CN104580960A - Laser television power source and constant-current control method thereof - Google Patents
Laser television power source and constant-current control method thereof Download PDFInfo
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Abstract
The invention relates to switch power source technology, and provides a laser television power source according to laser power source characteristics. The laser television power source comprises a processor, a boost module, a laser source module, a Vce voltage drop feedback module and an operation amplifier. The boost module is connected with the input voltage, the laser source module and the processor, the processor is connected with the Vce voltage drop feedback module, the operation amplifier is connected with the processor and the Vce voltage drop feedback module, and the laser source module is connected with the Vce voltage drop feedback module. The processor is used for comparing the detected Vce voltage with a preset Vce control voltage range and adjusting output feedback voltage according to comparing results. The boost module is used for boosting the input voltage; the laser source module is used for providing a laser source, the Vce voltage drop feedback module is used for providing triode Vce voltage drop feedback for the processor according to reference voltage of the processor and sampling voltage of a sampler, and the operation amplifier is used for amplifying the reference voltage of the processor. The laser television power source is applicable to televisions.
Description
Technical field
The present invention relates to switch power technology, particularly laser television power supply.
Background technology
TV, color monitor have become the necessity of the modern life, each state be all devoted to development high definition and large screen display to meet the demand of people to the continuous renewal of this product, such as: large screen plasma body display (PDP), liquid crystal display (LCD, LED) etc.Be a kind of trend of Development of Laser Technology using laser as the light source of color monitor, be also the dream of researcher simultaneously always.In succession succeeding in developing and putting on market along with red, green, yellow, blue four coloured light semiconductor lasers, makes the appearance of laser television become possibility, and becomes the most strong competitor in 21 century monitor market.The monochromaticjty of laser is good, in color and luster, laser can control output wavelength more accurately, compare with traditional high image quality display, the color that laser represents is more sufficient and true to nature, the color of reproduced image can not only be ensured, and also can show the high saturation that occurring in nature is difficult to see.The high directivity of laser, the diversity of light beam is very little, thus beats and remain a gem-pure sparklet on screen, substantially increase the definition of image, laser display can control laser spots exactly and beat the position on screen, can overcome the distortion of image problem that traditional monitor exists.Except the remarkable advantage of color and luster, definition aspect, laser display is low to environmental requirement, and usually without the need to any optical focusing system, display size can adjust arbitrarily, can develop into over-large screen display system.Can find out that the laser television of large-screen has wide potential market and development space, the power supply therefore realizing light source driving arises at the historic moment.
Summary of the invention
The object of the invention is the implementation in order to provide a kind of laser television light source to drive.
The technical scheme that the present invention solves its technical problem is: a kind of laser television power supply constant current control method, comprises the steps:
A. according to LASER Light Source required voltage, the initial feedback amount of initial voltage, the control voltage scope of Vce, the initial baseline value of processor and processor that default input voltage, boost boost;
B. comparator is according to the sampled value adjustment output voltage of sampling resistor, and the magnitude of voltage that processor is fed back equals the initial baseline value of processor;
C. adjust output voltage by amplifier, control Darlington transistor realizes output current and reaches required current value;
D. processor is according to the control voltage scope control output voltage of the Vce voltage detected with the Vce preset, to ensure that output current keeps constant.
Particularly, in step C, when depend merely on amplifier adjustment output voltage control triode can not realize output current reach required current value time, the feedback quantity that processor is supplied to boost according to the Vce feedback signal adjustment received changes output voltage thus adjusts output current.
Particularly, the concrete steps controlling output voltage in step D are as follows:
When the Vce voltage detected is greater than the higher limit of default control voltage scope, processor improves output feedack voltage signal to reduce output voltage, when the Vce voltage detected is less than the lower limit of default control voltage scope, processor reduces output feedack voltage signal to improve output voltage.
Particularly, TV set core by UART signal and described processor with communicate.
A kind of laser television power supply provided by the invention, comprise processor, boost boost module, laser light source module, Vce pressure drop feedback module and operational amplifier, described boost boost module connects input voltage, laser light source module and processor, described processor is connected with Vce pressure drop feedback module, described operational amplifier is connected with processor and Vce pressure drop feedback module, and described laser light source module is connected with Vce pressure drop feedback module;
Processor, for comparing according to according to the control voltage scope of the Vce voltage detected with the Vce preset, according to comparative result adjustment output feedack voltage;
Boost boost module, for boosting to input voltage;
Laser light source module, for providing lasing light emitter;
Vce pressure drop feedback module, the Vce voltage range preset according to processor and the sampled voltage of sampler provide triode Vce pressure drop to feed back for processor;
Operational amplifier, for amplifying the reference voltage of processor.
Particularly, described pressure drop feedback module comprises triode, sampler and comparator, and described triode is connected with sampler and comparator, and described sampler is connected with comparator.
Particularly, described UART port is connected with processor, for carrying out data communication between TV set core.
The invention has the beneficial effects as follows: the scheme realizing LASER Light Source constant current based on MCU provided by the invention, taken into full account that debugging is simple, control precision is high, and a kind of scheme realizing laser television drive circuit proposed.This programme not only can realize common constant current output, can also realize the unequal electric current of multistage current value and export.Can communication function be realized by URAT port, can revise, adjust the control voltage of output.
Accompanying drawing explanation
Fig. 1 is the theory diagram of laser television power supply of the present invention.
Fig. 2 is the MCU feedback of embodiment and the connection diagram of boost boost module.
Fig. 3 is the amplifier of embodiment and the connection diagram of Vce voltage detection module
Embodiment
Below in conjunction with drawings and Examples, technical scheme of the present invention is further described, it should be noted that embodiment is only used to help reader to understand technical scheme of the present invention better, not in order to limit the protection range of the claims in the present invention.
The present invention proposes a kind of laser television power supply constant current control method, and the program comprises the steps:
A. according to LASER Light Source required voltage, the initial feedback amount of initial voltage, the control voltage scope of Vce, the initial baseline value of processor and processor that default input voltage, boost boost;
B. comparator is according to the sampled value adjustment output voltage of sampling resistor, and the magnitude of voltage that processor is fed back equals the initial baseline value of processor;
C. adjust output voltage by amplifier, control Darlington transistor realizes output current and reaches required current value;
D. processor is according to the control voltage scope control output voltage of the Vce voltage detected with the Vce preset, to ensure that output current keeps constant.
Accordingly, laser television power supply provided by the invention, as shown in Figure 1, comprise processor, boost boost module, laser light source module, Vce pressure drop feedback module and operational amplifier, described boost boost module connects input voltage, laser light source module and processor, described processor is connected with Vce pressure drop feedback module, described operational amplifier is connected with processor and Vce pressure drop feedback module, described laser light source module is connected with Vce pressure drop feedback module, described pressure drop feedback module comprises triode, sampler and comparator, described triode is connected with sampler and comparator, described sampler is connected with comparator, processor, for comparing according to according to the control voltage scope of the Vce voltage detected with the Vce preset, according to comparative result adjustment output feedack voltage, Boost boost module, for boosting to input voltage, laser light source module, for providing lasing light emitter, Vce pressure drop feedback module, provides triode Vce pressure drop to feed back according to the Vce voltage range preset of processor and the sampled voltage of sampler for processor, operational amplifier, for amplifying the reference voltage of processor.
Embodiment
With reference to Fig. 2 and Fig. 3, with an example, technical scheme of the present invention is described in detail below.
Step S1: according to LASER Light Source required voltage, presets the initial feedback amount of input voltage, the voltage range of initial voltage U1, Vce presetting boost boosting, the initial baseline of MCU and MCU.The initial baseline of processor determines the initial current of LASER Light Source, and the initial feedback amount of processor determines the initial voltage of LASER Light Source.Detailed process is as follows:
A: directly write the initial feedback amount of MCU, the voltage range of Vce and initial baseline value in a program according to practical application.
B: the voltage needed for LASER Light Source, preset suitable input voltage, by isolating transformer, constant voltage exports and realizes, within default input voltage is generally 85% of LASER Light Source required voltage, can adjust according to the power of reality and heat dispersal situations, ensure that boost boosting is operated in safe range (temperature rise, derate meet the demands).
C: the initial voltage U1 presetting boost boosting, initial voltage U1=(Vfb1 ÷ R7) × (R7+R5+R6), Vfb1 are the VFB pin voltage of boost boosting IC is also the reference voltage of this IC;
D: the feedback of MCU is joined in boost boost feedback loop, the output signal of MCU is PWM ripple, and the feedback signal of boost boosting IC is voltage signal, therefore needs to export in the feedback of MCU to add R1, R2, C1, the PWM feedback signal of MCU is carried out RC integration and obtains Vfbout.The VFB pin that Vfbout is boosted by R17 and boost connects, because Vfb1 and Vfbout exists voltage difference after connection, namely have electric current I fb and flow through R17Ifb=(Vfb1-Vfbout) ÷ R17, therefore LASER Light Source voltage V can be obtained, V=(Vfb1 ÷ R7+Ifb) × (R5+R6)+(Vfb1 ÷ R7) × R7, arrange the feedback Vfbout of V=(Vfb1 ÷ R7) × (R7+R5+R6)+Ifb × (R5+R6) i.e. V=U1+Ifb × (R5+R6), MCU impel boost voltage be changed to Ifb × (R5+R6).
Therefore, LASER Light Source voltage V just equals voltage Ifb × (R5+R6) of the caused change of feedback of the initial voltage U1+MCU that default boost boosts.The size of the initial voltage U1 value of the boost boosting thus preset should be less than the lower limit of the voltage V needed for LASER Light Source.And the scope of the voltage V needed for LASER Light Source, affects the difference of principal element electric current and light source itself needed for light source of V voltage.Resistance R1, R2, R17 and R5 and R6 (affecting the parameter of Ifb × (R5+R6) value) are set, ensure that the maximum of U1+Ifb × (R5+R6) is greater than the higher limit of LASER Light Source V, and the LASER Light Source voltage V set by MCU initial feedback amount preset is the central value of this light source required voltage.
E: the initial feedback amount presetting MCU, reserved R3, R4 are convenient to the feedback quantity adjusting MCU feedback signal, ensure that the voltage range after the boost boosting that the change of the feedback quantity of MCU causes is greater than the voltage requirements scope of LASER Light Source.
Step S2: initial start stage, comparator is according to the sampled value adjustment output voltage of sampling resistor, and the magnitude of voltage causing MCU to feed back equals initial baseline value.
Step S3: can not realize that when output current reaches required current value I, (I is LASER Light Source electric current when depending merely on amplifier adjustment output voltage control triode, the benchmark Vref finally obtained by comparator and sampling resistor resistance determine), MCU can be supplied to boost feedback quantity according to the Vce feedback signal adjustment received changes output voltage thus adjustment output current.
Step S4:MCU pre-sets the control voltage scope of Vce.When the Vce voltage detected is greater than the higher limit of the control voltage scope of setting (now output current is normal, and triode loss is serious), MCU improves output feedback signal thus reduces output voltage; When the Vce magnitude of voltage detected is less than the lower limit of the control voltage scope of setting (now output current is on the low side, triode saturation conduction), MCU reduces output feedback signal thus improves output voltage.MCU, by the voltage detecting to Vce, achieves constant current function and reduces triode loss and ensure that it is normally operated in amplification region.
A:RC2 is the benchmark that MCU provides, and is undertaken after RC integration through amplifier out1 isolation and amplifier Vout1 by R20, R21, C20.Amplifier isolation can play the function improving reference signal and drive, the benchmark provided because of MCU can be avoided to drive the problem of the not enough signal attenuation caused, this isolation method is tracking mode isolation, can not decay and also can not amplify the original signal that MCU provides, and can improve anti-interference energy.
B: the Vout1 of isolation and amplifier obtains benchmark Vref, Vref=Vout1 ÷ (R27+R28+R29) × (R27+R28+R29+R30) again after amplifier is amplified.Reserved R28, R29 are convenient to the multiplication factor adjusting amplifier.
C: benchmark Vref inputs as the anode of comparator, because the negative terminal voltage of amplifier comparator is equal with positive terminal voltage, I1=Vref ÷ (R36+R37) (I1 is the electric current that LASER Light Source needs.The electric current that general default MCU initial baseline obtains is the central value of LASER Light Source current range).
D: the saturation conduction pressure drop of triode is about 1.4V (what use in example is Darlington triode), reference voltage is Vref (voltage on the negative terminal voltage of amplifier and sampling resistor).Therefore the Vce voltage arranged is Vce=1.4+Vref, then the cathode voltage of D20 is Vce+0.7, and this voltage obtains the detection signal of RA3 after R39, R40 dividing potential drop, Vra3=(Vce+0.7) × R40 ÷ (R39+R40).RA3 is directly connected with MCU, and namely MCU detects the voltage of Vce by RA3.
E: laser television movement provides synchronizing signal synchronous to what realize that laser television light source and laser television drives, avoids light source to drive and colour wheel not corresponding.The object of adding 12VM signal provides a voltage (this value is 12VM × R35 ÷ (R33+R35)) to the negative terminal of comparator for 12VM, avoid when comparator anode and negative terminal are low level simultaneously, comparator drives has output, causes power supply misoperation.Power supply action before receiving synchronizing signal can be avoided simultaneously.Because 12VM provides a level to the negative terminal of comparator, cause the feedback of comparator to there is error with between actual demand, this error is determined by R33, R35, and therefore the benchmark of MCU provides B1, B2, the fine setting be used for benchmark.
F: can the LASER Light Source of simultaneously control realization more than three.
Step S5:MCU can be communicated by UART (a kind of Universal Serial Bus) signal with between laser television movement, and namely laser television movement can adjust to feature the feedback quantity of MCU, benchmark Vref and revise according to itself.
Claims (7)
1. laser television power supply constant current control method, is characterized in that, comprises the steps:
A. according to LASER Light Source required voltage, the initial feedback amount of initial voltage, the control voltage scope of Vce, the initial baseline value of processor and processor that default input voltage, boost boost;
B. comparator is according to the sampled value adjustment output voltage of sampling resistor, and the magnitude of voltage that processor is fed back equals the initial baseline value of processor;
C. adjust output voltage by amplifier, control Darlington transistor realizes output current and reaches required current value;
D. processor is according to the control voltage scope control output voltage of the Vce voltage detected with the Vce preset, to ensure that output current keeps constant.
2. laser television power supply constant current control method as claimed in claim 1, it is characterized in that, in step C, when depend merely on amplifier adjustment output voltage control Darlington transistor can not realize output current reach required current value time, the feedback quantity that processor is supplied to boost according to the Vce feedback signal adjustment received changes output voltage thus adjusts output current.
3. laser television power supply constant current control method as claimed in claim 1, it is characterized in that, the concrete steps controlling output voltage in step D are as follows:
When the Vce voltage detected is greater than the higher limit of default control voltage scope, processor improves output feedack voltage signal to reduce output voltage, when the Vce voltage detected is less than the lower limit of default control voltage scope, processor reduces output feedack voltage signal to improve output voltage.
4. the laser television power supply constant current control method as described in claim 1 or 2 or 3, it is characterized in that, described processor is communicated by UART with between TV set core.
5. laser television power supply, it is characterized in that, comprise processor, boost boost module, laser light source module, Vce pressure drop feedback module and operational amplifier, described boost boost module connects input voltage, laser light source module and processor, described processor is connected with Vce pressure drop feedback module, described operational amplifier is connected with processor and Vce pressure drop feedback module, and described laser light source module is connected with Vce pressure drop feedback module;
Processor, for comparing according to according to the control voltage scope of the Vce voltage detected with the Vce preset, according to comparative result adjustment output feedack voltage;
Boost boost module, for boosting to input voltage;
Laser light source module, for providing lasing light emitter;
Vce pressure drop feedback module, according to the reference voltage of processor and the sampled voltage of sampler for processor provides triode Vce pressure drop to feed back;
Operational amplifier, for amplifying the reference voltage of processor.
6. laser television power supply as claimed in claim 5, it is characterized in that, described pressure drop feedback module comprises triode, sampler and comparator, and described triode is connected with sampler and comparator, and described sampler is connected with comparator.
7. the laser television power supply as described in claim 5 or 6, is characterized in that, also comprises UART port, and described UART port is connected with processor, for carrying out data communication between TV set core.
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Cited By (5)
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| CN105208739A (en) * | 2015-10-21 | 2015-12-30 | 广东威创视讯科技股份有限公司 | Constant-current driving device for laser light source |
| CN105487588A (en) * | 2016-01-12 | 2016-04-13 | 四川长虹电器股份有限公司 | Constant current source circuit capable of being regulated and controlled in real time and constant current control method thereof |
| CN108011293A (en) * | 2017-12-16 | 2018-05-08 | 南京理工大学 | A kind of burst pulse infrared semiconductor laser radiating circuit |
| CN109765474A (en) * | 2019-01-25 | 2019-05-17 | 无锡固电半导体股份有限公司 | A kind of test method of Darlington transistor parameter |
| WO2021121300A1 (en) * | 2019-12-19 | 2021-06-24 | 深圳光峰科技股份有限公司 | Current control circuit and method, and projection device |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105208739A (en) * | 2015-10-21 | 2015-12-30 | 广东威创视讯科技股份有限公司 | Constant-current driving device for laser light source |
| CN105208739B (en) * | 2015-10-21 | 2019-05-07 | 广东威创视讯科技股份有限公司 | Laser light source constant current driving device |
| CN105487588A (en) * | 2016-01-12 | 2016-04-13 | 四川长虹电器股份有限公司 | Constant current source circuit capable of being regulated and controlled in real time and constant current control method thereof |
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| WO2021121300A1 (en) * | 2019-12-19 | 2021-06-24 | 深圳光峰科技股份有限公司 | Current control circuit and method, and projection device |
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Application publication date: 20150429 |