CN104219812A - Constant current sampling circuit and lamp thereof - Google Patents
Constant current sampling circuit and lamp thereof Download PDFInfo
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- CN104219812A CN104219812A CN201310209970.8A CN201310209970A CN104219812A CN 104219812 A CN104219812 A CN 104219812A CN 201310209970 A CN201310209970 A CN 201310209970A CN 104219812 A CN104219812 A CN 104219812A
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Abstract
This invention provides a constant current sampling circuit and a lamp thereof. The constant current sampling circuit includes: an operational amplifier circuit that is coupled between the negative electrode of a light-emitting diode and the chip feedback end of a constant current output chip. The operational amplifier circuit includes: an operational amplifier, a first resistor, a second resistor, a third resistor, a reverse prevention diode a first capacitor, and a fourth resistor. The non-inverting input end of the operational amplifier is coupled with the negative electrode of the light emitting diode, the inverted input end of the operational amplifier is coupled with the output end of the operational amplifier via the first resistor, the inverted input end of the operational amplifier is also coupled with one ends of the first resistor and the third resistor, the other end of the third resistor is grounded, the output end of the operational amplifier is coupled with one end of the second resistor, the other end of the second resistor is coupled with the positive electrode of the reverse protection diode, the negative electrode of the reverse protection diode is coupled with the other end of the first resistor and the chip feedback end of the current constant output chip. The negative electrode of the light-emitting diode is grounded via the fourth resistor.
Description
Technical field
The present invention relates to constant-current circuit field, particularly adopt constant current sample circuit and the light fixture thereof of discharge circuit.
Background technology
Along with a lot of LED lamp constant current output is all do current sampling with resistance at present, this makes inherently to produce certain power consumption on this resistance, if original lamp power is less, output voltage is lower, electric current is large, and the pressure drop occupying several volt that this resistance is constant, this conversion efficiency driven whole constant current is extremely low.
Fig. 1 illustrates a kind of LED lamp constant current output circuit figure of prior art.As shown in Figure 1, the positive pole of light-emitting diode 7 couples the power output end 91 of electric current constant current output chip 9, ground connection after negative pole series connection the 4th resistance 4.Pressure drop on 4th resistance 4 is directly coupled to chip feedback end.The pressure drop on the 4th resistance 4 is then needed to arrive the predeterminated voltage of chip feedback port, generally be about 2.5V, low for compliance voltage like this, that electric current is large circuit is totally unfavorable, because the pressure drop of about 2.5V can take very large power consumption, is that circuit efficiency greatly reduces.
In view of this, constant current sample circuit and light fixture thereof is inventor provided.
Summary of the invention
For defect of the prior art, the invention provides constant current sample circuit and light fixture thereof, overcome the difficulty of prior art, by increasing by an amplifying circuit between current sampling resistor and chip feedback end, solving the problem that power consumption is excessive, promoting circuit efficiency.
According to an aspect of the present invention, a kind of constant current sample circuit of light fixture is provided, described light fixture also comprises an electric current constant current output chip and at least one light-emitting diode, the power output end of described electric current constant current output chip is coupled to the positive pole of described light-emitting diode, and described constant current sample circuit comprises:
One discharge circuit, described discharge circuit is coupling between the negative pole of described light-emitting diode and the chip feedback end of described electric current constant current output chip, and described discharge circuit comprises:
One operational amplifier, one first resistance, one second resistance, one the 3rd resistance, one counnter attack diode and one first electric capacity, wherein, the in-phase input end of described operational amplifier is couple to the negative pole of light-emitting diode, the inverting input of described operational amplifier is couple to the output of operational amplifier by described first resistance, the inverting input of described operational amplifier is also coupled to one end of described first resistance and one end of described 3rd resistance, the other end ground connection of described 3rd resistance, the output of described operational amplifier is couple to one end of described second resistance, the other end of described second resistance is couple to the positive pole of described counnter attack diode, the negative pole of described counnter attack diode is couple to the other end of described first resistance and the chip feedback end of described electric current constant current output chip, and
4th resistance, the negative pole of described light-emitting diode is through described 4th grounding through resistance.
Preferably, one end of described first electric capacity couples the output of described operational amplifier, and the other end couples the inverting input of described operational amplifier.
Preferably, the 4th ohmically pressure drop sampling voltage is amplified through discharge circuit by described discharge circuit, makes the output voltage after amplification equal with chip feedback end voltage.
Preferably, the predeterminated voltage of the chip feedback end of described electric current constant current output chip is 2.5V.
Preferably, the multiplication factor of described discharge circuit is 5 times to 25 times.
According to another aspect of the present invention, a kind of light fixture is also provided, comprise: a constant current sample circuit, an electric current constant current output chip and at least one light-emitting diode, the power output end of described electric current constant current output chip is coupled to the positive pole of described light-emitting diode, and described constant current sample circuit comprises:
One discharge circuit, described discharge circuit is coupling between the negative pole of described light-emitting diode and the chip feedback end of described electric current constant current output chip, and described discharge circuit comprises:
One operational amplifier, one first resistance, one second resistance, one the 3rd resistance, one counnter attack diode and one first electric capacity, wherein, the in-phase input end of described operational amplifier is couple to the negative pole of light-emitting diode, the inverting input of described operational amplifier is couple to the output of operational amplifier by described first resistance, the inverting input of described operational amplifier is also coupled to one end of described first resistance and one end of described 3rd resistance, the other end ground connection of described 3rd resistance, the output of described operational amplifier is couple to one end of described second resistance, the other end of described second resistance is couple to the positive pole of described counnter attack diode, the negative pole of described counnter attack diode is couple to the other end of described first resistance and the chip feedback end of described electric current constant current output chip, and
4th resistance, the negative pole of described light-emitting diode is through described 4th grounding through resistance.
Preferably, one end of described first electric capacity couples the output of described operational amplifier, and the other end couples the inverting input of described operational amplifier.
Preferably, the 4th ohmically pressure drop sampling voltage is amplified through discharge circuit by described discharge circuit, makes the output voltage after amplification equal with chip feedback end voltage.
Preferably, the predeterminated voltage of the chip feedback end of described electric current constant current output chip is 2.5V.
Preferably, the multiplication factor of described discharge circuit is 5 times to 25 times.
Compared with prior art, owing to employing above technology, constant current sample circuit of the present invention and light fixture thereof by increasing by an amplifying circuit between current sampling resistor and chip feedback end, solve the problem that power consumption is excessive, promote circuit efficiency, the present invention designs very simple and reliable, low cost, is suitably for the LED constant current circuit exported as voltage high-current.
Accompanying drawing explanation
By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:
Fig. 1 illustrates a kind of LED lamp constant current output circuit figure of prior art; And
Fig. 2 illustrates according to a specific embodiment of the present invention, the circuit diagram of constant current sample circuit of the present invention.
Reference numeral
1 first resistance
2 second resistance
3 the 3rd resistance
4 the 4th resistance
5 counnter attack diodes
6 first electric capacity
7 light-emitting diodes
8 operational amplifiers
81 outputs
82 in-phase input ends
83 inverting inputs
9 electric current constant current output chips
91 power output ends
92 chip feedback ends
10 discharge circuits
Embodiment
It will be appreciated by those skilled in the art that those skilled in the art can realize change case in conjunction with prior art and above-described embodiment, do not repeat them here.Such change case does not affect flesh and blood of the present invention, does not repeat them here.
Fig. 2 illustrates according to a specific embodiment of the present invention, the circuit diagram of constant current sample circuit of the present invention.As shown in Figure 2, the invention provides constant current sample circuit.Constant current sample circuit comprises: the dotted line frame in the 4th resistance 4 and a discharge circuit 10(accompanying drawing 2).The power output end 91 of electric current constant current output chip 9 is coupled to the positive pole of light-emitting diode 7, and the negative pole of light-emitting diode 7 is not through the 4th resistance 4 ground connection (the polarity closure of light-emitting diode is seen in original statement, unclear).Discharge circuit 10 is coupling between the negative pole of light-emitting diode 7 and the chip feedback end 92 of electric current constant current output chip 9.
Wherein, discharge circuit 10 comprises operational amplifier 8,1 first resistance 1,1 second resistance 2,1 the 3rd resistance 3, one counnter attack diode 5 and one first electric capacity 6.The in-phase input end 82 of operational amplifier 8 is couple to the negative pole of light-emitting diode 7.The inverting input 83 of operational amplifier 8 is couple to the output 81 of operational amplifier 8 by the first resistance 1.The inverting input 83 of operational amplifier 8 is also coupled to one end of the first resistance 1 and one end of the 3rd resistance 3.The other end ground connection of the 3rd resistance 3.The output 81 of operational amplifier 8 is couple to one end of the second resistance 2.The other end of the second resistance 2 is couple to the positive pole of counnter attack diode 5.The negative pole of counnter attack diode 5 is couple to the other end of the first resistance 1 and the chip feedback end 92 of electric current constant current output chip 9.One end of described first electric capacity 6 couples the output of described operational amplifier 8, and the other end couples the inverting input of described operational amplifier 8.
Continue with reference to accompanying drawing 2, operation principle of the present invention is as follows:
The circuit diagram (Fig. 1) of contrast prior art is known, and the present invention increases operational amplification circuit 10 between the negative pole and chip feedback end 92 of light-emitting diode 7, to reduce the pressure drop on the 4th resistance 4, improves circuit efficiency.
Pressure drop sampling voltage on 4th resistance 4 is amplified through discharge circuit 10 by the positive input terminal of discharge circuit 10, makes the output voltage after amplification equal with chip feedback end 92 voltage, so just can make to realize constant current output.The predeterminated voltage of the chip feedback end 92 of electric current constant current output chip 9 is 2.5V.The multiplication factor of discharge circuit 10 is 5 times to 25 times.
If the resistance of the first resistance 1 is R1, the resistance of the 3rd resistance 3 is RF, and the resistance as the 4th resistance 4 of sample resistance is R4, and the current value that electric current constant current output chip exports is I.
According to the sampling voltage V on electric current constant current output current value and circuit conversion efficiency setting the 4th resistance 4
ref=R4*I, sampling voltage is determined to obtain Vo=V according to voltage amplification factor afterwards
ref* (1+R1/RF), obviously, voltage amplification factor can be decided by setting R1 and RF value, make sampling voltage V
refreach the predeterminated voltage of chip feedback end 92.
Further, the current-limiting resistance that exports for amplifier of the second resistance 2.The effect of counnter attack diode 5 prevents the voltage string of chip feedback end 92 to discharge circuit 10.First electric capacity 6 eliminates the vibration of circuit with the output of stable discharge circuit 10.The second resistance 2, first electric capacity 6 in discharge circuit 10 can omit cancellation, and not as limit.
Suppose exporting in the constant-current circuit for 700mA/18V, if do not have discharge circuit 10, then the power consumption on its 4th resistance 4 is W=2.5*0.7=1.75W.And after increasing discharge circuit 10, be 25 and 5 times (now the value of R1/RF is 24 and 4) as arranged multiplication factor, pressure drop so on the 4th resistance 4 is 100 to 500mV, its power consumption is 0.07W and 0.35W, 25 times and 5 times are reduced than 1.75W when not using discharge circuit 10, visible, the present invention improves the efficiency of circuit greatly.
Present invention also offers a kind of light fixture, comprise: a constant current sample circuit, one electric current constant current output chip and at least one light-emitting diode, the power output end of electric current constant current output chip is coupled to the positive pole of light-emitting diode, constant current sample circuit comprises: a discharge circuit, discharge circuit is coupling between the negative pole of light-emitting diode and the chip feedback end of electric current constant current output chip, discharge circuit comprises: an operational amplifier, one first resistance, one second resistance, one the 3rd resistance, one counnter attack diode and one first electric capacity, wherein, the in-phase input end of operational amplifier is couple to the negative pole of light-emitting diode, the inverting input of operational amplifier is couple to the output of operational amplifier by the first resistance, the inverting input of operational amplifier is also coupled to one end of the first resistance and one end of the 3rd resistance, the other end ground connection of the 3rd resistance, the output of operational amplifier is couple to one end of the second resistance, the other end of the second resistance is couple to the positive pole of counnter attack diode, the negative pole of counnter attack diode is couple to the other end of the first resistance and the chip feedback end of electric current constant current output chip, and the 4th resistance, the negative pole of light-emitting diode is through the 4th grounding through resistance.
One end of first electric capacity couples the output of operational amplifier, and the other end couples the inverting input of operational amplifier.4th ohmically pressure drop sampling voltage is amplified through discharge circuit by the positive input terminal of discharge circuit, makes the output voltage after amplification equal with chip feedback end voltage.The predeterminated voltage of the chip feedback end of electric current constant current output chip is 2.5V.The multiplication factor of discharge circuit is 5 times to 25 times.Obviously, have employed above-mentioned constant current sample circuit in this light fixture, relevant circuit theory and function repeat no more herein.
In summary, constant current sample circuit of the present invention and light fixture thereof by increasing by an amplifying circuit between current sampling resistor and chip feedback end, solve the problem that power consumption is excessive, promote circuit efficiency, the present invention designs very simple and reliable, low cost, is suitably for the LED constant current circuit exported as voltage high-current.
Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.
Claims (10)
1. the constant current sample circuit of a light fixture, described light fixture also comprises an electric current constant current output chip and at least one light-emitting diode, the power output end of described electric current constant current output chip is coupled to the positive pole of described light-emitting diode, it is characterized in that, described constant current sample circuit comprises:
One discharge circuit, described discharge circuit is coupling between the negative pole of described light-emitting diode and the chip feedback end of described electric current constant current output chip, and described discharge circuit comprises:
One operational amplifier, one first resistance, one second resistance, one the 3rd resistance, one counnter attack diode and one first electric capacity, wherein, the in-phase input end of described operational amplifier is couple to the negative pole of light-emitting diode, the inverting input of described operational amplifier is couple to the output of operational amplifier by described first resistance, the inverting input of described operational amplifier is also coupled to one end of described first resistance and one end of described 3rd resistance, the other end ground connection of described 3rd resistance, the output of described operational amplifier is couple to one end of described second resistance, the other end of described second resistance is couple to the positive pole of described counnter attack diode, the negative pole of described counnter attack diode is couple to the other end of described first resistance and the chip feedback end of described electric current constant current output chip, and
4th resistance, the negative pole of described light-emitting diode is through described 4th grounding through resistance.
2. constant current sample circuit as claimed in claim 1, is characterized in that: one end of described first electric capacity couples the output of described operational amplifier, and the other end couples the inverting input of described operational amplifier.
3. constant current sample circuit as claimed in claim 2, is characterized in that: the 4th ohmically pressure drop sampling voltage is amplified through discharge circuit by described discharge circuit, makes the output voltage after amplification equal with chip feedback end voltage.
4. constant current sample circuit as claimed in claim 3, is characterized in that: the predeterminated voltage of the chip feedback end of described electric current constant current output chip is 2.5V.
5. constant current sample circuit as claimed in claim 3, is characterized in that: the multiplication factor of described discharge circuit is 5 times to 25 times.
6. a light fixture, it is characterized in that, comprise: a constant current sample circuit, an electric current constant current output chip and at least one light-emitting diode, the power output end of described electric current constant current output chip is coupled to the positive pole of described light-emitting diode, and described constant current sample circuit comprises:
One discharge circuit, described discharge circuit is coupling between the negative pole of described light-emitting diode and the chip feedback end of described electric current constant current output chip, and described discharge circuit comprises:
One operational amplifier, one first resistance, one second resistance, one the 3rd resistance, one counnter attack diode and one first electric capacity, wherein, the in-phase input end of described operational amplifier is couple to the negative pole of light-emitting diode, the inverting input of described operational amplifier is couple to the output of operational amplifier by described first resistance, the inverting input of described operational amplifier is also coupled to one end of described first resistance and one end of described 3rd resistance, the other end ground connection of described 3rd resistance, the output of described operational amplifier is couple to one end of described second resistance, the other end of described second resistance is couple to the positive pole of described counnter attack diode, the negative pole of described counnter attack diode is couple to the other end of described first resistance and the chip feedback end of described electric current constant current output chip, and
4th resistance, the negative pole of described light-emitting diode is through described 4th grounding through resistance.
7. light fixture as claimed in claim 6, is characterized in that: one end of described first electric capacity couples the output of described operational amplifier, and the other end couples the inverting input of described operational amplifier.
8. light fixture as claimed in claim 7, is characterized in that: the 4th ohmically pressure drop sampling voltage is amplified through discharge circuit by described discharge circuit, makes the output voltage after amplification equal with chip feedback end voltage.
9. light fixture as claimed in claim 8, is characterized in that: the predeterminated voltage of the chip feedback end of described electric current constant current output chip is 2.5V.
10. light fixture as claimed in claim 8, is characterized in that: the multiplication factor of described discharge circuit is 5 times to 25 times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310209970.8A CN104219812A (en) | 2013-05-30 | 2013-05-30 | Constant current sampling circuit and lamp thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310209970.8A CN104219812A (en) | 2013-05-30 | 2013-05-30 | Constant current sampling circuit and lamp thereof |
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| CN104219812A true CN104219812A (en) | 2014-12-17 |
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| CN201310209970.8A Pending CN104219812A (en) | 2013-05-30 | 2013-05-30 | Constant current sampling circuit and lamp thereof |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110018446A1 (en) * | 2009-07-21 | 2011-01-27 | Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. | Light emitting diode lamp protecting circuit |
| CN202085367U (en) * | 2011-06-13 | 2011-12-21 | 深圳市莱福德光电有限公司 | Light emitting diode (LED) constant-current driving power supply |
| CN202818688U (en) * | 2012-07-06 | 2013-03-20 | 成都市思博睿科技有限公司 | Constant-current drive apparatus used for LED circuit |
| CN202857054U (en) * | 2012-09-07 | 2013-04-03 | 成都默一科技有限公司 | Constant-current drive device for LED circuit |
| CN103068096A (en) * | 2011-10-21 | 2013-04-24 | 海洋王照明科技股份有限公司 | Light-emitting diode (LED) lamp, current sampling circuit and drive circuit of LED lamp |
-
2013
- 2013-05-30 CN CN201310209970.8A patent/CN104219812A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110018446A1 (en) * | 2009-07-21 | 2011-01-27 | Fu Zhun Precision Industry (Shen Zhen) Co., Ltd. | Light emitting diode lamp protecting circuit |
| CN202085367U (en) * | 2011-06-13 | 2011-12-21 | 深圳市莱福德光电有限公司 | Light emitting diode (LED) constant-current driving power supply |
| CN103068096A (en) * | 2011-10-21 | 2013-04-24 | 海洋王照明科技股份有限公司 | Light-emitting diode (LED) lamp, current sampling circuit and drive circuit of LED lamp |
| CN202818688U (en) * | 2012-07-06 | 2013-03-20 | 成都市思博睿科技有限公司 | Constant-current drive apparatus used for LED circuit |
| CN202857054U (en) * | 2012-09-07 | 2013-04-03 | 成都默一科技有限公司 | Constant-current drive device for LED circuit |
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Application publication date: 20141217 |