CN201360365Y - Power supply control circuit and projector scope with the circuit - Google Patents
Power supply control circuit and projector scope with the circuit Download PDFInfo
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- CN201360365Y CN201360365Y CNU2009200226708U CN200920022670U CN201360365Y CN 201360365 Y CN201360365 Y CN 201360365Y CN U2009200226708 U CNU2009200226708 U CN U2009200226708U CN 200920022670 U CN200920022670 U CN 200920022670U CN 201360365 Y CN201360365 Y CN 201360365Y
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Abstract
The utility model discloses a power supply control circuit and a projector scope with the circuit which comprise a power supply and a feedback control circuit which is connected with the output side of the power supply, wherein the feedback control circuit comprises a constant-current control circuit, the constant-current control circuit comprises a sampling resistance, a comparator and a precision voltage regulator, the sampling resistance is connected between the output side of the power supply and the connecting return circuit of loading in series, the precision voltage regulator is connected on the output side of the power supply, reference voltage thereof and sampling voltage which is obtained through the sampling resistance are input to the comparator for comparing, and the comparator outputs voltage signals which are transmitted to a control circuit on the input side of the power supply according to the comparing results for regulating the current and the voltage on the output side of the power supply. The power supply circuit has fast feedback and regulation and no lag, output voltage is not affected by the loading, the power supply control circuit is applicable to high-power LED light sources, and can effectively guarantee performances of the LED light sources and service life of products.
Description
Technical field
The utility model belongs to the power circuit technical field, specifically, relates to a kind of constant-current and constant-voltage control circuit that designs for stabilized power supply output and the led light source projecting apparatus that adopts described power control circuit to design.
Background technology
Led light source is the typical current device, only applies light characteristic and useful life that constant electric current could guarantee LED.Simultaneously, when the temperature of LED separator changes, can cause that forward voltage drop changes, thereby cause forward current to change, cause that the color bits skew takes place LED.The power supply that for this reason requires LED is constant current mode, especially great power LED, and constant current accuracy is not high or directly power with the constant voltage mode, and greatly shortened the useful life of LED, and performance also can be subjected to very big influence.
Present constant-current circuit is varied, and the simplest have a series resistance detection method, and the technology that adopts triode and Voltage Feedback control method to realize constant current constant voltage is also arranged, and also has to carry out technology that constant current constant voltage controls or the like by the electric voltage dropping compensation method.But all there are some defectives in these methods, and therefore degradation under the voltage can not effectively guarantee the performance of led light source and the useful life of product when, load not high such as control lag, current stability increased.
The utility model content
The utility model is in order to solve not problem accurately of traditional constant-current circuit Current Control, provide a kind of simple in structure, regulate power control circuit rapidly, by the power supply that is applied to load is sampled, and sampled signal relatively amplified the output of regulating power circuit afterwards accurately, thereby guaranteed the stable of power circuit output, can obtain higher constant current accuracy.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of power control circuit comprises power supply and the feedback control circuit that is connected described power supply outlet side; In order to make electric current have higher constant current accuracy, in described feedback control circuit, be provided with a constant-current control circuit by described power supply output; In described constant-current control circuit, comprise sampling resistor, comparator and accurate voltage adjuster; Described sampling resistor is connected in the link circuit of power supply outlet side and load, precisely voltage adjuster is connected the outlet side of power supply, its reference voltage is input in the comparator jointly with the sampled voltage that obtains by described sampling resistor and compares, described comparator transfers to the control circuit of power supply input side according to the comparative result output voltage signal, to regulate the voltage of power supply outlet side.
Further, described power supply is a Switching Power Supply, comprises a switch transformer, and wherein one road secondary coil of described switch transformer connects described load, and output voltage is an electric; Described sampling resistor is connected between the different name end and ground of described secondary coil, precisely the reference voltage utmost point of voltage adjuster connects the different name end of described secondary coil by bleeder circuit, the dividing potential drop node of described bleeder circuit connects the inverting input of described comparator, the in-phase input end ground connection of comparator, output is by optical coupling isolation circuit or directly connect the elementary ON-OFF control circuit of described switch transformer, by changing the duty ratio of PWM switch controlling signal in the ON-OFF control circuit, realize effective adjusting to the switch transformer output voltage.
For fear of when short trouble appears in load, described power control circuit still can operate as normal, to guarantee circuit safety, is provided with the multichannel outlet side in described power supply, and wherein one road outlet side connects described load, and output voltage is an electric; Other one road outlet side connects the negative electrode of described accurate voltage adjuster, the plus earth of described accurate voltage adjuster.
Further again, keep constant in order to make the voltage that is applied to load, in described feedback control circuit, also be provided with a constant-voltage control circuit, comprise bleeder circuit and another comparator; The outlet side that is connected load in described bleeder circuit and the described power supply is connected, its dividing potential drop node connects wherein one road input of described another comparator, other one road input of described comparator connects the reference voltage utmost point of accurate voltage adjuster, output is by optical coupling isolation circuit or directly connect the control circuit of described power supply input side, by the output voltage of power supply and the reference voltage of accurate voltage adjuster are compared, and then generate control signal corresponding and regulate the output of power supply, thereby guarantee the constant of switch power source output voltage.
Further, between the inverting input of described two-way comparator and output, be connected with the phase compensating circuit that a routing resistance and capacitances in series form separately.
Based on above-mentioned power control circuit structure, the utility model also provides a kind of projecting apparatus that adopts described power control circuit design, set up constant current, the constant-voltage control circuit of forming by sampling resistor, bleeder circuit, accurate voltage adjuster and comparator by the outlet side of existing power supply in projecting apparatus, thereby make the power supply that is applied to load be constant current, constant-voltage characteristic.
Compared with prior art, advantage of the present utility model and good effect are: power control circuit of the present utility model is used to control power supply and produces electric current and voltage accurately, and feedback regulation is rapid, nothing lags behind, and output voltage is not subjected to the influence of load variations.In addition, this power control circuit is simple in structure, with low cost, is applicable to led light source, can effectively guarantee the useful life of led light source performance and product, be particularly useful for adopting in the household appliances of great power LED as light source, such as projector, rear-projection TV set etc.
After reading the detailed description of the utility model execution mode in conjunction with the accompanying drawings, other characteristics of the present utility model and advantage will become clearer.
Description of drawings
Fig. 1 is the circuit theory diagrams of a kind of embodiment of the power control circuit that proposes of the utility model;
Fig. 2 is the schematic block circuit diagram of a kind of embodiment of internal circuit that adopts the projecting apparatus of power control circuit shown in Figure 1.
Embodiment
Below in conjunction with accompanying drawing specific embodiment of the utility model is described in detail.
The utility model is abandoned existing constant current, constant-voltage control circuit structure, employing is sampled to the power supply that is applied to load, and sampled signal is carried out precisely relatively amplification adjusted the mode that power supply is exported afterwards, obtain the output characteristic of power supply constant current, constant voltage, thereby overcome not defective accurately of traditional circuit Current Control, played very crucial effect improving LED properties of product and reliability.
In power control circuit of the present utility model, mainly comprise power supply, the feedback control circuit that is connected the control circuit of power supply input side and is connected the power supply outlet side.In order to make power supply output to direct current supply constant current, the constant voltage of load, constant-current control circuit and constant-voltage control circuit in feedback control circuit of the present utility model, have been designed respectively.Wherein, constant-current control circuit mainly adopts sampling resistor, comparator and accurate voltage adjuster to design, by sampling resistor being connected in the link circuit of power supply outlet side and load, and then the sampled voltage that will obtain by sampling resistor compares with the accurate reference voltage of voltage adjuster, thereby generate the control circuit that control signal corresponding transfers to the power supply input side, with the voltage of adjusting power supply outlet side, and then reach the constant purpose of design of output current.Constant-voltage control circuit mainly adopts the bleeder circuit that is connected the power supply outlet side, comparator and accurate voltage adjuster design, carry out dividing potential drop by the supply power voltage that power supply is exported to load, and then compare with the reference voltage of accurate voltage adjuster, thereby generate the control circuit that control signal corresponding exports the power supply input side to, ON-OFF control circuit such as the Switching Power Supply input side, to produce corresponding switch controlling signal, such as PWM switch controlling signal with certain duty ratio, and then the output of by-pass cock power supply, make output voltage keep constant.
Elaborate the concrete composition structure and the operation principle thereof of described power control circuit below by a specific embodiment.
Embodiment one, and present embodiment is that example is specifically addressed with the Switching Power Supply.Described Switching Power Supply can adopt reverse exciting topological frame mode commonly used at present to design, and comprises switch transformer and is connected the elementary ON-OFF control circuit of switch transformer.The framework of described ON-OFF control circuit is constant substantially, generally comprises current rectifying and wave filtering circuit, EMI inhibition circuit, power factor correction circuit, PWM ON-OFF control circuit, feedback loop and other auxiliary power supply circuit etc.Here the ON-OFF control circuit of switch primary is not done introduction, selective analysis is connected the secondary feedback control circuit part of switch transformer.
Fig. 1 is the circuit theory diagrams of a kind of embodiment of described power control circuit, only shows two-way secondary coil Lp1 and the Lp2 of switch transformer T among the figure.Voltage by secondary coil Lp2 induction output exports filter network to and handles after diode VD2 rectification.Described filter network can adopt the filter circuit of the π type filter circuit be made up of inductance L 1 and capacitor C 2, C3 or other versions to realize, and then to produce pure direct voltage Uout be load (such as led light source) power supply.
In order to make the current constant that flows through load, present embodiment has designed a constant-current control circuit in feedback control circuit, comprises sampling resistor R1, accurate voltage adjuster U2 and comparator N1A etc.For the electric current of convection current overload is sampled, at first sampling resistor R1 is connected between the different name end and ground GND of secondary coil Lp2, by the voltage that is applied to sampling resistor R1 two ends is taken a sample, to obtain current value indirectly.Because flow through the electric current I c right-to-left of sampling resistor R1, therefore, sampled voltage Uc is a negative value.For when load is short-circuited fault, feedback control circuit still can operate as normal, and it is accurate voltage adjuster U2 power supply that present embodiment adopts the direct voltage VCC of another road secondary coil Lp1 output of switch transformer T.Wherein, the voltage by described secondary coil Lp1 induction output carries out producing pure direct voltage VCC connects accurate voltage adjuster U2 by current-limiting resistance R4 negative electrode after rectifying and wave-filtering handles through diode VD1 and filter capacitor C1.The plus earth of described accurate voltage adjuster U2, reference voltage utmost point R connects the different name end of secondary coil Lp2 by the bleeder circuit of being made up of resistance R 2, R3.The inverting input of the dividing potential drop node connection comparator N1A of described divider resistance R2, R3-, in-phase input end+ground connection.When the absolute value of sampled voltage Uc greater than the accurate reference voltage V of voltage adjuster U2
Ref(V
Ref=2.5V) time, export to comparator N1A inverting input-voltage be negative voltage, after comparator N1A negate, by its output output high level error signal, and then be converted to current signal through diode VD3 and resistance R 10, export the luminous end of optical coupling isolator U1 to, flow through the electric current of light-emitting diode among the optocoupler U1 with change.The control signal that produces by optocoupler U1 light-receiving end exports the ON-OFF control circuit of switch transformer T primary side to, changing the duty ratio of PWM switch controlling signal, and then the output of by-pass cock transformer T primary side, with the electric current of stable flow overload.
In order to make the voltage constant that is applied to load, present embodiment has also designed a constant-voltage control circuit in feedback control circuit, mainly partly is made up of bleeder circuit, comparator N1B and accurate voltage adjuster U2 etc.Wherein, bleeder circuit is connected between direct voltage Uout output and the ground, realizes the sampling to direct voltage Uout.In the present embodiment, described bleeder circuit is formed by connecting by two divider resistance R6, R7, the in-phase input end of its dividing potential drop node connection comparator N1B+.In order to realize the effective adjusting to dividing point voltage U a, described divider resistance R7 preferably adopts adjustable precision resistance to realize.The inverting input of described comparator N1B-connect the reference voltage utmost point R of accurate voltage adjuster U2 by resistance R 5 is by with dividing point voltage U a and reference voltage V
RefCompare, whether promptly judge Ua, and then generate the output output of control signal corresponding by comparator N1B greater than 2.5V.When the direct voltage Uout that is applied to load raise, dividing potential drop voltages at nodes Ua increased, this voltage and comparator N1B inverting input-the 2.5V reference voltage V
RefRelatively, the output error control signal becomes current signal by diode VD4 and resistance R 10, flow into the luminous end among the optocoupler U1, flow through the electric current of light-emitting diode among the optocoupler U1 by change, and then the light-receiving end by optocoupler U1 sends control signal corresponding and exports the elementary ON-OFF control circuit of switch transformer T to, with the open the light duty ratio of control signal PWM of change, realization is to effective adjusting of switch transformer T primary side output voltage, and then makes the direct voltage Uout that is applied to load be operated in pressure constant state.
In addition, for circuit is relatively carried out phase compensation, between the inverting input of described two-way comparator N1A, N1B and output, be connected with the phase compensating circuit that a routing capacitance C4 (or C5) and resistance R 8 (or R9) are in series separately.
Through evidence, adopt constant voltage, the constant-current control circuit formed by elements such as comparator N1A, N1B and accurate voltage adjuster U2, can realize very high constant voltage and constant current accuracy.The resistance of sampling resistor R1 is chosen as m Ω level, therefore, circuit conversion efficient is not had influence substantially.
Below with the LED projecting apparatus be example set forth described power control circuit in projecting apparatus concrete application and the good effect of generation.
Light-source illuminating system is the basis of whole projection optical system, and UHP (ultra-high pressure gas discharge lamp) is extensively applied on front projection machine and the rear-projection TV as the projection light source lamp at present.And LED also more and more is subjected to people's attention as novel lighting source, compare with the UHP lamp, LED has a series of advantages, it utilizes the solid semiconductor chip as luminescent material, when two ends add forward voltage, charge carrier in the semiconductor takes place compound, emits superfluous energy and causes that photo emissions produces visible light.Therefore, LED can be applied in the projecting apparatus, as the light source of projecting apparatus.
Owing to used led light source, for the DLP projection, can save the colour wheel device, thereby improve the efficient of light source greatly.In addition, because the change of light source heat radiation mode, the projection products of employing led light source can be quieter, more energy-conservation, lighter than general projecting apparatus.
Fig. 2 is the schematic block circuit diagram of power unit in the projecting apparatus, comprises chief components such as current rectifying and wave filtering circuit, switching power circuit and high-power LED light source.Wherein, the 220V electric main is input to current rectifying and wave filtering circuit by master switch K1, temperature detect switch (TDS) K2 and gate controlled switch K3, exports switching power circuit to after changing alternating voltage into direct voltage by current rectifying and wave filtering circuit.Described switching power circuit can adopt the reverse exciting topological structural design to form, and the direct voltage that current rectifying and wave filtering circuit is exported is converted to the required direct voltage of high-power LED light source, is the high-power LED light source power supply; Generate the mainboard that the multichannel low-voltage dc power supply exports projecting apparatus to simultaneously, for each functional circuit on the mainboard provides working power.
In order to make the voltage and current that exports high-power LED light source to present constant voltage, constant-current characteristics, can be in the switching power circuit of projecting apparatus with feedback control circuit design shown in Figure 1.By the effect of test and use, this constant voltage, the constant-current control circuit that is made of the reference comparison circuit has good volt-ampere characteristic, the most approaching desirable output state.In the power supply power supply that is high-power LED light source, can make LED be operated in optimum state this circuit application, fully guarantee the characteristic of LED current device, make the luminosity of LED even, to great help is arranged the useful life of improving LED.
Certainly, the power control circuit of present embodiment can be applied to adopt in the household appliances such as rear-projection TV set of great power LED as light source equally.
Should be understood that; the above only is a kind of preferred implementation of the present utility model; for those skilled in the art; under the prerequisite that does not break away from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.
Claims (10)
1, a kind of power control circuit comprises power supply and the feedback control circuit that is connected described power supply outlet side; It is characterized in that: in described feedback control circuit, include a constant-current control circuit, in described constant-current control circuit, comprise sampling resistor, comparator and accurate voltage adjuster; Described sampling resistor is connected in the link circuit of power supply outlet side and load, precisely voltage adjuster is connected the outlet side of power supply, its reference voltage is input in the comparator jointly with the sampled voltage that obtains by described sampling resistor and compares, described comparator transfers to the control circuit of power supply input side according to the comparative result output voltage signal, to regulate the voltage of power supply outlet side.
2, power control circuit according to claim 1 is characterized in that: described power supply is a Switching Power Supply, comprises a switch transformer, and wherein one road secondary coil of described switch transformer connects described load, and output voltage is an electric; Described sampling resistor is connected between the different name end and ground of described secondary coil, precisely the reference voltage utmost point of voltage adjuster connects the different name end of described secondary coil by bleeder circuit, the dividing potential drop node of described bleeder circuit connects the inverting input of described comparator, the in-phase input end ground connection of comparator, output are by optical coupling isolation circuit or directly connect the elementary ON-OFF control circuit of described switch transformer.
3, power control circuit according to claim 1 is characterized in that: described power supply comprises the multichannel outlet side, and wherein one road outlet side connects described load, and output voltage is an electric; Other one road outlet side connects the negative electrode of described accurate voltage adjuster, the plus earth of described accurate voltage adjuster.
4, according to claim 1 or 2 or 3 described power control circuits, it is characterized in that: in described feedback control circuit, also include a constant-voltage control circuit, comprise bleeder circuit and another comparator; The outlet side that is connected load in described bleeder circuit and the described power supply is connected, its dividing potential drop node connects wherein one road input of described another comparator, other one road input of described comparator connects the reference voltage utmost point of accurate voltage adjuster, and output is by optical coupling isolation circuit or directly connect the control circuit of described power supply input side.
5, power control circuit according to claim 4 is characterized in that: be connected with the phase compensating circuit that a routing resistance and capacitances in series form between the inverting input of described two-way comparator and output separately.
6, a kind of projecting apparatus comprises power supply and the feedback control circuit that is connected described power supply outlet side; It is characterized in that: in described feedback control circuit, include a constant-current control circuit, in described constant-current control circuit, comprise sampling resistor, comparator and accurate voltage adjuster; Described sampling resistor is connected in the link circuit of power supply outlet side and load, precisely voltage adjuster is connected the outlet side of power supply, its reference voltage is input in the comparator jointly with the sampled voltage that obtains by described sampling resistor and compares, described comparator transfers to the control circuit of power supply input side according to the comparative result output voltage signal, to regulate the voltage of power supply outlet side.
7, projecting apparatus according to claim 6 is characterized in that: described power supply is a Switching Power Supply, comprises a switch transformer, and wherein one road secondary coil of described switch transformer connects described load, and output voltage is an electric; Described sampling resistor is connected between the different name end and ground of described secondary coil, precisely the reference voltage utmost point of voltage adjuster connects the different name end of described secondary coil by bleeder circuit, the dividing potential drop node of described bleeder circuit connects the inverting input of described comparator, the in-phase input end ground connection of comparator, output are by optical coupling isolation circuit or directly connect the elementary ON-OFF control circuit of described switch transformer.
8, projecting apparatus according to claim 6 is characterized in that: described power supply comprises the multichannel outlet side, and wherein one road outlet side connects described load, and output voltage is an electric; Other one road outlet side connects the negative electrode of described accurate voltage adjuster, the plus earth of described accurate voltage adjuster.
9, according to claim 6 or 7 or 8 described projecting apparatus, it is characterized in that: in described feedback control circuit, also include a constant-voltage control circuit, comprise bleeder circuit and another comparator; The outlet side that is connected load in described bleeder circuit and the described power supply is connected, its dividing potential drop node connects wherein one road input of described another comparator, other one road input of described comparator connects the reference voltage utmost point of accurate voltage adjuster, and output is by optical coupling isolation circuit or directly connect the control circuit of described power supply input side.
10, projecting apparatus according to claim 9 is characterized in that: be connected with the phase compensating circuit that a routing resistance and capacitances in series form between the inverting input of described two-way comparator and output separately.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2009200226708U CN201360365Y (en) | 2009-02-26 | 2009-02-26 | Power supply control circuit and projector scope with the circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2009200226708U CN201360365Y (en) | 2009-02-26 | 2009-02-26 | Power supply control circuit and projector scope with the circuit |
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| CN201360365Y true CN201360365Y (en) | 2009-12-09 |
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| CNU2009200226708U Expired - Fee Related CN201360365Y (en) | 2009-02-26 | 2009-02-26 | Power supply control circuit and projector scope with the circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102005748A (en) * | 2010-11-10 | 2011-04-06 | 中国兵器工业集团第二一四研究所苏州研发中心 | Isolation type positive-negative output constant current protective device |
| WO2019029140A1 (en) * | 2017-08-08 | 2019-02-14 | 深圳光峰科技股份有限公司 | Switching power supply and projector |
| CN111526641A (en) * | 2020-05-15 | 2020-08-11 | 深圳市洲明科技股份有限公司 | Back pressure self-adjusting method and device |
| CN116488487A (en) * | 2023-04-06 | 2023-07-25 | 广东工业大学 | Novel alternating-current multi-level photon electric energy converter topology and modulation mode thereof |
-
2009
- 2009-02-26 CN CNU2009200226708U patent/CN201360365Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102005748A (en) * | 2010-11-10 | 2011-04-06 | 中国兵器工业集团第二一四研究所苏州研发中心 | Isolation type positive-negative output constant current protective device |
| CN102005748B (en) * | 2010-11-10 | 2013-09-18 | 中国兵器工业集团第二一四研究所苏州研发中心 | Isolation type positive-negative output constant current protective device |
| WO2019029140A1 (en) * | 2017-08-08 | 2019-02-14 | 深圳光峰科技股份有限公司 | Switching power supply and projector |
| CN111526641A (en) * | 2020-05-15 | 2020-08-11 | 深圳市洲明科技股份有限公司 | Back pressure self-adjusting method and device |
| CN116488487A (en) * | 2023-04-06 | 2023-07-25 | 广东工业大学 | Novel alternating-current multi-level photon electric energy converter topology and modulation mode thereof |
| CN116488487B (en) * | 2023-04-06 | 2023-11-17 | 广东工业大学 | Modulation method of alternating-current multi-level photon electric energy converter topology |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091209 Termination date: 20120226 |