CN209201210U - Backlight control circuit and electronic equipment - Google Patents
Backlight control circuit and electronic equipment Download PDFInfo
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- CN209201210U CN209201210U CN201920230145.9U CN201920230145U CN209201210U CN 209201210 U CN209201210 U CN 209201210U CN 201920230145 U CN201920230145 U CN 201920230145U CN 209201210 U CN209201210 U CN 209201210U
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Abstract
The utility model discloses a control circuit and electronic equipment are shaded. The circuit includes: the first output end of the flyback power supply module is connected with the first end of the voltage stabilizing module, and the second output end of the flyback power supply module is connected with the first end of the logic control module; the second end of the logic control module is connected with the second end of the voltage stabilizing module; the first end of the boosting module is connected with the third end of the voltage stabilizing module, and the second end of the boosting module is connected with the load module; when the second end of the voltage stabilizing module receives the high level signal and the first voltage value output by the first output end of the flyback power supply module reaches the breakdown conduction voltage of the voltage stabilizing module, the voltage stabilizing module is conducted to control the first voltage value to be smaller than the load working voltage value required by the load module. The utility model discloses a voltage stabilizing module has guaranteed that first voltage value is less than load operating voltage value, has effectively avoided LED in a poor light to appear slightly bright phenomenon under the flyback circuit unbalance loading condition among the liquid crystal display device, does not increase liquid crystal display device's stand-by power consumption simultaneously.
Description
Technical field
The utility model embodiment is related to power technology more particularly to a kind of backlight control circuit and electronic equipment.
Background technique
Continuous with intelligent TV set (for example, liquid crystal panel TV set) is popularized, and the size of liquid crystal panel TV set is got over
Come it is bigger, for example, the size of common liquid crystal panel TV set be 32 cun, 43 cun, 49 cun etc. so that the power of TV SKD
It is increasing, while as the function of intelligent use software is more and more, therefore have more to the power unit of liquid crystal panel TV set
High requirement.
Currently, liquid crystal panel TV set, as one of liquid crystal apparatus, power supply is mainly more using flyback topologies
The mode of road output.Wherein, flyback topologies are that transformation output multi-channel DC voltage is isolated in electric main, for example, in television set
Two-way DC voltage is mainly exported in mainboard, wherein DC voltage is the central processing unit (Central of TV SKD all the way
Processing Unit, CPU), power amplifier and its peripheral circuit power supply；In addition all the way DC voltage generally according to different size liquid
The backlight LED voltage specifications design of brilliant panel TV set, designs the voltage that the road is exported, for backlight LED power supply.
But just powered in liquid crystal panel TV set, but and during not entering standby mode, the CPU of TV SKD is logical
It often needs to run at high speed to open software systems, the branch for CPU power supply is in heavy condition at this time, and is backlight LED power supply
Branch be in light condition, due in circuit of reversed excitation unbalance loading, the power band of branch of backlight LED carries lighter, and institute is defeated
Voltage out floats height, so that glimmer phenomenon occurs in backlight LED in power up, reduces the usage experience of user
Utility model content
In view of this, the present invention provides a kind of backlight control circuit and electronic equipments, effectively prevent liquid crystal apparatus
There is glimmer phenomenon in circuit of reversed excitation unbalance loading in middle backlight LED.
In a first aspect, the utility model embodiment provides a kind of backlight control circuit, comprising: flyback sourse module, steady
Die block, boost module, load blocks and Logic control module；
First output end of the flyback sourse module is connect with the first end of the Voltage stabilizing module, the flyback sourse mould
The second output terminal of block is connect with the first end of the Logic control module；The second end of the Logic control module and described steady
The second end of die block connects；The first end of the boost module is connect with the third end of the Voltage stabilizing module, the boosting mould
The second end of block is connect with the load blocks；
When the second end of the Voltage stabilizing module receives high level signal, and the first output of the flyback sourse module
When exported the first voltage value being held to reach the breakdown conducting voltage of the Voltage stabilizing module, the Voltage stabilizing module conducting, with control
Loaded work piece voltage value needed for the first voltage value is less than the load blocks.
Further, the Voltage stabilizing module includes: voltage regulation unit, switch unit and switch driving unit；
The first end of the voltage regulation unit respectively with the first output end of the flyback sourse module and the boosting mould
The first end of block connects；The second end of the voltage regulation unit is connect with the first end of the switch unit, the switch unit
Second end is connect with the first end of the switch driving unit；The second end and Logic control module of the switch driving unit
Second end connection；The third end of the switch driving unit and the third end of the switch unit are grounded.
Further, the voltage regulation unit includes: zener diode, first resistor and second resistance；
The cathode of the zener diode respectively with the first end of the first resistor and the second resistance first
End connection；The anode of the zener diode is connect with the first end of the switch unit；The second end of the first resistor with
And the second end of the second resistance with the first output end of the flyback sourse module and the boost module first
End connection.
Further, the switch unit includes: the first transistor；
The first end of the first transistor is connect with the anode of the zener diode；The second of the first transistor
It holds and is connect with the first end of the switch driving unit；The third end of the first transistor is grounded.
Further, the switch driving unit includes: first capacitor, 3rd resistor and the 4th resistance；
The first end of the first capacitor first end with the second end of the first transistor, the 3rd resistor respectively
And the first end connection of the 4th resistance；The second end of the first capacitor and the second end of the 4th resistance are grounded；Institute
The second end for stating 3rd resistor is connect with the second end of the Logic control module.
Further, the backlight control circuit, further includes: power supply module and negative feedback module；The flyback sourse mould
Block includes: flyback sourse primary circuit, transformer, the first rectification unit and the second rectification unit；
The first input end of the flyback sourse primary circuit is connect with the power supply module, the flyback sourse primary side electricity
Second input terminal on road is connect with the first end of the negative feedback module, the output end of the flyback sourse primary circuit with it is described
The input terminal of transformer connects；First output end of the transformer is connect with the first end of first rectification unit, described
The second output terminal of transformer is connect with the first end of second rectification unit；The second end of first rectification unit and institute
State the first end connection of Voltage stabilizing module, the second end of second rectification unit and the first end of the Logic control module and
The second end of the negative feedback module connects.
Further, the boost module includes: second transistor, the first inductance, first diode and the first electrolysis electricity
Hold；
The first end of the second transistor respectively with the first end of first inductance and the first diode
First end connection；The second end of the first diode respectively with the first end of first electrolytic capacitor and the load mould
Block connection；The second end of the second transistor and the second end of first electrolytic capacitor are grounded；The second transistor
Third end connect with pulse signal generator；The second end of first inductance respectively with the second end of the first resistor with
And the second end connection of the second resistance.
Further, first rectification unit includes: the second electrolytic capacitor, the second diode, the second capacitor and the 5th
Resistance；
The first end of second diode and the first end of second capacitor are defeated with the first of the transformer
Outlet connection；The second end of second capacitor is connect with the first end of the 5th resistance, and the second of second diode
End is connect with the first end of the second end of the 5th resistance and the second electrolytic capacitor；The second end of second diode,
The second end of 5th resistance and the first end of second electrolytic capacitor are connect with the first end of the Voltage stabilizing module.
Further, second rectification unit includes: third electrolytic capacitor, third diode, third capacitor and the 6th
Resistance；
The first end of the third diode and the first end of the third capacitor are exported with the second of the transformer
End connection；The second end of the third capacitor is connect with the first end of the 6th resistance, the second end of the third diode
It is connect with the first end of the second end of the 6th resistance and third electrolytic capacitor；The second end of the third diode, institute
The first end of the second end and the third electrolytic capacitor of stating the 6th resistance with the second end of the Logic control module with
And the second end connection of the negative feedback module.
Second aspect, the utility model embodiment provide a kind of electronic equipment, and the electronic equipment includes such as first party
Backlight control circuit described in face.
Above-mentioned utility model embodiment is connected by the first output end of flyback sourse module and the first end of Voltage stabilizing module,
The second output terminal of flyback sourse module and the first end of Logic control module connect；The second end and pressure stabilizing of Logic control module
The second end of module connects；The third end of the first end of boost module and Voltage stabilizing module connects, the second end of boost module and negative
Carry module connection；When the second end of Voltage stabilizing module receives high level signal, and the first output end of flyback sourse module
When the first voltage value reaches the breakdown conducting voltage of Voltage stabilizing module, Voltage stabilizing module conducting is less than load to control the first voltage value
Loaded work piece voltage value needed for module.Backlight control circuit in the utility model ensure that flyback electricity by Voltage stabilizing module
Loaded work piece voltage value needed for the first voltage value of first output end of source module is less than load blocks, effectively prevents liquid crystal
There is glimmer phenomenon in circuit of reversed excitation unbalance loading in backlight LED in equipment, to reduce the stand-by power consumption of liquid crystal apparatus.
Detailed description of the invention
Fig. 1 is a kind of structural block diagram of backlight control circuit provided by the embodiment of the utility model；
Fig. 2 is a kind of structural schematic diagram of Voltage stabilizing module provided by the embodiment of the utility model；
Fig. 3 is the structural schematic diagram of another Voltage stabilizing module provided by the embodiment of the utility model；
Fig. 4 is the structural schematic diagram of another Voltage stabilizing module provided by the embodiment of the utility model；
Fig. 5 is the structural block diagram of another backlight control circuit provided by the embodiment of the utility model；
Fig. 6 is a kind of circuit diagram of backlight control circuit provided by the utility model.
Specific embodiment
The utility model is described in further detail with reference to the accompanying drawings and examples.It is understood that herein
Described specific embodiment is used only for explaining the utility model, rather than the restriction to the utility model.It further needs exist for
It is bright, part relevant to the utility model is illustrated only for ease of description, in attached drawing rather than entire infrastructure.
Fig. 1 is a kind of structural block diagram of backlight control circuit provided by the embodiment of the utility model, and the present embodiment is applicable
In avoiding liquid crystal apparatus from the case where glimmer phenomenon occur, which be may be disposed in electronic equipment.Wherein, electronic equipment can be intelligence
The liquid crystal apparatus such as energy television set.
With reference to Fig. 1, which includes: flyback sourse module 110, Voltage stabilizing module 120, boost module 130, bears
Carry module 140 and Logic control module 150；
First output end of flyback sourse module 110 is connect with the first end of Voltage stabilizing module 120, flyback sourse module 110
Second output terminal connect with the first end of Logic control module 150；The second end and Voltage stabilizing module of Logic control module 150
120 second end connection；The first end of boost module 130 is connect with the third end of Voltage stabilizing module 120, and the of boost module 130
Two ends are connect with load blocks 140；
When the second end of Voltage stabilizing module 120 receives high level signal, and the first output end of flyback sourse module 110
When the first voltage value exported reaches the breakdown conducting voltage of Voltage stabilizing module 120, Voltage stabilizing module 120 is connected, to control first
Loaded work piece voltage value needed for voltage value is less than load blocks 140.
In embodiment, after flyback sourse module 110 accesses alternating current, flyback sourse module 110 has by itself
Standby rectification unit carries out rectification processing to alternating current, to obtain direct current, and will direct current that rectification obtains export respectively to
Voltage stabilizing module 120 and Logic control module 150.It is corresponding to the direct current after Voltage stabilizing module 120 receives direct current
DC voltage carries out steady pressure treatment, and is input to boost module 130, to be boosted by boost module 130 to DC voltage
Processing, to be powered to load blocks 140；Certainly, while Logic control module 150 receives direct current, with logic
The Voltage stabilizing module 120 that control module 150 is connected can receive high level signal, since liquid crystal apparatus is entering open state,
But and during not entering standby mode, the mainboard CPU needs in liquid crystal apparatus run at high speed to open software systems, at this time
Branch corresponding to 110 second output terminal of flyback sourse module for CPU power supply, which enters, eats heavy condition, i.e. flyback sourse module
The corresponding power of 110 second output terminal is higher, and the first output end of flyback sourse module 110 corresponds to branch and is substantially at sky
It carries, since the intersection adjustment characteristic of flyback sourse causes the output voltage of the second output terminal of flyback sourse module 110 higher.This
When, breakdown needed for reaching Voltage stabilizing module 120 in the first voltage value that is exported of the first output end of flyback sourse module 110 is led
When the pressure that is powered, Voltage stabilizing module 120 is in the conductive state, is carried out by the voltage-stabilizing device in Voltage stabilizing module 120 to the first voltage value
Pressure stabilizing control, to control the first voltage value less than loaded work piece voltage value needed for load blocks 140, thus in start process
The phenomenon that being not in backlight LED glimmer.Wherein, loaded work piece voltage value can be understood as so that 140 lightly conducting of load blocks
Voltage value, i.e., so that the voltage value of the LED glimmer in load blocks 140, but and not up to load blocks 140 work normally institute
Required voltage value.Certainly, so-called lightly conducting is exactly misleading for load blocks 140.
Certainly, when the second end of Voltage stabilizing module 120 receives low level signal, Voltage stabilizing module 120 is turned off, so that liquid crystal
Equipment can reduce the stand-by power consumption of itself in the standby state.It is to be appreciated that liquid crystal apparatus enter it is standby after, be liquid
The light load of branch corresponding to the second output terminal of the flyback sourse module 110 of CPU power supply in brilliant equipment, that is, be not required to pressure stabilizing
The first voltage value that module 120 exports the first output end of flyback sourse module 110 carries out pressure stabilizing control, flyback sourse mould
The first voltage value that first output end of block 110 is exported will not float excessively high because of two-way unbalance loading, can disconnect pressure stabilizing mould
Block 120, at this point, low level signal can be provided for the second end of Voltage stabilizing module 120 by Logic control module 150, so that pressure stabilizing
Module 120 is in an off state, to not influence the stand-by power consumption of liquid crystal apparatus.
The embodiments of the present invention are connected by the first output end of flyback sourse module and the first end of Voltage stabilizing module
It connects, the second output terminal of flyback sourse module and the first end of Logic control module connect；The second end of Logic control module with
The second end of Voltage stabilizing module connects；The first end of boost module and the third end of Voltage stabilizing module connect, the second end of boost module
It is connect with load blocks；When the second end of Voltage stabilizing module receives high level signal, and the first output of flyback sourse module
When exported the first voltage value being held to reach the breakdown conducting voltage of Voltage stabilizing module, Voltage stabilizing module conducting, to control first voltage
Loaded work piece voltage value needed for value is less than load blocks.Backlight control circuit in the utility model, is protected by Voltage stabilizing module
Loaded work piece voltage needed for the first voltage value that the first output end of flyback sourse module is exported is less than load blocks is demonstrate,proved
Value, effectively prevents backlight LED in liquid crystal apparatus and glimmer phenomenon occurs, and do not increase the stand-by power consumption of liquid crystal apparatus again.
Fig. 2 is a kind of structural schematic diagram of Voltage stabilizing module provided by the embodiment of the utility model.The present embodiment is above-mentioned
On the basis of embodiment, Voltage stabilizing module 120 is further embodied.
With reference to Fig. 2, Voltage stabilizing module 120 includes: voltage regulation unit 1201, switch unit 1202 and switch driving unit 1203；
Wherein, the first end of voltage regulation unit 1201 respectively with the first output end of flyback sourse module 110 and boosting mould
The first end of block 130 connects；The second end of voltage regulation unit 1201 is connect with the first end of switch unit 1202, switch unit 1202
Second end with switch driving unit 1203 first end connect；Switch the second end and Logic control module of driving unit 1203
150 second end connection；The third end at the third end and switch unit 1202 that switch driving unit 1203 is grounded.
In embodiment, after switch driving unit 1203 receives the level signal of the transmission of Logic control module 150,
Driving unit 1203 is switched according to the height of level signal come the on or off of control switch unit 1202.Specifically, exist
After liquid crystal apparatus powers on, but and during not entering standby mode, switch driving unit 1203 can receive high level letter
Number, i.e., switch unit 1202 is in the conductive state；Conversely, switching driving unit 1203 when liquid crystal apparatus enters standby mode
It can receive low level signal, i.e. switch unit 1202 is in an off state.It is in the conductive state in switch unit 1202, and
Liquid crystal apparatus be in power on but and during not entering standby mode, due to the of the flyback sourse module 110 powered for CPU
The heavier loads of branch corresponding to two deferent segments, and the load of branch corresponding to the first output end of flyback sourse module 110 compared with
Gently, so that unbalance loading occurs in two-way branch, at this point, the first output of flyback sourse module 110 can be controlled by voltage regulation unit 1201
Hold exported the first voltage value Vbl so that the first voltage value Vbl be in pressure stabilizing state, i.e. the first voltage value Vbl less than so that
Voltage value needed for 140 lightly conducting of load blocks is less than loaded work piece voltage value, to enter standby mode in liquid crystal apparatus
Before, it avoids liquid crystal apparatus and the phenomenon that backlight LED glimmer occurs.Certainly, during liquid crystal apparatus is in standby,
The light load of the branch as corresponding to the second output terminal for the flyback sourse module 110 powered for CPU, i.e. the first voltage value
Vbl will not float too high because of unbalance loading, then be not required to Voltage stabilizing module 120 and carry out pressure stabilizing control, switch unit 1202 can be located at this time
In off state, so that not influencing the stand-by power consumption of liquid crystal apparatus.Wherein, Logic control module 150 to switch driving unit
The level signal of 1203 inputs is provided by the mainboard CPU of liquid crystal apparatus, may generally be 3.3V.It is to be understood that in flyback
The second output terminal of power module 110 be liquid crystal apparatus mainboard CPU power supply after, mainboard CPU to switch driving unit 1203
Incoming level signal, with the on-off of control switch unit 1202.
In embodiment, voltage regulation unit 1201 includes: zener diode ZD1, first resistor R1 and second resistance R2；Its
In, the cathode of zener diode ZD1 is connect with the first end of the first end of first resistor R1 and second resistance R2 respectively；Pressure stabilizing
The anode of diode ZD1 is connect with the first end of switch unit 1202；The second end of first resistor R1 and second resistance R2's
Second end is connect with the first end of the first output end of flyback sourse module 110 and boost module 130.
Wherein, switch unit 1202 includes: the first transistor Q1；The first end and zener diode of the first transistor Q1
The anode connection of ZD1；The second end of the first transistor Q1 is connect with the first end of switch driving unit 1203；The first transistor Q1
Third end ground connection.
Wherein, switch driving unit 1203 includes: first capacitor C1,3rd resistor R3 and the 4th resistance R4；First capacitor
The first end of the C1 first end with the second end of the first transistor Q1, the first end of 3rd resistor R3 and the 4th resistance R4 respectively
Connection；The second end of first capacitor C1 and the second end of the 4th resistance R4 are grounded；The second end and logic control of 3rd resistor R3
The second end of molding block 110 connects.
It should be noted that first resistor R1 and second resistance R2 is current-limiting resistance, for limiting Voltage stabilizing module 120
Electric current, and protect zener diode ZD1 and the first transistor Q1 be no more than its rated current, or be no more than its rated dissipation
Power.Wherein, the first transistor Q1 can be triode, or field-effect tube illustrates only first crystal in Fig. 2
Pipe Q1 be triode, and be NPN type triode the case where.It in the actual operation process, can be by the first transistor Q1 by NPN type
Triode replaces with PNP type triode or field-effect tube.In embodiment, first capacitor C1 is filter capacitor, is patrolled for absorbing
The voltage and current noise that control module 150 is generated by switch driving unit 1203 is collected, so that the workability of Voltage stabilizing module 120
It can be more stable；3rd resistor R3 and the 4th resistance R4 is divider resistance, for that will pass through a part of Logic control module 150
Input voltage point is on 3rd resistor R3 and the 4th resistance R4.Logic control module 150 is inputted to switch driving unit 1203
Level signal is the control signal of the first transistor Q1, which provided by the mainboard CPU of liquid crystal apparatus.
On the basis of Fig. 2, the first transistor Q1 can be used different forms and be replaced.Fig. 3 is the utility model reality
The structural schematic diagram of another Voltage stabilizing module of example offer is provided.As shown in figure 3, the first transistor Q1 is replaced by NPN type triode
It is changed to PNP type triode.
On the basis of Fig. 2, the first transistor Q1 can be used different forms and be replaced.Fig. 4 is the utility model reality
The structural schematic diagram of another Voltage stabilizing module of example offer is provided.As shown in figure 4, the first transistor Q1 is replaced by NPN type triode
It is changed to NPN type field-effect tube.Certainly, NPN type field-effect tube shown in Fig. 4 can also be changed to positive-negative-positive field-effect tube.It needs herein
It should be noted that the difference of NPN type and positive-negative-positive the first transistor is the level signal pair that Logic control module 150 is exported
The control of switch unit 1202 is inverse relationship, and details are not described herein.
Fig. 5 is the structural block diagram of another backlight control circuit provided by the embodiment of the utility model, the present embodiment be
On the basis of above-described embodiment, backlight control circuit is further embodied.
As shown in figure 5, the backlight control circuit further include: power supply module 160 and negative feedback module 170；The flyback electricity
Source module 110 includes: flyback sourse primary circuit 1101, transformer 1102, the first rectification unit 1103 and the second rectification unit
1104；
The first input end of flyback sourse primary circuit 1101 is connect with power supply module 160, flyback sourse primary circuit
1101 the second input terminal is connect with the first end of negative feedback module 170, the output end of flyback sourse primary circuit 1101 and change
The input terminal of depressor 1102 connects；First output end of transformer 1102 is connect with the first end of the first rectification unit 1103, is become
The second output terminal of depressor 1102 is connect with the first end of the second rectification unit 1104；The second end of first rectification unit 1103 with
The first end of Voltage stabilizing module 120 connects, the second end of the second rectification unit 1104 and the first end of Logic control module 150 and
The second end of negative feedback module 170 connects.
In embodiment, when power supply module 160 is started to work, flyback sourse primary circuit 1101 is by power supply module 160
The alternating current of output is input in transformer 1102, and transformer 1102 carries out voltage conversion to alternating current, and after converting the voltage into
The alternating voltage exported is separately input into the first rectification unit 1103 and the second rectification unit 1104, the first rectification unit 1103
Rectification processing is carried out to alternating voltage with the second rectification unit 1104, to be converted to DC voltage.Meanwhile first rectification unit
1103 DC voltages exported are that load blocks 140 are powered, and the DC voltage that the second rectification unit 1104 is exported is
Mainboard CPU is powered.
Preferably, Fig. 6 is a kind of circuit diagram of backlight control circuit provided by the utility model.The present embodiment be
On the basis of above-described embodiment, as a preferred embodiment, show between the modules or unit in backlight control circuit
Circuit connecting relation.
With reference to Fig. 6, the circuit connecting relation between the modules or unit of the backlight control circuit is specific as follows shown:
Wherein, boost module 130 includes: second transistor Q2, the first inductance L1, the electrolysis electricity of first diode D1 and first
Hold E1；The first end of second transistor Q2 connects with the first end of the first inductance L1 and the first end of first diode D1 respectively
It connects；The second end of first diode D1 is (i.e. as shown in FIG. 6 with the first end of the first electrolytic capacitor E1 and load blocks respectively
LED+ it) connects；The second end of second transistor Q2 and the second end of the first electrolytic capacitor E1 are grounded；The of second transistor Q2
Three ends are connect with pulse signal generator (being shown in the form of rectangular wave)；The second end of first inductance L1 respectively with first resistor
The second end of R1 and the second end connection of second resistance R2.
First rectification unit 1103 includes: the second electrolytic capacitor E2, the second diode D2, the second capacitor C2 and the 5th resistance
R5；Wherein, the first end of the second diode D2 and the first end of the second capacitor C2 connect with the first output end of transformer TB1
It connects；The second end of second capacitor C2 is connect with the first end of the 5th resistance R5, the second end and the 5th resistance of the second diode D2
The second end of R5 and the connection of the first end of the second electrolytic capacitor E2；The of the second end of second diode D2, the 5th resistance R5
Two ends and and the first end of the second electrolytic capacitor E2 connect with the first end of Voltage stabilizing module 120.
Wherein, the second rectification unit 1104 includes: third electrolytic capacitor E3, third diode D3, third capacitor C3 and
Six resistance R6；The first end of third diode D3 and the first end of third capacitor C3 connect with the second output terminal of transformer TB1
It connects；The second end of third capacitor C3 is connect with the first end of the 6th resistance R6, the second end and the 6th resistance of third diode D3
The second end of R6 and the first end connection of third electrolytic capacitor E3；The of the second end of third diode D3, the 6th resistance R6
The first end of two ends and third electrolytic capacitor E3 with the second end of Logic control module 110 and negative feedback module 170
First end connection.
Wherein, pulse signal generator can be understood as generating the signal generator of pulse signal.In embodiment, pulse
Pulse signal caused by signal generator can modulate (Pulse Width Modulation, PWM) wave for pulse width, so that
Second transistor Q2 itself conducting and off state are controlled according to the height of pulse signal.
It should be noted that the second electrolytic capacitor E2 be for the second diode D2 rectification after direct current into
Row energy storage pressure stabilizing can provide burning voltage when in order to power to load blocks 140；Similarly, third electrolytic capacitor E3 is to use
The direct current come after rectifying to third diode D3 carries out energy storage pressure stabilizing, when in order to power to Logic control module 150, energy
Burning voltage is provided.
Wherein, former to the work of backlight control circuit by taking backlight control circuit is applied in liquid crystal panel TV set as an example
Reason is illustrated.Meanwhile power supply module 160 is the electric main of 220V.Specifically, the working principle of backlight control circuit is such as
Under:
When the electric main of liquid crystal panel TV set access 220V, before the mainboard CPU starting in liquid crystal panel TV set
The pin of modules can be initialized, during initialization, Logic control module 110 exports 3.3V voltage value, so that
The Z_ON/OFF signal for controlling the first transistor Q1 is high level signal, when the first transistor Q1 receives high level signal,
The first transistor Q1 is in the conductive state, and Voltage stabilizing module 120, which is in, at this time waits on state；Subsequent CPU starts activation system,
For CPU power supply flyback sourse module 110 second output terminal correspond to branch entrance eat heavy condition, the i.e. corresponding load of Vcpu
Weight, and correspond to branch substantially non-loaded for the first output end of flyback sourse module 110, i.e. the corresponding load of Vbl gently, leads to first
Voltage value Vbl drift is high；When the first voltage value Vbl reaches the breakdown conducting voltage of zener diode ZD1, Voltage stabilizing module 120 is led
Logical, zener diode ZD1 pressure stabilizing is within the scope of its nominal voltage, so that floating high the first voltage value Vbl passes through pressure stabilizing two
Pole pipe ZD1, current-limiting resistance R1 and R2 stablize in the voltage range being pre-designed, i.e., so that Vbl is micro- less than needed for backlight LED
Turn-on voltage, i.e. Vbl are less than loaded work piece voltage value, so that backlight LED is not in glimmer phenomenon in start process；
After liquid crystal panel TV set enters standby mode, Vcpu it is corresponding load it is extremely light, even if the first voltage value Vbl not over
Voltage stabilizing module 120 carries out pressure stabilizing control, and what will not be floated is excessively high, it can Voltage stabilizing module 120 is disconnected, it at this time can be by Z_ON/OFF
Signal is set to low level signal, and the first transistor Q1 is closed, and Voltage stabilizing module 120 is in an off state, so that it is flat not influence liquid crystal
The stand-by power consumption of plate television set.
In embodiment, Logic control module 110 can be main control chip, be used to believe to 120 transmission level of Voltage stabilizing module
Number, to control the on-off of Voltage stabilizing module 120.
It should be noted that the reckoning process to the key parameter in backlight control circuit is illustrated.Assuming that not having
Have and increases Voltage stabilizing module 120, and, it is assumed that for Vcpu in load peak, the accessible ceiling voltage of Vbl is Vbl_max, pressure stabilizing
The clamp voltage of diode ZD1 is Vz, is R, pressure stabilizing two by the current-limiting resistance resistance value that first resistor R1 and second resistance R2 are formed
The maximum diffipation power of pole pipe ZD1 is Pmax, and the clamp voltage of preset Voltage stabilizing module 120 is Vclamp.It wherein, usually will most
Big dissipated power drop volume be 70% carry out using.Then the relational expression between each key parameter can be with are as follows:
Current-limiting resistance resistance value R can be extrapolated according to above-mentioned formula are as follows:
It is to be understood that can probably be estimated by the clamp voltage Vz and current-limiting resistance resistance value R that select zener diode
The clamp voltage Vclamp of the Voltage stabilizing module 120.Wherein, the difference voltage between Vbl_max and Vclamp is zener diode
The function and effect of ZD1 stabilizing voltage characteristic.
Above-described embodiment is applied under the scene of glimmer occurs in backlight LED in control liquid crystal panel TV set power up,
The technical solution of the utility model also can be applicable to backlight LED when closing backlight listens to music and the scene of glimmer flashing occurs.
In the prior art, some music players have the function of closing screen while playing music, at this point, due to Vcpu
The heavier loads of corresponding branch, but Vbl corresponds to that branch is substantially unloaded, and during playing music, Vcpu corresponds to the load of branch
Switch in weight, correspondingly, the first voltage value Vbl that Vbl corresponds to branch is also drifting about up and down, so that backlight LED be caused to occur
Glimmer, and the phenomenon that follow music to flash.
In order to avoid the phenomenon that during closing screen listens to music, backlight LED follows music to flash, this reality can be used
With novel technical solution, increases Voltage stabilizing module 120 in backlight control circuit, follow music to flash to avoid backlight LED.Its
In, the connection relationship between modules, unit or component does not change, but the course of work changes, and detailed process is as follows:
Before the screen and backlight LED for closing liquid crystal apparatus, the first transistor Q1 is controlled by Logic control module 150
Z_ON/OFF signal be high level signal, when the first transistor Q1 receives high level signal, the first transistor Q1 is in
On state, Voltage stabilizing module 120, which is in, at this time waits on state；When closing backlight LED broadcasting music, due to being supplied for CPU
The load that the second output terminal of the flyback sourse module 110 of electricity corresponds to branch is laid particular stress on, and the first of flyback sourse module 110 the output
Hold the load of corresponding branch partially light, to cause the first voltage value Vbl drift high, when the first voltage value Vbl reaches zener diode
When the breakdown conducting voltage of ZD1, Voltage stabilizing module 120 be connected, zener diode ZD1 pressure stabilizing within the scope of its nominal voltage, thus
Stablized by zener diode ZD1, current-limiting resistance R1 and R2 in the voltage model being pre-designed so that floating high the first voltage value Vbl
In enclosing, i.e., so that Vbl is less than loaded work piece voltage value needed for backlight LED, backlight LED is not in glimmer in start process
Or the phenomenon that being flashed with music；After the screen or backlight LED for opening liquid crystal apparatus, Z_ON/OFF signal can be set to low electricity
Ordinary mail number, the first transistor Q1 close, Voltage stabilizing module 120 is in an off state so that do not influence liquid crystal panel TV set to
Machine power consumption.
Certainly, when normally opening backlight LED sees TV, backlight LED is opened, and the main board of CPU runs well, thus
The load relative equilibrium of branch corresponding to Vcpu and Vbl, boost module 130 work normally.At this point, Logic control module can be passed through
Z_ON/OFF signal is set to low level signal by 150, can turn off Voltage stabilizing module 120, to reduce the power consumption of backlight control circuit.
Certainly, the zener diode ZD1 of larger pressure stabilizing value can also be chosen, so that when normally opening backlight LED sees TV, two pole of pressure stabilizing
The corresponding clamp voltage Vz of pipe ZD1 is greater than Vbl, so that zener diode ZD1 is not turned on, i.e., Voltage stabilizing module 120 is in open circuit shape
State.
It should be noted that the corresponding circuit of Voltage stabilizing module 120 belongs to auxiliary circuit, not power circuit, thus
Fever is greatly lowered, it is possible to reduce the effective rate of utilization of pcb board has can be improved in the heat dissipation area of pcb board.Meanwhile first is brilliant
Body pipe Q1 uses triode or field-effect tube, and cost is relatively low, also, the on-off of Voltage stabilizing module 120 can pass through first crystal
Pipe Q1 is controlled, so that Voltage stabilizing module 120 is turned off, to reduce the stand-by power consumption of liquid crystal apparatus under standby scene.
The utility model embodiment additionally provides a kind of electronic equipment, which includes as provided in above-described embodiment
Any backlight control circuit.
Backlight control circuit provided by the utility model any embodiment can be performed in above-mentioned electronic equipment, has in execution
State the corresponding functional module of backlight control circuit and beneficial effect.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is contained at least one embodiment or example of the utility model.In the present specification, to the schematic table of above-mentioned term
Stating may not refer to the same embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be
It can be combined in any suitable manner in any one or more embodiment or examples.
Note that above are only the preferred embodiment and institute's application technology principle of the utility model.Those skilled in the art's meeting
Understand, the utility model is not limited to specific embodiment described here, is able to carry out for a person skilled in the art various bright
Aobvious variation, readjustment and substitution is without departing from the protection scope of the utility model.Therefore, although passing through above embodiments
The utility model is described in further detail, but the utility model is not limited only to above embodiments, is not departing from
It can also include more other equivalent embodiments in the case that the utility model is conceived, and the scope of the utility model is by appended
Scope of the claims determine.
Claims (10)
1. a kind of backlight control circuit characterized by comprising flyback sourse module, Voltage stabilizing module, boost module, load mould
Block and Logic control module；
First output end of the flyback sourse module is connect with the first end of the Voltage stabilizing module, the flyback sourse module
Second output terminal is connect with the first end of the Logic control module；The second end of the Logic control module and the pressure stabilizing mould
The second end of block connects；The first end of the boost module is connect with the third end of the Voltage stabilizing module, the boost module
Second end is connect with the load blocks；
When the second end of the Voltage stabilizing module receives high level signal, and the first output end institute of the flyback sourse module
When the first voltage value of output reaches the breakdown conducting voltage of the Voltage stabilizing module, the Voltage stabilizing module conducting, described in control
Loaded work piece voltage value needed for the first voltage value is less than the load blocks.
2. circuit according to claim 1, which is characterized in that the Voltage stabilizing module include: voltage regulation unit, switch unit and
Switch driving unit；
The first end of the voltage regulation unit respectively with the first output end of the flyback sourse module and the boost module
First end connection；The second end of the voltage regulation unit is connect with the first end of the switch unit, and the second of the switch unit
It holds and is connect with the first end of the switch driving unit；The second of the second end for switching driving unit and Logic control module
End connection；The third end of the switch driving unit and the third end of the switch unit are grounded.
3. circuit according to claim 2, which is characterized in that the voltage regulation unit includes: zener diode, first resistor
And second resistance；
The cathode of the zener diode connects with the first end of the first end of the first resistor and the second resistance respectively
It connects；The anode of the zener diode is connect with the first end of the switch unit；The second end of the first resistor and institute
The second end for stating second resistance connects with the first end of the first output end of the flyback sourse module and the boost module
It connects.
4. circuit according to claim 3, which is characterized in that the switch unit includes: the first transistor；
The first end of the first transistor is connect with the anode of the zener diode；The second end of the first transistor with
The first end connection of the switch driving unit；The third end of the first transistor is grounded.
5. circuit according to claim 4, which is characterized in that the switch driving unit includes: first capacitor, third electricity
Resistance and the 4th resistance；
The first end of the first capacitor respectively with the second end of the first transistor, the first end of the 3rd resistor and
The first end of 4th resistance connects；The second end of the first capacitor and the second end of the 4th resistance are grounded；Described
The second end of three resistance is connect with the second end of the Logic control module.
6. circuit according to claim 3, which is characterized in that further include: power supply module and negative feedback module；The flyback
Power module includes: flyback sourse primary circuit, transformer, the first rectification unit and the second rectification unit；
The first input end of the flyback sourse primary circuit is connect with the power supply module, the flyback sourse primary circuit
Second input terminal is connect with the first end of the negative feedback module, the output end of the flyback sourse primary circuit and the transformation
The input terminal of device connects；First output end of the transformer is connect with the first end of first rectification unit, the transformation
The second output terminal of device is connect with the first end of second rectification unit；The second end of first rectification unit and described steady
The first end of die block connects, the second end of second rectification unit and the first end of the Logic control module and described
The second end of negative feedback module connects.
7. circuit according to claim 6, which is characterized in that the boost module includes: second transistor, the first electricity
Sense, first diode and the first electrolytic capacitor；
The first end of the second transistor respectively with the first end of first inductance and the first diode first
End connection；The second end of the first diode connects with the first end of first electrolytic capacitor and the load blocks respectively
It connects；The second end of the second transistor and the second end of first electrolytic capacitor are grounded；The of the second transistor
Three ends are connect with pulse signal generator；The second end of first inductance respectively with the second end of the first resistor and institute
State the second end connection of second resistance.
8. circuit according to claim 6, which is characterized in that first rectification unit includes: the second electrolytic capacitor,
Two diodes, the second capacitor and the 5th resistance；
The first end of second diode and the first end of second capacitor with the first output end of the transformer
Connection；The second end of second capacitor is connect with the first end of the 5th resistance, the second end of second diode with
The second end of 5th resistance and the first end connection of second electrolytic capacitor；The second end of second diode,
The second end of 5th resistance and the first end of second electrolytic capacitor are connect with the first end of the Voltage stabilizing module.
9. circuit according to claim 6, which is characterized in that second rectification unit includes: third electrolytic capacitor,
Three diodes, third capacitor and the 6th resistance；
The first end of the third diode and the first end of the third capacitor connect with the second output terminal of the transformer
It connects；The second end of the third capacitor is connect with the first end of the 6th resistance, the second end of the third diode and institute
State the second end of the 6th resistance and the first end connection of the third electrolytic capacitor；The second end of the third diode, institute
The first end of the second end and the third electrolytic capacitor of stating the 6th resistance with the second end of the Logic control module with
And the second end connection of the negative feedback module.
10. a kind of electronic equipment, which is characterized in that the electronic equipment includes the backlight control as described in claim 1-9 is any
Circuit processed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920230145.9U CN209201210U (en) | 2019-02-20 | 2019-02-20 | Backlight control circuit and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920230145.9U CN209201210U (en) | 2019-02-20 | 2019-02-20 | Backlight control circuit and electronic equipment |
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| Publication Number | Publication Date |
|---|---|
| CN209201210U true CN209201210U (en) | 2019-08-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920230145.9U Active CN209201210U (en) | 2019-02-20 | 2019-02-20 | Backlight control circuit and electronic equipment |
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| Country | Link |
|---|---|
| CN (1) | CN209201210U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112866526A (en) * | 2021-01-07 | 2021-05-28 | 南昌欧菲光电技术有限公司 | Power control circuit, lens assembly and electronic equipment |
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2019
- 2019-02-20 CN CN201920230145.9U patent/CN209201210U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112866526A (en) * | 2021-01-07 | 2021-05-28 | 南昌欧菲光电技术有限公司 | Power control circuit, lens assembly and electronic equipment |
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