CN204046857U - A kind of LED drive chip, LED drive circuit and LED lamp - Google Patents
A kind of LED drive chip, LED drive circuit and LED lamp Download PDFInfo
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- CN204046857U CN204046857U CN201420197392.0U CN201420197392U CN204046857U CN 204046857 U CN204046857 U CN 204046857U CN 201420197392 U CN201420197392 U CN 201420197392U CN 204046857 U CN204046857 U CN 204046857U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model belongs to lighting technical field, particularly a kind of LED drive chip, LED drive circuit and LED lamp.LED drive chip provided by the utility model connects rectifier bridge and LED group, comprises detection module, signal output module and control module.Wherein, detection module, control module and LED group connect rectifier bridge, detection module connection signal output module, signal output module link control module.Rectifier bridge incoming transport civil power, and power for control module and LED group; Detection module, by detecting the output voltage of each commutation cycle, judges that this voltage is higher than time of preset voltage value or maximum voltage value.Each commutation cycle that can obtain output voltage due to this chip is higher than time of preset voltage value or maximum voltage value, and then accurately can judge the amplitude regulating electric current, restrained effectively the LED light-emitting flash that the voltage fluctuation because of electric main causes, the light output maintaining LED is constant.
Description
Technical field
The utility model belongs to lighting technical field, particularly a kind of LED drive chip, LED drive circuit and LED lamp.
Background technology
LED lamp, with high efficiency, high integration and the advantage of high life, obtains applying more and more widely at lighting field.In LED lamp, due to the requirement to integrated level and manufacturing cost, the share that the AC LED drive scheme of the energy storage devices such as non-inductance electric heating appearance accounts in the market is increasing, inherently becomes main flow in future.This kind of drive scheme is by the break-make of control chip control switch pipe to regulate the quantity of the LED group of real work, thus reaches the object that the size of current of LED group is flow through in restriction.
Traditional LED lamp by resistance pressure-dividing network detect line voltage go forward side by side line correlation adjustment, because traditional LED adopts constant current constant voltage to drive, its front stage circuits generally has stronger filter function, and its testing requirement for output voltage is not high, and this detection mode is enough.
But, different from traditional LED lamp, adopt the power output of the light fixture of AC LED drive scheme to be easy to the impact being subject to mains fluctuation, and also lack relevant power invariability scheme in the prior art, require further improvement.Further, in the LED lamp exchanging drive scheme, the detection signal received due to control module is the instant voltage signal that magnitude of voltage ceaselessly changes, and control module is difficult to judge for Current adjustment amplitude.Therefore, carry out Current adjustment operation according to this magnitude of voltage, power invariability effect is poor.
Therefore, there is Current adjustment amplitude and judge inaccurate problem in the LED lamp of existing employing AC LED drive scheme.
Utility model content
The purpose of this utility model is to provide a kind of LED drive chip, and the LED lamp being intended to solve existing employing AC LED drive scheme exists Current adjustment amplitude and judges inaccurate problem.
The utility model is achieved in that a kind of LED drive chip, is connected, and comprises control module with rectifier bridge and LED group; Described rectifier bridge exports described LED group to after carrying out rectification process to alternating current, and the operating current of current regulating signal to described LED group that described control module receives according to its controlled end regulates;
Described LED drive circuit also comprises detection module and signal output module;
Input and the output of described detection module are connected the output of described rectifier bridge and the input of described signal output module respectively, and the output of described signal output module connects the controlled end of described control module.
Another object of the present utility model is also to provide a kind of LED drive circuit, comprises rectifier bridge, also comprises above-mentioned LED drive chip.
Another object of the present utility model is also to provide a kind of LED lamp, comprises housing, also comprises above-mentioned LED drive circuit.
LED drive chip provided by the utility model connects rectifier bridge and LED group, comprises detection module, signal output module and control module.Wherein, detection module, control module and LED group connect rectifier bridge, detection module connection signal output module, signal output module link control module.Rectifier bridge incoming transport civil power, and power for control module and LED group; Detection module, by detecting the output voltage of each commutation cycle, judges that this voltage is higher than time of preset voltage value or maximum voltage value, flows through the electric current of LED group to make control module according to received signal controlling.Each commutation cycle that can obtain output voltage due to this LED drive chip is higher than time of preset voltage value or maximum voltage value, its method detecting instant magnitude of voltage relative to traditional resistance pressure-dividing network has higher accuracy, make control module accurately can judge the amplitude of Current adjustment, restrained effectively because the fluctuate pressure that causes of ac commercial power voltage is dodged, ensure that LED light stable output.
Accompanying drawing explanation
Fig. 1 is the function structure chart of the first embodiment of LED drive chip provided by the utility model;
Fig. 2 is the function structure chart of the signal output module of the first embodiment of LED drive chip provided by the utility model;
Fig. 3 is the exemplary circuit structure chart of the adjustable current source of the first embodiment of LED drive chip provided by the utility model;
Fig. 4 is the function structure chart of the second embodiment of LED drive chip provided by the utility model;
Fig. 5 is the exemplary circuit structure chart of the voltage comparison module of the second embodiment of LED drive chip provided by the utility model;
Fig. 6 is the voltage oscillogram in the commutation cycle of the rectifier bridge of the second embodiment of LED drive chip provided by the utility model;
Fig. 7 is the function structure chart of the 3rd embodiment of LED drive chip provided by the utility model.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
LED drive chip provided by the utility model comprises detection module, signal output module and control module.Wherein, detection module is connected rectifier bridge with control module, detection module connection signal output module, signal output module link control module.There is Current adjustment amplitude and judge inaccurate problem in the LED lamp solving existing employing AC LED drive scheme.
embodiment 1
Fig. 1 show the present embodiment the modular structure of LED drive chip is provided, for convenience of explanation, illustrate only part related to the present embodiment, details are as follows:
The LED drive chip that the present embodiment provides, is connected with rectifier bridge 10 and LED group 30.
In the present embodiment, the quantity of LED group 30 can be one or more, and its connection belongs to prior art, does not repeat them here.
LED drive chip also comprises control module 20, the input of the output LED group 30 of rectifier bridge 10, and the output of LED group 30 connects the input of described control module 20, and the output of control module 20 connects the direct-flow input end of rectifier bridge 10.
Concrete, the ac input end incoming transport civil power of rectifier bridge 10, and export LED group 30 to after rectification process is carried out to electric main, the current regulating signal that control module 20 receives according to controlled end regulates the operating current flowing through LED group 30.
In addition, control module 20 can obtain operating current by the output of rectifier bridge 10, also can access other power supplys.
Further, LED drive circuit also comprises detection module 50 and signal output module 40;
Input and the output of detection module 50 are connected the output of rectifier bridge 10 and the input of signal output module 40, the controlled end of the output link control module 20 of signal output module 40 respectively;
Detection module 50 exports maximum voltage value according to the output voltage of described rectifier bridge 10, or count higher than during preset voltage value at output voltage, and after counting terminates, export count results, signal output module 40 according to maximum voltage value or count results output current conditioning signal to control module 20.
In the present embodiment, each commutation cycle that can obtain output voltage due to this LED drive chip is higher than time of preset voltage value or maximum voltage value, it has higher accuracy relative to traditional resistance pressure-dividing network detection method, make control module accurately can judge the amplitude of Current adjustment, restrained effectively because the fluctuate pressure that causes of ac commercial power voltage is dodged, ensure that LED light stable output.
Further, as shown in Figure 2, signal output module 40 comprises inverter 41 and D/A converter module 42;
The input of inverter 41 is inputs of signal output module 40, and the output of inverter 41 connects the input of D/A converter module 42, and the output of D/A converter module 42 is outputs of signal output module 40.
In the present embodiment, inverter 41 can adopt model to be inverter 41 chip of 74LS125, or the inverter 41 of the figure place identical with counter 53a of other models; D/A converter module 42 can model be the analog-digital chip of DAC0832, or the digital-to-analogue conversion device of the figure place identical with counter 53a of other models.Wherein, the effect of inverter 41 is the inversely proportional relations of output numerical value making the output voltage of D/A converter module 42 and counter 53a.
In addition, inverter 41 also can use subtracter to replace, and namely deducts by a suitable fixed numbers numerical value that counter 53a or memory module 52b exports, makes the inversely proportional relation of output numerical value of the output voltage of D/A converter module 42 and counter 53a equally.
Further, control module 20 can comprise adjustable current source;
The controlled end of adjustable current source and input are controlled end and the input of control module 20.
Concrete, as shown in Figure 3, adjustable current source can comprise:
First resistance R1, NMOS tube Q1 and the first operational amplifier Q2;
The first input end of the first operational amplifier Q2 is the controlled end of adjustable current source, the output of the first operational amplifier Q2 connects the grid of NMOS tube Q1, second input of the first operational amplifier Q2 and the first end of the first resistance R1 are connected to the source electrode of NMOS tube Q1 altogether, the drain electrode of NMOS tube Q1 is the input of adjustable current source, and second end of the first resistance R1 and the substrate of NMOS tube Q1 are connected to ground altogether.
In the present embodiment, according to profound and negative feedbck principle, two input terminal voltages of the first operational amplifier Q2 can be tending towards equal, therefore the voltage of the first end of change first resistance R1 can be removed by the voltage changing first input end, and then change the size of current flow through on the first resistance R1, namely flow through the operating current size in LED group 30.
embodiment 2
The enforcement of the present embodiment is based upon on the basis of an embodiment.
Fig. 4 show the present embodiment the modular structure of LED drive chip is provided, for convenience of explanation, illustrate only part related to the present embodiment, details are as follows:
In the present embodiment, detection module 50 comprises signal source of clock 52a, counter 53a and voltage comparison module 51a;
The input of voltage comparison module 51a is the input of detection module 50, Enable Pin and the input of counter 53a are connected the output of voltage comparison module 51a and the output of signal source of clock 52a respectively, and the output of counter 53a is the output of detection module 50;
When the output voltage of described rectifier bridge 10 is higher than preset voltage value, voltage comparison module 51a control counter 53a counts the clock signal that signal source of clock 52a exports, counter 53a exports count results after counting terminates, signal output module 40 according to count results output current conditioning signal to control module 20.
In the present embodiment, these modules above can be integrated in driving chip, also can build with discrete device.When using discrete device to build, signal source of clock 52a can use crystal oscillator to produce high-precision clock signal, as the PureEdge TM clock series of products of ONNN, the oscillator of other types also can be used, as LC oscillator, RC oscillator etc.; The binary counter 53a that counter 53a can use model to be 74LS590, or the binary counter 53a of other other models of figure place.When by above-mentioned module integration in chip time, corresponding can adopt the structure identical with said chip, following module is identical all therewith, does not repeat them here.
In the present embodiment, control module 20 regulates operating current, the operating current of LED group 30 and the inversely proportional relation of count results of LED group 30 according to current regulating signal.
Concrete, count results is less, and current regulating signal is larger, and the operating current of LED group 30 is also larger; Count results is larger, and current regulating signal is less, and the operating current of LED group 30 is also less.
Further, voltage comparison module 51a can comprise:
Second resistance R2, the 3rd resistance R3, the second operational amplifier Q3 and reference voltage source 511;
The first end of the second resistance R2 is the input of voltage comparison module 51a, second end of the second resistance R2 and the first end of the 3rd resistance R3 are connected to the first input end of the second operational amplifier Q3 altogether, the second end ground connection of the 3rd resistance R3, the output of reference voltage source 511 connects second input of the second operational amplifier Q3, and the output of the second operational amplifier Q3 is the output of voltage comparison module 51a.
In the present embodiment, the second operational amplifier Q3 operational amplifier that model can be used to be TLV2461.Second resistance R2 and the 3rd resistance R3 forms resistance pressure-dividing network, gathers the instant voltage of the output of rectifier bridge 10.The preset voltage value that the more instant voltage of second operational amplifier Q3 and reference voltage source 511 export, if instant voltage is higher than preset voltage value, second operational amplifier Q3 exports high level, if instant voltage is lower than preset voltage value, and the second operational amplifier Q3 output low level.
Below in conjunction with Fig. 4 to Fig. 6, the operation principle of the LED drive chip that the present embodiment provides is described further:
When the second operational amplifier Q3 exports high level, flip-flop number 53a starts working, and counts the clock signal that signal source of clock 52a exports.The numerical value counted to get is by being input in the middle of D/A converter module 42 after inverter 41, D/A converter module 42 exports corresponding voltage according to the numerical value of input.Due to the existence of inverter 41, the output numerical value of counter 53a is larger, and the output voltage of D/A converter module 42 is less.
In a commutation cycle, because counter 53a counts higher than carrying out in the time of preset voltage value at the output voltage of rectifier bridge, so the output voltage height direct proportionality of the size of count value and current commutation cycle, namely output voltage is higher, and the numerical value that counter 53a counts to get is larger.Control module 20 regulates LED operating current according to count value, if output voltage height, electric current is turned down, if output voltage is low, electric current is tuned up, and so can realize maintaining power output substantially constant when output voltage there are differences or float.
As shown in Figure 6, curve Vac1 and curve Vac2 is the waveforms of two different output voltages a commutation cycle, and straight line V1 is preset voltage value.Visible, different output voltages, its magnitude of voltage is different higher than the time length of V1.If T is clock signal period, N1 and N2 is respectively the different numerical value that counter 53a counts to get curve Vac1 and curve Vac2, t1 and t2 be respectively curve Vac1 and curve Vac2 magnitude of voltage higher than the time span of V1, namely have:
t1＝N1×T
t2＝N2×T
Curve Vac1 and the curve Vac2 magnitude of voltage time span higher than V1 can be drawn thus.According to the size of N1 and N2, control module 20 is with regard to adjustable LED lamp group 30 operating current size.Because output voltage is higher, the ON time of LED group 30 is longer, if keep the operating current of LED group 30 constant, and situation about increasing occurring the power output of LED group 30 to increase along with output voltage.
So the power output of LED group 30 will be kept constant, output voltage is higher, and LED operating current should be made less; Output voltage is lower, and LED group 30 operating current should be made larger.Because control module 20 includes adjustable current source, according to negative-feedback principle, the voltage of comparator 53b two inputs can be tending towards equal, therefore, when output voltage increases, the numerical value that counter 53a exports is larger, and the output voltage of D/A converter module 42 is less, namely the voltage on the first resistance R1 is also less, thus reduces the electric current flow through in LED group 30.On the contrary, the operating current flow through in LED group 30 also can be caused when output voltage reduces to increase.
embodiment 3
Fig. 7 show the present embodiment the modular structure of LED drive chip is provided, for convenience of explanation, illustrate only part related to the present embodiment, details are as follows:
The embodiment of the present embodiment is set up on the basis of a upper embodiment; The detection module 50 that structure is different is adopted, to detect the voltage max of each commutation cycle unlike, the present embodiment with a upper embodiment.
In the present embodiment, detection module 50 can comprise:
Analog-to-digital conversion module 51b, memory module 52b and comparator 53b;
The input of analog-to-digital conversion module 51b is the input of detection module 50, the first input end of comparator 53b and the input of memory module 52b are connected to the output of analog-to-digital conversion module 51b altogether, the output of comparator 53b connects the Enable Pin of memory module 52b, and the output of memory module 52b and second input of comparator 53b connect the output forming detection module 50 altogether;
Analog-to-digital conversion module 51b exports instant magnitude of voltage according to the output voltage of rectifier bridge 10, comparator 53b compares the voltage reference value in instant magnitude of voltage and memory module 52b, and higher than controlling memory module 52b during voltage reference value, voltage reference value is updated to instant magnitude of voltage at instant magnitude of voltage, memory module 52b using upgrade after voltage reference value export signal output module 40 to as maximum voltage value, signal output module 40 according to maximum voltage value output current conditioning signal to control module 20.
In the present embodiment, these modules above can be integrated in driving chip, also can build with discrete device.When using discrete device to build, analog-to-digital conversion module 51b can adopt model to be the modulus conversion chip of ADC0808 or ADC0809 or the modulus conversion chip of other models; Memory module 52b can adopt model to be eight two-way displacement/memory registers of 54LS299 or 74LS299, or the memory register of other serial model No.s; Comparator 53b can adopt model to be the digital comparator 53b of 74LS682 or 74LS684.When by above-mentioned module integration in chip time, corresponding can adopt the structure identical with said chip, not repeat them here.
In the present embodiment, control module 20 regulates operating current, the operating current of LED group 30 and the inversely proportional relation of maximum voltage value of LED group 30 according to current regulating signal
Concrete, maximum voltage value is less, and current regulating signal is larger, and the operating current of LED group 30 is also larger; Maximum voltage value is larger, and current regulating signal is less, and the operating current of LED group 30 is also larger.
Below in conjunction with Fig. 7, the operation principle of the LED drive chip that the present embodiment provides is described further:
In the present embodiment, utilize analog to digital converter module directly output voltage to be converted to numerical value, comparator 53b compares the numerical values recited that the output numerical value of analog-to-digital conversion module 51b and memory module 52b store.When analog-to-digital conversion module 51b output numerical value is greater than the numerical value of memory module 52b storage, comparator 53b output enable signal makes memory module 52b store the output numerical value of current analog-to-digital conversion module 51b.So, memory module 52b final numerical value stored within the current commutation cycle is the maximum voltage value that analog-to-digital conversion module 51b exports, i.e. the maximum of output voltage.
In the next commutation cycle, the numerical value stored according to memory module 52b is regulated the operating current size of LED group 30 by control module 20, and numerical value is greatly then turned electric current down, and numerical value is little, and electric current is tuned up.Further, memory module 52b synchronously resets, so that the next commutation cycle stores new numerical value.
The firm power principle of the present embodiment is identical with a upper embodiment, and difference is the mode recording output voltage, therefore repeats no more its concrete firm power principle.
Another object of the present utility model is also to provide a kind of LED drive circuit, comprises rectifier bridge 10, also comprises the LED drive chip that above-mentioned any embodiment provides.
Another object of the present utility model is also to provide a kind of LED lamp, comprises housing, also comprises above-mentioned LED drive circuit.
In the present embodiment, each commutation cycle that can obtain output voltage due to this LED drive chip is higher than time of preset voltage value or maximum voltage value, it has higher accuracy relative to traditional resistance pressure-dividing network detection method, make control module 20 accurately can judge the amplitude of Current adjustment, restrained effectively because the fluctuate pressure that causes of ac commercial power voltage is dodged, ensure that LED light stable output.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all do within spirit of the present utility model and principle any amendment, equivalent to replace and improvement etc., all should be included within protection range of the present utility model.
Claims (8)
1. a LED drive chip, is connected with rectifier bridge and LED group, and comprises control module; Described rectifier bridge exports described LED group to after carrying out rectification process to alternating current, and the operating current of current regulating signal to described LED group that described control module receives according to its controlled end regulates; It is characterized in that:
Described LED drive circuit also comprises detection module and signal output module;
Input and the output of described detection module are connected the output of described rectifier bridge and the input of described signal output module respectively, and the output of described signal output module connects the controlled end of described control module; Described detection module exports maximum voltage value according to the output voltage of described rectifier bridge, or count higher than during preset voltage value at output voltage, and count results is exported after counting terminates, described signal output module is according to maximum voltage value or count results output current conditioning signal extremely described control module.
2. LED drive chip as claimed in claim 1, it is characterized in that, described detection module comprises signal source of clock, counter and voltage comparison module;
The input of described voltage comparison module is the input of described detection module, Enable Pin and the input of described counter are connected the output of described voltage comparison module and the output of described signal source of clock respectively, and the output of described counter is the output of described detection module.
3. LED drive chip as claimed in claim 2, it is characterized in that, voltage comparison module comprises:
Second resistance, the 3rd resistance, the second operational amplifier and reference voltage source;
The first end of described second resistance is the input of described voltage comparison module, second end of described second resistance and the first end of described 3rd resistance are connected to the first input end of described second operational amplifier altogether, second end ground connection of described 3rd resistance, the output of described reference voltage source connects the second input of described second operational amplifier, and the output of described second operational amplifier is the output of described voltage comparison module.
4. LED drive chip as claimed in claim 1, it is characterized in that, described signal output module comprises inverter and D/A converter module;
The input of described inverter is the input of described signal output module, and the output of described inverter connects the input of described D/A converter module, and the output of described D/A converter module is the output of described signal output module.
5. LED drive chip as claimed in claim 1, it is characterized in that, described control module comprises adjustable current source, and the controlled end of described adjustable current source and input are controlled end and the input of control module;
Described adjustable current source comprises:
First resistance, NMOS tube and the first operational amplifier;
The first input end of described first operational amplifier is the controlled end of described adjustable current source, the output of described first operational amplifier connects the grid of described NMOS tube, second input of described first operational amplifier and the first end of described first resistance are connected to the source electrode of described NMOS tube altogether, the drain electrode of described NMOS tube is the input of described adjustable current source, and described second end of the first resistance and the substrate of described NMOS tube are connected to ground altogether.
6. LED drive chip as claimed in claim 1, it is characterized in that, described detection module comprises:
Analog-to-digital conversion module, memory module and comparator;
The input of described analog-to-digital conversion module is the input of described detection module, the first input end of described comparator and the input of described memory module are connected to the output of described analog-to-digital conversion module altogether, the output of described comparator connects the Enable Pin of described memory module, and the output of described memory module and the second input of described comparator connect the output forming described detection module altogether.
7. a LED drive circuit, comprises rectifier bridge, it is characterized in that, described LED drive circuit also comprises the LED drive chip as described in any one of claim 1 to 6.
8. a LED lamp, comprises housing, it is characterized in that, described LED drives light fixture also to comprise LED drive circuit as claimed in claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420197392.0U CN204046857U (en) | 2014-04-22 | 2014-04-22 | A kind of LED drive chip, LED drive circuit and LED lamp |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420197392.0U CN204046857U (en) | 2014-04-22 | 2014-04-22 | A kind of LED drive chip, LED drive circuit and LED lamp |
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| CN204046857U true CN204046857U (en) | 2014-12-24 |
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| CN201420197392.0U Withdrawn - After Issue CN204046857U (en) | 2014-04-22 | 2014-04-22 | A kind of LED drive chip, LED drive circuit and LED lamp |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103957630A (en) * | 2014-04-22 | 2014-07-30 | 深圳市晟碟半导体有限公司 | LED driving chip, LED driving circuit and LED lamp |
| CN104809992A (en) * | 2015-04-03 | 2015-07-29 | 深圳市金立通信设备有限公司 | Device for determining reference voltage of display screen |
-
2014
- 2014-04-22 CN CN201420197392.0U patent/CN204046857U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103957630A (en) * | 2014-04-22 | 2014-07-30 | 深圳市晟碟半导体有限公司 | LED driving chip, LED driving circuit and LED lamp |
| CN103957630B (en) * | 2014-04-22 | 2016-09-28 | 深圳市晟碟半导体有限公司 | A kind of LED drive chip, LED drive circuit and LED lamp |
| CN104809992A (en) * | 2015-04-03 | 2015-07-29 | 深圳市金立通信设备有限公司 | Device for determining reference voltage of display screen |
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