CN105636302B - LED dimming device - Google Patents
LED dimming device Download PDFInfo
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- CN105636302B CN105636302B CN201410607239.5A CN201410607239A CN105636302B CN 105636302 B CN105636302 B CN 105636302B CN 201410607239 A CN201410607239 A CN 201410607239A CN 105636302 B CN105636302 B CN 105636302B
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Abstract
The present invention relates to LED dimming devices, including dim signal generation module, frequency modulation(PFM) module and LED drive module；The output end of dim signal generation module is connected with the input terminal of frequency modulation(PFM) module, the output end of frequency modulation(PFM) module is connected with the input terminal of LED drive module, the frequency modulation(PFM) module includes the first current source (U1) and first switch (S1), the second current source (U2) and second switch (S2), capacitor (C) and comparator (COMP), and the dim signal generation module is adjustable resistance (R).Using LED dimming device of the invention, resistance value by adjusting adjustable resistance is modulated the working frequency of circuit, change the duty ratio of the switching tube in LED drive module, final realize dims LED, circuit structure is simple, and peak point current reduction not will increase working frequency, reduces the switching tube loss in LED drive module, the operation is stable, it is at low cost.
Description
Technical field
The present invention relates to electronic technology field more particularly to circuit design, in particular to a kind of LED dimming devices.
Background technique
Energy conservation is most prominent one of the advantage of LED, if introducing the performance that light regulating technology can be bigger in general lighting
The power savings advantages of LED illumination.The linear light modulation of currently used light regulating technology, PWM light modulation and controllable silicon light modulation etc., middle line
Property light adjusting circuit it is fairly simple, be to change the peak point current of inductance by changing voltage or resistance to change LED drive current,
The disadvantage is that peak point current, which becomes smaller, will increase the working frequency of driving circuit, while increasing switching loss, while reducing LED current
White light can be caused to deviate to yellow spectrum.And controllable silicon light modulation and the light modulation cost of MCU control are all higher in existing light regulating technology,
Fairly simple is to change the peak point current of inductance by changing voltage or resistance to change LED drive current.
Refering to Figure 1, non-isolated LED drives work wave, switching tube conducting, inductive current is started from scratch rising,
Switching tube shutdown, inductive current are begun to decline from peak value, a duty cycle time T=TON+TOFF∝IPK, the work frequency of circuit
Rate is multiplied with the reduction of peak point current, and white light can be caused to deviate while reducing LED current to yellow spectrum.
Summary of the invention
The purpose of the present invention is overcoming the above-mentioned prior art, providing one kind can be by adjusting variable resistance
Resistance value the working frequency of circuit is modulated, the duty ratio that changes switching tube turn-on time in LED drive module, electricity
Line structure is simple, peak point current reduces not will increase working frequency, reduces switching tube loss, the work in LED drive module
LED dimming device stable, at low cost.
To achieve the goals above, LED dimming device of the invention has following constitute：
The LED dimming device, is mainly characterized by, and the device includes dim signal generation module, frequency modulation(PFM) mould
Block and LED drive module；The input terminal phase of the output end of the dim signal generation module and the frequency modulation(PFM) module
Connection, the output end of the frequency modulation(PFM) module are connected with the input terminal of the LED drive module.
Further, the dim signal generation module is adjustable resistance (R).
Further, the frequency modulation(PFM) module includes the first current source (U1) and first switch (S1), the second electricity
Stream source (U2) and second switch (S2), capacitor (C) and comparator (COMP)；The output end of first current source (U1) with
The first end of the first switch (S1) is connected, the output end of second current source (U2) and the second switch
(S2) first end is connected, and the input terminal of first current source and the input terminal of the second current source respectively can with described
Resistance (R) is adjusted to be connected；It is the second end of the first switch (S1), the second end of the second switch (S2), described
The first end of capacitor (C) is connected and the positive input of the comparator (COMP) is connected, and the of the capacitor (C)
Two ends are connected to the ground, and the output end of the comparator (COMP) is connected with the input terminal of the LED drive module.
Still further, first current source (U1) and the second current source (U2) are controlled current source.
Still further, the first switch (S1) and second switch (S2) are HF switch.
Further, the LED drive module is the converter for working in high frequency switch-mode.
Further, the dimming device further includes power module and LED module, the LED drive module it is defeated
Outlet is connected with LED module, and the power module is connected with the LED drive module.
It is had the advantages that compared with prior art using the LED dimming device in the invention：
LED dimming device of the invention, the resistance value by adjusting variable resistance are modulated the working frequency of circuit,
Change the duty ratio of switching tube turn-on time in LED drive module, final realize dims LED；LED of the invention dims dress
It sets, circuit structure is simple, and peak point current reduction not will increase working frequency, the loss of switching tube in LED drive module is reduced,
The operation is stable, it is at low cost.
Detailed description of the invention
Fig. 1 is the waveform diagram of LED dimming device in the prior art.
Fig. 2 is LED dimming device structural schematic diagram of the invention.
Fig. 3 is the circuit diagram of LED dimming device of the invention.
Fig. 4 is the waveform diagram of non-isolated LED drive circuit of the invention.
Fig. 5 is the waveform diagram of isolation LED drive circuit of the invention.
Specific embodiment
It is further to carry out combined with specific embodiments below in order to more clearly describe technology contents of the invention
Description.
It please refers to shown in Fig. 2 to Fig. 5, LED dimming device of the invention is light adjusting circuit and realization side based on PFM mode
Formula.
Please refer to shown in Fig. 2, LED dimming device of the invention include dim signal generation module, frequency modulation(PFM) module and
LED drive module；The output end of the dim signal generation module is connected with the input terminal of the frequency modulation(PFM) module
It connects, the output end of the frequency modulation(PFM) module is connected with the input terminal of the LED drive module.It is logicalOverregulating can power transformation
ResistanceRResistance value the working frequency of circuit is modulated, increase LED drive module in switching tube opening time come change switch
The duty ratio of pipe turn-on time, final realize dim LED.
Wherein, the dim signal generation module is adjustable resistance R.
It please refers to shown in Fig. 3, the frequency modulation(PFM) module includes the first current source U1 and first switch S1, the second electricity
Stream source U2 and second switch S2, capacitor C1 and comparator COMP；The output end of the first current source U1 and described the
The first end of one switch S1 is connected, the first end phase of the output end and the second switch S2 of the second current source U2
Connection, the input terminal of first current source and the input terminal of the second current source are connected with the adjustable resistance R respectively；
The second end of the first switch S1, the second end of the second switch S2, the first end of the capacitor C1 are connected
And the positive input of the comparator COMP is connected, the second end of the capacitor C1 is connected to the ground, the ratio
Output end compared with device COMP is connected with the input terminal of the LED drive module.
Wherein, the first current source U1 and the second current source U2 is controlled current source.The first switch S1 and
Second switch S2 is HF switch.
Size of the adjustable resistance R for changing the first current source U1 and the second current source U2, first switch S1 closure, I1 pairs
Capacitor C1 charging, first switch S1 are opened, and second switch S2 closure, capacitor C1 is discharged by I2.The capacitor C1 charge and discharge time
It is related with the size of I1, I2, the switching tube opening time increased in LED drive module is controlled by the capacitor C1 charge and discharge time
To change the duty ratio of switching tube turn-on time.
The LED drive module is the converter for working in high frequency switch-mode.The dimming device further includes electricity
The output end of source module and LED module, the LED drive module is connected with LED module, the power module with it is described
LED drive module be connected.
Fig. 3 and as shown in connection with fig. 4 is please referred to, the wave dimmed for non-isolated LED drive circuit of the invention based on PFM mode
Shape figure, wherein it works when uncomfortable smooth without frequency modulation(PFM) module, LED current IL=IPK/ 2, IPKFor inductance peak point current.It needs
Frequency modulation module controls LED drive module when light modulation, and one duty cycle of circuit is t1 when uncomfortable smooth, in t1
In time, capacitor C1 charging, the t1 time terminates, and I2=I1/N, discharge time t2 is arranged by adjustable resistance in capacitor C1 electric discharge
=Nt1, the switching tube in LED drive module control LED drive module, which is delayed after the t2 time after inductive current is reduced to 0, to be entered
Next cycle, IL=IPK/2(1+N)。
Fig. 3 and as shown in connection with fig. 5 is please referred to, the waveform dimmed for isolation LED drive circuit of the invention based on PFM mode
Figure, wherein first switch S1 closure, I1 charge to capacitor C1, VC>VREF, LED drive module control in LED drive module
Switching tube closure, main coil current IPRise, reach peak point current, switching tube is opened, and first switch S1 is opened, second switch S2
Closure, capacitor C1 are discharged by I2, subordinate line loop current ISStart to reduce (ISKFor the peak point current of auxiliary winding), when being reduced to 0,
First switch S1 closure, second switch S2 are opened, and capacitor C1 electric discharge terminates, and discharge time t2, I1 fill capacitor C1 again
Electricity, VC>VREF, switching tube are again turned on, IPReach peak point current again, when switching tube turns off, capacitor C charging terminates, and charges
Time is t1.
Adjustable resistance R can obtain I1=I2/N, t1=Nt2, I to the first current source U1 adjustingLED=ISKWhen/2 (1+N), N=1
For not light-modulating mode.
It is had the advantages that compared with prior art using the LED dimming device in the invention：
LED dimming device of the invention, the resistance value by adjusting variable resistance are modulated the working frequency of circuit,
Change the duty ratio of switching tube turn-on time in LED drive module, final realize dims LED；LED of the invention dims dress
It sets, circuit structure is simple, and peak point current reduction not will increase working frequency, the loss of switching tube in LED drive module is reduced,
The operation is stable, it is at low cost.
In this description, the present invention is described with reference to its specific embodiment.But it is clear that can still make
Various modifications and alterations are without departing from the spirit and scope of the invention.Therefore, the description and the appended drawings should be considered as illustrative
And not restrictive.
Claims (5)
1. a kind of LED dimming device, which is characterized in that the device includes dim signal generation module, frequency modulation(PFM) module
And LED drive module；The output end of the dim signal generation module is connected with the input terminal of the frequency modulation(PFM) module
It connects, the output end of the frequency modulation(PFM) module is connected with the input terminal of the LED drive module, the dim signal
Generation module is adjustable resistance (R), and the frequency modulation(PFM) module includes the first current source (U1), first switch (S1), second
Current source (U2), second switch (S2), capacitor (C) and comparator (COMP)；The output end of first current source (U1) with
The first end of the first switch (S1) is connected, the output end of second current source (U2) and the second switch
(S2) first end is connected, and the input terminal of first current source and the input terminal of the second current source respectively can with described
Resistance (R) is adjusted to be connected；It is the second end of the first switch (S1), the second end of the second switch (S2), described
The first end of capacitor (C) is connected with the positive input of the comparator (COMP), the second end of the capacitor (C)
It is connected to the ground, the output end of the comparator (COMP) is connected with the input terminal of the LED drive module, described
LED dimming device realizes non-isolated LED light modulation dress by the timing of the control first switch and the second switch
The driving set.
2. LED dimming device according to claim 1, which is characterized in that first current source (U1) and the second electricity
Stream source (U2) is controlled current source.
3. LED dimming device according to claim 1, which is characterized in that the first switch (S1) and second switch
It (S2) is HF switch.
4. LED dimming device according to claim 1, which is characterized in that the LED drive module is to work in high frequency
The converter of switching mode.
5. LED dimming device according to claim 1, which is characterized in that the dimming device further includes power module
And LED module, the output end of the LED drive module are connected with LED module, the power module and the LED
Drive module is connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410607239.5A CN105636302B (en) | 2014-10-31 | 2014-10-31 | LED dimming device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410607239.5A CN105636302B (en) | 2014-10-31 | 2014-10-31 | LED dimming device |
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| Publication Number | Publication Date |
|---|---|
| CN105636302A CN105636302A (en) | 2016-06-01 |
| CN105636302B true CN105636302B (en) | 2018-11-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410607239.5A Active CN105636302B (en) | 2014-10-31 | 2014-10-31 | LED dimming device |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112822817B (en) * | 2019-11-15 | 2022-10-18 | 华润微集成电路(无锡)有限公司 | Drive control circuit structure for realizing dimming function |
| CN112822818B (en) * | 2019-11-15 | 2023-11-10 | 华润微集成电路(无锡)有限公司 | Circuit structure for realizing electrodeless dimming function |
| CN114980418A (en) * | 2021-02-18 | 2022-08-30 | 华润微集成电路(无锡)有限公司 | Circuit structure for realizing LED dimming |
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| CN101436859A (en) * | 2007-11-16 | 2009-05-20 | 安凡微电子(上海)有限公司 | Rapidly-locked frequency generator |
| CN102024426A (en) * | 2009-09-14 | 2011-04-20 | 三星电机株式会社 | Reference signal generator and PWM control circuit for LCD backlight |
| CN103296894A (en) * | 2013-05-21 | 2013-09-11 | 辉芒微电子（深圳）有限公司 | Controllable constant-current output circuit |
| CN103337943A (en) * | 2013-07-02 | 2013-10-02 | 上海新进半导体制造有限公司 | Conducting time generating circuit, method, as well as control circuit and switching power supply employing same |
| CN103427656A (en) * | 2013-07-11 | 2013-12-04 | 江苏大学 | Staggered parallel flyback LED driving power supply and PFM (pulse width modulation) control circuit thereof |
| CN204090257U (en) * | 2014-10-31 | 2015-01-07 | 无锡华润矽科微电子有限公司 | LED light modulating device |
-
2014
- 2014-10-31 CN CN201410607239.5A patent/CN105636302B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101436859A (en) * | 2007-11-16 | 2009-05-20 | 安凡微电子(上海)有限公司 | Rapidly-locked frequency generator |
| CN102024426A (en) * | 2009-09-14 | 2011-04-20 | 三星电机株式会社 | Reference signal generator and PWM control circuit for LCD backlight |
| CN103296894A (en) * | 2013-05-21 | 2013-09-11 | 辉芒微电子（深圳）有限公司 | Controllable constant-current output circuit |
| CN103337943A (en) * | 2013-07-02 | 2013-10-02 | 上海新进半导体制造有限公司 | Conducting time generating circuit, method, as well as control circuit and switching power supply employing same |
| CN103427656A (en) * | 2013-07-11 | 2013-12-04 | 江苏大学 | Staggered parallel flyback LED driving power supply and PFM (pulse width modulation) control circuit thereof |
| CN204090257U (en) * | 2014-10-31 | 2015-01-07 | 无锡华润矽科微电子有限公司 | LED light modulating device |
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| CN105636302A (en) | 2016-06-01 |
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Address after: 214135 -6, Linghu Avenue, Wuxi Taihu international science and Technology Park, Wuxi, Jiangsu, China, 180 Patentee after: China Resources micro integrated circuit (Wuxi) Co., Ltd Address before: No.180-22, Linghu Avenue, Taihu International Science and Technology Park, Wuxi, Jiangsu 214135 Patentee before: WUXI CHINA RESOURCES SEMICO Co.,Ltd. |
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