CN112822818B - Circuit structure for realizing electrodeless dimming function - Google Patents
Circuit structure for realizing electrodeless dimming function Download PDFInfo
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- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The invention relates to a circuit structure for realizing an electrodeless dimming function, which comprises a first current generation circuit module, a second current generation circuit module and a first current generation circuit module, wherein the first current generation circuit module is used for realizing continuous linear change output of a first current; the second current generation circuit module is used for realizing continuous linear change output of the second current; the first switch module is used for controlling the charge and discharge time of the capacitor; the second switch module is used for controlling the charge and discharge time of the capacitor; the frequency modulation module is used for frequency modulating the first current and the second current; and the LED driving module is used for realizing dimming of the LED light source. The circuit structure for realizing the electrodeless dimming function is adopted, wherein a dimming circuit and an implementation mode based on a PFM mode are provided, the working frequency of the circuit is modulated, the turn-off time of a switching tube is increased to change the duty ratio of the turn-on time of the switching tube, the dimming of an LED is finally realized, the output current of the LED can linearly change along with a dimming control signal, and an electrodeless dimming scheme can be realized.
Description
Technical Field
The invention relates to the field of intelligent home, in particular to the field of LED dimming, and particularly relates to a circuit structure for realizing an electrodeless dimming function.
Background
Along with the development and popularization of the Internet of things and intelligent home, the light source dimming requirements are more and more, and the dimming quality requirements are higher and more. Therefore, the dimming technology of the LED needs to be continuously advanced to exert the advantages of the LED, and the LED is in line with the development trend of intelligent home.
The current common dimming technologies include linear dimming, PWM dimming, and silicon controlled rectifier dimming, where the linear dimming circuit is relatively simple, and changes the peak current of the inductor by changing the voltage or the resistor to change the LED driving current, which has the disadvantages that the decreasing peak current increases the operating frequency of the driving circuit, increases the switching loss, and simultaneously reduces the LED current and causes the white light to shift to the yellow spectrum.
The PWM dimming method changes the output current by controlling the duty ratio of the PWM wave, and when the PWM is high, the power loop of the circuit is operated, and when the PWM is low, the power loop of the circuit is stopped. When the PWM frequency is lower, the LED light source can generate stroboscopic, noise which can be perceived by human ears can be emitted, and higher dimming precision and depth are difficult to realize when the frequency is higher.
The circuit structure of the prior invention d is shown in figure 1, the adjustable resistor is used for changing the size of a current source 1/a current source 2, a switch 1 is closed, a capacitor C1 is charged by I1, the switch 1 is opened, a switch 2 is closed, and the capacitor C1 is discharged through I2. The charge and discharge time of the capacitor is related to the sizes of I1 and I2, and the switch tube turn-off time is increased through the control of the charge and discharge time of the capacitor so as to change the duty ratio of the switch tube turn-on time.
Waveform diagram as shown in fig. 2, for a non-isolated LED driving circuit, one implementation of PFM-mode based dimming is: when not dimming, the LED current I does not need to work by a frequency modulation circuit LED_100％ ＝I PK /2，I PK Is the peak inductor current. The frequency modulation circuit is used for controlling the LED drive when dimming is needed, one working period of the circuit is t1 when dimming is not needed, in the time t1, the capacitor is charged, the end of the time t1 is the end of the demagnetization of the inductor, the capacitor is discharged, the adjustable resistor is set to I2=I1/N, the discharge time t2=Nt1, the LED drive control circuit controls the switching tube to enter the next period after the time delay t2 time is delayed after the inductor current is reduced to 0, and I LED ＝I PK /2(1+N)＝I LED_100％ /(1+N)。
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a circuit structure which has the advantages of high precision, simple structure and wider application range and realizes the electrodeless dimming function.
In order to achieve the above purpose, the circuit structure for realizing the electrodeless dimming function of the invention is as follows:
the circuit structure for realizing the electrodeless dimming function is mainly characterized by comprising the following components:
the first current generation circuit module is used for realizing continuous linear change output of the first current;
the second current generation circuit module is used for realizing continuous linear change output of the second current;
the first switch module is connected with the first current generation circuit module and used for controlling the charge and discharge time of the capacitor;
the second switch module is connected with the second current generation circuit module and used for controlling the charge and discharge time of the capacitor;
the frequency modulation module is connected with the first current generation circuit module and the second current generation circuit module and is used for frequency modulating the first current and the second current;
and the LED driving module is connected with the frequency modulation module and is used for realizing dimming of the LED light source.
Preferably, the first current generating circuit module includes a first constant voltage source unit and a first resistor unit, the first constant voltage source unit is connected with the first resistor unit, and the first resistor unit is connected with the first switch module.
Preferably, the second current generating circuit module includes a variable voltage source unit and a variable resistance unit, the variable voltage source unit is connected with the variable resistance unit, and the variable resistance unit is connected with the second switch module.
Preferably, the first current generating circuit module further includes a first current mirror unit, an input end of the first current mirror unit is connected to the first resistor unit, and an output end of the first current mirror unit is connected to the first switch module to adjust a direction of the first current.
Preferably, the first constant voltage source unit comprises a first operational amplifier and a first triode, the first resistor unit comprises a first resistor, the positive input end of the first operational amplifier is connected with a constant voltage, the negative input end of the first operational amplifier is connected with the first resistor, the output end of the first operational amplifier is connected with the first triode, one end of the first resistor is connected with the first triode, the other end of the first resistor is grounded, and the first current mirror unit is connected with the first triode.
Preferably, the second current generating circuit module further includes a second current mirror unit, an input end of the second current mirror unit is connected to the variable resistor unit, and an output end of the second current mirror unit is connected to the second switch module to adjust a direction of the second current.
Preferably, the variable resistance unit comprises a digital-to-analog converter, a second operational amplifier and a second triode, the variable resistance unit comprises a variable resistor, the input end of the digital-to-analog converter is respectively connected with a constant voltage and a dimming control signal, the output end of the variable resistor is connected with the positive input end of the second operational amplifier, the variable resistor is connected with the negative input end of the second operational amplifier, the dimming control signal and the second triode and is grounded, and the second current mirror unit is connected with the second triode and the variable resistor.
Preferably, the voltage value of the variable voltage source unit satisfies the formula:
V 2 ＝V 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein V is 2 Is the voltage value of the variable voltage unit, V 1 Is a voltage value of a constant voltage.
Preferably, the resistance value of the variable resistance unit satisfies the formula:
R 2 ＝R 1 －R 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein R is 2 R is the resistance of the variable resistance unit 1 Is the resistance of the first resistor.
The circuit structure for realizing the electrodeless dimming function is adopted, a dimming circuit and an implementation mode based on a PFM mode are provided, the working frequency of the circuit is modulated, the turn-off time of a switching tube is increased to change the duty ratio of the turn-on time of the switching tube, the dimming of an LED is finally realized, the output current of the LED can linearly change along with a dimming control signal, and the electrodeless dimming scheme can be realized.
Drawings
Fig. 1 is a circuit configuration diagram of the prior art.
Fig. 2 is a waveform diagram of the prior art.
Fig. 3 is a schematic diagram of a circuit structure for realizing the electrodeless dimming function.
Fig. 4 is a block diagram of a first current generation circuit module of the circuit structure for realizing the electrodeless dimming function of the present invention.
Fig. 5 is a block diagram of a second current generating circuit module of the circuit structure for realizing the electrodeless dimming function of the present invention.
Detailed Description
In order to more clearly describe the technical contents of the present invention, a further description will be made below in connection with specific embodiments.
In a specific embodiment of the invention, a circuit structure for realizing the electrodeless dimming function is disclosed, and as shown in fig. 3, the circuit structure comprises a first current generation circuit module, a second current generation circuit module, a first switch module, a second switch module, a frequency modulation module and an LED driving module. The first current generation circuit module is connected with the first switch module and the frequency modulation module, the second current generation circuit module is connected with the second switch module and the frequency modulation module, and the frequency modulation module is also connected with the LED driving module.
The first current generation circuit module of the present invention, as shown in fig. 4, includes a first constant voltage source unit, a first resistor unit, and a first current mirror unit, for generating a first current, and implementing continuous linear variation output of the first current. The first resistor unit is connected with the first switch module and the first constant voltage source unit respectively, the input end of the first current mirror unit is connected with the first resistor unit, and the output end of the first current mirror unit is connected with the first switch module and used for adjusting the direction of the first current.
The first constant voltage source unit comprises a first operational amplifier and a first triode, the first resistor unit comprises a first resistor, the positive input end of the first operational amplifier is connected with constant voltage, the negative input end of the first operational amplifier is connected with the first resistor, the output end of the first operational amplifier is connected with the first triode, one end of the first resistor is connected with the first triode, the other end of the first resistor is grounded, and the first current mirror unit is connected with the first triode. In fig. 4, AMP is a first operational amplifier, M1 is a first triode, and R1 is a first resistor.
The second current generating circuit module of the present invention, as shown in fig. 5, includes a variable voltage source unit, a variable resistance unit, and a second current mirror unit, for generating a second current, and linearly changing an output current by adjusting the variable voltage source and the variable resistance, so as to realize continuous linear change output of the second current. The variable resistor unit is connected with the variable voltage source unit and the second switch module respectively, the input end of the second current mirror unit is connected with the variable resistor unit, and the output end of the second current mirror unit is connected with the second switch module and used for adjusting the direction of the second current.
The variable resistance unit comprises a digital-to-analog converter, a second operational amplifier, a second triode and a variable resistor, wherein the input end of the digital-to-analog converter is respectively connected with a constant voltage and a dimming control signal, the output end of the digital-to-analog converter is connected with the positive input end of the second operational amplifier, the variable resistor is connected with the negative input end of the second operational amplifier, the dimming control signal and the second triode and grounded, and the second current mirror unit is connected with the second triode and the variable resistor. In fig. 5, DAC is a digital-to-analog converter, AMP is a second operational amplifier, M2 is a second triode, and R2 is a variable resistor.
The voltage value of the variable voltage source unit satisfies the formula:
V 2 ＝V 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein V is 2 Can be made intoVoltage value of voltage-variable unit, V 1 Is a voltage value of a constant voltage.
The resistance value of the variable resistance unit satisfies the formula:
R 2 ＝R 1 －R 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein R is 2 R is the resistance of the variable resistance unit 1 Is the resistance of the first resistor.
The first switch module and the frequency modulation module are both connected with the first current generation circuit module, the frequency modulation module is also connected with the second current generation circuit module, the first switch module is used for controlling the charge and discharge time of the capacitor, and the frequency modulation module is used for frequency modulating the first current and the second current. The second switch module is connected with the second current generation circuit module and used for controlling the charge and discharge time of the capacitor. The LED driving module is connected with the frequency modulation module and used for realizing dimming of the LED light source.
In the prior art, setting of a certain current value is easy to realize, but continuous linear change of output current cannot be realized, so that the scheme is suitable for a switching dimming scheme and is not suitable for an electrodeless dimming scheme. As shown in fig. 2, which is a waveform diagram of the prior art, the frequency modulation circuit is not required to work when dimming is not performed, one working period of the circuit is t1, the capacitor is charged in the time t1, and the end of the time t1 is the end of the demagnetization of the inductor and the discharge of the capacitor. LED current I LED_100％ ＝I PK /2，I PK Is the peak inductor current. When dimming is needed, the frequency modulation circuit controls the LED drive, the adjustable resistor is set to I2=I1/N, the discharge time t 2=Nt1, the capacitor is charged in the t1 time, the LED drive control circuit delays the time t2 after the inductor current is reduced to 0 and the LED drive control circuit enters the next period, I LED ＝I PK /2(1+N)＝I LED_100％ /(1+N). To achieve 50% output current, the resistor sets the discharge current I 2 ＝I 1 ，I LED ＝50％×I LED_100％ 。
The invention is to realize continuous linear change of output current, and is assumed to be I LED ＝X×I LED_100％ (X represents a percentage) the dimming signal controls the variable voltage source and the variable resistor to change simultaneously so that I 2 ＝I 1 X/(1-X), where I 1 For charging current, I 2 Is the discharge current.
The voltage value of the first constant voltage source is V 1 The first resistance value is R 1 In order to linearly decrease the output current, the voltage value of the variable voltage source is varied in a range of V 1 Linearly decreasing to 0V, the variable resistance varying in the range of 0 to R 1 Linearly increasing.
Constant voltage V 1 Generating charging current I through LDO circuit 1 ：I 1 ＝V 1 /R 1 ；
The n-bit dimming control signal controls the DAC to output a variable voltage signal V 2 ＝V 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
The n-bit dimming control signal controls the R_DAC to obtain the variable resistor R 2 ＝R 1 －R 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
Variable voltage V 2 And a variable resistor R 2 The discharge current I is obtained after the current mirror image is generated by the LDO circuit 2 。
Set (b) n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n X, then I 2 And I 1 Satisfy the relation I 2 ＝I 1 ×X/(1－X)。
Control of simultaneous linear variation of variable voltage source and variable resistor by dimming signalChange to charge current I 1 Unchanged, discharge current I 2 And I 1 Is related as I 2 ＝I 1 X X/(1-X) can make the LED output current I LED Linear variation.
The circuit structure for realizing the electrodeless dimming function is adopted, a dimming circuit and an implementation mode based on a PFM mode are provided, the working frequency of the circuit is modulated, the turn-off time of a switching tube is increased to change the duty ratio of the turn-on time of the switching tube, the dimming of an LED is finally realized, the output current of the LED can linearly change along with a dimming control signal, and the electrodeless dimming scheme can be realized.
In this specification, the invention has been described with reference to specific embodiments thereof. It will be apparent, however, that various modifications and changes may be made without departing from the spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
Claims (8)
1. The circuit structure for realizing the electrodeless dimming function is characterized by comprising:
the first current generation circuit module is used for realizing continuous linear change output of the first current;
the second current generation circuit module is used for realizing continuous linear change output of the second current;
the first switch module is connected with the first current generation circuit module and used for controlling the charge and discharge time of the capacitor;
the second switch module is connected with the second current generation circuit module and used for controlling the charge and discharge time of the capacitor;
the frequency modulation module is connected with the first current generation circuit module and the second current generation circuit module and is used for frequency modulating the first current and the second current;
the LED driving module is connected with the frequency modulation module and is used for realizing dimming of the LED light source;
the second current generation circuit module comprises a variable voltage source unit and a variable resistance unit, the variable voltage source unit is connected with the variable resistance unit, and the variable resistance unit is connected with the second switch module;
the variable voltage source and the variable resistor are controlled to linearly change simultaneously by the dimming signal.
2. The circuit structure for realizing the electrodeless dimming function as claimed in claim 1, wherein the first current generating circuit module comprises a first constant voltage source unit and a first resistor unit, the first constant voltage source unit is connected with the first resistor unit, and the first resistor unit is connected with the first switch module.
3. The circuit structure for realizing the electrodeless dimming function according to claim 2, wherein the first current generating circuit module further comprises a first current mirror unit, an input end of the first current mirror unit is connected with the first resistor unit, and an output end of the first current mirror unit is connected with the first switch module for adjusting the direction of the first current.
4. The circuit structure for realizing the electrodeless dimming function according to claim 3, wherein the first constant voltage source unit comprises a first operational amplifier and a first triode, the first resistor unit comprises a first resistor, the positive input end of the first operational amplifier is connected with a constant voltage, the negative input end of the first operational amplifier is connected with the first resistor, the output end of the first operational amplifier is connected with the first triode, one end of the first resistor is connected with the first triode, the other end of the first resistor is grounded, and the first current mirror unit is connected with the first triode.
5. The circuit structure for realizing the electrodeless dimming function according to claim 1, wherein the second current generating circuit module further comprises a second current mirror unit, an input end of the second current mirror unit is connected with the variable resistance unit, and an output end of the second current mirror unit is connected with the second switch module for adjusting a direction of the second current.
6. The circuit structure for realizing the electrodeless dimming function according to claim 5, wherein the variable resistance unit comprises a digital-to-analog converter, a second operational amplifier and a second triode, the variable resistance unit comprises a variable resistor, the input end of the digital-to-analog converter is respectively connected with a constant voltage and a dimming control signal, the output end of the digital-to-analog converter is connected with the positive input end of the second operational amplifier, the variable resistor is connected with the negative input end of the second operational amplifier, the dimming control signal and the second triode and is grounded, and the second current mirror unit is connected with the second triode and the variable resistor.
7. The circuit structure for realizing the electrodeless dimming function as claimed in claim 1, wherein the voltage value of the variable voltage source unit satisfies the formula:
V 2 ＝V 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein V is 2 Is the voltage value of the variable voltage unit, V 1 Is a voltage value of a constant voltage.
8. The circuit structure for realizing the electrodeless dimming function as claimed in claim 1, wherein the resistance value of the variable resistance unit satisfies the formula:
R 2 ＝R 1 －R 1 ×(b n－1 ×2 n－1 +b n－2 ×2 n－2 +……+b i ×2 i +……+b 1 ×2 1 +b 0 )/2 n ；
wherein R is 2 R is the resistance of the variable resistance unit 1 Is the resistance of the first resistor.
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| CN201911117934.2A CN112822818B (en) | 2019-11-15 | 2019-11-15 | Circuit structure for realizing electrodeless dimming function |
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| CN201911117934.2A CN112822818B (en) | 2019-11-15 | 2019-11-15 | Circuit structure for realizing electrodeless dimming function |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4516086A (en) * | 1982-07-07 | 1985-05-07 | 501 Telecommunications Radioelectriques et Telephoniques | Frequency modulator for the transmission of analog data |
| CN101562932A (en) * | 2009-05-07 | 2009-10-21 | 董学文 | Colorless bleaching LED linearity light adjusting system based on PFM |
| CN101998745A (en) * | 2009-08-19 | 2011-03-30 | 上海星调光电照明科技有限公司 | PWM/PFM synchronous control dimming circuit |
| CN103296894A (en) * | 2013-05-21 | 2013-09-11 | 辉芒微电子（深圳）有限公司 | Controllable constant-current output circuit |
| CN104377945A (en) * | 2014-11-21 | 2015-02-25 | 成都芯源系统有限公司 | Reference signal generating circuit and method thereof |
| CN205213084U (en) * | 2015-12-18 | 2016-05-04 | 厦门英诺尔充源电子有限公司 | Be used for light source driven to adjust luminance and current -limiting circuit |
| CN105636302A (en) * | 2014-10-31 | 2016-06-01 | 无锡华润矽科微电子有限公司 | LED light modulation device |
| CN108923639A (en) * | 2018-08-28 | 2018-11-30 | 南京微盟电子有限公司 | A kind of circuit for eliminating primary side feedback Switching Power Supply audio-frequency noise |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006319621A (en) * | 2005-05-12 | 2006-11-24 | Matsushita Electric Ind Co Ltd | Oscillator and pll circuit using same |
-
2019
- 2019-11-15 CN CN201911117934.2A patent/CN112822818B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4516086A (en) * | 1982-07-07 | 1985-05-07 | 501 Telecommunications Radioelectriques et Telephoniques | Frequency modulator for the transmission of analog data |
| CN101562932A (en) * | 2009-05-07 | 2009-10-21 | 董学文 | Colorless bleaching LED linearity light adjusting system based on PFM |
| CN101998745A (en) * | 2009-08-19 | 2011-03-30 | 上海星调光电照明科技有限公司 | PWM/PFM synchronous control dimming circuit |
| CN103296894A (en) * | 2013-05-21 | 2013-09-11 | 辉芒微电子（深圳）有限公司 | Controllable constant-current output circuit |
| CN105636302A (en) * | 2014-10-31 | 2016-06-01 | 无锡华润矽科微电子有限公司 | LED light modulation device |
| CN104377945A (en) * | 2014-11-21 | 2015-02-25 | 成都芯源系统有限公司 | Reference signal generating circuit and method thereof |
| CN205213084U (en) * | 2015-12-18 | 2016-05-04 | 厦门英诺尔充源电子有限公司 | Be used for light source driven to adjust luminance and current -limiting circuit |
| CN108923639A (en) * | 2018-08-28 | 2018-11-30 | 南京微盟电子有限公司 | A kind of circuit for eliminating primary side feedback Switching Power Supply audio-frequency noise |
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