CN111194112B - Ripple suppressor - Google Patents
Ripple suppressor Download PDFInfo
- Publication number
- CN111194112B CN111194112B CN201811342684.8A CN201811342684A CN111194112B CN 111194112 B CN111194112 B CN 111194112B CN 201811342684 A CN201811342684 A CN 201811342684A CN 111194112 B CN111194112 B CN 111194112B
- Authority
- CN
- China
- Prior art keywords
- voltage
- constant current
- compensation value
- generating circuit
- coupled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention discloses a ripple suppressor. The ripple suppressor comprises a constant current generating circuit and a voltage stabilizing circuit. The constant current generating circuit is used for generating a detection voltage and generating a constant current to a light emitting diode string; the voltage stabilizing circuit is used for enabling the constant current generating circuit to generate the constant current according to the detection voltage and a compensation value, or enabling the constant current generating circuit to generate the constant current according to the detection voltage, wherein the compensation value can change along with an average voltage generated by the voltage stabilizing circuit, and the average voltage is related to the voltage at one end of the light emitting diode string. Therefore, the ripple suppressor disclosed by the invention can not only save the electric energy loss when the dimming duty ratio of the power correction voltage converter driving the light-emitting diode string is high, but also prevent the light-emitting diode string from flickering when the dimming duty ratio of the power correction voltage converter is low.
Description
Technical Field
The present invention relates to a ripple suppressor, and more particularly, to a ripple suppressor capable of saving power consumption when a dimming duty ratio of a power correction voltage converter driving a light emitting diode string is high, and preventing the light emitting diode string from flickering when the dimming duty ratio of the power correction voltage converter is low.
Background
Because of high light emitting efficiency and low power consumption, Light Emitting Diodes (LEDs) have been widely used as illumination light sources. In the prior art, a driving circuit for driving a light emitting diode only uses a single stage of a Power Factor Correction (PFC) voltage converter to drive the light emitting diode, but the characteristic of the PFC voltage converter is that the driving voltage generated by the PFC voltage converter to drive the light emitting diode also has a large ripple (ripple). The ripple may cause a power transistor coupled to the light emitting diode to be in a triode region (triode region) at a low light duty ratio, so that the power transistor cannot provide a stable driving current, which may cause the light emitting diode to flicker. Therefore, how to design a ripple suppressor becomes an important issue.
Disclosure of Invention
One embodiment of the present invention discloses a ripple suppressor. The ripple suppressor comprises a constant current generating circuit and a voltage stabilizing circuit. The constant current generating circuit is coupled to a light emitting diode string and used for generating a detection voltage and generating a constant current for the light emitting diode string; the voltage stabilizing circuit is coupled to the light emitting diode string and the constant current generating circuit, and is used for enabling the constant current generating circuit to generate the constant current according to the detection voltage and a compensation value, or enabling the constant current generating circuit to generate the constant current according to the detection voltage, wherein the compensation value can change along with an average voltage generated by the voltage stabilizing circuit, and the average voltage is related to the voltage at one end of the light emitting diode string.
The invention discloses a ripple suppressor. The ripple suppressor can utilize a voltage stabilizing circuit to determine whether to generate a compensation value according to an average voltage related to a voltage at one end of a light emitting diode string coupled with the ripple suppressor, and utilize the voltage stabilizing circuit to enable a constant current generating circuit to generate a constant current according to a detection voltage generated by the constant current generating circuit and the compensation value, or enable the constant current generating circuit to generate the constant current according to the detection voltage. Therefore, compared with the prior art, the compensation value is not generated by the voltage stabilizing circuit when the dimming duty ratio of the power correction voltage converter of the light emitting diode string is high and the compensation value is generated by the voltage stabilizing circuit when the dimming duty ratio of the power correction voltage converter is low, so that the ripple suppressor disclosed by the invention can not only save the electric energy loss when the dimming duty ratio of the power correction voltage converter is high, but also prevent the light emitting diode string from flickering when the dimming duty ratio of the power correction voltage converter is low.
Drawings
Fig. 1 is a schematic diagram of a ripple suppressor according to a first embodiment of the present invention.
Fig. 2 is a diagram illustrating the relationship between the drain-source voltage and the constant current of the power transistor.
Fig. 3 is a schematic diagram of a ripple suppressor according to a second embodiment of the present invention.
Wherein the reference numerals are as follows:
100. 300 ripple wave suppressor
102 constant current generating circuit
104. 304 voltage stabilizing circuit
1022 power transistor
1024 current detection resistor
1026 operational amplifier
1042 low-pass filter
1044 offset value generating circuit
1046 multiplying unit
10422 gain amplifier
10424 capacitance
200 light emitting diode string
210 power correction voltage converter
3042A divider
FSV first set voltage
GND ground terminal
IF constant current
IM current
LVDS, L1-L5 curves
SSV second set voltage
VC compensation voltage
VD detection voltage
VOUT output voltage
VDR drive Voltage
Voltage of VMD
Average voltage of VA
VDS drain-source voltage
VGS1-VGS5 gate-source voltage
Corresponding value of VP
Detailed Description
Referring to fig. 1, fig. 1 is a schematic diagram of a ripple suppressor 100 according to a first embodiment of the present invention, in which the ripple suppressor 100 includes a constant current generating circuit 102 and a voltage regulator circuit 104, the constant current generating circuit 102 is coupled to a light emitting diode string 200, the voltage regulator circuit 104 is coupled to the light emitting diode string 200 and the constant current generating circuit 102, and the light emitting diode string 200 includes at least one light emitting diode. As shown in fig. 1, the constant current generating circuit 102 includes a power transistor 1022, a current detecting resistor 1024, and an operational amplifier 1026. As shown in fig. 1, the power transistor 1022 has a drain, a source and a gate, wherein the drain of the power transistor 1022 is coupled to the led string 200; the current sensing resistor 1024 is coupled between the source of the power transistor 1022 and a ground GND, wherein when the power transistor 1022 operates in a saturation region (saturation region), the power transistor 1022 can generate a constant current IF to the led string 200, and the constant current IF and the current sensing resistor 1024 are used to determine a sensing voltage VD. As shown in fig. 1, the output terminal of the operational amplifier 1026 is coupled to the gate of the power transistor 1022, and the output voltage VOUT of the output terminal is used to make the gate-source voltage of the power transistor 1022 greater than the threshold voltage VTN of the power transistor 1022.
As shown in fig. 1, the voltage regulator circuit 104 includes a low pass filter 1042, a compensation value generating circuit 1044, and a multiplier 1046, wherein the low pass filter 1042 includes a gain amplifier 10422 and a capacitor 10424, the low pass filter 1042 is coupled to the led string 200, the compensation value generating circuit 1044 is coupled to the constant current generating circuit 102 and the low pass filter 1042, and the multiplier 1046 is coupled to the compensation value generating circuit 1044, the constant current generating circuit 102, and the low pass filter 1042. As shown in fig. 1, the gain amplifier 10422 has a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal of the gain amplifier 10422 is coupled to the led string 200, the negative input terminal of the gain amplifier 10422 is coupled to the negative input terminal of the operational amplifier 1026 and the multiplier 1046, and the output terminal of the gain amplifier 10422 is coupled to the positive input terminal of the operational amplifier 1026; the capacitor 10424 has a first terminal and a second terminal, wherein the first terminal of the capacitor 10424 is coupled to the output terminal of the gain amplifier 10422, and the second terminal of the capacitor 10424 is coupled to the ground GND.
As shown in fig. 1, the led string 200 is driven by a driving voltage VDR generated by a power correction voltage converter 210, but the driving voltage VDR has a large ripple due to the characteristics of the power correction voltage converter 210, so that the voltage VMD (the drain voltage of the power transistor 1022) at one end of the led string 200 also has a large ripple. However, since the low pass filter 1042 is coupled to the led string 200, the low pass filter 1042 can be used for filtering the ripple of the voltage VMD and generating an average voltage VA according to the voltage VMD, wherein the average voltage VA is related to the voltage VMD. As shown in fig. 1, the compensation value generating circuit 1044 can determine whether to generate a compensation value according to the average voltage VA, that is, when the average voltage VA is greater than a predetermined value (corresponding to the high dimming duty ratio of the power correction voltage converter 210), the compensation value generating circuit 1044 does not generate the compensation value. That is to say, as shown in fig. 2, when the drain-source voltage VDS of the power transistor 1022 is greater than a corresponding value VP, the compensation value generation circuit 1044 may not generate the compensation value, where the vertical axis of fig. 2 represents the current IM flowing through the power transistor 1022, the horizontal axis of fig. 2 represents the voltage, the curve LVDS represents the drain-source voltage VDS of the power transistor 1022, and the curves L1-L5 correspond to the gate-source voltages VGS1-VGS5 of the power transistor 1022, respectively, where the gate-source voltage VGS5 is greater than the gate-source voltage VGS4, the gate-source voltage VGS4 is greater than the gate-source voltage VGS3, the gate-source voltage VGS3 is greater than the gate-source voltage VGS2, the gate-source voltage VGS2 is greater than the gate-source voltage VGS1, the gate-source voltage VGS1 is greater than the threshold voltage VTN of the power transistor 1022, and the corresponding value VP is the corresponding power transistor 1022. The curves L1 to L5 correspond to different constant currents IF on the right side of the LVDS curve.
In addition, since the average voltage VA is related to the voltage VMD (drain voltage of the power transistor 1022), when the average voltage VA is greater than the predetermined value, the corresponding value VP of the drain-source voltage VDS of the power transistor 1022 may refer to fig. 2. Therefore, as shown in fig. 1, when the compensation value generating circuit 1044 does not generate the compensation value, the compensation value generating circuit 1044 can let the detection voltage VD pass, and the multiplier 1046 generates a first setting voltage FSV according to the detection voltage VD, wherein the first setting voltage FSV is greater than the detection voltage VD. In addition, the compensation value generating circuit 1044 generates the compensation value when the average voltage VA is less than the predetermined value (corresponding to the low dimming duty ratio of the power correction voltage converter 210). That is, as shown in fig. 2, when the drain-source voltage VDS of the power transistor 1022 is smaller than the corresponding value VP, the compensation value generating circuit 1044 generates the compensation value. Therefore, as shown in fig. 1, when the compensation value generating circuit 1044 generates the compensation value, the compensation value generating circuit 1044 can generate a compensation voltage VC according to the detected voltage VD and the compensation value, and the multiplier 1046 generates the first setting voltage FSV according to the compensation voltage VC, wherein the first setting voltage FSV is greater than the compensation voltage VC.
As shown in fig. 1, after the first setting voltage FSV is generated, the operational amplifier 1026 coupled to the multiplier 1046 may make the average voltage VA equal to the first setting voltage FSV, resulting in the voltage VMD being increased (i.e. the drain-source voltage VDS of the power transistor 1022 is increased). Therefore, as shown in fig. 2, since the drain-source voltage VDS of the power transistor 1022 is increased, the drain-source voltage VDS of the power transistor 1022 is greater than the difference between the gate-source voltage of the power transistor 1022 and the critical voltage of the power transistor 1022, that is, the drain-source voltage VDS of the power transistor 1022 must be greater than the difference between the gate-source voltage and the critical voltage and the gate-source voltage must be greater than the critical voltage to ensure that the power transistor 1022 operates in the saturation region, when the power transistor 1022 operates in the saturation region, the power transistor 1022 may generate the constant current IF so as not to generate the flicker in the light emitting diode string 200.
Referring to fig. 3, fig. 3 is a schematic diagram of a ripple suppressor 300 according to a second embodiment of the present invention, wherein the ripple suppressor 300 includes a constant current generating circuit 102 and a voltage regulating circuit 304. As shown in fig. 3, the difference between the ripple suppressor 300 and the ripple suppressor 100 is that the voltage regulator 304 includes a divider 3042 without the multiplier 1046, the offset generation circuit 1044 is coupled to the constant current generation circuit 102 and the low pass filter 1042, and the divider 3042 is coupled to the negative input terminal and the output terminal of the gain amplifier 10422 and the positive input terminal of the operational amplifier 1026. As shown in fig. 3, the divider 3042 is used for generating a second setting voltage SSV according to the average voltage VA. In addition, as shown in fig. 3, the compensation value generating circuit 1044 can determine whether to generate the compensation value according to the average voltage VA, that is, when the average voltage VA is greater than the predetermined value, the compensation value generating circuit 1044 does not generate the compensation value. Therefore, as shown in fig. 3, when the compensation value generating circuit 1044 does not generate the compensation value, the compensation value generating circuit 1044 can pass the detection voltage VD to the operational amplifier 1026. As shown in fig. 3, when the compensation value generating circuit 1044 passes the detection voltage VD to the operational amplifier 1026, the operational amplifier 1026 may make the second setting voltage SSV equal to the detection voltage VD to increase the average voltage VA, resulting in the voltage VMD being increased (i.e. the drain-source voltage VDs of the power transistor 1022 being increased). Therefore, as shown in fig. 2, since the drain-source voltage VDS of the power transistor 1022 is increased, the drain-source voltage VDS of the power transistor 1022 is greater than the difference between the gate-source voltage of the power transistor 1022 and the threshold voltage of the power transistor 1022, that is, the drain-source voltage VDS of the power transistor 1022 must be greater than the difference between the gate-source voltage and the threshold voltage and the gate-source voltage must be greater than the threshold voltage to ensure that the power transistor 1022 operates in the saturation region where the power transistor 1022 may generate the constant current IF.
In addition, the compensation value generating circuit 1044 generates the compensation value when the average voltage VA is smaller than the predetermined value. Therefore, as shown in fig. 3, when the compensation value generation circuit 1044 generates the compensation value, the compensation value generation circuit 1044 can generate the compensation voltage VC to the operational amplifier 1026 according to the detection voltage VD and the compensation value. Therefore, as shown in fig. 3, when the compensation value generating circuit 1044 does not generate the compensation value, the compensation value generating circuit 1044 can pass the detection voltage VD to the operational amplifier 1026. As shown in fig. 3, when the offset value generating circuit 1044 generates the offset voltage VC to the operational amplifier 1026, the operational amplifier 1026 may make the second setting voltage SSV equal to the offset voltage VC to increase the average voltage VA, resulting in the voltage VMD being increased (i.e. the drain-source voltage VDS of the power transistor 1022 being increased). Therefore, as shown in fig. 2, since the drain-source voltage VDS of the power transistor 1022 is increased, the drain-source voltage VDS of the power transistor 1022 is greater than the difference between the gate-source voltage of the power transistor 1022 and the threshold voltage of the power transistor 1022, that is, the drain-source voltage VDS of the power transistor 1022 must be greater than the difference between the gate-source voltage and the threshold voltage and the gate-source voltage must be greater than the threshold voltage to ensure that the power transistor 1022 operates in the saturation region.
In addition, the operation principle of the constant current generating circuit 102 and the low pass filter 1042 in the ripple suppressor 300 can refer to the operation principle of the constant current generating circuit 102 and the low pass filter 1042 in the ripple suppressor 100, and will not be described herein again.
In summary, the ripple suppressor disclosed in the present invention may determine whether to generate the compensation value according to the average voltage related to the voltage at one end of the light emitting diode string by using the voltage regulator circuit, and enable the constant current generating circuit to generate the constant current according to the detection voltage and the compensation value generated by the constant current generating circuit by using the voltage regulator circuit, or enable the constant current generating circuit to generate the constant current according to the detection voltage. Therefore, compared with the prior art, because the voltage stabilizing circuit does not generate the compensation value when the dimming duty ratio of the power correction voltage converter is high, and the voltage stabilizing circuit generates the compensation value when the dimming duty ratio of the power correction voltage converter is low, the ripple suppressor disclosed by the invention can save electric energy loss when the dimming duty ratio of the power correction voltage converter is high, and prevent the light emitting diode string from generating flicker when the dimming duty ratio of the power correction voltage converter is low.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A ripple suppressor, comprising:
a constant current generating circuit coupled to a light emitting diode string for generating a detection voltage and generating a constant current to the light emitting diode string; and
the ripple suppressor is characterized by further comprising:
a voltage regulator circuit coupled to the LED string and the constant current generator circuit for enabling the constant current generator circuit to generate the constant current according to the detection voltage and a compensation value, or enabling the constant current generator circuit to generate the constant current according to the detection voltage,
the compensation value can change along with an average voltage generated by the voltage stabilizing circuit, and the average voltage is related to the voltage at one end of the light emitting diode string.
2. The ripple suppressor of claim 1 wherein the constant current generating circuit comprises: a power transistor having a drain, a source and a gate, wherein the drain is coupled to the end of the LED string;
a current sense resistor coupled between the source and a ground, wherein the constant current and the current sense resistor are used to determine the sensing voltage, and the constant current is related to the voltage at the end of the led string;
an operational amplifier, wherein an output terminal of the operational amplifier is coupled to the gate, an output voltage of the output terminal is used to make a gate-source voltage of the power transistor greater than a threshold voltage of the power transistor and make the power transistor generate the constant current, and a voltage of the end of the light emitting diode string coupled to the drain is greater than a difference between the gate-source voltage and the threshold voltage.
3. The ripple suppressor of claim 1, wherein the voltage regulator circuit comprises:
a low pass filter coupled to the led string for filtering out ripples of the voltage at the end of the led string and generating the average voltage according to the voltage at the end of the led string;
a compensation value generating circuit, coupled to the constant current generating circuit and the low pass filter, for determining whether to generate the compensation value according to the average voltage, wherein when the compensation value generating circuit generates the compensation value, the compensation value generating circuit generates a compensation voltage according to the detection voltage and the compensation value, and when the compensation value generating circuit does not generate the compensation value, the compensation value generating circuit allows the detection voltage to pass through;
and
a multiplier, coupled to the compensation value generating circuit, the constant current generating circuit and the low pass filter, for generating a first setting voltage according to the compensation voltage or the detection voltage, wherein an operational amplifier included in the constant current generating circuit makes the average voltage equal to the first setting voltage to increase the voltage at the end of the led string.
4. The ripple suppressor of claim 3 wherein the low pass filter comprises:
a gain amplifier having a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal of the gain amplifier is coupled to the end of the light emitting diode string, the negative input terminal of the gain amplifier is coupled to the negative input terminal of the operational amplifier and the multiplier, and the output terminal of the gain amplifier is coupled to the positive input terminal of the operational amplifier; and
a capacitor having a first end and a second end, wherein the first end of the capacitor is coupled to the output end of the gain amplifier, and the second end of the capacitor is coupled to a ground.
5. The ripple suppressor of claim 1, wherein the voltage regulator circuit comprises:
a low pass filter coupled to the led string for filtering out ripples of the voltage at the end of the led string and generating the average voltage according to the voltage at the end of the led string;
a compensation value generating circuit, coupled to the constant current generating circuit and the low pass filter, for determining whether to generate the compensation value according to the average voltage, wherein when the compensation value generating circuit generates the compensation value, the compensation value generating circuit generates a compensation voltage to the constant current generating circuit according to the detection voltage and the compensation value, and when the compensation value generating circuit does not generate the compensation value, the compensation value generating circuit allows the detection voltage to pass through to the constant current generating circuit; and
a divider coupled between the low pass filter and the constant current generating circuit for generating a second setting voltage according to the average voltage, wherein an operational amplifier included in the constant current generating circuit makes the second setting voltage equal to the compensation voltage to increase the voltage at the end of the led string, or makes the second setting voltage equal to the detection voltage to increase the voltage at the end of the led string.
6. The ripple suppressor of claim 5 wherein the low pass filter comprises:
a gain amplifier having a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal of the gain amplifier is coupled to the end of the LED string, the negative input terminal of the gain amplifier is coupled to the divider, and the output terminal of the gain amplifier is coupled to the divider; and
a capacitor having a first end and a second end, wherein the first end of the capacitor is coupled to the output end of the gain amplifier, and the second end of the capacitor is coupled to a ground.
7. The ripple suppressor of claim 3 or 5, wherein the voltage at the end of the LED string is used to operate a power transistor included in the constant current generating circuit in a saturation region.
8. The ripple suppressor of claim 3 or 5, wherein the compensation value generating circuit generates the compensation value when the average voltage is less than a predetermined value.
9. The ripple suppressor of claim 1 wherein the led string comprises at least one led.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811342684.8A CN111194112B (en) | 2018-11-13 | 2018-11-13 | Ripple suppressor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811342684.8A CN111194112B (en) | 2018-11-13 | 2018-11-13 | Ripple suppressor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111194112A CN111194112A (en) | 2020-05-22 |
| CN111194112B true CN111194112B (en) | 2021-06-25 |
Family
ID=70706975
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811342684.8A Active CN111194112B (en) | 2018-11-13 | 2018-11-13 | Ripple suppressor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111194112B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102958236A (en) * | 2011-08-31 | 2013-03-06 | 美国亚德诺半导体公司 | Current control circuit and light emitting diode driver as well as manufacturing method thereof |
| CN103533721A (en) * | 2013-10-31 | 2014-01-22 | 矽力杰半导体技术(杭州)有限公司 | Pulse type current LED drive circuit |
| CN203884058U (en) * | 2014-06-11 | 2014-10-15 | 无锡硅动力微电子股份有限公司 | LED constant-current driving circuit capable of increasing demagnetizing detection precision |
| CN106879109A (en) * | 2017-02-09 | 2017-06-20 | 上海晶丰明源半导体股份有限公司 | Controller, chip and method for eliminating LED drive system current ripples |
| CN206585793U (en) * | 2017-02-09 | 2017-10-24 | 上海晶丰明源半导体股份有限公司 | Controller, chip and LED drive system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9661704B2 (en) * | 2015-05-27 | 2017-05-23 | Panasonic Intellectual Property Management Co., Ltd. | Semiconductor light source drive device |
-
2018
- 2018-11-13 CN CN201811342684.8A patent/CN111194112B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102958236A (en) * | 2011-08-31 | 2013-03-06 | 美国亚德诺半导体公司 | Current control circuit and light emitting diode driver as well as manufacturing method thereof |
| CN103533721A (en) * | 2013-10-31 | 2014-01-22 | 矽力杰半导体技术(杭州)有限公司 | Pulse type current LED drive circuit |
| CN203884058U (en) * | 2014-06-11 | 2014-10-15 | 无锡硅动力微电子股份有限公司 | LED constant-current driving circuit capable of increasing demagnetizing detection precision |
| CN106879109A (en) * | 2017-02-09 | 2017-06-20 | 上海晶丰明源半导体股份有限公司 | Controller, chip and method for eliminating LED drive system current ripples |
| CN206585793U (en) * | 2017-02-09 | 2017-10-24 | 上海晶丰明源半导体股份有限公司 | Controller, chip and LED drive system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111194112A (en) | 2020-05-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10721799B2 (en) | LED driving device, constant-power dimming circuit and dimming method thereof | |
| US10531528B2 (en) | LED drive circuit with a programmable input for LED lighting | |
| CN108200685B (en) | LED lighting system for silicon controlled switch control | |
| US20110115391A1 (en) | Led lamp and led lamp module | |
| US20150312981A1 (en) | Current adjusting device and adjustment method thereof | |
| US10624169B1 (en) | LED current ripple elimination circuit applicable to very low TRIAC dimming depth | |
| US9799263B2 (en) | Power supply circuit and organic light-emitting diode display device | |
| EP3731601A1 (en) | Current drive circuit, and light emitting diode lighting device using the same | |
| Mu et al. | A high precision constant current source applied in LED driver | |
| CN103281834B (en) | Overvoltage protection circuit applied to alternative current LED drive system | |
| US11540371B2 (en) | Systems and methods for controlling power factors of LED lighting systems | |
| US10638580B2 (en) | Multi-mode dimming control method and dimming circuit | |
| EP3675603A1 (en) | Driving circuit and driving method for driving light emitting diode load | |
| KR20110014506A (en) | Constant current device and its application | |
| TW201434344A (en) | LED driving device | |
| CN114384964A (en) | Control circuit for power improving circuit and semiconductor integrated circuit device | |
| US10708994B2 (en) | System and method for shaping input current in light emitting diode (LED) system | |
| US8853969B1 (en) | Light emitting element drive device | |
| CN111194112B (en) | Ripple suppressor | |
| CN111642041B (en) | Linear LED driving circuit, system and driving method thereof | |
| JP6978914B2 (en) | Power supply unit and light irradiation system equipped with it | |
| US10694602B2 (en) | Ripple suppressor | |
| US9967929B1 (en) | High performance linear LED driving circuit | |
| US9693412B2 (en) | Dimming driver circuit and control method thereof | |
| US20160239030A1 (en) | Feedback Device and Method for Constant Current Driver |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |