CN100383692C - High efficiency constant current source - Google Patents
High efficiency constant current source Download PDFInfo
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- CN100383692C CN100383692C CNB2005100242868A CN200510024286A CN100383692C CN 100383692 C CN100383692 C CN 100383692C CN B2005100242868 A CNB2005100242868 A CN B2005100242868A CN 200510024286 A CN200510024286 A CN 200510024286A CN 100383692 C CN100383692 C CN 100383692C
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Abstract
The present invention relates to a high efficiency constant current source circuit. An adjustable direct current output switching power supply is utilized to supply power to the constant current source circuit and a load circuit, and the voltage drop of the constant current source circuit is used as a control signal of the output voltage of the switching power supply, so that voltage at both ends of the constant current source circuit is maintained within the lowest range allowed by the constant current source circuit and does not change with a load, and high efficiency and high performance are realized. The present invention is suitable for any occasion using a constant current source.
Description
Technical field:
The present invention relates to a kind of high efficiency constant current source.
Technical background:
Constant current source is in a lot of occasions application to be arranged all, is characterized in that the electric current by it is a steady state value, and the variation with the pull-up resistor size does not change, but as active circuit, operate as normal that certain supply voltage must be arranged.All require under maximum load resistance or minimum input supply voltage energy operate as normal for usually the supply voltage of constant current source, mutually should current source loads resistance relatively little or input voltage when big pressure drop on constant-current source circuit increase, the power consumption that causes constant current source increases, especially when the constant current source electric current is big, if its load is little, then can bring problem inefficient and heat radiation greatly because of its power consumption, it as the patent No. constant current source described in 89101207.9 the patent, pressure drop on the resistance hour adjustment pipe of its load will increase, and efficient reduces.Though adopt the constant current source of chopping way work to solve efficiency for solving efficiency, its electric current is inevitable pulsation of current because of chopping way has, the constant current poor effect can not satisfy high performance requirement.
Summary of the invention
The object of the present invention is to provide a kind of high efficiency high-efficiency constant-current source of taking into account, avoid occurring in the work pulsation of current, can satisfy high performance requirements.
For achieving the above object, design of the present invention is: utilize adjustable DC output Switching Power Supply to provide power supply for constant-current source circuit and load circuit, utilize the control signal of the voltage drop of constant-current source circuit itself as Switching Power Supply output, thereby realize that the constant-current source circuit both end voltage remains on the lowest range that constant-current source circuit allows, the variation with load does not change, and realizes high-level efficiency and high-performance.
According to above-mentioned design, the present invention adopts following technical proposals:
A kind of high efficiency constant current source, comprise a constant-current source circuit and the coupled load circuit that gets, it is characterized in that being output as constant-current source circuit and load circuit provides power supply by adjustable DC output Switching Power Supply, be that described constant-current source circuit is connected with load circuit, and form the load of described adjustable DC output switching power circuit jointly, wherein: the output terminal of the termination adjustable DC output Switching Power Supply of load circuit, the output terminal of another termination constant-current source circuit of load circuit, the return terminal of another termination adjustable DC output Switching Power Supply of constant-current source circuit, i.e. ground terminal; Also have a feedback network in parallel with constant-current source circuit, promptly its two ends are in parallel with the input and output of constant-current source circuit respectively; The feedback signal that adopts feedback network output to be directly proportional with the constant-current source circuit both end voltage is exported the voltage control signal of Switching Power Supply as adjustable DC, receive the adjustment end of adjustable DC output Switching Power Supply, in the time can adjusting Switching Power Supply work, its output voltage is controlled by the feedback adjusting terminal voltage, it adjusts feedback procedure automatically remains unchanged the adjustment terminal voltage, thereby realize that the constant-current source circuit both end voltage remains on the lowest range that constant-current source circuit allows, and realizes high-level efficiency.
Above-mentioned adjustable DC output Switching Power Supply can adopt the buck working method, and its a kind of circuit structure of realizing is: a model is the switching power source chip of MC33063, and its 1 pin connects 8 pin; 4 pin connect the ground wire of externally fed through first electric capacity; 6 pin simultaneously also connect power supply 20V anode input end and connect 7 pin through a resistance, and 20V anode input end also and connect ground wire behind the 3rd electric capacity; 2 pin connect the negative electrode of a diode and an end of an inductance simultaneously, and the plus earth line of this diode also constitutes the output terminal of adjustable DC output Switching Power Supply by the other end that second electric capacity connects described inductance; And the adjustment end of the external formation adjustable DC output of the COMP pin of switching power source chip Switching Power Supply.
Above-mentioned adjustable DC output Switching Power Supply also can adopt the boost type working method, its a kind of circuit structure of realizing is: a model is the switching power source chip of MC33063, its 1 pin connects the anode of a diode and an end of an inductance, another termination 6 pin of this inductance, the negative electrode of this diode picks out the output terminal into adjustable DC output Switching Power Supply, and connects 2 pin and ground connection through second electric capacity; 3 pin are through first electric capacity and 4 pin ground connection together, and 6 pin also connect resistance and 5V power supply, and another termination 7 pin of this resistance also connect 8 pin through another resistance; The 5V circuit is also exported the return terminal of Switching Power Supply, i.e. ground terminal through the 3rd the external formation adjustable DC of electric capacity; The adjustment end of the external formation adjustable DC output of 5 pin of switching power source chip Switching Power Supply.
A kind of structure that realizes of the circuit of above-mentioned constant-current source circuit is: the integrated stable voltage circuit chip that model is LM337, its 1 pin connects load circuit, simultaneously connect 2 pin, connect 3 pin through an electric capacity through a resistance, 3 pin also connect the return terminal that adjustable DC is exported Switching Power Supply, i.e. ground terminal; And 2 pin and connect feedback network.
The circuit structure of above-mentioned feedback network is: the resistance of two series connection, the one end connects 2 pin of integrated stable voltage circuit chip in the constant-current source circuit.The other end connects 3 pin of this chip, and the series connection line of this two resistance connects the adjustment end of adjustable DC output Switching Power Supply.The present invention compared with prior art, have following conspicuous outstanding feature and remarkable advantage: utilize common high-performance constant-current source circuit that needed electric current is provided, realize high-performance, utilize adjustable DC output Switching Power Supply to provide power supply for constant-current source circuit, guarantee that the voltage of constant-current source circuit work remains on the minimum of permission, realizes high-level efficiency.The present invention can be applicable to the occasion of any employing constant-current source circuit.
Principle of work of the present invention is as follows:
1. in the time can adjusting Switching Power Supply (1) work, its output voltage (VCC) is by feedback adjusting end (ADJ2) Control of Voltage, and it adjusts feedback procedure automatically remains unchanged adjustment end (ADJ2) voltage;
2. the transmission coefficient of establishing feedback network (2) is K, and then (ADJ2) terminal voltage size is as follows with constant-current source circuit both end voltage (FB) relation: ADJ2=FB * K
3. when the load (4) of constant-current source circuit when changing, corresponding meeting causes the change of (FB) voltage, thereby the voltage of (ADJ2) is changed, and can adjust Switching Power Supply (1) and transfer according to the variation of (ADJ2)
Whole output voltage changes its output voltage (VCC), makes FB voltage get back to original size again.
4. definite method of feedback network transfer coefficient K: it is FB that constant-current source circuit keeps the two ends minimum voltage of operate as normal, and adjusting terminal voltage during the Switching Power Supply operate as normal is ADJ2, then has:
ADJ2=FB * K, promptly
K＝ADJ2/FB
The present invention compared with prior art, have following conspicuous outstanding feature and remarkable advantage: utilize common high-performance constant-current source circuit that needed electric current is provided, realize high-performance, utilize adjustable DC output Switching Power Supply to provide power supply for constant-current source circuit, guarantee that the voltage of constant-current source circuit work remains on the minimum of permission, realizes high-level efficiency.The present invention can be applicable to the occasion of any employing constant-current source circuit.
Description of drawings:
Fig. 1 is a theory diagram of the present invention.
Fig. 2 is the circuit theory diagrams of one embodiment of the present of invention;
Fig. 3 is the circuit theory diagrams of an alternative embodiment of the invention;
Embodiment:
Embodiment one: referring to Fig. 1 and Fig. 2, adopt buck adjustable DC output Switching Power Supply working method in this efficient constant current source.Its circuit structure and principle of work are described in detail in detail below: among Fig. 2, the supply voltage of system is 20 volts, and two feeder ears are respectively 20v and ground wire, and structure is composed as follows:
Switching power source chip MC33063 is the U1 among Fig. 2, and the U2 among Fig. 2 is integrated stable voltage circuit LM337.1 pin of U1 connects 8 pin, and 4 pin of U1 connect the ground wire of externally fed; 6 pin of U1 simultaneously and connect an end of power supply 20V anode input end and resistance R 2, the other end of R2 is received 7 pin of U1; 3 pin of U1 connect an end of capacitor C 1, the other end ground wire of C1; 2 pin of U1 connect negative electrode and inductance L 1 one ends of D1 simultaneously, the plus earth line of D1, and the other end while of L1 also connects the positive terminal of C2 and the end of R1, and the other end of R1 is received 1 pin of U2, the negative pole end ground wire of C2; 1 pin of the termination LM337 of R5,2 pin of another termination U2; 1 pin of the termination U2 of C4, other end ground wire; 2 pin of R3 one termination U2, the other end while also connects 5 pin of U1 and the end of R4, the other end ground wire of R4; The 3 pin ground wires of U2.
All are that the element of sign is a resistance with R, and unit be ohm, are that what identify is electric capacity with C, and L1 is an energy storage inductor, and D1 is the high speed commutation diode, plays the afterflow effect here; U1 is for adjusting step-up/step-down type dc output switching power source chip MC33063, here use the step-down working method (when input voltage low, when current source loads resistance is high, can uses the mode of operation of boosting of MC33063 and power, as shown in Figure 3) to constant-current source circuit; R2 is a current-limiting resistance, effect is protection MC33063, U2 can adjust stabilized voltage supply LM337 for three commonly used ends are negative, and here as constant current source, the continuous current size that needs equals its adjustment terminal voltage and the difference of output end voltage (being fixed as 1.25 volts) divided by resistance R 5; C1 control switching MC33063 frequency of operation makes the MC33063 frequency of operation at 100KHz here; C2, C3 are filter capacitor, and C4 is a decoupling capacitor, and it makes the LM337 working stability.Require input and output pressure reduction to be at least 3 volts during the U2 operate as normal, for guaranteeing in Switching Power Supply output operate as normal under certain fluctuation situation is arranged, the pressure difference is 3.5 volts.The electric current of constant-current source circuit is by resistance R 5 decisions, and size is 1.25V/R5, and getting R5 here is 125 ohm, and then electric current I is 100mA, and R1 is the load of constant current source.
When the MC33063 operate as normal, adjust terminal voltage and remain on 1.25 volts, so negate feedforward coefficient K=1.25/3.5, here negate feed resistance R4=18K, R3=10K, obtain feedback end voltage ADJ2=K * 3.5=R3/ (R3+R4) * 3.5=1.25 (volt), then when constant-current source circuit LM337 operate as normal, its input and output pressure reduction is 3.5 volts.Here the value of R3, R4 should make electric current by R3, R4 less than 1/10 of constant-current source circuit working current, reduces the influence to the constant current source electric current.Electric current by R3, R4 equals FB/ (R3+R4).FB is LM337 input and output pressure reduction.
System's supply voltage is 20 volts in the circuit, owing to can adjust the effect of Switching Power Supply MC33063, when current source loads R1 gets 0 during to maximum 150 ohm load, the input and output pressure reduction of LM337 remains on 3.5 volts, thereby realizes that circuit remains under high-performance and the high efficiency duty.
R1 also can use and have reactive load such as inductive type load in this circuit.
Embodiment two: referring to Fig. 1 and Fig. 3, adopt boost type adjustable DC output Switching Power Supply working method in this efficient constant current source.Its circuit structure and principle of work are described in detail in detail below: system's supply voltage is 5 volts among Fig. 3, when pull-up resistor is 100 ohm, as to require continuous current I be 100 milliamperes, then require constant current source power supply voltage greater than 14 volts, need to adopt the working method of boosting of MC33063, its principle is described identical with Fig. 2, and system architecture is composed as follows:
The supply voltage of system is 5 volts, and two feeder ears are respectively 5v end and ground terminal.Switching power source chip MC33063 is the U1 among Fig. 3, and the U2 among Fig. 3 is integrated stable voltage circuit LM337.1 pin of U1 connects the anode of D1 and the end of L1,6 pin of another termination U1 of L1, and the negative electrode of D1 connects the end of R1 and the anode of C2,1 pin of another termination U2 of R1, the plus earth line of C2; 2 pin of U1 and 4 pin connect the ground wire of externally fed; 3 pin of the termination U1 of C1, the other end ground wire of C1; 8 pin of the termination U1 of R6,7 pin of another termination U1; 6 pin of the termination U1 of R2,7 pin of another termination U1; The anode of C3 connects the 5V feeder ear, the plus earth line of C3; 5 pin of the termination U1 of R4, other end ground wire; 5 pin of the termination U1 of R3,2 pin of another termination U2; 2 pin of the termination U2 of R5,1 pin of another termination U2; 1 pin of the termination U2 of C4, other end ground wire; The 3 pin ground wires of U2.
Except that having illustrated, all elements there is not specific (special) requirements in the above-mentioned two embodiment circuit.Constant-current source circuit and adjustable direct current output switching power circuit can adopt other similar products among the embodiment.
MC33063 is an on semiconductor company product.
Claims (5)
1. high efficiency constant current source, comprise a constant-current source circuit (3) and coupled load circuit (4), it is characterized in that being output as constant-current source circuit (3) and load circuit (4) provides power supply by adjustable DC output Switching Power Supply (1), be that described constant-current source circuit (3) is connected with load circuit (4), and form the load of described adjustable DC output switching power circuit (1) jointly, wherein: the output terminal of the termination adjustable DC output Switching Power Supply (1) of load circuit (4), the output terminal of another termination constant-current source circuit (3) of load circuit (4), the return terminal of another termination adjustable DC output Switching Power Supply (1) of constant-current source circuit (3), i.e. ground terminal; Also have a feedback network (2) in parallel with constant-current source circuit (3), promptly its two ends are in parallel with the input and output of constant-current source circuit (3) respectively; The feedback signal that adopts feedback network (2) output to be directly proportional with constant-current source circuit (3) both end voltage is exported the voltage control signal of Switching Power Supply (1) as adjustable DC, receive the adjustment end of adjustable DC output Switching Power Supply (1), in the time can adjusting Switching Power Supply (1) work, its output voltage is controlled by the feedback adjusting terminal voltage, it adjusts feedback procedure automatically remains unchanged the adjustment terminal voltage, thereby realize that constant-current source circuit (3) both end voltage remains on the lowest range that constant-current source circuit allows, and realizes high-level efficiency.
2. high efficiency constant current source according to claim 1 is characterized in that, adjustable DC output Switching Power Supply (1) can adopt the buck working method, and its circuit structure is: the switching power source chip (U1) that model is MC33063, and its 1 pin connects 8 pin; 4 pin connect the ground wire of externally fed through first capacitor C 1; 6 pin simultaneously also connect power supply 20V anode input end and connect 7 pin through a resistance R 2, and 20V anode input end also and connect the 3rd capacitor C 3 back ground wires; 2 pin connect the negative electrode of a diode D1 and an end of an inductance L 1 simultaneously, and the plus earth line of this diode D1 also constitutes the output terminal of adjustable DC output Switching Power Supply (1) by the other end that second capacitor C 2 connects described inductance L 1; And the adjustment end of the external formation adjustable DC output Switching Power Supply of the COMP pin of switching power source chip (U1) (1).
3. high efficiency constant current source according to claim 1, it is characterized in that, adjustable DC output Switching Power Supply (1) also can adopt the boost type working method, its circuit structure is: the switching power source chip (U1) that model is MC33063, its 1 pin connects the anode of a diode D1 and an end of an inductance L 1, another termination 6 pin of this inductance L 1, the negative electrode of this diode D1 pick out the output terminal into adjustable DC output Switching Power Supply (1), and connect 2 pin and ground connection through second capacitor C 2; 3 pin are through first capacitor C 1 and 4 pin ground connection together, and 6 pin also connect a resistance R 2 and 5V power supply, and another termination 7 pin of this resistance R 2 also connect 8 pin through another resistance R 6; The 5V circuit is also exported the return terminal of Switching Power Supplies (1), i.e. ground terminal through the 3rd capacitor C 3 external formation adjustable DC; The adjustment end of the external formation adjustable DC output Switching Power Supplies of 5 pin of switching power source chip (U1) (1).
4. high efficiency constant current source according to claim 1, it is characterized in that, the circuit structure of constant-current source circuit (3) is: the integrated stable voltage circuit chip (U2) that model is LM337, its 1 pin connects load circuit (4, be R1), simultaneously connect 2 pin, connect 3 pin through a capacitor C 4 through a resistance R 5,3 pin also connect the return terminal that adjustable DC is exported Switching Power Supply (1), i.e. ground terminal; And 2 pin and connect feedback network (2).
5. high efficiency constant current source according to claim 4, it is characterized in that, the circuit structure of feedback network (2) is: the resistance R 3 and the R4 of two series connection, the one end connects 2 pin of integrated stable voltage circuit chip (U2) in the constant-current source circuit (3), the other end connects 3 pin of this chip (U2), and the series connection line of this two resistance R 3 and R4 is connected the adjustment end of adjustable DC output Switching Power Supply (1).
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| CNB2005100242868A CN100383692C (en) | 2005-03-10 | 2005-03-10 | High efficiency constant current source |
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| CNB2005100242868A CN100383692C (en) | 2005-03-10 | 2005-03-10 | High efficiency constant current source |
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| CN100383692C true CN100383692C (en) | 2008-04-23 |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100392549C (en) * | 2006-01-05 | 2008-06-04 | 大连大学 | Current source controller with external load power supply |
| CN101581945B (en) * | 2009-06-24 | 2012-05-23 | 深圳市风发科技发展有限公司 | Voltage regulating method, device and system |
| CN102591397A (en) * | 2012-03-06 | 2012-07-18 | 广州金升阳科技有限公司 | A constant current source circuit of negative resistance characteristic |
| CN105094191A (en) * | 2015-09-23 | 2015-11-25 | 湖南工业大学 | Current expanding type direct-current auxiliary power source achieving voltage dividing through constant current circuit |
| CN105138061A (en) * | 2015-09-23 | 2015-12-09 | 湖南工业大学 | Direct-current auxiliary power supply for constant current circuit voltage division |
| CN106020307B (en) * | 2016-06-23 | 2017-08-25 | 电子科技大学 | A kind of linear constant current power supply of constant power dissipation |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08205534A (en) * | 1995-01-26 | 1996-08-09 | Tokimec Inc | Switching power supply circuit |
| JP2002084747A (en) * | 2000-09-01 | 2002-03-22 | Hitachi Ltd | Small power consumption current output device |
| CN1435942A (en) * | 2002-01-29 | 2003-08-13 | 松下电器产业株式会社 | Switch Power supply circuit |
| US20030210504A1 (en) * | 2002-05-10 | 2003-11-13 | Toko Kabushiki Kaisha | Boost-type switching power device |
| JP2005051883A (en) * | 2003-07-31 | 2005-02-24 | Toko Inc | Switching constant-current power supply device |
-
2005
- 2005-03-10 CN CNB2005100242868A patent/CN100383692C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08205534A (en) * | 1995-01-26 | 1996-08-09 | Tokimec Inc | Switching power supply circuit |
| JP2002084747A (en) * | 2000-09-01 | 2002-03-22 | Hitachi Ltd | Small power consumption current output device |
| CN1435942A (en) * | 2002-01-29 | 2003-08-13 | 松下电器产业株式会社 | Switch Power supply circuit |
| US20030210504A1 (en) * | 2002-05-10 | 2003-11-13 | Toko Kabushiki Kaisha | Boost-type switching power device |
| JP2005051883A (en) * | 2003-07-31 | 2005-02-24 | Toko Inc | Switching constant-current power supply device |
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