CN217690461U

CN217690461U - Multi-partition independent dimming Mini LED backlight driving device

Info

Publication number: CN217690461U
Application number: CN202220896941.8U
Authority: CN
Inventors: 毛鹏; 褚俊杰; 段世太
Original assignee: Suzhou Northen Microelectronics Technology Co ltd
Current assignee: Suzhou Northen Microelectronics Technology Co ltd
Priority date: 2022-04-18
Filing date: 2022-04-18
Publication date: 2022-10-28
Anticipated expiration: 2032-04-18

Abstract

The application discloses a Mini LED backlight driving device capable of independently dimming in multiple zones. The device comprises an EMI rectification filter circuit, a Boost PFC circuit, a voltage stabilizing unit, a half-bridge LLC resonance circuit, an MCU constant current control circuit, a plurality of LED drive circuits and an LED backlight board. The utility model provides a Mini LED drive arrangement that is shaded from sun that many divisions independently adjusted luminance has following beneficial effect: (1) The device can realize multiple partitions, the more the partitions are, the higher the picture adjustable degree is, and the clearer the picture quality is. (2) The backlight partitions from A-1 to A-n can be independently controlled, when only a small white area exists in a picture, the partition backlight only turns on the backlight of the small white area, and the rest backlights are directly turned off to realize black in the true sense, and meanwhile, the power loss is also reduced.

Description

Mini LED backlight driving device with multiple partitions for independent dimming

Technical Field

The utility model relates to a Mini LED technical field that is shaded especially relates to a Mini LED drive arrangement that is shaded that many divisions independently adjusted luminance.

Background

After the 21 st century, the living standard of people in China is continuously improved. With the promotion of the use demands of consumers and the assistance of the high-speed development of the LED industry, high-definition and high-visibility scientific and technological convenience products such as high-definition liquid crystal televisions, stage LED background display walls, automotive panels and the like gradually enter the lives of people. The backlight surface of the traditional non-backlight partition LCD display is complete, and the backlight surface emits white light and then obtains the required color after being deflected by a liquid crystal layer. However, the liquid crystal layer cannot be completely closed, and white light can be leaked out when a black picture is displayed, so that the black is not pure enough. The Mini LED backlight is a latest Liquid Crystal Display (LCD) backlight technology at present, and has a more elaborate light control technology. The backlight surface is divided into a plurality of areas, and the different areas can be separately controlled in a partitioned mode to achieve higher contrast, so that the user can experience the image quality of a fine and smooth film under a large-size screen.

The Mini LED backlight is a popular technology for the display screen backlight technology due to its advantages of high brightness, high contrast, divisional dimming, and low power consumption. Meanwhile, a driving device matched with the Mini LED backlight system also becomes a hot driving device. The backlight driving device is a common power electronic device, and supplies power to the LED backlight module through ac/dc conversion. The traditional alternating current-direct current conversion process has the problems of current harmonic distortion, low power factor and the like because of the use of an uncontrolled rectification technology, so that the traditional alternating current-direct current conversion process is difficult to provide high-quality power supply support, and therefore, the Mini LED backlight driving device still has a large performance improvement space.

SUMMERY OF THE UTILITY MODEL

Aiming at the problems, the multi-partition independent dimming Mini LED backlight driving device is provided to realize multi-partition, the more partitions are, the higher the picture controllability is, the clearer the picture quality is, each backlight partition can realize independent control, and meanwhile, the power loss is also reduced.

In order to achieve the above object, an embodiment of the present invention provides a multi-partition independent dimming Mini LED backlight driving device, which includes an EMI rectifying and filtering circuit, a Boost PFC circuit, a voltage stabilizing unit, a half-bridge LLC resonant circuit, an MCU constant current control circuit, a plurality of LED driving circuits, and an LED backlight board; the input end of the EMI rectifying and filtering circuit is connected to a mains supply, the output end of the EMI rectifying and filtering circuit is connected to the Boost PFC circuit, the half-bridge LLC resonance circuit is connected to the output end of the Boost PFC circuit, the voltage stabilizing unit is located between the Boost PFC circuit and the half-bridge LLC resonance circuit, the PWM dimming feedback control circuit is connected to the output end of the half-bridge LLC resonance circuit, the LED driving circuits are connected to the half-bridge LLC resonance circuit, the LED backlight plate is provided with a plurality of LED backlight partitions, and each LED backlight partition is connected to one LED driving circuit; the MCU constant current control circuit is a PWM dimming feedback control circuit and comprises an MCU controller CC2530; the LED driving circuit comprises a main control chip SN3350 and a voltage output shunt monitoring meter INA193; the voltage output shunt monitoring meter INA193 samples real-time current flowing through the LED backlight panel and sends the real-time current to the MCU controller CC2530 for processing, and after the MCU controller CC2530 receives a current signal sent by the voltage output shunt monitoring meter INA193, the MCU controller CC2530 sends a PWM signal to the main control chip SN3350 for dimming control.

Further, the EMI rectification filter circuit comprises a common-mode inductor CMC1, a resistor R2, a capacitor CX1, a capacitor CX2, a capacitor CY1, a capacitor CY2, a rectification bridge Br1 and a capacitor C1, wherein the rectification bridge Br1 is provided with a rectification positive output end, a rectification negative output end, a first alternating current input end and a second alternating current input end; common mode inductance CMC1 is equipped with two inputs and two outputs common mode inductance CMC1 between two inputs parallel connection electric capacity CX1 with resistance R2 and access interchange commercial power connect between two outputs of common mode inductance CMC1 electric capacity CX2 is connected to respectively first AC input end with second AC input end first AC input end with still series connection between the second AC input end electric capacity CY1 with electric capacity CY2, electric capacity CY1 with node ground connection between electric capacity CY2, the positive output of rectification with connect between the rectification negative output electric capacity C1, the positive output of rectification with the rectification negative output is EMI rectifier filter circuit's output.

Further, the EMI rectifying and filtering circuit further includes a fuse F1 and a thermistor NTC, one input end of the common mode inductor CMC1 is connected to the utility power through the fuse F1, and the other input end of the common mode inductor CMC1 is connected to the utility power through the thermistor NTC.

Further, the Boost PFC circuit comprises a back-end LC circuit and a first control loop; the mains supply is rectified by the rectifier bridge Br1 to obtain direct current, the direct current is filtered by the rear-end LC circuit to obtain stable power supply voltage VBus, and the power supply voltage VBus is output from the output end of the Boost PFC circuit; the rear-end LC circuit comprises an inductor L1, a diode D1 and a switching tube S1; an inductor L1, a diode D1 and the voltage stabilizing unit are sequentially connected in series between the rectification anode output end and the rectification cathode output end of the rectifier bridge Br 1; the voltage stabilizing unit is a capacitor CBus, a switching tube S1 is further arranged between a connecting node of the inductor L1 and the diode D1 and the output end of the rectification negative pole, and the power supply voltage VBus is output from two ends of the capacitor CBus; the first control loop comprises a main control chip UCC28019, the power supply voltage VBus is input to the main control chip UCC28019, a voltage sample is output to the main control chip UCC28019 at the rectified positive electrode output end, and a current sample is output to the main control chip UCC28019 at the rectified negative electrode output end; the main control chip UCC28019 is connected to the gate of the switching tube S1.

Furthermore, the half-bridge LLC resonant circuit is provided with a VBus + input end, a VBus-input end, a Vo + output end and a Vo-output end; the VBus + input end and the VBus-input end are respectively connected to the output end of the Boost PFC circuit; the half-bridge LLC resonant circuit comprises a transistor S2, a transistor S3, a capacitor C2, an inductor L2, a first transformer, a diode D2, a diode D3, a capacitor C3, a resistor R3 and a second control loop; the first transformer is provided with an input coil N1, an output coil N2 and an output coil N3, and the output coil N2 and the output coil N3 are arranged in series; the second control loop comprises a main control chip L6599A; the VBus-input end is grounded, a transistor S2 and a transistor S3 are arranged between the VBus + input end and the VBus-input end in series, the grid electrodes of the transistor S2 and the transistor S3 are connected to the output end of the second control loop, a capacitor C2, an inductor L2 and an input coil N1 are connected between the transistor S2 and the transistor S3 in series, one end of the output coil N2 is connected to the Vo + output end through a diode D2, the other end of the output coil N2 is connected to the Vo-output end, a capacitor C3 and a resistor R3 are arranged between the Vo + output end and the Vo-output end in parallel, one end of the output coil N3 is connected to the Vo-output end, and the other end of the output coil N3 is connected to the Vo + output end through a diode D3; an output voltage between the Vo + output terminal and the Vo-output terminal is input to the second control loop.

Furthermore, the multi-partition independent dimming Mini LED backlight driving device further comprises an auxiliary power supply circuit; the auxiliary source power supply circuit comprises a second transformer, and the second transformer is provided with an input coil Np and an output coil Ns1; the two ends of a branch of the input coil Np connected with the switching tube S4 in series are connected to the output end of the Boost PFC circuit; one end of the output coil Ns1 is connected to the anode of a diode D4, a capacitor C4 and a resistor R4 are connected in parallel between the cathode of the diode D4 and the other end of the output coil Ns1, the other end of the output coil Ns1 is grounded, and the cathode of the diode D4 outputs a first auxiliary voltage.

Further, in the auxiliary power supply circuit, the second transformer is further provided with an output coil Ns2; one end of the output coil Ns2 is connected in series with the ground end of the output coil Ns1; the other end of the output coil Ns2 is connected to the anode of a diode D5, the cathode of the diode D5 is connected to one side of a capacitor C6, the other side of the capacitor C6 is grounded, the diode D5 is connected in parallel with a branch formed by connecting the capacitor C5 and a resistor R5 in series, and the cathode of the diode D5 outputs a second auxiliary voltage.

Further, the first auxiliary voltage is 12V; the second auxiliary voltage is 3.3V.

Further, in the LED driving circuit, the voltage output shunt monitor INA193 Is provided with a Vin + pin, a Vin-pin, a V + pin, a Vout pin, and a GND pin, and the main control chip SN3350 Is provided with a Vin pin, an Is pin, an LX pin, a GND pin, and an ADJ pin; a second auxiliary voltage is input into the V + pin; the Vin-pin is directly connected to the anode of the LED lamp in the LED backlight partition, the Vin-pin is further connected to the LX pin through a circuit formed by connecting an inductor L3 and a branch formed by connecting a resistor R8 and a capacitor C9 in parallel in series, and a connection node of the inductor L3 and the branch formed by connecting the resistor R8 and the capacitor C9 in parallel is connected to the cathode of the LED lamp in the LED backlight partition; the Vin pin Is connected to the Vin + pin and the Vo + output end, the Is pin Is connected to the Vin-pin, a resistor R9, a resistor R10 and a diode D6 are further arranged between the Vin + pin and the Vin-pin in parallel, and the anode of the diode D6 Is connected to the Vin-pin; the pin Vout is connected with a resistor R6 and then outputs the real-time current Iout of the LED backlight partition; the GND pin is grounded and is connected to the real-time current output side of the resistor R6 through a capacitor C10; the GND pin of the master control chip SN3350 is grounded and connected to the Vo-output end; a capacitor C7 and a capacitor C8 are arranged in parallel between the GND pin of the main control chip SN3350 and the Vin pin; and the ADJ pin is connected with a resistor R7 and then outputs a PWM signal.

Further, in the MCU constant current control circuit, the MCU controller CC2530 is provided with an RST pin, a current collection pin, a VDD pin, a GND pin, and a dimming signal output pin; a second auxiliary voltage is input after the RST pin is connected with the resistor R11, and the RST pin is grounded after being connected with the capacitor C12; the current acquisition pin correspondingly inputs the corresponding real-time current Iout of the LED backlight subarea; the VDD pin inputs a second auxiliary voltage, the GND pin is grounded, and the VDD pin is connected to the GND pin through a capacitor C11; and the dimming signal output pin outputs a PWM signal corresponding to the LED backlight partition.

(in this embodiment, the LED backlight partitions are divided into six LED backlight partitions a-1, \8230;, and LED backlight partitions a-6; the current collection pins include P00 pins, P01 pins, \8230;, and P06 pins, the real-time currents Iout1, \8230;, and the real-time currents Iout6 corresponding to the LED backlight partitions a-1 are respectively input, the dimming signal output pins include P22 pins, \8230;, P18 pins, and P14 pins, and the PWM1 signals, \828230;, and the PWM6 signals corresponding to the LED backlight partitions a-6 are respectively output.

The utility model provides a Mini LED drive arrangement that is shaded from sun that many partitions independently adjusted luminance has following beneficial effect: (1) The device can realize multiple partitions, the more partitions are, the higher the adjustable degree of the picture is, and the clearer the picture quality is. (2) The backlight partitions from A-1 to A-n can be independently controlled, when only a small white area exists in a picture, the partition backlight only turns on the backlight of the small white area, and the rest backlights are directly turned off to realize black in the true sense, and meanwhile, the power loss is also reduced.

Drawings

The following detailed description of the embodiments of the present application, taken in conjunction with the accompanying drawings, presents the technical solutions and other advantages of the present application.

Fig. 1 is a schematic circuit structure diagram of a multi-partition independent dimming Mini LED backlight driving device according to an embodiment of the present application.

Fig. 2 is a schematic circuit structure diagram of an EMI rectifying and filtering circuit according to an embodiment of the present disclosure.

Fig. 3 is a schematic circuit structure diagram of a Boost PFC circuit provided in an embodiment of the present application.

Fig. 4 is a schematic circuit structure diagram of a half-bridge LLC resonant circuit provided in the embodiment of the present application.

Fig. 5 is a schematic circuit structure diagram of an auxiliary power supply circuit according to an embodiment of the present disclosure.

Fig. 6 is a schematic circuit structure diagram of an LED driving circuit according to an embodiment of the present disclosure.

Fig. 7 is a schematic circuit structure diagram of an MCU constant current control circuit (i.e., a PWM dimming feedback control circuit) provided in the embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

In order to realize the above-mentioned programmed functions, please refer to fig. 1 to fig. 7, the present application provides a multi-partition independent dimming Mini LED backlight driving device, which basically comprises the following circuits: the LED dimming circuit comprises an EMI rectification filter circuit, a Boost PFC circuit, a half-bridge LLC resonance circuit, an auxiliary source power supply circuit, an LED drive circuit and a PWM dimming feedback control circuit, and the specific circuits and functions are as follows:

(1) EMI rectification filter circuit: an EMI filter consisting of an X capacitor, a Y capacitor and a common-mode inductor is adopted to filter an input power supply which generates noise voltage and mainly generates common-mode interference. CX1 and CX2 are X capacitors to prevent differential mode interference, and when the differential mode interference is large, the value can be increased to suppress the differential mode interference. CY1 and CY2 are Y capacitors, so that common mode interference is prevented, and when the common mode interference is large, the value of the common mode interference can be increased to inhibit the common mode interference. F1 is a fuse which can be fused to cut off the current when the current abnormally rises to a certain height, so that the effect of protecting the safe operation of the circuit is achieved; the NTC is a negative temperature coefficient thermistor and can restrain surge current when the power supply is started.

(2) Boost PFC circuit: the Boost PFC circuit adopts a control scheme based on a main control chip UCC 28019. Namely, the PFC function is realized, the harmonic component is reduced, and a stable direct-current voltage with the voltage value of VBus is provided for a rear-stage circuit.

(3) Half-bridge LLC resonant circuit: the half-bridge LLC resonant circuit adopts a control scheme based on a main control chip L6599. And the stable control of the output voltage and the output current is completed by sampling the output voltage of the rear stage.

(4) Auxiliary source supply circuit: the auxiliary source power supply circuit adopts a scheme based on a flyback topological structure. Through flyback two-way output, the output voltage VBus of the front stage is respectively reduced to +12V and +3.3V, and stable power supply support is provided for other working circuits.

(5) LED drive circuit: the LED driving circuit adopts a control scheme based on a master control chip SN3350 and a voltage output shunt monitoring meter INA 193. The INA193 is used for sampling the real-time current flowing through the load LED and sending the real-time current to the MCU controller CC2530 for processing, and the MCU controller CC2530 sends a PWM signal to the main control chip SN3350 for dimming control.

(6) PWM adjusts luminance feedback control circuit: the PWM dimming feedback control circuit adopts a control scheme based on the MCU CC 2530. After receiving the current signal sent by INA193, CC2530 sends a PWM dimming signal to main control chip SN3350, so that it completes the dimming driving control.

Specifically, please refer to fig. 1 to 7, in one embodiment of the present invention, a multi-partition independent dimming Mini LED backlight driving device is provided, which includes an EMI rectifying and filtering circuit, a Boost PFC circuit, a voltage stabilizing unit, a half-bridge LLC resonant circuit, an MCU constant current control circuit, a plurality of LED driving circuits, and an LED backlight board; the input end of the EMI rectifying and filtering circuit is connected to a mains supply, the output end of the EMI rectifying and filtering circuit is connected to the Boost PFC circuit, the half-bridge LLC resonance circuit is connected to the output end of the Boost PFC circuit, the voltage stabilizing unit is located between the Boost PFC circuit and the half-bridge LLC resonance circuit, the PWM dimming feedback control circuit is connected to the output end of the half-bridge LLC resonance circuit, the LED driving circuits are connected to the half-bridge LLC resonance circuit, the LED backlight plate is provided with a plurality of LED backlight partitions, and each LED backlight partition is connected to one LED driving circuit; each LED backlight subarea comprises a plurality of LED lamps which are connected in series; the MCU constant current control circuit is a PWM dimming feedback control circuit and comprises an MCU controller CC2530; the LED driving circuit comprises a main control chip SN3350 and a voltage output shunt monitoring meter INA193; the voltage output shunt monitoring meter INA193 samples real-time current flowing through the LED backlight panel and sends the real-time current to the MCU controller CC2530 for processing, and after the MCU controller CC2530 receives a current signal sent by the voltage output shunt monitoring meter INA193, the MCU controller CC2530 sends a PWM signal to the main control chip SN3350 for dimming control.

Referring to fig. 2, further, the EMI rectifying and filtering circuit includes a common mode inductor CMC1, a resistor R2, a capacitor CX1, a capacitor CX2, a capacitor CY1, a capacitor CY2, a rectifying bridge Br1, and a capacitor C1, where the rectifying bridge Br1 is provided with a rectifying positive output end, a rectifying negative output end, a first ac input end, and a second ac input end; common mode inductance CMC1 is equipped with two inputs and two outputs common mode inductance CMC1 between two inputs parallel connection electric capacity CX1 with resistance R2 and access interchange commercial power connect between two outputs of common mode inductance CMC1 electric capacity CX2 is connected to respectively first AC input end with second AC input end first AC input end with still series connection between the second AC input end electric capacity CY1 with electric capacity CY2, electric capacity CY1 with node ground connection between electric capacity CY2, the positive output of rectification with connect between the rectification negative output electric capacity C1, the positive output of rectification with the rectification negative output is EMI rectifier filter circuit's output.

Referring to fig. 2, further, the EMI rectifying and filtering circuit further includes a fuse F1 and a thermistor NTC, one input end of the common mode inductor CMC1 is connected to the utility power through the fuse F1, and another input end of the common mode inductor CMC1 is connected to the utility power through the thermistor NTC.

Referring to fig. 3, further, the Boost PFC circuit includes a back-end LC circuit and a first control loop; the mains supply is rectified by the rectifier bridge Br1 to obtain direct current, the direct current is filtered by the rear-end LC circuit to obtain stable power supply voltage VBus, and the power supply voltage VBus is output from the output end of the Boost PFC circuit; the rear-end LC circuit comprises an inductor L1, a diode D1 and a switching tube S1; an inductor L1, a diode D1 and the voltage stabilizing unit are sequentially connected in series between the rectification anode output end and the rectification cathode output end of the rectifier bridge Br 1; the voltage stabilizing unit is a capacitor CBus, a switching tube S1 is further arranged between a connecting node of the inductor L1 and the diode D1 and the output end of the rectification negative pole, and the power supply voltage VBus is output from two ends of the capacitor CBus; the first control loop comprises a main control chip UCC28019, the supply voltage VBus is input to the main control chip UCC28019, a voltage sample is output to the main control chip UCC28019 at the rectified positive output terminal, and a current sample is output to the main control chip UCC28019 at the rectified negative output terminal; the main control chip UCC28019 is connected to the gate of the switching tube S1.

Referring to fig. 4, further, the half-bridge LLC resonant circuit is provided with a VBus + input terminal, a VBus-input terminal, a Vo + output terminal, and a Vo-output terminal; the VBus + input end and the VBus-input end are respectively connected to the output end of the Boost PFC circuit; the half-bridge LLC resonant circuit comprises a transistor S2, a transistor S3, a capacitor C2, an inductor L2, a first transformer, a diode D2, a diode D3, a capacitor C3, a resistor R3 and a second control loop; the first transformer is provided with an input coil N1, an output coil N2 and an output coil N3, and the output coil N2 and the output coil N3 are arranged in series; the second control loop comprises a main control chip L6599A; the VBus-input end is grounded, a transistor S2 and a transistor S3 are arranged between the VBus + input end and the VBus-input end in series, the grid electrodes of the transistor S2 and the transistor S3 are connected to the output end of the second control loop, a capacitor C2, an inductor L2 and an input coil N1 are connected between the transistor S2 and the transistor S3 in series, one end of the output coil N2 is connected to the Vo + output end through a diode D2, the other end of the output coil N2 is connected to the Vo-output end, a capacitor C3 and a resistor R3 are arranged between the Vo + output end and the Vo-output end in parallel, one end of the output coil N3 is connected to the Vo-output end, and the other end of the output coil N3 is connected to the Vo + output end through a diode D3; an output voltage between the Vo + output terminal and the Vo-output terminal is input to the second control loop.

Referring to fig. 5, further, the multi-partition independent dimming Mini LED backlight driving device further includes an auxiliary power supply circuit, where the auxiliary power supply circuit is connected to the first control loop as a power supply module; the auxiliary source power supply circuit comprises a second transformer, and the second transformer is provided with an input coil Np and an output coil Ns1; the two ends of a branch of the input coil Np connected with the switching tube S4 in series are connected to the output end of the Boost PFC circuit; one end of the output coil Ns1 is connected to the anode of a diode D4, a capacitor C4 and a resistor R4 are connected in parallel between the cathode of the diode D4 and the other end of the output coil Ns1, the other end of the output coil Ns1 is grounded, and the cathode of the diode D4 outputs a first auxiliary voltage.

Referring to fig. 5, further, in the auxiliary power supply circuit, the second transformer is further provided with an output coil Ns2; one end of the output coil Ns2 is connected in series with the ground end of the output coil Ns1; the other end of the output coil Ns2 is connected to the anode of a diode D5, the cathode of the diode D5 is connected to one side of a capacitor C6, the other side of the capacitor C6 is grounded, the diode D5 is connected in parallel with a branch formed by connecting the capacitor C5 and a resistor R5 in series, and the cathode of the diode D5 outputs a second auxiliary voltage.

Referring to fig. 6, further, in the LED driving circuit, the voltage output shunt monitor INA193 Is provided with a Vin + pin, a Vin-pin, a V + pin, a Vout pin, and a GND pin, and the main control chip SN3350 Is provided with a Vin pin, an Is pin, an LX pin, a GND pin, and an ADJ pin; the V + pin inputs a second auxiliary voltage; the Vin-pin is directly connected to the anode of the LED lamp in the LED backlight partition, the Vin-pin is further connected to the LX pin through a circuit formed by connecting an inductor L3 and a branch formed by connecting a resistor R8 and a capacitor C9 in parallel in series, and a connection node of the inductor L3 and the branch formed by connecting the resistor R8 and the capacitor C9 in parallel is connected to the cathode of the LED lamp in the LED backlight partition; the Vin pin Is connected to the Vin + pin and the Vo + output end, the Is pin Is connected to the Vin-pin, a resistor R9, a resistor R10 and a diode D6 are further arranged between the Vin + pin and the Vin-pin in parallel, the anode of the diode D6 Is connected to the Vin-pin, and the cathode of the diode D6 Is connected to the Vin + pin; the pin Vout is connected with a resistor R6 and then outputs the real-time current Iout of the LED backlight partition; the GND pin is grounded and is connected to the real-time current output side of the resistor R6 through a capacitor C10; the GND pin of the master control chip SN3350 is grounded and connected to the Vo-output end; a capacitor C7 and a capacitor C8 are arranged in parallel between the GND pin of the main control chip SN3350 and the Vin pin; and the ADJ pin is connected with a resistor R7 and then outputs a PWM signal.

In the embodiment, the LED backlight subareas are divided into six LED backlight subareas A-1, \8230 \ 8230;, and an LED backlight subarea A-6; the current acquisition pins comprise a P00 pin, a P01 pin, \8230;, and a P06 pin, which are respectively input with real-time currents Iout1, \8230;, and Iout6 corresponding to the LED backlight partition A-6; the dimming signal output pins comprise pins P22, \8230 \ 8230;, pins P18 and P14, which respectively output PWM1 signals, \8230; \ 8230;, and PWM6 signals corresponding to the LED backlight partition A-6.

According to the hardware architecture introduced above, after the power supply is connected to the commercial power, the ac voltage flows into the EMI rectifying and filtering unit shown in fig. 2, and the EMI filtering circuit can prevent the electromagnetic interference of the power grid from entering the rear-stage driving circuit through the power line, and at the same time, is used to prevent the electromagnetic interference generated during the operation of the driving circuit from interfering with the power grid through the power line. After rectification by the rectifier bridge, a dc voltage with a peak value of 220 × v 2 is formed at the capacitor C1. After the PFC circuit is started, the output voltage and the input voltage form a reference of the input current inside the chip UCC28019 under the action of the multiplier, and the input current completes the power factor correction process by tracking the reference in a sinusoidal form. Meanwhile, a stable direct current voltage with a voltage value of VBus is provided for a later stage circuit at the electrolytic capacitor CBus through the control of a voltage loop of the chip UCC 28019.

The flyback power supply circuit takes the output voltage VBus of the front stage as an input voltage, the topology comprises two paths of output of a main circuit Ns1 and an auxiliary circuit Ns2, the VBus is respectively reduced to +12V and +3.3V, and stable power supply support is provided for an LED driving circuit and a PWM dimming feedback control circuit of the rear stage. The half-bridge LLC resonant circuit also takes the output voltage VBus of the previous stage as the input voltage, the topology comprises two windings of N2 and N3, the voltage loop at the output filter capacitor C3 collects the output voltage Vo of the half-bridge LLC resonant circuit, and PWM square wave driving signals are respectively sent to the switching tubes S2 and S3 through the logic operation in the main control chip L6599 to control the switching on and off of the switching tubes. And finally, the stabilization of the output voltage Vo is realized. The step-down type inductive current continuous mode driving chip SN3350 and the voltage output shunt monitor INA193 work in a combined mode to form an LED driving circuit, and in the LED driving circuit 1, the SN3350 and the INA193 are responsible for completing the independent dimming function of the backlight partition A-1. In the backlight partition A-1, the monitor INA193 is used for detecting the real-time current Iout1 passing through the LED load and sending the real-time current Iout1 into a port P00 of the MCU, and then the MCU CC2530 sends a dimming signal with the value of PWM1 to an ADJ pin of the chip SS3350 through a port P22, thereby completing the independent dimming task of the backlight partition A-1. In the LED driving circuit 2, SN3350 and INA193 are responsible for performing an independent dimming function of the backlight partition a-2, the monitor INA193 is configured to detect a real-time current Iout2 passing through an LED load and send the real-time current Iout2 to a P01 port of the MCU, and then the MCU CC2530 sends a dimming signal with a PWM2 value to an ADJ pin of the chip SS3350 through a P21 port, thereby performing an independent dimming task of the backlight partition a-2. And by analogy, the independent dimming function from the LED backlight subarea A-1 to the backlight subarea A-n is finally realized.

The utility model provides a Mini LED drive arrangement that is shaded from sun that many partitions independently adjusted luminance has following beneficial effect: (1) The device can realize multiple partitions, the more the partitions are, the higher the picture adjustable degree is, and the clearer the picture quality is. (2) The backlight partitions from A-1 to A-n can be independently controlled, when only a small white area exists in a picture, the partition backlight only turns on the backlight of the small white area, and the rest backlights are directly turned off to realize black in the true sense, and meanwhile, the power loss is also reduced.

The above embodiments of the present application are described in detail, and specific examples are applied in the present application to explain the principles and implementations of the present application, and the description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A multi-partition independent dimming Mini LED backlight driving device is characterized by comprising an EMI rectification filter circuit, a Boost PFC circuit, a voltage stabilizing unit, a half-bridge LLC resonant circuit, an MCU constant current control circuit, a plurality of LED driving circuits and an LED backlight board; the input end of the EMI rectifying and filtering circuit is connected to a mains supply, the output end of the EMI rectifying and filtering circuit is connected to the Boost PFC circuit, the half-bridge LLC resonance circuit is connected to the output end of the Boost PFC circuit, the voltage stabilizing unit is located between the Boost PFC circuit and the half-bridge LLC resonance circuit, the MCU constant current control circuit is connected to the output end of the half-bridge LLC resonance circuit, the LED driving circuits are connected to the half-bridge LLC resonance circuit, the LED backlight plate is provided with a plurality of LED backlight partitions, and each LED backlight partition is connected to one LED driving circuit;

the MCU constant current control circuit is a PWM dimming feedback control circuit and comprises an MCU controller CC2530; the LED driving circuit comprises a main control chip SN3350 and a voltage output shunt monitoring meter INA193; the voltage output shunt monitoring meter INA193 samples real-time current flowing through the LED backlight board and sends the real-time current to the MCU controller CC2530 for processing, and after the MCU controller CC2530 receives a current signal sent by the voltage output shunt monitoring meter INA193, the MCU controller CC2530 sends a PWM signal to the main control chip SN3350 for dimming control.

2. The multi-partition independent dimming Mini LED backlight driving device according to claim 1, wherein the EMI rectifying and filtering circuit comprises a common mode inductor CMC1, a resistor R2, a capacitor CX1, a capacitor CX2, a capacitor CY1, a capacitor CY2, a rectifying bridge Br1 and a capacitor C1, wherein the rectifying bridge Br1 is provided with a rectifying positive output terminal, a rectifying negative output terminal, a first AC input terminal and a second AC input terminal; common mode inductance CMC1 is equipped with two inputs and two outputs common mode inductance CMC1 between two inputs parallel connection electric capacity CX1 with resistance R2 and access interchange commercial power connect between two outputs of common mode inductance CMC1 electric capacity CX2 is connected to respectively first AC input end with second AC input end first AC input end with still series connection between the second AC input end electric capacity CY1 with electric capacity CY2, electric capacity CY1 with node ground connection between electric capacity CY2, the positive output of rectification with connect between the rectification negative output electric capacity C1, the positive output of rectification with the rectification negative output is EMI rectifier filter circuit's output.

3. The multi-zone independent dimming Mini LED backlight driving device according to claim 2, wherein the EMI rectifying and filtering circuit further comprises a fuse F1 and a thermistor NTC, one input terminal of the common-mode inductor CMC1 is connected to the commercial power through the fuse F1, and the other input terminal of the common-mode inductor CMC1 is connected to the commercial power through the thermistor NTC.

4. The multi-zone independent dimming Mini LED backlight driving apparatus according to claim 2,

the Boost PFC circuit comprises a rear-end LC circuit and a first control loop;

the mains supply is rectified by the rectifier bridge Br1 to obtain direct current, the direct current is filtered by the rear-end LC circuit to obtain stable power supply voltage VBus, and the power supply voltage VBus is output from the output end of the Boost PFC circuit;

the rear-end LC circuit comprises an inductor L1, a diode D1 and a switching tube S1; an inductor L1, a diode D1 and the voltage stabilizing unit are sequentially connected in series between the rectification anode output end and the rectification cathode output end of the rectifier bridge Br 1; the voltage stabilizing unit is a capacitor CBus, a switching tube S1 is further arranged between a connecting node of the inductor L1 and the diode D1 and the output end of the rectification negative pole, and the power supply voltage VBus is output from two ends of the capacitor CBus;

the first control loop comprises a main control chip UCC28019, the power supply voltage VBus is input to the main control chip UCC28019, a voltage sample is output to the main control chip UCC28019 at the rectified positive electrode output end, and a current sample is output to the main control chip UCC28019 at the rectified negative electrode output end; the main control chip UCC28019 is connected to the gate of the switching tube S1.

5. The multi-zone independent dimming Mini LED backlight driving apparatus according to claim 1,

the half-bridge LLC resonant circuit is provided with a VBus + input end, a VBus-input end, a Vo + output end and a Vo-output end; the VBus + input end and the VBus-input end are respectively connected to the output end of the Boost PFC circuit;

the half-bridge LLC resonant circuit comprises a transistor S2, a transistor S3, a capacitor C2, an inductor L2, a first transformer, a diode D2, a diode D3, a capacitor C3, a resistor R3 and a second control loop; the first transformer is provided with an input coil N1, an output coil N2 and an output coil N3, and the output coil N2 and the output coil N3 are arranged in series; the second control loop comprises a main control chip L6599A;

the VBus-input end is grounded, a transistor S2 and a transistor S3 are arranged between the VBus + input end and the VBus-input end in series, the grid electrodes of the transistor S2 and the transistor S3 are connected to the output end of the second control loop, a capacitor C2, an inductor L2 and an input coil N1 are connected between the transistor S2 and the transistor S3 in series, one end of the output coil N2 is connected to the Vo + output end through a diode D2, the other end of the output coil N2 is connected to the Vo-output end, a capacitor C3 and a resistor R3 are arranged between the Vo + output end and the Vo-output end in parallel, one end of the output coil N3 is connected to the Vo-output end, and the other end of the output coil N3 is connected to the Vo + output end through a diode D3; an output voltage between the Vo + output terminal and the Vo-output terminal is input to the second control loop.

6. The multi-zone independent dimming Mini LED backlight driving device according to claim 1, further comprising an auxiliary power supply circuit;

the auxiliary source power supply circuit comprises a second transformer, and the second transformer is provided with an input coil Np and an output coil Ns1;

the two ends of a branch of the input coil Np connected with the switching tube S4 in series are connected to the output end of the Boost PFC circuit;

one end of the output coil Ns1 is connected to the anode of the diode D4, a capacitor C4 and a resistor R4 are connected in parallel between the cathode of the diode D4 and the other end of the output coil Ns1, the other end of the output coil Ns1 is grounded, and the cathode of the diode D4 outputs a first auxiliary voltage.

7. The multi-zone independent dimming Mini LED backlight driving device according to claim 6, wherein in the auxiliary power supply circuit, the second transformer is further provided with an output coil Ns2;

one end of the output coil Ns2 is connected in series with the ground end of the output coil Ns1;

the other end of the output coil Ns2 is connected to the anode of a diode D5, the cathode of the diode D5 is connected to one side of a capacitor C6, the other side of the capacitor C6 is grounded, the diode D5 is connected in parallel with a branch formed by connecting the capacitor C5 and a resistor R5 in series, and the cathode of the diode D5 outputs a second auxiliary voltage.

8. The multi-zone independent dimming Mini LED backlight driving apparatus according to claim 7,

the first auxiliary voltage is 12V; the second auxiliary voltage is 3.3V.

9. The multi-zone independent dimming Mini LED backlight driving device according to claim 5,

in the LED driving circuit, the voltage output shunt monitoring meter INA193 Is provided with a Vin + pin, a Vin-pin, a V + pin, a Vout pin and a GND pin, and the main control chip SN3350 Is provided with a Vin pin, an Is pin, an LX pin, a GND pin and an ADJ pin;

the V + pin inputs a second auxiliary voltage;

the Vin-pin is directly connected to the anode of the LED lamp in the LED backlight subarea, the Vin-pin is further connected to the LX pin through a circuit formed by connecting an inductor L3 and a branch circuit formed by connecting a resistor R8 and a capacitor C9 in parallel in series, and a connection node of the inductor L3 and the branch circuit formed by connecting the resistor R8 and the capacitor C9 in parallel is connected to the cathode of the LED lamp in the LED backlight subarea;

the Vin pin Is connected to the Vin + pin and the Vo + output end, the Is pin Is connected to the Vin-pin, a resistor R9, a resistor R10 and a diode D6 are further arranged between the Vin + pin and the Vin-pin in parallel, and the anode of the diode D6 Is connected to the Vin-pin;

the pin Vout is connected with a resistor R6 and then outputs the real-time current Iout of the LED backlight partition; the GND pin is grounded and is connected to the real-time current output side of the resistor R6 through a capacitor C10;

the GND pin of the master control chip SN3350 is grounded and connected to the Vo-output end; a capacitor C7 and a capacitor C8 are arranged in parallel between the GND pin of the master control chip SN3350 and the Vin pin;

and the ADJ pin is connected with a resistor R7 and then outputs a PWM signal.

10. The multi-partition independent dimming Mini LED backlight driving device according to claim 9, wherein in the MCU constant current control circuit, the MCU controller CC2530 is provided with a RST pin, a current collection pin, a VDD pin, a GND pin and a dimming signal output pin;

a second auxiliary voltage is input after the RST pin is connected with the resistor R11, and the RST pin is grounded after being connected with the capacitor C12;

the current acquisition pin correspondingly inputs the corresponding real-time current Iout of the LED backlight subarea;

the VDD pin is input with a second auxiliary voltage, the GND pin is grounded, and the VDD pin is connected to the GND pin through a capacitor C11;

and the dimming signal output pin outputs PWM signals corresponding to the LED backlight partitions.