CN111681617A - Double-display-screen backlight driving circuit and method and double-display-screen equipment - Google Patents

Double-display-screen backlight driving circuit and method and double-display-screen equipment Download PDF

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Publication number
CN111681617A
CN111681617A CN202010591048.XA CN202010591048A CN111681617A CN 111681617 A CN111681617 A CN 111681617A CN 202010591048 A CN202010591048 A CN 202010591048A CN 111681617 A CN111681617 A CN 111681617A
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circuit
backlight
display
screen
voltage
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董坤
姜滨
迟小羽
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Goertek Techology Co Ltd
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Goertek Techology Co Ltd
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The application discloses a double-display-screen backlight driving circuit and method and double-display-screen equipment. After receiving a screen backlight starting instruction, the controller controls the boosting circuit to boost the input voltage of the controller to provide a conducting voltage for the left backlight circuit and the right backlight circuit on one hand, and controls the combined backlight modulation circuit to be communicated with working branches of the left backlight circuit and the right backlight circuit alternately on the other hand, so that the left backlight circuit and the right backlight circuit work alternately. Therefore, the black insertion technology is applied to the independent display of the left display screen and the independent display of the right display screen and the backlight driving of the display screen, the left display screen and the right display screen are controlled to be alternately opened to achieve the purpose that the left display screen and the right display screen are simultaneously driven by one path of booster circuit, and under the condition, two paths of backlight currents can be alternately opened to carry out current superposition, so that the input current of the booster circuit is reduced to the allowable input current value, the cost of the double-display-screen backlight driving circuit is reduced, and the area of a circuit board is reduced.

Description

Double-display-screen backlight driving circuit and method and double-display-screen equipment
Technical Field
The application relates to the field of dual-display-screen backlight driving, in particular to a dual-display-screen backlight driving circuit and method and dual-display-screen equipment.
Background
At present, in order to realize real immersive display of VR (Virtual Reality) devices, left and right display screens need to be controlled to independently display, so that a set of backlight LED (Light emitting diode) circuits is required for each of the left and right display screens. Meanwhile, in order to eliminate the problem of image smear of VR devices, black insertion technology is applied during backlight driving, and the backlight is generally controlled to reach 10% of the normal display time. However, the VR display screen is located inside the VR device housing, and requires higher brightness than the display of the products outside the screen, and if it is desired to obtain higher brightness when the backlight has only 10% of the display time, the backlight driving circuit is required to output a larger current.
In the prior art, a set of backlight LED circuits generally has a four-string and three-parallel structure, as shown in fig. 1, the turn-on voltage of a single LED is generally 7V, the current of a set of backlight LED circuits can reach 80mA, and the voltage can reach 28V. Currently, a backlight IC (integrated circuit) is separately provided for each set of backlight LED circuit, as shown in fig. 2, the working principle is as follows: the controller outputs enabling signals to EN ends of the left backlight IC and the right backlight IC after receiving a screen backlight starting instruction, and sends the screen backlight starting instruction to an LCD (Liquid Crystal Display) module; after receiving the screen backlight starting instruction, the LCD module simultaneously outputs a PWM _ L (Pulse Width Modulation) signal and a PWM _ R signal to the left backlight IC and the right backlight IC, respectively, so that the left backlight IC and the right backlight IC respectively drive the left backlight LED circuit and the right backlight LED circuit to operate.
Specifically, the number setting of the backlight ICs is explained in principle: fig. 3 shows a specific schematic diagram of the backlight driving of the VR display screen, and the known relationship Vbus IL1*E＝Vout1*IledWherein Vbus is the battery voltage, and the lowest value of the Vbus is 3.4V; i isL1Is the current at the inductance L1; e is the actual working efficiency of the left backlight IC, and the value of E is 80%; vout1 is the turn-on voltage of the backlight LED circuit, which is 28V; i isledThe current of the left backlight LED circuit is 80 mA; the current I at the inductance L1L128V 80 mA/(0.80V 3.4V) 820mA, which is the average current at the inductor L1. Due to the existence of the black insertion technology, the current of the backlight LED circuit has large overshoot in the black insertion process,generally, a pulse of about 1.5A is achieved, if the same backlight IC is used to drive the left and right backlight LED circuits simultaneously, the peak current at the inductor connected to the SW end of the backlight IC can reach a current of nearly 3A (superposition of left and right backlight currents), which results in that a switching tube for boosting voltage inside the backlight IC needs to bear a current capability greater than 3A, but there is no backlight IC that supports both VR black insertion technology and a current capability greater than 3A (mainly, the current of 3A exceeds the allowable input current value of the boosting circuit corresponding to the backlight IC), so the existing scheme is to separately set one backlight IC for each set of backlight LED circuit, which results in higher cost of the VR display backlight driving circuit and larger circuit board area.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The application aims at providing a double-display-screen backlight driving circuit, a double-display-screen backlight driving method and double-display-screen equipment, based on the characteristics that a left display screen and a right display screen independently display and a display screen backlight driving are applied with black insertion technology, the left display screen and the right display screen backlight circuits can be controlled to be alternately opened to realize that the left display screen and the right display screen backlight circuits are simultaneously driven by one path of booster circuit, under the condition, two paths of backlight currents can be alternately opened to carry out current superposition, so that the input current of the booster circuit is reduced to the allowable input current value, the cost of the double-display-screen backlight driving circuit is reduced, and the area of a.
In order to solve the above technical problem, the present application provides a dual display screen backlight driving circuit, which is applied to a dual display screen device including a left backlight circuit for providing backlight for a left display screen and a right backlight circuit for providing backlight for a right display screen, and includes:
the boosting circuit is respectively connected with the left backlight circuit and the right backlight circuit;
the combined backlight modulation circuit is respectively connected with the left backlight circuit and the right backlight circuit;
and the controller is respectively connected with the booster circuit and the combined backlight modulation circuit and is used for controlling the booster circuit to carry out boosting operation on self input voltage after receiving a screen backlight starting instruction so as to provide conduction voltage for the left backlight circuit and the right backlight circuit and controlling the combined backlight modulation circuit to be alternately communicated with working branches of the left backlight circuit and the right backlight circuit so as to enable the left backlight circuit and the right backlight circuit to alternately work.
Preferably, the controller is connected with a display screen module of the dual-display screen device;
the controller is specifically used for informing the display screen module to output a first PWM signal and a second PWM signal with the same waveform after receiving a screen backlight starting instruction; controlling the first backlight circuit to work under a certain frequency according to the received first PWM signal, and controlling the second backlight circuit to work under a certain frequency according to the received second PWM signal delay, so that the two backlight circuits work alternately;
the second backlight circuit delays the starting working time of the first backlight circuit to be less than the working period of the first backlight circuit and the second backlight circuit to be less than the persistence effect time; the first backlight circuit is the left backlight circuit or the right backlight circuit, and correspondingly, the second backlight circuit is the right backlight circuit or the left backlight circuit.
Preferably, the combined backlight modulation circuit comprises a first switch tube, a second switch tube, a first resistor and a second resistor; wherein:
the first end of the first switch tube is connected with the negative end of the power supply of the left backlight circuit, the second end of the first switch tube is connected with the first end of the first resistor, the second end of the first resistor is grounded, the first end of the second switch tube is connected with the negative end of the power supply of the right backlight circuit, the second end of the second switch tube is connected with the first end of the second resistor, the second end of the second resistor is grounded, and the control end of the first switch tube and the control end of the second switch tube are both connected with the controller;
correspondingly, the controller is specifically configured to control the working branches of the left backlight circuit and the right backlight circuit to be alternately connected by controlling on/off states of the first switch tube and the second switch tube, so that the left backlight circuit and the right backlight circuit alternately work.
Preferably, the combined backlight modulation circuit further comprises:
the first pull-down resistor is connected with the control end of the first switching tube at the first end and grounded at the second end;
and the first end of the second pull-down resistor is connected with the control end of the second switching tube, and the second end of the second pull-down resistor is grounded.
Preferably, the boost circuit includes a first capacitor, a second capacitor, a third capacitor, an inductor, a diode, and a third switching tube; wherein:
the first end of the first capacitor is connected with the first end of the inductor, the common end of the first capacitor is connected with a voltage to be boosted, the second end of the inductor is respectively connected with the anode of the diode and the first end of the third switching tube, the second end of the third switching tube is grounded, the control end of the third switching tube is connected with the controller, the positive power supply end of the left backlight circuit is respectively connected with the cathode of the diode and the first end of the second capacitor, the second end of the second capacitor is grounded, the positive power supply end of the right backlight circuit is respectively connected with the cathode of the diode and the first end of the third capacitor, and the second end of the third capacitor is grounded;
correspondingly, the controller is specifically configured to control the voltage boosting circuit to boost the voltage to be boosted by controlling the on-off state of the third switching tube, so as to provide a conduction voltage for the left backlight circuit and the right backlight circuit.
Preferably, the controller is further configured to control the voltage boost circuit to perform an overvoltage boost operation on the input voltage of the voltage boost circuit after receiving a screen backlight end instruction, so that the output voltage of the voltage boost circuit is greater than the preset on-voltage value; wherein the preset voltage value is less than the breakover voltage.
Preferably, the dual display backlight driving circuit further includes:
the voltage detection circuit is respectively connected with the booster circuit and the controller and is used for detecting the output voltage of the booster circuit to obtain a voltage detection signal;
correspondingly, the controller is further used for judging whether the boosting circuit is in a boosting state matched with the current screen backlight instruction or not according to the voltage detection signal; and if not, adjusting the booster circuit to enable the booster circuit to be in a boosting state matched with the current screen backlight instruction.
Preferably, the voltage detection circuit includes a third resistor and a fourth resistor; wherein:
the first end of the third resistor is connected to the output voltage of the booster circuit, the second end of the third resistor is connected to the first end of the fourth resistor, the common end of the third resistor is connected to the controller, and the second end of the fourth resistor is grounded.
In order to solve the above technical problem, the present application further provides a dual-display backlight driving method, which is applied to any one of the dual-display backlight driving circuits, and includes:
when a screen backlight starting instruction is received, controlling the boosting circuit to boost the input voltage of the boosting circuit to provide conducting voltage for the left backlight circuit and the right backlight circuit;
and when the screen backlight starting instruction is received, controlling the combined backlight modulation circuit to alternately communicate with the working branches of the left backlight circuit and the right backlight circuit so as to alternately work the left backlight circuit and the right backlight circuit.
In order to solve the above technical problem, the present application further provides a dual display device, including:
a left display screen and a right display screen;
a left backlight circuit for providing backlight for the left display screen;
a right backlight circuit for providing backlight to the right display screen;
a dual display backlight driving circuit; the double-display-screen backlight driving circuit is any one of the double-display-screen backlight driving circuits.
Preferably, the dual display screen device is specifically a VR device.
The application provides a double-display-screen backlight driving circuit which comprises a booster circuit, a combined backlight modulation circuit and a controller. After receiving a screen backlight starting instruction, the controller controls the boosting circuit to boost the input voltage of the controller to provide a conducting voltage for the left backlight circuit and the right backlight circuit on one hand, and controls the combined backlight modulation circuit to be communicated with working branches of the left backlight circuit and the right backlight circuit alternately on the other hand, so that the left backlight circuit and the right backlight circuit work alternately. Therefore, the black insertion technology is applied to the independent display of the left display screen and the independent display of the right display screen and the backlight driving of the display screen, the left display screen and the right display screen are controlled to be alternately opened to achieve the purpose that the left display screen and the right display screen are simultaneously driven by one path of booster circuit, and under the condition, two paths of backlight currents can be alternately opened to carry out current superposition, so that the input current of the booster circuit is reduced to the allowable input current value, the cost of the double-display-screen backlight driving circuit is reduced, and the area of a circuit board is reduced.
The application also provides a double-display-screen backlight driving method and double-display-screen equipment, and the double-display-screen backlight driving method and the double-display-screen equipment have the same beneficial effects as the backlight driving circuit.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and the embodiments are briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a set of backlight LED circuits in the prior art;
FIG. 2 is a schematic diagram of a VR display backlight driving scheme in the prior art;
FIG. 3 is a detailed schematic diagram of a VR display backlight driver in the prior art;
fig. 4 is a schematic structural diagram of a dual-display backlight driving circuit according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of a dual-display backlight driving circuit according to an embodiment of the present disclosure;
fig. 6 is a schematic diagram illustrating an operating principle of a dual-display backlight driving circuit according to an embodiment of the present disclosure.
Detailed Description
The core of the application is to provide a double-display-screen backlight driving circuit, a double-display-screen backlight driving method and double-display-screen equipment, based on the characteristics that the left display screen and the right display screen independently display and the display screen backlight driving apply black insertion technology, the left display screen and the right display screen backlight circuit can be alternately opened through controlling to realize that the left display screen and the right display screen backlight circuit are simultaneously driven by one path of booster circuit, under the condition, two paths of backlight currents can be alternately opened to carry out current superposition, so that the input current of the booster circuit is reduced to the allowable input current value, the cost of the double-display-screen backlight driving circuit is reduced, and the area of a.
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, 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, and it is obvious that the described embodiments are some embodiments of the present application, but 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.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a dual-display backlight driving circuit according to an embodiment of the present disclosure.
The double-display-screen backlight driving circuit is applied to: a dual display panel device (e.g., VR device) including a left backlight circuit D1 for backlighting a left display panel and a right backlight circuit D2 for backlighting a right display panel, the dual display panel backlight driver circuit comprising:
the booster circuit 1 is connected with the left backlight circuit D1 and the right backlight circuit D2 respectively;
a combined backlight modulation circuit 2 connected to the left backlight circuit D1 and the right backlight circuit D2, respectively;
and the controller 3 is respectively connected with the voltage boost circuit 1 and the combined backlight modulation circuit 2, and is used for controlling the voltage boost circuit 1 to boost the input voltage of the voltage boost circuit 1 after receiving a screen backlight starting instruction so as to provide conducting voltage for the left backlight circuit D1 and the right backlight circuit D2, and controlling the combined backlight modulation circuit 2 to alternately communicate with the working branches of the left backlight circuit D1 and the right backlight circuit D2 so as to alternately work the left backlight circuit D1 and the right backlight circuit D2.
Specifically, the dual-display-screen backlight driving circuit of the present application includes a boost circuit 1, a combined backlight modulation circuit 2 and a controller 3, and the working principle thereof is as follows:
based on the characteristic that the left display screen and the right display screen of the dual-display-screen device display independently, the dual-display-screen device needs to set a set of backlight circuit for each of the left display screen and the right display screen, wherein the circuit for providing backlight for the left display screen is called a left backlight circuit D1, the circuit for providing backlight for the right display screen is called a right backlight circuit D2, and the specific structures of the left backlight circuit D1 and the right backlight circuit D2 can be as shown in fig. 1.
Meanwhile, the dual-display backlight driving based on the dual-display device employs the black insertion technique, and it is known that the left backlight circuit D1 and the right backlight circuit D2 do not operate at 100% of the display time, and the specific display time ratio value is determined by the specific black insertion setting, and generally controls the backlight to reach 10% of the normal display time, that is, within one duty cycle of the backlight circuit, the duty cycle of the backlight circuit is 10% × the duty cycle. In addition, it should be noted that the duty cycle of the left backlight circuit D1 and the right backlight circuit D2 should be less than the human persistence time (13ms), so as to make human eyes not feel that the display screen is on or off periodically, thereby improving the user experience.
Based on this, the black insertion setting of the dual-display-screen backlight driving can be utilized in the application, so that the alternating operation of the left backlight circuit D1 and the right backlight circuit D2 is realized, that is, the left backlight circuit D1 and the right backlight circuit D2 do not operate at the same time, that is, when the left backlight circuit D1 is in the black insertion state, the right backlight circuit D2 enters into operation, when the left backlight circuit D1 enters into operation, the right backlight circuit D2 already enters into the black insertion state, and the two backlight circuits do not operate at the same time like the prior art.
On the basis of the alternate operation of the left backlight circuit D1 and the right backlight circuit D2, the backlight current of the left backlight circuit D1 and the backlight current of the right backlight circuit D2 can be staggered for current superposition, which allows one path of voltage boosting circuit to be used for driving the left backlight circuit D1 and the right backlight circuit D2 simultaneously.
Therefore, the dual-display-screen backlight driving circuit of the present application includes the boost circuit 1, the combined backlight modulation circuit 2 and the controller 3, specifically, after the controller 3 receives a screen backlight turn-on command, the boost circuit 1 is controlled to boost the input voltage of the controller, so that the boost circuit 1 provides the turn-on voltage for the left backlight circuit D1 and the right backlight circuit D2 at the same time, and at the same time, the combined backlight modulation circuit 2 is controlled to alternately communicate with the working branches of the left backlight circuit D1 and the right backlight circuit D2, so that the left backlight circuit D1 and the right backlight circuit D2 alternately work.
The application provides a double-display-screen backlight driving circuit which comprises a booster circuit, a combined backlight modulation circuit and a controller. After receiving a screen backlight starting instruction, the controller controls the boosting circuit to boost the input voltage of the controller to provide a conducting voltage for the left backlight circuit and the right backlight circuit on one hand, and controls the combined backlight modulation circuit to be communicated with working branches of the left backlight circuit and the right backlight circuit alternately on the other hand, so that the left backlight circuit and the right backlight circuit work alternately. Therefore, the black insertion technology is applied to the independent display of the left display screen and the independent display of the right display screen and the backlight driving of the display screen, the left display screen and the right display screen are controlled to be alternately opened to achieve the purpose that the left display screen and the right display screen are simultaneously driven by one path of booster circuit, and under the condition, two paths of backlight currents can be alternately opened to carry out current superposition, so that the input current of the booster circuit is reduced to the allowable input current value, the cost of the double-display-screen backlight driving circuit is reduced, and the area of a circuit board is reduced.
On the basis of the above-described embodiment:
referring to fig. 5, fig. 5 is a schematic structural diagram of a dual-display backlight driving circuit according to an embodiment of the present disclosure.
As an alternative embodiment, the controller 3 is connected to the display screen module of the dual-display device;
the controller 3 is specifically used for informing the display screen module to output a first PWM signal and a second PWM signal with the same waveform after receiving a screen backlight starting instruction; controlling the first backlight circuit to work under a certain frequency according to the received first PWM signal, and controlling the second backlight circuit to work under a certain frequency according to the received second PWM signal delay, so that the two backlight circuits work alternately;
the second backlight circuit delays the starting working time of the first backlight circuit to be less than the working period of the first backlight circuit and the second backlight circuit to be less than the persistence effect time; the first backlight circuit is the left backlight circuit D1 or the right backlight circuit D2, and correspondingly, the second backlight circuit is the right backlight circuit D2 or the left backlight circuit D1.
Specifically, this application can be directly carried out two display screen backlight drive's black insertion by controller 3 and set up to based on inserting black equipment control left backlight circuit D1 and right backlight circuit D2 and work in turn, also can be carried out two display screen backlight drive's black insertion by controller 3 with the help of the display screen module of two display screen equipment and set up, concrete means of realization do:
the controller 3 is connected to the display screen module of the dual-display device, and after receiving the screen backlight turn-on command, the controller 3 sends the screen backlight turn-on command to the display screen module, for example, the controller 3 selects a CPU, and the CPU and the display screen module transmit the command in LP mode through MIPI (Mobile Industry Processor Interface). After receiving a screen backlight starting instruction, the display screen module simultaneously outputs a first PWM signal and a second PWM signal (e.g., a PWM waveform with a 90 Hz/10% duty ratio) with the same waveform to the controller 3. After receiving the first PWM signal and the second PWM signal, the controller 3 controls the first backlight circuit to operate at a certain frequency according to the first PWM signal, and controls the second backlight circuit to operate at a certain frequency according to the second PWM signal, so that the first backlight circuit and the second backlight circuit operate alternately. In addition, it should be noted that, after the second backlight circuit delays the start working time of the first backlight circuit < the working cycle of the first backlight circuit and the second backlight circuit < the persistence of vision effect time, human eyes do not feel that the left and right display screens are on and off periodically, and do not feel that the left and right display screens are on and off alternately, thereby further improving the user experience.
More specifically, the first backlight circuit of the present embodiment may be the left backlight circuit D1, the first PWM signal is the PWM _ L signal, and the second backlight circuit is the right backlight circuit D2, and the second PWM signal is the PWM _ R signal, that is, the left backlight circuit D1 is turned on first; alternatively, the first backlight circuit may be the right backlight circuit D2, the first PWM signal is the PWM _ R signal, the second backlight circuit is the left backlight circuit D1, and the second PWM signal is the PWM _ L signal, i.e., the right backlight circuit D2 is turned on first.
As an alternative embodiment, the combined backlight modulation circuit 2 includes a first switch Q1, a second switch Q2, a first resistor R1 and a second resistor R2; wherein:
a first end of a first switch tube Q1 is connected with a negative power supply end of the left backlight circuit D1, a second end of a first switch tube Q1 is connected with a first end of a first resistor R1, a second end of the first resistor R1 is grounded, a first end of a second switch tube Q2 is connected with a negative power supply end of the right backlight circuit D2, a second end of a second switch tube Q2 is connected with a first end of a second resistor R2, a second end of the second resistor R2 is grounded, and a control end of the first switch tube Q1 and a control end of the second switch tube Q2 are both connected with the controller 3;
accordingly, the controller 3 is specifically configured to control the on-off states of the first switch Q1 and the second switch Q2 to control the operation branches of the left backlight circuit D1 and the right backlight circuit D2 to be alternately connected, so that the left backlight circuit D1 and the right backlight circuit D2 are alternately operated.
Specifically, the combined backlight modulation circuit 2 of the present application includes a first switch Q1, a second switch Q2, a first resistor R1 and a second resistor R2, and its operation principle is:
when the first switch tube Q1 is turned on, the working branch of the left backlight circuit D1 is connected, and the left backlight circuit D1 is turned on to work under the voltage provided by the voltage boost circuit 1; when the first switch Q1 is turned off, the working branch of the left backlight circuit D1 is turned off, and the left backlight circuit D1 is not operated. Similarly, when the second switch Q2 is turned on, the working branch of the right backlight circuit D2 is connected, and the right backlight circuit D2 is turned on to work under the voltage provided by the voltage boost circuit 1; when the second switch Q2 is turned off, the working branch of the right backlight circuit D2 is turned off, and the right backlight circuit D2 does not work.
Based on this, the controller 3 controls the on-off states of the first switch tube Q1 and the second switch tube Q2 to control the working branches of the left backlight circuit D1 and the right backlight circuit D2 to be alternately connected, so that the left backlight circuit D1 and the right backlight circuit D2 are alternately operated.
For example, the first switch Q1 and the second switch Q2 are both high-level conducting and low-level blocking switches (such as NPN transistors), and the control principles of the two switches are shown in fig. 6. When the driving signal Sink _ PWM _ L (the same as the duty ratio of the PWM _ L signal) output to the first switching tube Q1 by the controller 3 is at a high level, the first switching tube Q1 is turned on, and the left backlight circuit D1 is turned on; when the driving signal Sink _ PWM _ L is at a low level, the first switching tube Q1 is turned off, and the left backlight circuit D1 does not operate. When the driving signal Sink _ PWM _ R (the same as the duty ratio of the PWM _ R signal) output to the second switching tube Q2 by the controller 3 is at a high level, the second switching tube Q2 is turned on, and the right backlight circuit D2 is turned on; when the driving signal Sink _ PWM _ R is at a low level, the second switching tube Q2 is turned off, and the right backlight circuit D2 does not operate. Therefore, the high level signals of the driving signals Sink _ PWM _ L and Sink _ PWM _ R are staggered with a 5ms difference, so that the left backlight circuit D1 and the right backlight circuit D2 work alternately.
As an alternative embodiment, the combined backlight modulation circuit 2 further includes:
a first pull-down resistor R11, the first end of which is connected with the control end of the first switch tube Q1, and the second end of which is grounded;
and a second pull-down resistor R12 having a first end connected to the control end of the second switch tube Q2 and a second end grounded.
Further, the combined backlight modulation circuit 2 of the present application further includes a first pull-down resistor R11 and a second pull-down resistor R12, and the operation principle thereof is as follows:
considering that when the dual-display-screen backlight driving circuit is just powered on, the voltage on each branch of the dual-display-screen backlight driving circuit is unstable and may have a virtual voltage, if the branch where the control ends of the first switch tube Q1 and the second switch tube Q2 are respectively located has a virtual voltage, based on that the first switch tube Q1 and the second switch tube Q2 are both switch tubes with high level conduction and low level cut-off, the first switch tube Q1 and the second switch tube Q2 are switched on by mistake, the application accesses the first pull-down resistor R11 to the control end of the first switch tube Q1, so that when the dual-display-screen backlight driving circuit is just powered on, the branch where the control end of the first switch tube Q1 is located is kept in a low level state to prevent the first switch tube Q1 from being switched on by mistake; similarly, the control end of the second switch tube Q2 is connected to the second pull-down resistor R12, so that when the dual-display-screen backlight driving circuit is just powered on, the branch at which the control end of the second switch tube Q2 is located is kept in a low level state, thereby preventing the second switch tube Q2 from being turned on by mistake.
As an alternative embodiment, the boost circuit 1 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, an inductor L, a diode D, and a third switching tube Q3; wherein:
a first end of a first capacitor C1 is connected with a first end of an inductor L, a common end of the first capacitor C1 is connected with a voltage to be boosted, a second end of the inductor L is respectively connected with an anode of a diode D and a first end of a third switching tube Q3, a second end of the third switching tube Q3 is grounded, a control end of the third switching tube Q3 is connected with the controller 3, a power positive end of a left backlight circuit D1 is respectively connected with a cathode of the diode D and a first end of a second capacitor C2, a second end of a second capacitor C2 is grounded, a power positive end of a right backlight circuit D2 is respectively connected with a cathode of the diode D and a first end of a third capacitor C3, and a second end of a third capacitor C3 is grounded;
accordingly, the controller 3 is specifically configured to control the voltage boosting circuit 1 to perform the voltage boosting operation on the voltage to be boosted by controlling the on-off state of the third switching tube Q3, so as to provide the on-state voltage for the left backlight circuit D1 and the right backlight circuit D2.
Specifically, the boost circuit 1 of the present application includes a first capacitor C1, a second capacitor C2, a third capacitor C3, an inductor L, a diode D, and a third switching tube Q3, and its operating principle is:
when the third switching transistor Q3 (such as a MOS transistor) is turned on, the input voltage flows through the inductor L, and the diode D prevents the second capacitor C2 and the third capacitor C3 from discharging to ground. Since direct current is input, the current on the inductor L increases linearly at a rate that is related to the inductance of the inductor L. As the current in the inductor L increases, some energy is stored in the inductor L. When the third switching tube Q3 is turned off, due to the current holding characteristic of the inductor L, the current flowing through the inductor L does not immediately become 0, but slowly changes from the value at the end of charging to 0, and the original circuit is turned off, the inductor L can only discharge through a new circuit, that is, the inductor L starts to charge the second capacitor C2 and the third capacitor C3, the voltages at the two ends of the second capacitor C2 and the third capacitor C3 rise, and at this time, the voltages at the two ends of the second capacitor C2 and the third capacitor C3 are higher than the input voltage, and the voltage rise is completed. In addition, the first capacitor C1 functions to stabilize the input voltage.
As an optional embodiment, the controller 3 is further configured to control the voltage boosting circuit 1 to perform an overvoltage voltage boosting operation on the input voltage of the voltage boosting circuit 1 after receiving a screen backlight ending instruction, so that the output voltage of the voltage boosting circuit 1 is greater than a preset voltage value of the turn-on voltage; wherein the preset voltage value is less than the breakover voltage.
Further, based on fig. 2 and 3, in the prior art, after receiving the screen backlight end instruction, the controller stops outputting the enable signal to the EN terminals of the left backlight IC and the right backlight IC, and sends the screen backlight end instruction to the LCD module; after receiving the screen backlight ending instruction, the LCD module stops outputting the PWM _ L signal and the PWM _ R signal so that the left backlight IC and the right backlight IC stop driving the left backlight LED circuit and the right backlight LED circuit. Therefore, when the left/right backlight IC does not work, the input voltage of the power supply positive end of the left/right backlight LED circuit is reduced to 0V; when the left/right backlight IC works, the input voltage of the power supply positive terminal of the left/right backlight LED circuit rises to 28V, and the response time required for the input voltage to change from 0V to 28V is longer.
Based on this, the controller 3 of the present application, after receiving the screen backlight end instruction, controls the voltage boost circuit 1 to perform an overvoltage boost operation on the input voltage of the voltage boost circuit 1, so that the output voltage of the voltage boost circuit 1 is greater than the on-voltage of the left/right backlight circuit by a certain value. It should be noted that the voltage value of the output voltage of the voltage boost circuit 1, which is greater than the turn-on voltage of the left/right backlight circuit, needs to be less than the turn-on voltage of the left/right backlight circuit, for example, the turn-on voltage of the left/right backlight circuit is 28V, and then the controller 3 controls the output voltage of the voltage boost circuit 1 to be 30V after receiving the screen backlight end instruction, so that the input voltage of the positive power supply terminal of the left/right backlight circuit is boosted to be 30V when the combined backlight modulation circuit 2 does not work; when the combined backlight modulation circuit 2 is operated, the input voltage of the power supply positive terminal of the left/right backlight circuit rises to 28V, and the response time required for the input voltage to change from 30V to 28V is short.
As an alternative embodiment, the dual display backlight driving circuit further includes:
the voltage detection circuit is respectively connected with the booster circuit 1 and the controller 3 and is used for detecting the output voltage of the booster circuit 1 to obtain a voltage detection signal;
correspondingly, the controller 3 is further configured to determine whether the voltage boost circuit 1 is in a boost state matched with the current screen backlight instruction according to the voltage detection signal; if not, the booster circuit 1 is adjusted to be in a boosting state matched with the current screen backlight instruction.
Further, the dual display screen backlight driving circuit of the application further comprises a voltage detection circuit, and the working principle of the dual display screen backlight driving circuit is as follows:
the voltage detection circuit is configured to detect an output voltage (Vout _ boost) of the voltage boost circuit 1, obtain a voltage detection signal representing the output voltage of the voltage boost circuit 1, and send the voltage detection signal to the controller 3. After receiving the voltage detection signal, the controller 3 determines the output voltage of the booster circuit 1 according to the voltage detection signal, and determines whether the booster circuit 1 is in a boosting state matched with the current screen backlight instruction according to the output voltage of the booster circuit 1; if the current screen backlight instruction is matched with the boost state, the boost state of the boost circuit 1 is kept, and the boost circuit 1 does not need to be adjusted; if the current screen backlight instruction is not matched with the boost state, the boost circuit 1 needs to be adjusted to the boost state matched with the current screen backlight instruction.
For example, after receiving a screen backlight turn-on command, the controller 3 controls the output voltage of the voltage boost circuit 1 to be 28V; after receiving the screen backlight end instruction, the output voltage of the booster circuit 1 is controlled to be 30V. After receiving the screen backlight starting instruction, the controller 3 determines whether the output voltage of the voltage boosting circuit 1 is 28V according to the received voltage detection signal, and if so, determines that the voltage boosting circuit 1 is in a boosting state matched with the screen backlight starting instruction; if not, the boosting circuit 1 is determined to be in a boosting state not matched with the screen backlight starting instruction, and the boosting circuit 1 needs to be adjusted so that the output voltage of the boosting circuit 1 reaches 28V. Similarly, after receiving the screen backlight ending instruction, the controller 3 determines whether the output voltage of the voltage boosting circuit 1 is 30V according to the received voltage detection signal, and if so, determines that the voltage boosting circuit 1 is in a voltage boosting state matched with the screen backlight ending instruction; if not, the booster circuit 1 is determined to be in a boosting state not matched with the screen backlight ending instruction, and the booster circuit 1 needs to be adjusted so that the output voltage of the booster circuit 1 reaches 30V.
As an alternative embodiment, the voltage detection circuit includes a third resistor R3 and a fourth resistor R4; wherein:
the first end of the third resistor R3 is connected to the output voltage of the voltage boost circuit 1, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4, the common end is connected to the controller 3, and the second end of the fourth resistor R4 is grounded.
Specifically, the voltage detection circuit of the present application includes a third resistor R3 and a fourth resistor R4, that is, the voltage division of the third resistor R3 and the fourth resistor R4 realizes real-time monitoring of the output voltage of the voltage boost circuit 1.
The application also provides a double-display-screen backlight driving method, which is applied to any one of the double-display-screen backlight driving circuits, and comprises the following steps:
when a screen backlight starting instruction is received, the boosting circuit is controlled to perform boosting operation on the input voltage of the boosting circuit, so that conducting voltage is provided for the left backlight circuit and the right backlight circuit;
when a screen backlight starting instruction is received, the combined backlight modulation circuit is controlled to alternately communicate with the working branches of the left backlight circuit and the right backlight circuit, so that the left backlight circuit and the right backlight circuit alternately work.
For the introduction of the dual-display backlight driving method provided in the present application, reference is made to the above-mentioned embodiments of the dual-display backlight driving circuit, which are not described herein again.
The application also provides a dual display screen device, including:
a left display screen and a right display screen;
a left backlight circuit for providing backlight for the left display screen;
a right backlight circuit for providing backlight to the right display screen;
a dual display backlight driving circuit; the double-display-screen backlight driving circuit is any one of the double-display-screen backlight driving circuits.
As an alternative embodiment, the dual-display device is specifically a VR device.
For the introduction of the dual-display device provided in the present application, please refer to the above-mentioned embodiment of the dual-display backlight driving circuit, which is not described herein again.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (11)

1. A dual display backlight driving circuit, applied to a dual display device including a left backlight circuit for providing backlight to a left display and a right backlight circuit for providing backlight to a right display, includes:
the boosting circuit is respectively connected with the left backlight circuit and the right backlight circuit;
the combined backlight modulation circuit is respectively connected with the left backlight circuit and the right backlight circuit;
and the controller is respectively connected with the booster circuit and the combined backlight modulation circuit and is used for controlling the booster circuit to carry out boosting operation on self input voltage after receiving a screen backlight starting instruction so as to provide conduction voltage for the left backlight circuit and the right backlight circuit and controlling the combined backlight modulation circuit to be alternately communicated with working branches of the left backlight circuit and the right backlight circuit so as to enable the left backlight circuit and the right backlight circuit to alternately work.
2. The dual display backlight driver circuit of claim 1, wherein the controller is connected to a display module of the dual display device;
the controller is specifically used for informing the display screen module to output a first PWM signal and a second PWM signal with the same waveform after receiving a screen backlight starting instruction; controlling the first backlight circuit to work under a certain frequency according to the received first PWM signal, and controlling the second backlight circuit to work under a certain frequency according to the received second PWM signal delay, so that the two backlight circuits work alternately;
the second backlight circuit delays the starting working time of the first backlight circuit to be less than the working period of the first backlight circuit and the second backlight circuit to be less than the persistence effect time; the first backlight circuit is the left backlight circuit or the right backlight circuit, and correspondingly, the second backlight circuit is the right backlight circuit or the left backlight circuit.
3. The dual display backlight driving circuit of claim 1, wherein the combined backlight modulation circuit comprises a first switch transistor, a second switch transistor, a first resistor and a second resistor; wherein:
the first end of the first switch tube is connected with the negative end of the power supply of the left backlight circuit, the second end of the first switch tube is connected with the first end of the first resistor, the second end of the first resistor is grounded, the first end of the second switch tube is connected with the negative end of the power supply of the right backlight circuit, the second end of the second switch tube is connected with the first end of the second resistor, the second end of the second resistor is grounded, and the control end of the first switch tube and the control end of the second switch tube are both connected with the controller;
correspondingly, the controller is specifically configured to control the working branches of the left backlight circuit and the right backlight circuit to be alternately connected by controlling on/off states of the first switch tube and the second switch tube, so that the left backlight circuit and the right backlight circuit alternately work.
4. The dual display backlight driver circuit of claim 3, wherein the combined backlight modulation circuit further comprises:
the first pull-down resistor is connected with the control end of the first switching tube at the first end and grounded at the second end;
and the first end of the second pull-down resistor is connected with the control end of the second switching tube, and the second end of the second pull-down resistor is grounded.
5. The dual display backlight driving circuit of claim 1, wherein the boost circuit comprises a first capacitor, a second capacitor, a third capacitor, an inductor, a diode, and a third switch tube; wherein:
the first end of the first capacitor is connected with the first end of the inductor, the common end of the first capacitor is connected with a voltage to be boosted, the second end of the inductor is respectively connected with the anode of the diode and the first end of the third switching tube, the second end of the third switching tube is grounded, the control end of the third switching tube is connected with the controller, the positive power supply end of the left backlight circuit is respectively connected with the cathode of the diode and the first end of the second capacitor, the second end of the second capacitor is grounded, the positive power supply end of the right backlight circuit is respectively connected with the cathode of the diode and the first end of the third capacitor, and the second end of the third capacitor is grounded;
correspondingly, the controller is specifically configured to control the voltage boosting circuit to boost the voltage to be boosted by controlling the on-off state of the third switching tube, so as to provide a conduction voltage for the left backlight circuit and the right backlight circuit.
6. The dual-display-screen backlight driving circuit according to any one of claims 1-5, wherein the controller is further configured to control the voltage boosting circuit to perform an over-voltage boosting operation on its own input voltage after receiving a screen backlight end instruction, so that the output voltage of the voltage boosting circuit is greater than the preset on-voltage value; wherein the preset voltage value is less than the breakover voltage.
7. The dual display backlight driver circuit of claim 6, wherein the dual display backlight driver circuit further comprises:
the voltage detection circuit is respectively connected with the booster circuit and the controller and is used for detecting the output voltage of the booster circuit to obtain a voltage detection signal;
correspondingly, the controller is further used for judging whether the boosting circuit is in a boosting state matched with the current screen backlight instruction or not according to the voltage detection signal; and if not, adjusting the booster circuit to enable the booster circuit to be in a boosting state matched with the current screen backlight instruction.
8. The dual display backlight driver circuit of claim 7, wherein the voltage detection circuit comprises a third resistor and a fourth resistor; wherein:
the first end of the third resistor is connected to the output voltage of the booster circuit, the second end of the third resistor is connected to the first end of the fourth resistor, the common end of the third resistor is connected to the controller, and the second end of the fourth resistor is grounded.
9. A dual display backlight driving method applied to the dual display backlight driving circuit according to any one of claims 1 to 8, comprising:
when a screen backlight starting instruction is received, controlling the boosting circuit to boost the input voltage of the boosting circuit to provide conducting voltage for the left backlight circuit and the right backlight circuit;
and when the screen backlight starting instruction is received, controlling the combined backlight modulation circuit to alternately communicate with the working branches of the left backlight circuit and the right backlight circuit so as to alternately work the left backlight circuit and the right backlight circuit.
10. A dual display screen device, comprising:
a left display screen and a right display screen;
a left backlight circuit for providing backlight for the left display screen;
a right backlight circuit for providing backlight to the right display screen;
a dual display backlight driving circuit; the dual display backlight driving circuit according to any one of claims 1 to 8.
11. A dual display device as claimed in claim 10, in particular a VR device.
CN202010591048.XA 2020-06-24 2020-06-24 Double-display-screen backlight driving circuit and method and double-display-screen equipment Pending CN111681617A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610200A (en) * 2012-04-01 2012-07-25 福建华映显示科技有限公司 Backlight module and control method thereof and display device applying backlight module
CN103680444A (en) * 2013-12-06 2014-03-26 深圳市华星光电技术有限公司 LED boost converter and backlight source LED driving device applying LED boost converter
CN105636280A (en) * 2016-03-31 2016-06-01 深圳多哚新技术有限责任公司 Backlight circuit of VR display
CN109741712A (en) * 2019-03-27 2019-05-10 京东方科技集团股份有限公司 Backlight driving method and device, display device
CN110890070A (en) * 2019-09-25 2020-03-17 歌尔科技有限公司 VR display equipment, double-screen backlight driving device and method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102610200A (en) * 2012-04-01 2012-07-25 福建华映显示科技有限公司 Backlight module and control method thereof and display device applying backlight module
CN103680444A (en) * 2013-12-06 2014-03-26 深圳市华星光电技术有限公司 LED boost converter and backlight source LED driving device applying LED boost converter
CN105636280A (en) * 2016-03-31 2016-06-01 深圳多哚新技术有限责任公司 Backlight circuit of VR display
CN109741712A (en) * 2019-03-27 2019-05-10 京东方科技集团股份有限公司 Backlight driving method and device, display device
CN110890070A (en) * 2019-09-25 2020-03-17 歌尔科技有限公司 VR display equipment, double-screen backlight driving device and method

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Application publication date: 20200918