Power supply control circuit and display device

Disclosed are a power supply control circuit and a display device. An output terminal of the power factor correction circuit is connected to the resonance circuit; a first output terminal of the resonance circuit is connected to the backlight module through the first rectification filter circuit, and a second output terminal of the resonance circuit is connected to the control circuit board and the communication circuit through the second rectification filter circuit; a third output terminal of the resonance circuit is connected to the control system and the communication circuit; the control circuit board is connected to the control system through the communication circuit; a first signal output terminal of the control system is connected to the power factor correction circuit; and a second signal output terminal of the control system is connected to the resonance circuit.

TECHNICAL FIELD

This application relates to the field of display technology, in particular to a power supply control circuit and a display device.

BACKGROUND

At present, the power supply control system of TV is mainly divided into flyback topology control, half-bridge resonance (LLC) topology control and power factor correction (PFC) circuit control. Flyback topology is mainly used for low-power power supplies (for example, 75 W or less), and PFC+LLC architecture is mainly used for medium and high-power power supplies (for example, 82 W or more). Since various chip parameters have been solidified by the manufacturers in the power supply control system used by medium and high-power TVs, when designing the power supply control system, it is necessary to adjust the device parameters of the peripheral circuit according to the size of the power supply and the requirements of the design specifications based on the chip parameters. For power supplies with different specifications and requirements in this way, the device parameters of the peripheral circuit need to be adjusted. As a result, the material list of power supply is complicated, which is not conducive to production and after-sales control.

SUMMARY

This application provides a power supply control circuit and a display device, which aims to set part of key parameters of a primary circuit of the power supply by a control circuit board, so as to reduce types of the material list and facilitate production and after-sales control.

In order to achieve the above object, this application provides a power supply control circuit, which is applied to a display device. The display device includes a control circuit board and a backlight module. The power supply control circuit includes a power factor correction circuit, a resonance circuit, a first rectification filter circuit, a second rectification filter circuit, a communication circuit and a control system.

An output terminal of the power factor correction circuit is connected to an input terminal of the resonance circuit; a first output terminal of the resonance circuit is connected to a power input terminal of the backlight module through the first rectification filter circuit, a second output terminal of the resonance circuit is connected to a power input terminal of the control circuit board through the second rectification filter circuit, and the second output terminal of the resonance circuit is connected to a second power input terminal of the communication circuit through the second rectification filter circuit; a third output terminal of the resonance circuit is connected to a power input terminal of the control system, and the third output terminal of the resonance circuit is further connected to a first power input terminal of the communication circuit; the control circuit board is in communication connection with the control system through the communication circuit; a first signal output terminal of the control system is connected to a signal input terminal of the power factor correction circuit; and a second signal output terminal of the control system is connected to a signal input of the resonance circuit.

In an embodiment, the power supply control circuit further includes a feedback circuit, a first input terminal of the feedback circuit is connected to an output terminal of the first rectification filter circuit, a second input terminal of the feedback circuit is connected to an output terminal of the second rectification filter circuit, and an output terminal of the feedback circuit is connected to a feedback terminal of the control system.

In an embodiment, the communication circuit includes a first voltage conversion circuit, a second voltage conversion circuit, a control chip, a first resistor, a second resistor, a third resistor, and a fourth resistor.

An input terminal of the first voltage conversion circuit is connected to the third output terminal of the resonance circuit, and a first output terminal of the first voltage conversion circuit is connected to a primary power supply terminal of the control chip; an input terminal of the second voltage conversion circuit is connected to the output terminal of the second rectification filter circuit, and a first output terminal of the second voltage conversion circuit is connected to a secondary power supply terminal of the control chip.

A primary data line of the control chip is connected to a first signal input terminal of the control system, and a primary clock line of the control chip is connected to a second signal input terminal of the control system; a secondary data line of the control chip is connected to a first signal output terminal of the control circuit board, and a secondary clock line of the control chip is connected to a second signal output terminal of the control circuit board; a first terminal of the first resistor is connected to a second output terminal of the second voltage conversion circuit, and a second terminal of the first resistor is connected to the secondary data line of the control chip; a first terminal of the second resistor is connected to the second output terminal of the second voltage conversion circuit, and a second terminal of the second resistor is connected to the secondary clock line of the control chip.

A first terminal of the third resistor is connected to a second output terminal of the first voltage conversion circuit, and a second terminal of the third resistor is connected to the primary data line of the control chip; and a first terminal of the fourth resistor is connected to the second output terminal of the first voltage conversion circuit, and a second terminal of the fourth resistor is connected to the primary clock line of the control chip.

In an embodiment, the power supply control circuit further includes a serial bus interface socket, a first pin1of the serial bus interface socket is grounded, a second pin2of the serial bus interface socket is connected to the secondary clock line of the control chip, and a third pin3of the serial bus interface socket is connected to the secondary data line of the control chip.

In an embodiment, the resonance circuit includes a fifth resistor, a sixth resistor, a first electronic switch, a second electronic switch, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a diode, and a transformer.

A controlled terminal of the first electronic switch is connected to a first control terminal of the control system through the fifth resistor, an input terminal of the first electronic switch is connected to the output terminal of the power factor correction circuit, and an output terminal of the first electronic switch is connected to an input terminal of the second electronic switch; a controlled terminal of the second electronic switch is connected to a second control terminal of the control system through the sixth resistor, and an output terminal of the second electronic switch is grounded.

A dotted terminal of a first primary coil of the transformer is connected to the output terminal of the first electronic switch, the dotted terminal of the first primary coil of the transformer is further connected to the second signal output terminal of the control system, a non-dotted terminal of the first primary coil of the transformer is connected to a current detection terminal of the control system through the second capacitor, one terminal of the first capacitor is connected to the non-dotted terminal of the first primary coil of the transformer, and the other terminal of the first capacitor is grounded; a dotted terminal of a second primary coil of the transformer is connected to a positive electrode of the diode, and a negative electrode of the diode is connected to the power input terminal of the control system; a non-dotted terminal of the second primary coil of the transformer is grounded; one terminal of the third capacitor is connected to the negative electrode of the diode, and the other terminal of the third capacitor is grounded.

A first secondary coil of the transformer is connected to the power input terminal of the backlight module through the first rectification filter circuit, and a second secondary coil of the transformer is connected to the power input terminal of the control circuit board through the second rectification filter circuit.

In an embodiment, the power supply control circuit further includes an electromagnetic interference (EMI) filter circuit and a rectification circuit, an input terminal of the EMI filter circuit is connected to an output terminal of an alternating current (AC) power supply, an output terminal of the EMI filter circuit is connected to an input terminal of the rectification circuit, and an output terminal of the rectification circuit is connected to an input terminal of the power factor correction circuit.

In an embodiment, the power supply control circuit further includes a voltage division detection circuit, an input terminal of the voltage division detection circuit is connected to the output terminal of the EMI filter circuit, and an output terminal of the voltage division detection circuit is connected to a voltage detection terminal of the control system.

In an embodiment, the voltage division detection circuit includes a seventh resistor and an eighth resistor, a first terminal of the seventh resistor is connected to the output terminal of the EMI filter circuit, a second terminal of the seventh resistor is connected to the voltage detection terminal of the control system, the second terminal of the seventh resistor is further connected to a first terminal of the eighth resistor, and a second terminal of the eighth resistor is grounded.

In an embodiment, the voltage division detection circuit includes a ninth resistor, a first terminal of the ninth resistor is connected to the output terminal of the power factor correction circuit, and a second terminal of the ninth resistor is connected to a trigger terminal of the control system.

In order to achieve the above object, this application further provides a display device. The display device includes a control circuit board, a backlight module, and the power supply control circuit according to any one of the above.

According to the technical solution of this application, after the normal operation of the system, the communication connection and data transmission between the control circuit board and the control system are realized through the communication circuit. For power supplies of different specifications, the parameters in the software of the control circuit board can be modified by the developer, and the modified parameters can be transmitted to the control system through the communication circuit, the control system then modifies the corresponding parameters of the power factor correction circuit and the corresponding parameters of the resonance circuit according to the received modified parameters. Such setting can maximize the matching of different output and setting requirements with a set of power supply hardware, thus reducing the types of the material list and facilitating production and after-sales control.

The realization of the object, functional characteristics, and advantages of this application will be further described in connection with the embodiments and with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following, the technical solutions in the embodiments of this application will be clearly and completely described in connection with the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the claimed scope of this application.

It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship, movement situation, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indication also changes accordingly.

In addition, the descriptions related to “first”, “second”, and the like in this application are for descriptive purposes only, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, features associated with “first” and “second” may explicitly or implicitly include at least one of such features. In addition, the technical solutions of the various embodiments can be combined with each other, but they must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist, or is not within the scope of protection defined by the claims of this application.

This application provides a power supply control circuit.

Referring toFIG.1, the power supply control circuit is applied to a display device. The display device includes a control circuit board80and a backlight module70. The power supply control circuit includes a power factor correction circuit10, a resonance circuit20, a first rectification filter circuit30, a second rectification filter circuit40, a communication circuit50and a control system60.

An output terminal of the power factor correction circuit10is connected to an input terminal of the resonance circuit20; a first output terminal of the resonance circuit20is connected to a power input terminal of the backlight module70through the first rectification filter circuit30, a second output terminal of the resonance circuit20is connected to a power input terminal of the control circuit board80through the second rectification filter circuit40, and the second output terminal of the resonance circuit20is connected to a second power input terminal of the communication circuit50through the second rectification filter circuit40; a third output terminal of the resonance circuit20is connected to a power input terminal of the control system, and the third output terminal of the resonance circuit20is further connected to a first power input terminal of the communication circuit50; the control circuit board80is in communication connection with the control system60through the communication circuit50; a first signal output terminal of the control system60is connected to a signal input terminal of the power factor correction circuit10; and a second signal output terminal of the control system60is connected to a signal input of the resonance circuit20.

In this embodiment, the control system60is configured to control a power factor correction (PFC) circuit and an LLC circuit (resonance circuit). The control system60may be integrated by a control system of the PFC circuit and a control system of the LLC circuit.

The communication circuit50is an I2C communication circuit50, and is configured for realizing communication connection and data transmission between the control circuit board80and the control system60, so that the control circuit board80can read data of the control system60in real time or regularly, or write data to the control system60through the communication circuit50.

The power supply control circuit may further include a starting circuit, an electromagnetic interference (EMI) filter circuit100, and a rectification circuit110. The starting circuit is electrically connected to the control system60, and the starting circuit is configured to provide a starting voltage for the control system60when the display device is powered on. An input terminal of the EMI filter circuit100is connected to an output terminal of an alternating current (AC) power supply, an output terminal of the EMI filter circuit100is connected to an input terminal of the rectification circuit110, and an output terminal of the rectification circuit110is connected to an input terminal of the power factor correction circuit10. The EMI filter circuit100and the rectification circuit110are configured to filter and rectify the AC output of the AC power supply, such as 100V to 240V AC, to input to the PFC circuit10.

Specifically, when the display device is powered on, the starting circuit of the system or the external starting circuit may first provide the starting voltage for the control system60to start the control system60. After the control system60is activated, the control system60generates a drive signal to a designated electronic switch in the resonance circuit20to control the electronic switch to turn on. When the electronic switch is turned on, a resonance loop composed of the conductive electronic switch, the transformer in the resonance circuit and the resonant capacitor starts to operate, and a second primary coil of the transformer of the resonance circuit20, that is, an auxiliary winding, provides a stable voltage for the control system60, so that the control system60can work normally. After the control system60works normally, the control system60disconnects the connection with the starting circuit and outputs a driving signal to two electronic switches in the resonance circuit20to control the two electronic switches in the resonance circuit20to turn on alternately. At this time, a resonance loop composed of the electronic switches, the transformer and the resonant capacitor in the resonance circuit20outputs energy to a secondary circuit of the power supply through the transformer.

Thereafter, for voltage output by the power supply, one branch is filtered and rectified by the first rectification filter circuit30to supply power to the backlight module70, and the other branch is filtered and rectified by the second rectification filter circuit40to supply power to the control circuit board80, a screen glass, a timing control board, a power amplifier, and an external equipment, etc. After the control circuit board80works normally, the control circuit board80outputs a dimming signal ADJ and an enable signal ENA to the backlight module70to light up the backlight module70.

After each circuit module of the display device works normally, the control circuit board80can read data in the control system60through the communication circuit50, and can also write data to the control system60through the communication circuit50. The control system60sets or modifies corresponding parameters of the PFC circuit10and the LLC circuit20according to the received data, that is, the control system60sets or modifies part of key parameters of the PFC circuit10and sets or modifies some key parameters of the LLC circuit20, so as to realize, for example, such as realizing setting and modifying output ripple of a PFC boost circuit, a PFC OVP voltage and a Brown-in/Brown-out voltage, realizing Burst mode frequency to the LLC circuit, over-power protection (OPP) of the LLC circuit and switching of different load LLC operating modes. That is to say, for power supplies of different specifications, the relevant design method needs to modify the device parameters of the peripheral circuit. While the power supply control circuit of this application can modify part of key parameters of the PFC circuit and LLC circuit through the control circuit board80, without modifying the device parameters of the peripheral circuit, so that a set of power supply hardware can maximize the matching of different output and parameter setting requirements, thereby reducing the types of the material list, and facilitating production and after-sales control.

According to the technical solution of this application, after the normal operation of the system, the communication connection and data transmission between the control circuit board80and the control system60are realized through the communication circuit50. For power supplies of different specifications, the parameters in the software of the control circuit board80can be modified by the developer, and the modified parameters can be transmitted to the control system60through the communication circuit50, the control system60then modifies the corresponding parameters of the power factor correction circuit10and the corresponding parameters of the resonance circuit20according to the received modified parameters. Such setting can maximize the matching of different output and setting requirements with a set of power supply hardware, thus reducing the types of the material list and facilitating production and after-sales control.

In an embodiment, referring toFIG.2, the power supply control circuit further includes a feedback circuit90, a first input terminal of the feedback circuit90is connected to an output terminal of the first rectification filter circuit30, a second input terminal of the feedback circuit90is connected to an output terminal of the second rectification filter circuit40, and an output terminal of the feedback circuit90is connected to a feedback terminal of the control system60.

The feedback circuit90is configured to detect a voltage output to the backlight module70, detect a voltage output to the control circuit board80, and feedback a detected voltage to the control system60, so that the control system60adjusts a voltage output to a back-end circuit, thereby achieving a stable output.

In an embodiment, referring toFIG.3, the power supply control circuit further includes an electromagnetic interference (EMI) filter circuit100and a rectification circuit110, an input terminal of the EMI filter circuit100is connected to an output terminal of an alternating current (AC) power supply, an output terminal of the EMI filter circuit100is connected to an input terminal of the rectification circuit110, and an output terminal of the rectification circuit110is connected to an input terminal of the power factor correction circuit10.

The EMI filter circuit100and the rectification circuit110are configured to filter and rectify the AC output of the AC power supply, such as 100V to 240V AC, to input to the PFC circuit10.

In an embodiment, referring toFIG.4, the power supply control circuit further includes a voltage division detection circuit120, an input terminal of the voltage division detection circuit120is connected to the output terminal of the EMI filter circuit100, and an output terminal of the voltage division detection circuit120is connected to a voltage detection terminal of the control system60.

The voltage division detection circuit120can be realized by a plurality of resistors in series voltage division. In an embodiment, referring toFIG.5, the voltage division detection circuit120includes a seventh resistor R7and an eighth resistor R8, a first terminal of the seventh resistor R7is connected to the output terminal of the EMI filter circuit100, a second terminal of the seventh resistor R7is connected to the voltage detection terminal of the control system60, the second terminal of the seventh resistor R7is further connected to a first terminal of the eighth resistor R8, and a second terminal of the eighth resistor R8is grounded.

Specifically, the voltage division detection circuit120detects a grid voltage filtered by the EMI filter circuit100, and transmits the detected grid voltage to the control system60for the control system60to perform corresponding operations, for example, the voltage division detection circuit120transmits the detected grid voltage to the control system60, and the control system60analyzes the received grid voltage by running its internal programs and modules, when the analysis finds that the grid voltage is lower than a preset voltage threshold, the control system60generates a control signal to control the resonance circuit20to stop working, to stop supplying power to the back-end circuit, so as to achieve the purpose of protecting the system.

In an embodiment, referring toFIG.5, the communication circuit50includes a first voltage conversion circuit501, a second voltage conversion circuit502, a control chip U1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

An input terminal of the first voltage conversion circuit501is connected to the third output terminal of the resonance circuit20, and a first output terminal of the first voltage conversion circuit501is connected to a primary power supply terminal of the control chip U1; an input terminal of the second voltage conversion circuit502is connected to the output terminal of the second rectification filter circuit40, and a first output terminal of the second voltage conversion circuit502is connected to a secondary power supply terminal of the control chip U1.

A primary data line SDA1of the control chip U1is connected to a first signal input terminal of the control system60, and a primary clock line SCL1of the control chip U1is connected to a second signal input terminal of the control system60; a secondary data line SDA2of the control chip U1is connected to a first signal output terminal of the control circuit board80, and a secondary clock line SCL2of the control chip U1is connected to a second signal output terminal of the control circuit board80; a first terminal of the first resistor R1is connected to a second output terminal of the second voltage conversion circuit502, and a second terminal of the first resistor R1is connected to the secondary data line SDA2of the control chip U1; a first terminal of the second resistor R2is connected to the second output terminal of the second voltage conversion circuit502, and a second terminal of the second resistor R2is connected to the secondary clock line SCL2of the control chip U1.

A first terminal of the third resistor R3is connected to a second output terminal of the first voltage conversion circuit501, and a second terminal of the third resistor R3is connected to the primary data line SDA1of the control chip U1; and a first terminal of the fourth resistor R4is connected to the second output terminal of the first voltage conversion circuit501, and a second terminal of the fourth resistor R4is connected to the primary clock line SCL1of the control chip U1.

The control chip U1is an I2C protocol control chip. The first voltage conversion circuit501is configured to convert a voltage output from the third output terminal of the resonance circuit20to provide a suitable voltage for the primary of the I2C protocol control chip. The second voltage conversion circuit502is configured to convert a voltage output by the second rectification filter circuit40to provide a suitable voltage to the secondary of the I2C protocol control chip U1. The first resistor R1is a pull-up resistor of the secondary data line SDA2of the I2C protocol control chip, and the second resistor R2is a pull-up resistor of the secondary clock line SCL2of the I2C protocol control chip. The third resistor R3is a pull-up resistor of the primary data line SDA1of the I2C protocol control chip, and the fourth resistor R4is a pull-up resistor of the primary clock line SCL1of the I2C protocol control chip, which is used to ensure the normal transmission of data from the primary and secondary clock lines and data lines. At the same time, the I2C protocol control chip U1can not only realize the data transmission between the control circuit board80and the control system60, but also can isolate the cold and hot ground to ensure the normal operation of the system.

In an embodiment, referring toFIG.5, the power supply control circuit further includes a serial bus interface socket130, a first pin1of the serial bus interface socket is grounded, a second pin2of the serial bus interface socket130is connected to the secondary clock line SCL2of the control chip U1, and a third pin3of the serial bus interface socket130is connected to the secondary data line SDA2of the control chip U1.

In this embodiment, the power supply control circuit further includes a serial bus interface socket130, through which online information of the control system60is read and analyzed when the power supply malfunctions or the power supply is abnormal, so that the developer can analyze the cause of the power supply malfunction or abnormity of the power supply. In addition, when the system is not connected to the control circuit board80, part of the key parameters of the primary circuit of the power supply can also be set and modified through the serial bus interface socket130, which improves the application range of the power supply control circuit.

In an embodiment, referring toFIG.5, the resonance circuit20includes a fifth resistor R5, a sixth resistor R6, a first electronic switch Q1, a second electronic switch Q2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a diode D, and a transformer T1.

A controlled terminal of the first electronic switch Q1is connected to a first control terminal of the control system60through the fifth resistor R5, an input terminal of the first electronic switch Q1is connected to the output terminal of the power factor correction circuit10, and an output terminal of the first electronic switch Q1is connected to an input terminal of the second electronic switch Q2; a controlled terminal of the second electronic switch Q2is connected to a second control terminal of the control system60through the sixth resistor R6, and an output terminal of the second electronic switch Q2is grounded.

A dotted terminal of a first primary coil N1of the transformer T1is connected to the output terminal of the first electronic switch Q1, the dotted terminal of the first primary coil N1of the transformer T1is further connected to the second signal output terminal of the control system60, a non-dotted terminal of the first primary coil N1of the transformer T1is connected to a current detection terminal of the control system60through the second capacitor C2, one terminal of the first capacitor C1is connected to the non-dotted terminal of the first primary coil N1of the transformer T1, and the other terminal of the first capacitor C1is grounded; a dotted terminal of a second primary coil N2of the transformer T1is connected to a positive electrode of the diode D, and a negative electrode of the diode D is connected to the power input terminal of the control system60; a non-dotted terminal of the second primary coil N2of the transformer T1is grounded; one terminal of the third capacitor C3is connected to the negative electrode of the diode D, and the other terminal of the third capacitor C3is grounded.

A first secondary coil N4of the transformer T1is connected to the backlight module70through the first rectification filter circuit30, and a second secondary coil N3of the transformer T1is connected to the control circuit board80through the second rectification filter circuit40.

Specifically, when the display device is powered on, the starting circuit of the system may first provide the starting voltage for the control system60to start the control system60. After the control system60starts running, the control system60generates a driving signal to the first electronic switch Q1to control the first electronic switch Q1to be turned on. After the first electronic switch Q1is turned on, a resonance loop composed of the first electronic switch Q1, the first primary coil N1of the transformer T1and the first capacitor C1starts to work. After the resonance circuit20is operated, the second primary coil N2and the diode D provide a stable voltage to the control system60so that the control system60can operate normally. After the control system60works normally, the control system60disconnects the connection with the starting circuit and outputs a driving signal to the first electronic switch Q1and the second electronic switch Q2to control the first electronic switch Q1and the second electronic switch Q2to turn on alternately. At this time, a resonance loop composed of the electronic switches, the transformer T1and the resonant capacitor C1in the resonance circuit20outputs energy to the secondary circuit through the transformer T1. The first electronic switch Q1and the second electronic switch Q2may be a transistor field effect transistor.

In an embodiment, referring toFIG.5, the voltage division detection circuit further includes a ninth resistor R9, a first terminal of the ninth resistor R9is connected to the output terminal of the power factor correction circuit10, and a second terminal of the ninth resistor R9is connected to a trigger terminal of the control system60.

In this embodiment, the ninth resistor R9is configured to provide a starting voltage to the control system60when the display device is powered on, so that the control system60can be started normally.

This application further provides a display device including the power supply control circuit, the control circuit board80, and the backlight module70according to any one of the above. For the detailed structure of the power supply control circuit, please refer to the above-mentioned embodiments, which will not be repeated here. It is understandable that since the above-mentioned power supply control circuit is included in the display device of this application, the embodiments of the display device of this application includes all the technical solutions of the above-mentioned power supply control circuit, and the achieved technical effects are also completely the same, which will not be repeated here.

In this embodiment, the display device may be a display device having a display panel, such as a television, a tablet computer, or a mobile phone.

The above are only optional embodiments of this application, and thus does not limit the scope of this application, and the equivalent structural transformation made by the content of the specification and the drawings of this application, or directly/indirectly applied to other related technical fields are all included in the scope of this application.