CN204906821U - Automatic linear constant current drive device and LED lamps and lanterns of balanced lamp cross luma degree - Google Patents
Automatic linear constant current drive device and LED lamps and lanterns of balanced lamp cross luma degree Download PDFInfo
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- CN204906821U CN204906821U CN201520685402.XU CN201520685402U CN204906821U CN 204906821 U CN204906821 U CN 204906821U CN 201520685402 U CN201520685402 U CN 201520685402U CN 204906821 U CN204906821 U CN 204906821U
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Abstract
The utility model discloses an automatic linear constant current drive device and LED lamps and lanterns of balanced lamp cross luma degree. Drive arrangement passes through intensity balancing control module, in a commutating period, lights order, the duration who at every turn lights and lights the number of times through what a N LED lamp that switch module control corresponds was gone here and there, makes a N total time that LED lamp cluster was lighted in a commutating period the same. Because intensity balancing control module has guaranteed that N is the same a total time that LED lamp cluster was lighted in a commutating period, so the power of every LED lamp cluster in a commutating period also is the same, certainly, the luminance and the life of each LED lamp cluster are just also the same, have realized the purpose of automatic equalization LED lamp cross luma degree. And each LED lamp cluster has just kept intensity balancing in a commutating period, very big improvement the lighting quality.
Description
Technical field
The utility model relates to field of LED illumination, particularly a kind of linear constant current drive unit of automatic equalization lamp cross luma degree and LED lamp.
Background technology
As shown in Figure 1, be the structured flowchart of conventional linear constant current driving system.The below of LED string 1 ~ 4 connects a constant-current source respectively to ground.Raise and decline process at voltage, the illuminating state of LED string 1 ~ LED string 4 can change thereupon.As shown in Figure 2, for conventional linear constant current driving system oscillogram.As can be seen from Figure 2, LED string 1 ~ LED string 4 is sequential illumination, inside the cycle that each rectifier bridge exports, the lighting time of LED string 1 is the longest, the lighting time of LED string 2 ~ LED string 4 reduces successively, finally causes LED string 1 to reduce successively within a rectifier bridge output cycle to the brightness of LED string 4.Different according to the quantity of each LED string, each LED string luminance difference is different, and by the configuration of generally common LED1 ~ LED4 equal number lamp pearl, the luminance difference of LED1 and LED4 can reach 3:1.Meanwhile, due to the difference of each LED string average lighting time (power or brightness), the light decay of each LED string can be caused different, and LED1 light decay can be much faster than LED4, and the life-span of whole like this LED lamp can be limited to the light decay life-span of LED1.
Adopt the LED lamp of conventional linear constant current driving as bulb lamp, fluorescent tube etc., because the luminosity (being caused by above-mentioned lighting time difference) of LED lamp bead is inconsistent, when distance light fixture is nearer (such as 0.5m ~ 0.6m), it is partially dark that human eye can find out some lamp pearl in light fixture very easily, and overall sensation light fixture exists hot spot.Especially for this application of fluorescent tube, LED lamp bead serial be arranged on fluorescent tube, the inconsistent hot spot caused of LED lamp bead brightness clearly, can have a strong impact on the visual effect of light fixture, even to the impression that client causes light fixture to damage.
Thus prior art need to improve.
Utility model content
In view of above-mentioned the deficiencies in the prior art part, the purpose of this utility model is the linear constant current drive unit and the LED lamp that provide a kind of automatic equalization lamp cross luma degree, the total time that each LED string is lighted within a commutation cycle is all identical with power, the balanced brightness of each LED string, improves the useful life of LED lamp.
In order to achieve the above object, the utility model takes following technical scheme:
A linear constant current drive unit for automatic equalization lamp cross luma degree, comprises
Alternating current for inputting outside carries out rectification and the rectification module of powering to LED string group;
LED string group, comprises N number of LED string, is connected in series between N number of LED string;
N number of for controlling the switch module that LED string is lighted and extinguished, a switch module correspondence controls a LED string;
For controlling electric current in LED string, making the tail current source module of the constant current hold of LED string;
Voltage in detecting real-time tail current source module, when the voltage in tail current source module is higher than first threshold voltage, output overvoltage signal is to luminance proportion control module; When the voltage in tail current source module is lower than Second Threshold voltage, export the detection module of under-voltage signal to luminance proportion control module;
For within a commutation cycle, control lighting order, the duration of at every turn lighting and lighting number of times, the luminance proportion control module that the total time that N number of LED string is lighted within a commutation cycle is identical of corresponding LED string by N number of switch module;
Wherein, N be more than or equal to 2 positive integer;
The input of described rectification module by LED string group connection detection module and the input of tail current source module, the output of described detection module connects the input of luminance proportion control module, the output head grounding of described tail current source module; N number of output of described luminance proportion control module connects N number of LED string by N number of switch module.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described luminance proportion control module comprises:
For within a commutation cycle, after receiving first overvoltage signal, light a LED string in turn by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have a LED string to be in illuminating state all the time; After receiving second overvoltage signal, light a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have two LED strings to be in illuminating state all the time; After receiving N-1 overvoltage signal, light a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-1 LED string to be in illuminating state all the time; After receiving N number of overvoltage signal, light by switch module the LED string that last is in OFF state, N number of LED string is all lighted; After receiving first under-voltage signal, extinguish a LED string by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-1 LED string to be in illuminating state all the time; After receiving second under-voltage signal, extinguish a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-2 LED string to be in illuminating state all the time; After receiving N-1 overvoltage signal, extinguish a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have a LED string to be in illuminating state all the time; After receiving N number of under-voltage signal, extinguish by switch module the LED string that last is in illuminating state, N number of LED string is all extinguished; Make within a commutation cycle, the luminance proportion control unit that each LED string total time of lighting is identical.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described linear constant current drive unit also comprises that N number of voltage for being exported by detection module carries out level shift, voltage shifts that detection module is exported is to the level shift module of the voltage domain of switch module, a corresponding switch module of level shift module, described luminance proportion control module is by the N number of switch module of N number of level shift model calling.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described switch module controls lighting and extinguishing of corresponding LED string by the break-make of self; The input of described switch module connects the positive pole of corresponding LED string, and the output of described switch module connects the negative pole of corresponding LED string, and the control end of described switch module connects the output of corresponding level shift module.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described switch module comprises the first resistance and the first metal-oxide-semiconductor; The source electrode of described first metal-oxide-semiconductor be switch module input, connect the positive pole of corresponding LED string, also connected the grid of the first metal-oxide-semiconductor by the first resistance, the drain electrode of described first metal-oxide-semiconductor be switch module output, connect the negative pole of corresponding LED string, the grid of described first metal-oxide-semiconductor is the control end of switch module, the output connecting corresponding level shift module.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described level shift module comprises the second resistance and the second metal-oxide-semiconductor, the grid of described second metal-oxide-semiconductor be level shift module input, connect output corresponding to luminance proportion control module, the drain electrode of described second metal-oxide-semiconductor is the control end of the output of level shift module, the switch module of connection correspondence, and the source electrode of described second metal-oxide-semiconductor is by the second grounding through resistance.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described tail current source module comprises the first power supply, operational amplifier, the 3rd resistance and the 3rd metal-oxide-semiconductor; The drain electrode of described 3rd metal-oxide-semiconductor is the input of tail current source module, the negative pole of connection LED string group, the inverting input of the source electrode concatenation operation amplifier of described 3rd metal-oxide-semiconductor, also by the 3rd grounding through resistance, the negative pole of described first power supply is the output of tail current source module, the minus earth of described first power supply, the normal phase input end of the positive pole concatenation operation amplifier of described first power supply, the output of described operational amplifier connects the grid of the 3rd metal-oxide-semiconductor.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described detection module comprises the 4th resistance, the 5th resistance, the 6th resistance, the first comparator, the second comparator and second source; One end of described 4th resistance be detection module input, connect the input of tail current source module and the negative pole of LED string group, the other end of described 4th resistance connects the normal phase input end of the first comparator, also connects one end of the 6th resistance and the normal phase input end of the second comparator by the 5th resistance; Described 6th grounding through resistance, the positive pole of described second source connects the inverting input of the first comparator and the inverting input of the second comparator, the minus earth of described second source; The output of described first comparator and the output of the second comparator be detection module output, be connected the input of luminance proportion control module.
In the linear constant current drive unit of described automatic equalization lamp cross luma degree, described N is 4.
A kind of LED lamp, comprises the linear constant current drive unit of automatic equalization lamp cross luma degree as above.
Compared to prior art, the linear constant current drive unit of the automatic equalization lamp cross luma degree that the utility model provides and LED lamp, by luminance proportion control module, within a commutation cycle, control lighting order, the duration of at every turn lighting and lighting number of times of corresponding LED string by N number of switch module, the total time that N number of LED string is lighted within a commutation cycle is identical.Because luminance proportion control module ensure that the total time that N number of LED string is lighted within a commutation cycle is all identical, therefore the power of each LED string within a commutation cycle is also identical, certainly, the brightness of each LED string is also just identical with useful life, achieves the object of automatic equalization LED cross luma degree.And within a commutation cycle, each LED string just maintains luminance proportion, greatly improves lighting quality.
Accompanying drawing explanation
Fig. 1 is the structured flowchart of existing linear constant current drive system.
Fig. 2 be existing linear constant current drive system oscillogram.
The structured flowchart of the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 3 provides for the utility model.
The oscillogram of the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 4 provides for the utility model.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 5 provides for the utility model, the circuit diagram of switch module.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 6 provides for the utility model, the circuit diagram of level shift module.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 7 provides for the utility model, the circuit diagram of tail current source module.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 8 provides for the utility model, the circuit diagram of detection module.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that Fig. 9 provides for the utility model, the structured flowchart of another embodiment.
Embodiment
The utility model provides a kind of linear constant current drive unit and LED lamp of automatic equalization lamp cross luma degree.For making the purpose of this utility model, technical scheme and effect clearly, clearly, referring to the accompanying drawing embodiment that develops simultaneously, the utility model is further described.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.
The linear constant current drive unit of the automatic equalization lamp cross luma degree that the utility model provides, wherein each module can adopt multiple connected mode, as shown in Figure 3, is a preferred embodiment of the present utility model.
The linear constant current drive unit of the automatic equalization lamp cross luma degree that the utility model provides, comprise rectification module 10, LED string group 20, tail current source module 30, detection module 40, luminance proportion control module 50 and N number of for controlling the switch module 70 that LED string is lighted and extinguished, wherein, a switch module correspondence controls a LED string.
Described rectification module 10, the alternating current for inputting outside carries out rectification and powers to LED string group 20; Preferably, described rectification module 10 is rectifier bridge.
Described LED string group 20, comprises N number of LED string, is connected in series between N number of LED string.
Described tail current source module 30, for controlling electric current in LED string, making the constant current hold of LED string.
Described detection module 40, for the voltage of the detecting real-time module in parallel with detection module 40, when the voltage in the module in parallel with detection module 40 is higher than first threshold voltage Vth1, output overvoltage signal is to luminance proportion control module 50; When voltage in the module in parallel with detection module 40 is lower than Second Threshold voltage Vth2, export under-voltage signal to luminance proportion control module 50.In the present embodiment, the module in parallel with detection module 40 is tail current source module 30.Therefore described detection module 40 is specifically for the voltage in detecting real-time tail current source module 30, and when the voltage in tail current source module 30 is higher than first threshold voltage Vth1, output overvoltage signal is to luminance proportion control module 50; When the voltage in tail current source module 30 is lower than Second Threshold voltage Vth2, export under-voltage signal to luminance proportion control module 50.First threshold voltage Vth1 is arranged so that the voltage in tail current source module 30 can not exceed first threshold voltage Vth1, serves the effect of overvoltage protection; Second Threshold voltage Vth2 is arranged so that the voltage in tail current source module 30 is not less than Second Threshold voltage Vth2, serves the effect of low-voltage variation; It can thus be appreciated that the utility model can by the voltage stabilization of tail current source module 30 between first threshold voltage Vth1 and Second Threshold voltage Vth2.
Described luminance proportion control module 50, for within a commutation cycle, control lighting order, the duration of at every turn lighting and lighting number of times of corresponding LED string by N number of switch module 70, the total time that N number of LED string is lighted within a commutation cycle is identical.Certainly, the total time that each LED string described in the utility model is lighted within a commutation cycle is identical, here identical and nisi identical, only need the total time of lighting close to, user's naked eyes can be made equally to seem that each LED luminance is identical.
Further, described luminance proportion control module 50 comprises luminance proportion control unit, described luminance proportion control unit, for within a commutation cycle, after receiving first overvoltage signal, light a LED string in turn by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have a LED string to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving second overvoltage signal, a LED string is lighted again by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have two LED strings to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving N-1 overvoltage signal, a LED string is lighted again by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have N-1 LED string to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving N number of overvoltage signal, light by switch module 70 the LED string that last is in OFF state, N number of LED string is all lighted; After receiving first under-voltage signal, a LED string is extinguished by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have N-1 LED string to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving second under-voltage signal, a LED string is extinguished again by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have N-2 LED string to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving N-1 overvoltage signal, a LED string is extinguished again by switch module 70, make N number of LED string with scheduled time Ts for interval is luminous in turn, and guarantee to only have a LED string to be in illuminating state all the time, make N number of LED string in N number of scheduled time Ts to light total time identical; After receiving N number of under-voltage signal, extinguish by switch module 70 the LED string that last is in illuminating state, N number of LED string is all extinguished; Make within a commutation cycle, the total time that each LED string is lighted is identical, concrete, within a commutation cycle, N number of LED string in N number of scheduled time Ts to light total time identical.Because luminance proportion control unit ensure that the total time that N number of LED string is lighted in N number of scheduled time Ts is all identical, therefore the power of each LED string in N number of scheduled time Ts is also identical, certainly, the brightness of each LED string is also just identical with useful life, achieve the object of automatic equalization LED cross luma degree, improve the useful life of light fixture.
Wherein, N be more than or equal to 2 positive integer, the best value of described N is 3 and 4.
Described scheduled time Ts is less than the time interval between time interval between each overvoltage signal and each under-voltage signal.Preferably, mean value ÷ N ÷ (n+1) in the time interval between each overvoltage signal of described scheduled time Ts=and the time interval between each under-voltage signal, wherein, n be more than or equal to 0 integer, preferably can guarantee that the total time that each LED string is lighted is identical like this.Described scheduled time Ts is less, and each LED string is alternately lighted and extinguished more frequent, and the homogeneity of each LED cross luma degree is better.
The input of described rectification module 10 by LED string group 20 connection detection module 40 and the input of tail current source module 30, the output of described detection module 40 connects the input of luminance proportion control module 50, the output head grounding of described tail current source module 30; N number of output of described luminance proportion control module 50 connects N number of LED string by N number of switch module 70.
Please continue to refer to Fig. 3, in the linear constant current drive unit of the automatic equalization lamp cross luma degree that the utility model provides, described N is preferably 4, namely, described LED string group 20 comprises four LED strings, be respectively the first LED string 210, second LED string 220, the 3rd LED string 230 and the 4th LED string 240, the lamp pearl quantity in each LED string can identical also can be different, determine as the case may be.
See also Fig. 4, Vac is the waveform of rectifier bridge output voltage, and VLED1, VLED2, VLED3 and VLED4 are respectively the voltage waveform of the first LED string 210, second LED string 220, the 3rd LED string 230 and the 4th LED string 240.T1 represents the time period between first overvoltage signal to second overvoltage signal, T2 represents the time period between second overvoltage signal to the 3rd overvoltage signal, T3 represents the time period between the 3rd overvoltage signal to the 4th overvoltage signal, T4 represents that 4 LED strings all light the lasting time period, T5 represents the time period between first under-voltage signal to second under-voltage signal, T6 represents the time period between second under-voltage signal to the 3rd under-voltage signal, and T7 represents the time period between the 3rd under-voltage signal to the 4th under-voltage signal.
In the linear constant current drive unit of the automatic equalization lamp cross luma degree that the utility model provides, described luminance proportion control module 50 has the mode of two kinds of balanced LED luminosity.
Wherein, mode one: before power supply, each LED string is all in OFF state.Commutation cycle is (when rectifier bridge starts to power) when starting, along with output voltage Vac progressively improves, voltage in tail current source module 30 increases, and detection module 40 detects voltage in tail current source module 30 higher than first threshold voltage Vth1, and output overvoltage signal is to luminance proportion control module 50.Luminance proportion control module 50 makes each LED string fluorescent lifetime in a commutation cycle T identical.Concrete, within the T1 time period, only light a LED string, and make 4 LED strings be in illuminating state in turn; When entering T2 time period, keeping the luminance of the existing LED string lighted constant, again lighting a LED string, under the condition only lighting two LED strings, making 4 LED strings be in illuminating state in turn; By that analogy, when extinguishing LED string (T5, T6, T7 time period), equally so, make four LED strings in 4 scheduled time Ts to light total time identical.
As shown in Figure 4, in T1 and the T7 time period, only light a LED string; In T2 and the T6 time period, light two LED strings; In T3 and the T5 time period, light three LED strings; In the T4 time period, light 4 LED strings.In T1 to T3, T5 to the T7 time period, every scheduled time Ts, do not changing the prerequisite of lightening LED lamp string quantity, alternately lightening LED lamp string 210,220,230 and 240.
For T1, in first Ts, lightening LED lamp string 210; In second Ts, lightening LED lamp string 220, extinguishes LED string 210; In 3rd Ts, lightening LED lamp string 230, extinguishes LED string 220.
At T1 ~ T3, in T5 ~ T7 time period, optimum alternately some bright light string algorithm is as follows: in same T1 ~ T3 T5 ~ T7 time period, in adjacent two Ts time periods, only have the illuminating state of a LED string different, optimum realizes according to following sequence:
When being in T1 and T7 time period:
| Time | 4n Ts | 4n+1 Ts | 4n+2 Ts | 4n+3 Ts |
| Be in the LED string of illuminating state | LED string 210 | LED string 220 | LED string 230 | LED string 240 |
When being in T2 and T6 time period:
| Time | 4n Ts | 4n+1 Ts | 4n+2 Ts | 4n+3 Ts |
| Be in the LED string of illuminating state | LED string 210,220 | LED string 220,230 | LED string 230,240 | LED string 240,210 |
When being in T3 and T5 time period:
| Time | 4n Ts | 4n+1 Ts | 4n+2 Ts | 4n+3 Ts |
| Be in the LED string of illuminating state | LED string 210,220,230 | LED string 220,230,240 | LED string 230,240,210 | LED string 240,210,220 |
In the process that T1 to T4 adjacent two time periods switch, optimum lights as far as possible few lamp string, the lighting lamp state of the namely optimum Ts of the kth from T1 is switched to a kth Ts lighting lamp state of T2, a kth Ts lighting lamp state of T3 is switched to from the lighting lamp state of a kth Ts of T2, be switched to a kth Ts lighting lamp state of T4 from the lighting lamp state of a kth Ts of T3, wherein k be to be greater than etc. 0 integer.
In the process that T4 to T7 adjacent two time periods switch, the lamp string that optimum extinguishing is as far as possible few, the lighting lamp state of the namely optimum Ts of the kth from T2 is switched to a kth Ts lighting lamp state of T1, a kth Ts lighting lamp state of T2 is switched to from the lighting lamp state of a kth Ts of T3, be switched to a kth Ts lighting lamp state of T3 from the lighting lamp state of a kth Ts of T4, wherein k be to be greater than etc. 0 integer.
In the process that T4 to T7 adjacent two time periods switch, the lamp string that the extinguishing of suboptimum is as far as possible few, namely the lighting lamp state of kth+1 Ts from T2 of suboptimum is switched to a kth Ts lighting lamp state of T1, a kth Ts lighting lamp state of T2 is switched to from the lighting lamp state of kth+1 Ts of T3, be switched to a kth Ts lighting lamp state of T3 from the lighting lamp state of kth+1 Ts of T4, wherein k be to be greater than etc. 0 integer.
Mode two: within T1 to T3, T5 to the T7 time period, alternately the control algolithm of lightening LED lamp string is as follows: in same T1 to T3 T5 to the T7 time period, in each Ts time period, selects a state to carry out lightening LED lamp string from respective illuminating state.Optimum for select to make LED string LED210,220,230,240 times of lighting as far as possible consistent state.
The illuminating state of LED string in the T1 time period:
| State 1 | State 2 | State 3 | State 4 |
| LED string 210 | LED string 220 | LED string 230 | LED string 240 |
The illuminating state of LED string in T2 and the T6 time period:
| State 1 | State 2 | State 3 | State 4 | State 5 | State 6 |
| LED string 210,220 | LED string 220,230 | LED string 230,240 | LED string 240,210 | LED string 230,210 | LED string 240,220 |
The illuminating state of LED string in T3 and the T5 time period:
| State 1 | State 2 | State 3 | State 4 |
| LED string 210,220,230 | LED string 220,230,240 | LED string 230,240,210 | LED string 240,210,220 |
In the process that T1 to T4 and T4 to T7 adjacent two time periods switch, from the illuminating state of next time period, select one carry out lightening LED lamp string, optimum selection make lamp string LED210,220,230 with 240 lighting time keep as far as possible consistent state.
Please continue to refer to Fig. 3, in the linear constant current drive unit of described automatic equalization lamp cross luma degree, also comprise that N number of voltage for being exported by detection module 40 carries out level shift, voltage shifts that detection module 40 is exported is to the level shift module 60 of the voltage domain of switch module 70, a corresponding switch module 70 of level shift module 60, described luminance proportion control module 50 connects N number of switch module 70 by N number of level shift module 60.Because luminance proportion control module 50 can carry out control switch module 70 according to the output of detection module 40, and the negative sense that the ground reference of detection module 40 and tail current source module 30 is rectification module 10 exports, its ground reference is different from the ground reference of switch module 70, so need the output of detection module 40 to carry out level shift.By described level shift module 60, make the control of luminance proportion control module 50 pairs of switch modules 70 more accurate, further increase the equilibrium degree of LED string luminescence.
Further, described switch module 70 controls the extinguishing of corresponding LED string by the break-make of self and lights; The input of described switch module 70 connects the positive pole of corresponding LED string, and the output of described switch module 70 connects the negative pole of corresponding LED string, and the control end of described switch module connects the output of corresponding level shift module 60.When switch module 70 is in off state, LED string is in illuminating state; When switch module 70 is in the state of unlatching, LED string is in the state that (extinguishing) extinguishes.Adopt the mode of path and short circuit to LED string light and extinguishing controls, simple and practical, the circuit without the need to complexity can complete.
Refer to Fig. 5, described switch module 70 comprises the first resistance R1 and the first metal-oxide-semiconductor Q1; The source electrode of described first metal-oxide-semiconductor Q1 be switch module 70 input, connect the positive pole of corresponding LED string, also connected the grid of the first metal-oxide-semiconductor Q1 by the first resistance R1, the drain electrode of described first metal-oxide-semiconductor Q1 be switch module 70 output, connect the negative pole of corresponding LED string, the grid of described first metal-oxide-semiconductor Q1 is the control end of switch module 70, the output connecting corresponding level shift module 60.
Refer to Fig. 6, described level shift module 60 comprises the second resistance R2 and the second metal-oxide-semiconductor Q2, the grid of described second metal-oxide-semiconductor Q2 is the input of level shift module 60, the output of connection luminance proportion control module 50 correspondence, the drain electrode of described second metal-oxide-semiconductor Q2 is the control end of the output of level shift module 60, the switch module 70 of connection correspondence, and the source electrode of described second metal-oxide-semiconductor Q2 is by the second resistance R2 ground connection.
Refer to Fig. 7, described tail current source module 30 comprises the first power supply V1, operational amplifier U1, the 3rd resistance R3 and the 3rd metal-oxide-semiconductor Q3; The drain electrode of described 3rd metal-oxide-semiconductor Q3 is the input of tail current source module 30, the negative pole of connection LED string group 20, the inverting input of the source electrode concatenation operation amplifier U1 of described 3rd metal-oxide-semiconductor Q3, also by the 3rd resistance R3 ground connection, the negative pole of described first power supply V1 is the output of tail current source module 30, the minus earth of described first power supply V1, the normal phase input end of the positive pole concatenation operation amplifier U1 of described first power supply V1, the output of described operational amplifier U1 connects the grid of the 3rd metal-oxide-semiconductor Q3.
Refer to Fig. 8, described detection module 40 comprises the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the first comparator U2, the second comparator U3 and second source V2; One end of described 4th resistance R4 be detection module 40 input, connect the input of tail current source module 30 and the negative pole of LED string group 20, the other end of described 4th resistance R4 connects the normal phase input end of the first comparator U2, also connects one end of the 6th resistance R6 and the normal phase input end of the second comparator U2 by the 5th resistance R5; Described 6th resistance R6 ground connection, the positive pole of described second source V2 connects the inverting input of the first comparator U2 and the inverting input of the second comparator U3, the minus earth of described second source V2; Output and the output of the second comparator U3 of described first comparator U2 be detection module 40 output, be connected the input of luminance proportion control module 50.That is, when the first comparator U2 output low level, this low level is under-voltage signal, and when the second comparator U3 exports high level, this high level is overvoltage signal.Concrete, the voltage that described second source V2 exports is 1.2V.The ratio of described 4th resistance R4, the 5th resistance R5 and the 6th resistance R6 resistance is: 25:4:1.Setting like this, be the voltage inputted in order to ensure the input of detection module 40 when being less than 6V, detection module 40 exports under-voltage signal, when the voltage of the input input of detection module 40 is greater than 36V, detection module 40 output overvoltage signal.In the present embodiment, the resistance of described 4th resistance R4, the 5th resistance R5 and the 6th resistance R6 is respectively 1M Europe, 160K Europe and 40K Europe.
In another embodiment of the present utility model, the structured flowchart of the linear constant current drive unit of described automatic equalization lamp cross luma degree as shown in Figure 9, in parallel with detection module is LED string group 20 and tail current source module 30, therefore, the output voltage of what described detection module 40 detected is rectifier bridge 10, namely LED string group 20 and tail current source module 30 voltage sum, namely, the output voltage of described detection module 40 detecting real-time rectifier bridge 10, when the output voltage of rectifier bridge is between first threshold and Second Threshold (when the output voltage of rectifier bridge is higher than first threshold), output status signal 1 is to luminance proportion control module, when the output voltage of rectifier bridge is between Second Threshold and the 3rd threshold value (when the output voltage of rectifier bridge is higher than Second Threshold), output status signal 2 is to luminance proportion control module, when the output voltage of rectifier bridge is between the 3rd threshold value and the 4th threshold value (when the output voltage of rectifier bridge is higher than the 3rd threshold value), output status signal 3 is to luminance proportion control module, when the output voltage of rectifier bridge is higher than the 4th threshold value, output status signal 4 is to luminance proportion control module, when the output voltage of rectifier bridge is higher than N threshold value, output status signal N is to luminance proportion control module, wherein, first threshold < Second Threshold < the 3rd threshold value < the 4th threshold value < ... < N threshold value.
The size of described threshold value is: the VF voltage of LED string group 20 and the minimum sum of tail current source module 30.That is, when the commutation cycle just starts, LED string group 20 neither one LED string is lit, and first threshold is the minimum of tail current source module 30.After the output voltage of rectifier bridge exceedes first threshold, luminance proportion control module 50 lights a LED string, and first threshold is the VF voltage (the VF voltage of the LED string lighted) of LED string group 20 and the minimum sum of tail current source module 30.……。The output voltage of rectifier bridge is more than after N-1 threshold value, luminance proportion control module 50 lights N-1 LED string, now total N-1 LED string is lit, and N-1 threshold value is the VF voltage (the VF voltage of N-1 the LED string lighted) of LED string group 20 and the minimum sum of tail current source module 30.The output voltage of rectifier bridge is more than after N number of threshold value, and all LED strings are lit.The like, when rectifier bridge output voltage declines, the flow process of closing LED string is also like this.Due to other operation principles in embodiment illustrated in fig. 9 identical with a upper embodiment (control of luminance proportion control module 50 makes overvoltage signal and under-voltage signal correspondence into each status signal), do not repeat them here.
Based on the linear constant current drive unit of the automatic equalization lamp cross luma degree that a upper embodiment provides, the utility model also provides a kind of LED lamp, comprises the linear constant current drive unit of automatic equalization lamp cross luma degree as above.Because the operation principle of described LED lamp and feature elaborate in the embodiment shown in fig. 3, do not repeat them here.
Be understandable that; for those of ordinary skills; can be equal to according to the technical solution of the utility model and utility model design thereof and replace or change, and all these change or replace the protection range that all should belong to the claim appended by the utility model.
Claims (10)
1. a linear constant current drive unit for automatic equalization lamp cross luma degree, is characterized in that, comprise
Alternating current for inputting outside carries out rectification and the rectification module of powering to LED string group;
LED string group, comprises N number of LED string, is connected in series between N number of LED string;
N number of for controlling the switch module that LED string is lighted and extinguished, a switch module correspondence controls a LED string;
For controlling electric current in LED string, making the tail current source module of the constant current hold of LED string;
Voltage in detecting real-time tail current source module, when the voltage in tail current source module is higher than first threshold voltage, output overvoltage signal is to luminance proportion control module; When the voltage in tail current source module is lower than Second Threshold voltage, export the detection module of under-voltage signal to luminance proportion control module;
For within a commutation cycle, control lighting order, the duration of at every turn lighting and lighting number of times, the luminance proportion control module that the total time that N number of LED string is lighted within a commutation cycle is identical of corresponding LED string by N number of switch module;
Wherein, N be more than or equal to 2 positive integer;
The input of described rectification module by LED string group connection detection module and the input of tail current source module, the output of described detection module connects the input of luminance proportion control module, the output head grounding of described tail current source module; N number of output of described luminance proportion control module connects N number of LED string by N number of switch module.
2. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 1, it is characterized in that, described luminance proportion control module comprises:
For within a commutation cycle, after receiving first overvoltage signal, light a LED string in turn by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have a LED string to be in illuminating state all the time; After receiving second overvoltage signal, light a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have two LED strings to be in illuminating state all the time; After receiving N-1 overvoltage signal, light a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-1 LED string to be in illuminating state all the time; After receiving N number of overvoltage signal, light by switch module the LED string that last is in OFF state, N number of LED string is all lighted; After receiving first under-voltage signal, extinguish a LED string by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-1 LED string to be in illuminating state all the time; After receiving second under-voltage signal, extinguish a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have N-2 LED string to be in illuminating state all the time; After receiving N-1 overvoltage signal, extinguish a LED string again by switch module, make N number of LED string be that interval is luminous in turn with the scheduled time, and guarantee to only have a LED string to be in illuminating state all the time; After receiving N number of under-voltage signal, extinguish by switch module the LED string that last is in illuminating state, N number of LED string is all extinguished; Make within a commutation cycle, the luminance proportion control unit that each LED string total time of lighting is identical.
3. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 2, it is characterized in that, described linear constant current drive unit also comprises that N number of voltage for being exported by detection module carries out level shift, voltage shifts that detection module is exported is to the level shift module of the voltage domain of switch module, a corresponding switch module of level shift module, described luminance proportion control module is by the N number of switch module of N number of level shift model calling.
4. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 3, is characterized in that, described switch module controls lighting and extinguishing of corresponding LED string by the break-make of self; The input of described switch module connects the positive pole of corresponding LED string, and the output of described switch module connects the negative pole of corresponding LED string, and the control end of described switch module connects the output of corresponding level shift module.
5. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 4, it is characterized in that, described switch module comprises the first resistance and the first metal-oxide-semiconductor; The source electrode of described first metal-oxide-semiconductor be switch module input, connect the positive pole of corresponding LED string, also connected the grid of the first metal-oxide-semiconductor by the first resistance, the drain electrode of described first metal-oxide-semiconductor be switch module output, connect the negative pole of corresponding LED string, the grid of described first metal-oxide-semiconductor is the control end of switch module, the output connecting corresponding level shift module.
6. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 5, it is characterized in that, described level shift module comprises the second resistance and the second metal-oxide-semiconductor, the grid of described second metal-oxide-semiconductor be level shift module input, connect output corresponding to luminance proportion control module, the drain electrode of described second metal-oxide-semiconductor is the control end of the output of level shift module, the switch module of connection correspondence, and the source electrode of described second metal-oxide-semiconductor is by the second grounding through resistance.
7. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 6, is characterized in that, described tail current source module comprises the first power supply, operational amplifier, the 3rd resistance and the 3rd metal-oxide-semiconductor; The drain electrode of described 3rd metal-oxide-semiconductor is the input of tail current source module, the negative pole of connection LED string group, the inverting input of the source electrode concatenation operation amplifier of described 3rd metal-oxide-semiconductor, also by the 3rd grounding through resistance, the negative pole of described first power supply is the output of tail current source module, the minus earth of described first power supply, the normal phase input end of the positive pole concatenation operation amplifier of described first power supply, the output of described operational amplifier connects the grid of the 3rd metal-oxide-semiconductor.
8. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 7, is characterized in that, described detection module comprises the 4th resistance, the 5th resistance, the 6th resistance, the first comparator, the second comparator and second source; One end of described 4th resistance be detection module input, connect the input of tail current source module and the negative pole of LED string group, the other end of described 4th resistance connects the normal phase input end of the first comparator, also connects one end of the 6th resistance and the normal phase input end of the second comparator by the 5th resistance; Described 6th grounding through resistance, the positive pole of described second source connects the inverting input of the first comparator and the inverting input of the second comparator, the minus earth of described second source; The output of described first comparator and the output of the second comparator be detection module output, be connected the input of luminance proportion control module.
9. the linear constant current drive unit of automatic equalization lamp cross luma degree according to claim 8, it is characterized in that, described N is 4.
10. a LED lamp, is characterized in that, comprises the linear constant current drive unit of the automatic equalization lamp cross luma degree as described in claim 1-9 any one.
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| CN201520685402.XU CN204906821U (en) | 2015-09-07 | 2015-09-07 | Automatic linear constant current drive device and LED lamps and lanterns of balanced lamp cross luma degree |
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| CN201520685402.XU CN204906821U (en) | 2015-09-07 | 2015-09-07 | Automatic linear constant current drive device and LED lamps and lanterns of balanced lamp cross luma degree |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107949105A (en) * | 2017-11-21 | 2018-04-20 | 深圳市明微电子股份有限公司 | Constant current driver circuit for LED and lamps and lanterns |
| CN112923997A (en) * | 2021-03-26 | 2021-06-08 | 美钻能源科技(上海)有限公司 | Water depth display device and underwater walking stick |
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2015
- 2015-09-07 CN CN201520685402.XU patent/CN204906821U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107949105A (en) * | 2017-11-21 | 2018-04-20 | 深圳市明微电子股份有限公司 | Constant current driver circuit for LED and lamps and lanterns |
| CN112923997A (en) * | 2021-03-26 | 2021-06-08 | 美钻能源科技(上海)有限公司 | Water depth display device and underwater walking stick |
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