CN203708589U - Linear constant current LED driving circuit possessing temperature compensation - Google Patents

Linear constant current LED driving circuit possessing temperature compensation Download PDF

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Publication number
CN203708589U
CN203708589U CN201420047169.8U CN201420047169U CN203708589U CN 203708589 U CN203708589 U CN 203708589U CN 201420047169 U CN201420047169 U CN 201420047169U CN 203708589 U CN203708589 U CN 203708589U
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China
Prior art keywords
temperature
reference voltage
offset current
compensator
thermo
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Expired - Lifetime
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CN201420047169.8U
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Chinese (zh)
Inventor
黄钦阳
邓小兵
张明明
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SHENZHEN TPOWER SEMICONDUCTOR Co Ltd
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SHENZHEN TPOWER SEMICONDUCTOR Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

The utility model discloses a linear constant current LED driving circuit possessing temperature compensation. The circuit comprises a temperature detection module, a temperature compensation module used for outputting more than one compensation currents, more than one temperature compensating resistors and a reference voltage generation circuit used for generating more than one reference voltages. An output terminal of the temperature detection module is connected to an input terminal of the temperature compensation module. Each output terminal of the compensation currents is connected to one end of each temperature compensating resistor respectively. The circuit adopts a temperature compensation mode. When a detected temperature is greater than a set limit value, a compensation current is output. Through temperature feedback, the driving circuit is ensured to always work in a condition where the temperature is lower than a set limit temperature. The driving circuit is guaranteed not to be damaged, the LED does not generate severe light attenuation and the service life is not shortened. A specified graph 2 is an abstract drawing.

Description

A kind of linear constant current LED drive circuit with temperature-compensating
Technical field
The utility model relates to a kind of linear constant current LED drive circuit, relates in particular to the linear constant current LED drive circuit with temperature compensation function under a kind of ac power supply application conditions.
Background technology
The operation principle of traditional linear constant current LED drive circuit is: under the control of operational amplifier, exchange in the input cycle at one, segmentation turning part LED lamp string or all LED lamp string step by step, when input voltage is greater than after whole LED total voltages, the pressure reduction of input voltage and LED total voltage is born by drive circuit.There is following problem in traditional linear constant current LED drive circuit: first, because the pressure drop on drive circuit is the difference of input voltage and LED lamp string forward voltage drop, so in the time exchanging input, near input voltage reaches peak value time, pressure drop on drive circuit will be larger, cause drive circuit temperature to raise; Particularly, when input voltage is higher or have part even all when the short circuit of LED lamp, the pressure drop on drive circuit will be very large, and drive circuit temperature rise is very high and exceed the maximum tolerable temperature of drive circuit and cisco unity malfunction even burns out drive circuit; The second, if current setting resistor short circuit and cause on LED electric current very large, or drive circuit ambient temperature of living in is very high, will aggravate the light decay of LED lamp, seriously shortens the life-span of LED lamp.Need badly now and a kind ofly can guarantee that drive circuit always works in below the limiting temperature setting by the mode of temperature-compensating and according to temperature feedback, with ensure drive circuit can be not damaged and LED there will not be serious light decay and the linear constant current LED drive circuit of reduction of service life.
Summary of the invention
The utility model wants technical solution problem to be, provide a kind of and guarantee that by the mode of temperature-compensating and according to temperature feedback drive circuit always works in below the limiting temperature setting, with ensure drive circuit can be not damaged and LED there will not be serious light decay and the linear constant current LED drive circuit of reduction of service life.
For solving above technical problem, the technical solution of the utility model is: a kind of linear constant current LED drive circuit with temperature-compensating, and its key is: comprising: one temperature detecting module; One for exporting the temperature compensation module of more than one offset current; More than one thermo-compensator; One generating circuit from reference voltage for generation of more than one reference voltage; The input of temperature compensation module described in the output termination of described temperature detecting module, each output of described offset current connects respectively one end of described thermo-compensator, and each output of the offset current of described temperature compensation module connects respectively the reverse input end of operational amplifier, the other end of thermo-compensator is respectively together with the source electrode of MOS driving tube and a termination of sampling resistor, the reference voltage of generating circuit from reference voltage output connects respectively the positive input of operational amplifier, and wherein n is equal to, or greater than 1 integer.
As improvement of the present utility model, when temperature detecting module detect system temperature higher than set limit value time, control temperature compensation module output offset current and divide and be clipped on thermo-compensator, further raise and reduce with temperature thereby make to export LED electric current.
Further improve as the utility model, described reference voltage meets reference voltage one < reference voltage and < ... < reference voltage n.
Further improve one as the utility model, described offset current is all 0 below the temperature limit value setting time, when described offset current is greater than after the temperature limit value setting, described offset current raises and increases and meet following relation with temperature: thermo-compensator one=thermo-compensator two=...=thermo-compensator n; Offset current one: offset current two: ...: offset current n=reference voltage one: reference voltage two: ...: reference voltage n.
Further improve two as the utility model, described offset current is all 0 below the temperature limit value setting time, when described offset current is greater than after the temperature limit value setting, described offset current raises and increases and meet following relation with temperature: offset current one=offset current two=...=offset current n; Thermo-compensator one: thermo-compensator two: ...: thermo-compensator n=reference voltage one): reference voltage two: ...: reference voltage n.
By implement the utility model desirable following beneficial effect:
A linear constant current LED drive circuit with temperature-compensating, comprising: one temperature detecting module; One for exporting the temperature compensation module of more than one offset current; More than one thermo-compensator; One generating circuit from reference voltage for generation of more than one reference voltage; The input of temperature compensation module described in the output termination of described temperature detecting module, each output of described offset current connects respectively one end of described thermo-compensator, and each output of the offset current of described temperature compensation module connects respectively the reverse input end of operational amplifier, the other end of thermo-compensator is respectively together with the source electrode of MOS driving tube and a termination of sampling resistor, the reference voltage of generating circuit from reference voltage output connects respectively the positive input of operational amplifier, and wherein n is equal to, or greater than 1 integer.Under the control of operational amplifier, in the time that input voltage is low, make part LED with reduced-current conducting, in the time that input voltage is higher, make again all LED with larger current lead-through, if while drive circuit temperature being elevated to set limit value due to situations such as too high, the part or all of LED short circuit of input voltage, ambient temperature are too high, current setting resistor short circuits, guarantee that by temperature feedback drive circuit always works in below the limiting temperature setting.The utility model compared with prior art, the utility model adopts the mode of temperature-compensating, in the time detecting that temperature is greater than the limit value setting, start to export offset current, guarantee that by temperature feedback drive circuit always works in below the limiting temperature setting, ensure drive circuit can be not damaged and LED there will not be serious light decay and reduction of service life.
Brief description of the drawings
Fig. 1 is traditional linear constant current LED drive circuit schematic diagram;
Fig. 2 is driving circuit principle figure of the present utility model;
Fig. 3 is the circuit theory diagrams of a specific embodiment of the present utility model.
Embodiment
As shown in Figure 1, the operation principle of traditional linear constant current LED drive circuit is: under the control of operational amplifier A MP1~AMPn, exchange in the input cycle at one, segmentation turning part LED lamp string or all LED lamp string step by step, when input voltage is greater than after whole LED total voltages, the pressure reduction of input voltage and LED total voltage is born by drive circuit.
As shown in Figure 2, a kind of linear constant current LED drive circuit with temperature-compensating, comprising: one temperature detecting module, one for exporting the temperature compensation module of more than one offset current IT1~ITn, more than one thermo-compensator RT1~RTn, one generating circuit from reference voltage for generation of more than one reference voltage VREF1~VREFn, the input of temperature compensation module described in the output termination of described temperature detecting module, each output of described offset current IT1~ITn connects respectively one end of described thermo-compensator RT1~RTn, and each output of the offset current IT1~ITn of described temperature compensation module connects respectively the reverse input end of operational amplifier A MP1~AMPn, the other end of thermo-compensator RT1~RTn is respectively together with the source electrode of MOS driving tube Q1~Qn and a termination of sampling resistor RCS, reference voltage VREF1~the VREFn of generating circuit from reference voltage output connects respectively the positive input of operational amplifier A MP1~AMPn, wherein n is equal to, or greater than 1 integer.When temperature detecting module detect system temperature higher than set limit value time, controlling temperature compensation module output offset current IT1~ITn divides and is clipped on thermo-compensator RT1~RTn, further raise and reduce with temperature thereby make to export LED electric current, described reference voltage VREF1~VREFn meets reference voltage one VREF1 < reference voltage and VREF2 < ... < reference voltage nVREFn.Described offset current IT1~ITn is all 0 below the temperature limit value setting time, when described offset current IT1~ITn is greater than after the temperature limit value setting, described offset current IT1~ITn raises and increases and meet following relation with temperature: thermo-compensator one RT1=thermo-compensator two RT2=...=thermo-compensator nRTn; Offset current one IT1: offset current two IT2: ...: offset current nITn=reference voltage one VREF1: reference voltage two VREF2: ...: reference voltage nVREFn.Described offset current IT1~ITn is all 0 below the temperature limit value setting time, when described offset current IT1~ITn is greater than after the temperature limit value setting, described offset current IT1~ITn raises and increases and meet following relation with temperature: offset current one IT1=offset current two IT2=...=offset current nITn; Thermo-compensator one RT1: thermo-compensator two RT2: ...: thermo-compensator nRTn=reference voltage one VREF1: reference voltage two VREF2: ...: reference voltage nVREFn.
As shown in Figure 3, thermo-compensator of the present utility model can have two kinds of different definite modes below from offset current:
First: each thermo-compensator is equal, and temperature-compensated current and reference voltage are proportional, meet two formulas: RT1=RT2=below ...=RTn; IT1:IT2: ...: ITn=VREF1:VREF2: ...: VREFn.Second: each temperature-compensated current is equal, and thermo-compensator and reference voltage are proportional, meet: IT1=IT2=...=ITn; RT1:RT2: ...: RTn=VREF1:VREF2: ...: VREFn.
The linear constant current LED drive circuit with temperature-compensating shown in the present embodiment, comprise a temperature detecting module, and the output of temperature detecting module connects the input of temperature compensation module, the output IT1 of temperature compensation module, IT2, IT3 connects respectively thermo-compensator RT1, RT2, one end of RT3 and operational amplifier A MP1, AMP2, the reverse input end of AMP3, thermo-compensator RT1, RT2, the other end of RT3 respectively with MOS driving tube Q1, Q2, one end of the source electrode of Q3 and sampling resistor RCS connects, the other end ground connection of sampling resistor RCS is for setting output LED electric current, the positive input of operational amplifier A MP1, AMP2, AMP3 connects respectively reference voltage 0.1V, 0.2V, 0.3V, and the output of operational amplifier A MP1, AMP2, AMP3 connects respectively the grid of MOS driving tube Q1, Q2, Q3, its input of rectifier bridge DB connects AC-input voltage it is carried out to rectification, LED light string LED1, LED2, LED3, the positive pole of LED1 connects the positive output end of rectifier bridge DB, the negative pole of LED1 connects the drain electrode of positive pole and the MOS driving tube Q1 of LED2, the negative pole of LED2 connects the drain electrode of positive pole and the MOS driving tube Q2 of LED3, the negative pole of LED3 connects the drain electrode of MOS driving tube Q3, the negative output terminal DB ground connection of rectifier bridge.
In the present embodiment, thermo-compensator meets RT1=RT2=RT3, and electric current I T1, IT2, IT3 meet IT1:IT2:IT3=0.1V:0.2V:0.3V=1:2:3.If drive circuit temperature does not reach the limit value setting, offset current IT1, IT2, IT3 is 0, CS voltage and AMP1, AMP2, the reverse input end voltage of AMP3 equates, when input voltage is during higher than LED1 voltage, LED1 lights, CS voltage is controlled by AMP1, electric current is 0.1V/RCS, when input voltage is during higher than the total voltage of LED1 and LED2, LED1 and LED2 are lit, CS voltage is controlled by AMP2, electric current is 0.2V/RCS, when input voltage is higher than LED1, when the total voltage of LED2 and LED3, LED1, LED2 and LED3 are lit, CS voltage is controlled by AMP3, electric current is 0.3V/RCS.If drive circuit detects temperature and reach the limit value setting, offset current IT1, IT2, IT3 are greater than 0, and further raise and increase with temperature; Now because offset current flows out and produces pressure drop through compensating resistance, so CS voltage no longer equates with the reverse input end voltage of AMP1, AMP2, AMP3.When input voltage is during higher than LED1 voltage, LED1 lights, electric current is (0.1V-IT1*RT1)/RCS, when input voltage is during higher than the total voltage of LED1 and LED2, LED1 and LED2 are lit, electric current is (0.2V-IT2*RT2)/RCS, when input voltage is higher than LED1, when the total voltage of LED2 and LED3, LED1, LED2 and LED3 are lit, electric current is (0.3V-IT3*RT3)/RCS, can find out from upper surface analysis, when temperature exceedes after the limit value setting, temperature is higher, offset current IT1, IT2, IT3 is larger, the electric current that flows through LED is just less.Can find out, in the linear constant current LED drive circuit system applies of mains-supplied, temperature compensation function can at utmost ensure life-span and the safety of drive circuit and LED.
Must be pointed out, some indefinitenesses that above-described embodiment is just made the utility model illustrate.But person of skill in the art will appreciate that; do not departing under aim of the present utility model and scope; can the utility model be made amendment, replaces and be changed; these amendments, replacement and change still belong to protection range of the present utility model; for example; also can setting compensation electric current I T1=IT2=...=ITn, and the resistor satisfied RT1:RT2 of setting compensation: ...: RTn=VREF1:VREF2: ...: VREFn.

Claims (5)

1. a linear constant current LED drive circuit with temperature-compensating, is characterized in that: comprising: one temperature detecting module, one for exporting the temperature compensation module of more than one offset current (IT1~ITn), more than one thermo-compensator (RT1~RTn), one generating circuit from reference voltage for generation of more than one reference voltage (VREF1~VREFn), the input of temperature compensation module described in the output termination of described temperature detecting module, each output of described offset current (IT1~ITn) connects respectively one end of described thermo-compensator (RT1~RTn), and each output of the offset current of described temperature compensation module (IT1~ITn) connects respectively the reverse input end of operational amplifier (AMP1~AMPn), the other end of thermo-compensator (RT1~RTn) is respectively together with the source electrode of MOS driving tube (Q1~Qn) and a termination of sampling resistor (RCS), the reference voltage (VREF1~VREFn) of generating circuit from reference voltage output connects respectively the positive input of operational amplifier (AMP1~AMPn), wherein n is equal to, or greater than 1 integer.
2. a kind of linear constant current LED drive circuit with temperature-compensating according to claim 1, it is characterized in that: when temperature detecting module detect system temperature higher than set limit value time, control temperature compensation module output offset current (IT1~ITn) point and be clipped to thermo-compensator (RT1~RTn) above, further raise and reduce with temperature thereby make to export LED electric current.
3. a kind of linear constant current LED drive circuit with temperature-compensating according to claim 2, is characterized in that: described reference voltage (VREF1~VREFn) meets reference voltage one (VREF1) < reference voltage and (VREF2) < ... < reference voltage n(VREFn).
4. a kind of linear constant current LED drive circuit with temperature-compensating according to claim 3, it is characterized in that: described offset current (IT1~ITn) is all 0 below the temperature limit value setting time, when described offset current (IT1~ITn) is greater than after the temperature limit value setting, described offset current (IT1~ITn) raises and increases and meet following relation with temperature: thermo-compensator one (RT1)=thermo-compensator two (RT2)=...=thermo-compensator n(RTn); Offset current one (IT1): offset current two (IT2): ...: offset current n(ITn)=reference voltage one (VREF1): reference voltage two (VREF2): ...: reference voltage n(VREFn).
5. a kind of linear constant current LED drive circuit with temperature-compensating according to claim 3, it is characterized in that: described offset current (IT1~ITn) is all 0 below the temperature limit value setting time, when described offset current (IT1~ITn) is greater than after the temperature limit value setting, described offset current (IT1~ITn) raises and increases and meet following relation with temperature: offset current one (IT1)=offset current two (IT2)=...=offset current n(ITn); Thermo-compensator one (RT1): thermo-compensator two (RT2): ...: thermo-compensator n(RTn)=reference voltage one (VREF1): reference voltage two (VREF2): ...: reference voltage n(VREFn).
CN201420047169.8U 2014-01-26 2014-01-26 Linear constant current LED driving circuit possessing temperature compensation Expired - Lifetime CN203708589U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106455230A (en) * 2016-11-18 2017-02-22 贵州恒芯微电子科技有限公司 Linear constant-current power source having sectional temperature compensation function
CN109788597A (en) * 2017-11-13 2019-05-21 广东工业大学 A kind of constant current driving Intelligent lamp

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106455230A (en) * 2016-11-18 2017-02-22 贵州恒芯微电子科技有限公司 Linear constant-current power source having sectional temperature compensation function
CN109788597A (en) * 2017-11-13 2019-05-21 广东工业大学 A kind of constant current driving Intelligent lamp
CN109788597B (en) * 2017-11-13 2021-11-12 广东工业大学 Constant current drive intelligence lamps and lanterns

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Granted publication date: 20140709

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