also connected to the mainboard module and the backlight module; The power management module is used to convert the output voltage of the power supply into a first power supply voltage and a second power supply voltage; The voltage conversion module is used to convert the first power supply voltage into a backlight module voltage; The mainboard module is used to operate according to the second power supply voltage, generate a backlight driving signal, and send the backlight driving signal to the constant current driving module; The constant current driving module is used to output the backlight module voltage to the backlight module when receiving the backlight driving signal; The constant current driving module includes a DC power supply unit, a micro control unit and a backlight control unit respectively connected to the DC power supply unit, the DC power supply unit is connected to the voltage conversion module, the micro control unit is also respectively connected to the backlight control unit and the main board module, and the backlight control unit is connected to the backlight module; The voltage conversion module is further used to convert the first supply voltage into a constant current driving voltage; The DC power supply unit is used to convert the constant current driving voltage into a third power supply voltage and a fourth power supply voltage when receiving an enable signal sent by the mainboard module, so as to supply power to the micro control unit and the backlight control unit respectively; The micro control unit is used to work according to the third power supply voltage, analyze the backlight driving signal, and output a micro control signal; the micro control signal is used to perform partition control and partition current size control on the backlight module; The backlight control unit is used to work according to the fourth power supply voltage and output the backlight module voltage to the backlight module when receiving the micro control signal; The power management module and the mainboard module constitute a split box system of the television, and the voltage conversion module, the constant current drive module and the backlight module constitute an on-screen system of the television.

2. The backlight constant current control circuit according to claim 1, characterized in that: The power management module includes a DC conversion unit, a first power conversion unit and a second power conversion unit respectively connected to the DC conversion unit; The DC conversion unit is used to convert the output voltage of the power supply into a DC voltage; The first power conversion unit is used to convert the DC voltage into a first power supply voltage; The second power conversion unit is used to convert the DC voltage into a second power supply voltage.

3. The backlight constant current control circuit according to claim 1, characterized in that: The voltage conversion module includes a resonant filter unit and a feedback voltage stabilizing unit, wherein the input end of the resonant filter unit is respectively connected to the output end of the power management module and the feedback voltage stabilizing unit, and the output end is respectively connected to the input end of the constant current driving module and the feedback voltage stabilizing unit, and the input end of the feedback voltage stabilizing unit is also connected to the constant current driving module; The constant current driving module is further used to receive the first feedback voltage of the backlight module and generate a feedback signal; The feedback voltage stabilizing unit is used to output a second feedback voltage according to the backlight module voltage and the feedback signal; The resonance filtering unit is used to perform resonance processing, voltage transformation processing and rectification and filtering processing on the first power supply voltage in sequence according to the second feedback voltage to obtain a backlight module voltage.

4. The backlight constant current control circuit as claimed in claim 3, characterized in that: The resonant filtering unit comprises a first LLC resonant circuit, a voltage transformation circuit and a first rectifier filtering circuit; The first LLC resonant circuit includes a field effect transistor Q1, a field effect transistor Q2 and a resonant controller U1; The drain of the field effect tube Q1 is respectively connected to the positive electrode of the power management module and the filter capacitor C1, the negative electrode of the filter capacitor C1 is grounded, the gate of the field effect tube Q1 is connected to the first pin HO of the resonance controller U1 through the resistor R1, and receives the high drive signal output by the first pin HO of the resonance controller U1, the source is respectively connected to the second pin HB of the resonance controller U1, the drain of the field effect tube Q2 is connected to the transformer circuit, the gate is connected to the third pin LO of the resonance controller U1 through the resistor R2, and receives the low drive signal output by the third pin LO of the resonance controller U1, the source is connected to the third pin LO of the resonance controller U1 through the capacitor C 2 is connected to the transformer circuit, and the source of the field effect tube Q2 is also grounded. The fourth pin CS of the resonant controller U1 is connected to the transformer circuit through the capacitor C3 to realize the soft start of the resonant controller U1. The fifth pin VCC of the resonant controller U1 is respectively connected to the positive electrode of the filter capacitor C4 and the negative electrode of the diode D1. The negative electrode of the filter capacitor C4 is grounded. The positive electrode of the diode D1 is connected to the transformer circuit to provide the working voltage of the resonant controller U1. The sixth pin FB of the resonant controller U1 is connected to the feedback voltage stabilizing unit to adjust the backlight module voltage according to the signal output by the feedback voltage stabilizing unit.

5. The backlight constant current control circuit as claimed in claim 4, characterized in that: The voltage conversion circuit includes a transformer T1; The first input end of the transformer T1 is connected to the source of the field effect transistor Q1, the second input end is respectively connected to one end of the capacitor C2 close to the transformer T1 and one end of the capacitor C3 close to the transformer T1, the third input end is connected to the positive electrode of the diode D1, the fourth input end is grounded, and the output ends are respectively connected to the first rectifier and filter circuit.

6. The backlight constant current control circuit as claimed in claim 5, characterized in that: The first rectifying and filtering circuit includes a diode D2, a diode D3, a diode D4 and a diode D5; The anode of the diode D2 is connected to the first output terminal of the transformer T1, the anode of the diode D3 is connected to the second output terminal of the transformer T1, the cathode of the diode D2 is connected to the cathode of the diode D3, and are respectively connected to the anode of the filter capacitor C5, the feedback voltage stabilizing unit and the backlight module, the first ground terminal of the transformer T1 is connected to the cathode of the filter capacitor C5 and is grounded, the anode of the diode D4 is connected to the third output terminal of the transformer T1, the anode of the diode D5 is connected to the fourth output terminal of the transformer T1, the cathode of the diode D4 is connected to the cathode of the diode D5, and are respectively connected to the anode of the filter capacitor C6 and the constant current driving module, and the second ground terminal of the transformer T1 is connected to the cathode of the filter capacitor C6 and is grounded.

7. The backlight constant current control circuit according to claim 1, characterized in that: The backlight constant current control circuit also includes a logic board module connected to the main board module; The mainboard module is also used to generate a low voltage differential signal; The logic board module is used to perform timing control on the low voltage differential signal, output row and column drive signals, and control the operation of the liquid crystal screen.

8. The backlight constant current control circuit according to claim 1, characterized in that: The backlight constant current control circuit also includes a sound module connected to the mainboard module; The power management module is also used to convert the output voltage of the power supply into a mainboard power amplifier voltage; The mainboard module is also used to output a sound control signal according to the mainboard power amplifier voltage to control the operation of the sound module.

9. A television set, characterized in that: The television set comprises: The backlight constant current control circuit according to any one of claims 1 to 8; A backlight module and a liquid crystal screen, wherein the backlight module and the liquid crystal screen are respectively connected to the backlight constant current control circuit.

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