CN110933812A - LED driving circuit and method and LED lamp - Google Patents
LED driving circuit and method and LED lamp Download PDFInfo
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- CN110933812A CN110933812A CN201911403168.6A CN201911403168A CN110933812A CN 110933812 A CN110933812 A CN 110933812A CN 201911403168 A CN201911403168 A CN 201911403168A CN 110933812 A CN110933812 A CN 110933812A
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Abstract
The invention relates to the technical field of LED driving, in particular to an LED driving circuit and method and an LED lamp. The invention discloses an LED driving circuit and method and an LED lamp, wherein the LED driving circuit comprises a rectifying circuit, a phase-shifting circuit and a constant current driving circuit, the input end of the phase-shifting circuit is connected with an alternating current input power supply and is used for shifting the phase of the voltage of the alternating current input power supply by 90 degrees, the rectifying circuit is used for rectifying the alternating current input power supply and the power supply after phase shifting of the phase-shifting circuit, then connecting the rectified alternating current input power supply and the power supply in parallel and outputting the rectified alternating current input power supply and the power supply to the constant current driving circuit, and the output end of the constant current driving circuit is. The invention greatly reduces the stroboscopic phenomenon of the LED, even realizes no stroboscopic, improves the efficiency, does not need an electrolytic capacitor, is not influenced by the service life of the electrolytic capacitor, prolongs the service life, and has simple circuit structure and easy realization.
Description
Technical Field
The invention belongs to the technical field of LED driving, and particularly relates to an LED driving circuit and method and an LED lamp.
Background
The LED lamp has been widely used in various places because of its advantages of high efficiency, energy saving, environmental protection, long service life, etc.
The LED lamp is usually driven by an alternating current power supply, a driving circuit of the LED lamp firstly rectifies the alternating current power supply into direct current, and then converts the direct current into a direct current constant current source to drive an LED light source, so that the LED light source has the stroboscopic problem and influences the luminous efficiency. At present, a common LED stroboscopic removing method in the industry is to use a two-stage loop cascade method, for example, an APFC circuit + a FLYBACK circuit, a FLYBACK circuit + a BUCK circuit, a PPF circuit C + hb (bright) circuit, or a FLYBACK circuit + an ldo circuit, etc., to reduce ripples, thereby removing stroboscopic. However, these methods require two series circuits, which are inefficient and complex in circuit structure, and cannot use electrolytic capacitors, resulting in the drive circuit being affected by the lifetime of the electrolytic capacitors and shortening the lifetime.
Disclosure of Invention
The invention aims to provide an LED driving circuit and method and an LED lamp to solve the existing technical problems.
In order to achieve the purpose, the invention adopts the technical scheme that: an input end of the phase shift circuit is connected with an alternating current input power supply and used for shifting the phase of the voltage of the alternating current input power supply by 90 degrees, the rectifying circuit is used for rectifying the alternating current input power supply and the power supply after phase shifting of the phase shift circuit, then the rectified power supply is connected in parallel and output to the constant current driving circuit, and the output end of the constant current driving circuit is the output end of the LED driving circuit and used for driving an LED load.
Further, the phase shift circuit is implemented by using a capacitor.
The phase-shifting circuit further comprises a switch circuit, wherein the switch circuit is connected in series with the output end of the phase-shifting circuit, and the control end of the switch circuit is connected with a control signal.
Furthermore, the switch circuit is realized by adopting an NMOS tube.
Further, the rectifying circuit is a full-wave rectifying circuit.
Furthermore, the rectification circuit is realized by adopting a full-bridge rectification bridge.
Furthermore, the power supply also comprises a filter circuit, and the filter circuit is connected with the output end of the rectifying circuit in parallel.
Further, the constant current driving circuit is a boost switching power supply circuit, a buck switching power supply circuit or a buck-boost switching power supply circuit.
The invention also provides an LED lamp which is provided with the LED drive circuit.
In addition, the invention also provides an LED driving method, which comprises the following steps:
s1, rectifying the alternating current input power supply to obtain a first direct current power supply;
s2, the alternating current input power supply is rectified after being shifted by 90 degrees to obtain a second direct current power supply;
and S3, connecting and combining the first direct current power supply and the second direct current power supply in parallel to be used as an input power supply of the constant current driving circuit, and driving the LED load by the constant current driving circuit.
The invention has the beneficial technical effects that:
the invention can greatly reduce the stroboscopic phenomenon of the LED and even realize no stroboscopic, improves the efficiency, does not need an electrolytic capacitor, and is not influenced by the service life of the electrolytic capacitor, thereby prolonging the service life, and the circuit has simple structure and is easy to realize.
The invention only needs one group of LED load, and has simple structure, easy production and manufacture and low cost.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a block diagram of a circuit configuration according to a first embodiment of the present invention;
FIG. 2 is a schematic circuit diagram according to a first embodiment of the present invention;
FIG. 3 is a graph of the voltage waveform of an AC input power source;
FIG. 4 is a graph of the voltage waveforms after rectification and after 90 ° phase shift re-rectification of the AC input power;
FIG. 5 is a graph of superimposed voltage waveforms of FIG. 4;
FIG. 6 is a schematic circuit diagram according to a second embodiment of the present invention;
FIG. 7 is a flowchart of a method according to an embodiment of the present invention.
Detailed Description
To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.
The invention will now be further described with reference to the accompanying drawings and detailed description.
Example one
As shown in fig. 1 and 2, an LED driving circuit includes a rectifying circuit 2, a phase shift circuit 1 and a constant current driving circuit 3, wherein an input terminal of the phase shift circuit 1 is connected to an ac input power source 4 for shifting a phase of a voltage of the ac input power source 4 by 90 °, the rectifying circuit 2 is configured to rectify the power source after the phase shift of the ac input power source 4 and the phase shift circuit 1, and then to connect in parallel and output the power source to the constant current driving circuit 3, and an output terminal of the constant current driving circuit 3 is an output terminal of the LED driving circuit for driving an LED load 5.
In this embodiment, the rectifying circuit 2 is preferably a full-wave rectifying circuit, so that the rectified voltage ripple is smaller and the efficiency is higher, but the invention is not limited thereto, and in other embodiments, the rectifying circuit 2 may also be a half-wave rectifying circuit.
Preferably, in this embodiment, the rectifier circuit 2 is implemented by using a full-bridge rectifier bridge, which is simple in structure, easy to implement, and low in cost, but not limited thereto, and in other embodiments, the rectifier circuit 2 may also be implemented by using another existing full-wave rectifier circuit.
Specifically, in this embodiment, the rectifier circuit 2 includes rectifier diodes D1, D2, D3, and D4, a positive terminal of the rectifier diode D1 and a negative terminal of the rectifier diode D2 are connected to the live line L of the ac input power source 4, a positive terminal of the rectifier diode D3 and a negative terminal of the rectifier diode D4 are connected to the neutral line N of the ac input power source 4, negative terminals of the rectifier diodes D1 and D3 are positive input terminals of the rectifier circuit 2 and are positive input terminals of the constant current driving circuit 3, and positive terminals of the rectifier diodes D2 and D4 are negative input terminals of the rectifier circuit 2 and are negative input terminals of the constant current driving circuit 3.
In this specific embodiment, the constant current driving circuit 3 is an existing buck-boost switching power supply circuit, and includes an inductor T1, an NMOS transistor Q1, and a sampling resistor R01, and certainly, further includes a switching power supply control IC (not shown in fig. 2), a control output PWM1 of the switching power supply control IC is connected to a gate of the NMOS transistor Q1, a sampling input end of the switching power supply control IC adopts an output Vref of a resistor R01, two ends of the inductor T1 are output ends of the constant current driving circuit 3, and are used for being connected to the LED load 5, and a specific circuit connection relationship is detailed in fig. 2.
The specific working principle of the buck-boost switching power supply circuit is already a mature prior art, and reference can be made to the prior art, which is not described in detail.
Of course, in other embodiments, the constant current driving circuit 3 may be other constant current driving circuits such as a step-up switching power supply circuit and a step-down switching power supply circuit.
In this embodiment, the phase shift circuit 1 is preferably implemented by using a capacitor, and has a simple structure, easy implementation, and low cost, but not limited thereto, and in other embodiments, the phase shift circuit 1 may also be implemented by using other existing phase shift circuits, such as a phase shift circuit formed by using an inductor.
Specifically, in this embodiment, the phase shift circuit 1 includes capacitors C01 and C02, a first end of the capacitor C01 is connected to the neutral line N of the ac input power source 4, a first end of the capacitor C02 is connected to the live line L of the ac input power source 4, and second ends of the capacitors C01 and C02 are connected to negative ends of the rectifier diodes D1 and D3.
In this embodiment, the voltage regulator further includes a filter circuit, and the filter circuit is connected in parallel with the output end of the rectifier circuit 2 to filter the output of the rectifier circuit 2, so as to improve the voltage stability.
Specifically, in this embodiment, the filter circuit includes a capacitor C1, a first terminal of the capacitor C1 is connected to negative terminals of the rectifier diodes D1 and D3, and a second terminal of the capacitor C2 is connected to positive terminals of the rectifier diodes D2 and D4.
The working principle is as follows:
an AC input power 4 (the voltage waveform of which is shown in figure 3) is rectified by a rectifying circuit 2 and then outputs a first DC power, the voltage waveform of the first DC power is shown by a solid line in figure 4, the AC input power 4 is subjected to 90-degree phase shift by a phase shift circuit 1 and then rectified by the rectifying circuit 2 and then outputs a second DC power, the voltage waveform of the second DC power is shown by a dotted line in figure 4, the first DC power and the second DC power are connected in parallel and combined (namely, the large voltage value of the two is taken as the combined voltage value) and then output to a constant current driving circuit 3, the waveform of the input power of the constant current driving circuit 3 is shown in figure 5, and it can be seen that the second DC power makes up the valley bottom voltage of the first DC power, the valley bottom voltage of the first DC power is raised, so that the voltage ripple of the input power of the constant current driving circuit 3 is small, and then the current peak value IPK of each period can be fixed by sampling the voltage of an output end Vref of, just so can ensure to flow through the current peak value IPK on inductance T1, because inductance T1 electric current can not break suddenly, the current peak value IPK that flows through on LED load 5 like this also is fixed, thereby realize not having the stroboscopic, and only need a set of LED load can, the LED load does not have the luminance and equals zero in the twinkling of an eye, the efficiency has been promoted, the manufacture is also more simple and convenient, therefore, the cost is low, and simultaneously, need not electrolytic capacitor, can not receive electrolytic capacitor life's influence, thereby the service life is prolonged, the circuit structure is simple, and the realization is easy.
Example two
As shown in fig. 6, the difference between the present embodiment and the first embodiment is: the present embodiment further includes a switch circuit, the switch circuit is connected in series to the output terminal of the phase shift circuit 1, and the control terminal of the switch circuit is connected to a control signal PWM 1. By arranging the switch circuit, the output power of the power supply after phase shifting can be controlled, for example, the voltage within the interval of 0-10 degrees, 80-100 degrees, 170-190 degrees and 350-360 degrees is controlled to be output, so that the power of the first direct current power supply and the second direct current power supply after parallel combination is controlled, and the input power of the constant current driving circuit 3 is further adjusted.
Specifically, in this embodiment, the switch circuit is preferably implemented by using an NMOS transistor Q01, a drain of the NMOS transistor Q01 is connected to the second ends of the capacitors C01 and C02, a source of the NMOS transistor Q01 is connected to the negative ends of the rectifier diodes D1 and D3, a gate of the NMOS transistor Q01 is connected to the control signal PWM1, and the control signal PWM1 may be output by the switching power supply control IC, or may be output by another PWM generating circuit. Of course, in other embodiments, the switching circuit may be implemented by using other switching transistors such as a triode.
The invention also provides an LED lamp which is provided with the LED drive circuit.
In addition, as shown in fig. 7, the present invention also provides an LED driving method, including the steps of:
and S1, rectifying the AC input power to obtain a first DC power.
And S2, performing phase shift on the alternating current input power supply by 90 degrees, and then performing rectification to obtain a second direct current power supply.
And S3, connecting and combining the first direct current power supply and the second direct current power supply in parallel to be used as an input power supply of the constant current driving circuit, and driving the LED load by the constant current driving circuit.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. An LED drive circuit, characterized by: the LED constant current drive circuit comprises a rectification circuit, a phase shift circuit and a constant current drive circuit, wherein the input end of the phase shift circuit is connected with an alternating current input power supply and is used for shifting the phase of the voltage of the alternating current input power supply by 90 degrees, the rectification circuit is used for rectifying the alternating current input power supply and the power supply after phase shifting of the phase shift circuit, then, the power supply is connected in parallel and output to the constant current drive circuit, and the output end of the constant current drive circuit is the output end of the LED drive circuit and is used.
2. The LED driving circuit according to claim 1, wherein: the phase shift circuit is realized by adopting a capacitor.
3. The LED driving circuit according to claim 1, wherein: the phase-shifting circuit also comprises a switch circuit, wherein the switch circuit is connected in series with the output end of the phase-shifting circuit, and the control end of the switch circuit is connected with a control signal.
4. The LED driving circuit according to claim 3, wherein: the switch circuit is realized by adopting an NMOS tube.
5. The LED driving circuit according to claim 1, wherein: the rectification circuit is a full-wave rectification circuit.
6. The LED driving circuit according to claim 5, wherein: the rectification circuit is realized by adopting a full-bridge rectification bridge.
7. The LED driving circuit according to claim 1, wherein: the filter circuit is connected with the output end of the rectifying circuit in parallel.
8. The LED driving circuit according to claim 1, wherein: the constant current driving circuit is a boost type switching power supply circuit, a buck type switching power supply circuit or a boost type switching power supply circuit.
9. An LED lamp, characterized in that: an LED driving circuit according to any one of claims 1 to 8 is provided.
10. An LED driving method, comprising the steps of:
s1, rectifying the alternating current input power supply to obtain a first direct current power supply;
s2, the alternating current input power supply is rectified after being shifted by 90 degrees to obtain a second direct current power supply;
and S3, connecting and combining the first direct current power supply and the second direct current power supply in parallel to be used as an input power supply of the constant current driving circuit, and driving the LED load by the constant current driving circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911403168.6A CN110933812A (en) | 2019-12-31 | 2019-12-31 | LED driving circuit and method and LED lamp |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911403168.6A CN110933812A (en) | 2019-12-31 | 2019-12-31 | LED driving circuit and method and LED lamp |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201986233U (en) * | 2011-03-22 | 2011-09-21 | 福建农林大学 | Phase-controlled constant-current and high-power LED (light-emitting diode) driving circuit |
| WO2011127638A1 (en) * | 2010-04-12 | 2011-10-20 | 东莞华明灯具有限公司 | Dimmable led driver |
| JP2014038826A (en) * | 2012-07-17 | 2014-02-27 | Rohm Co Ltd | Led lighting device |
| JP2014217257A (en) * | 2013-04-30 | 2014-11-17 | 株式会社ブリッジ・マーケット | Power supply circuit, drive load, and led lighting |
| CN105142300A (en) * | 2015-09-23 | 2015-12-09 | 广州硅能照明有限公司 | Strobe-free LED alternating-current driving device and method |
| CN211240189U (en) * | 2019-12-31 | 2020-08-11 | 厦门阳光恩耐照明有限公司 | LED drive circuit and LED lamp |
-
2019
- 2019-12-31 CN CN201911403168.6A patent/CN110933812A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011127638A1 (en) * | 2010-04-12 | 2011-10-20 | 东莞华明灯具有限公司 | Dimmable led driver |
| CN201986233U (en) * | 2011-03-22 | 2011-09-21 | 福建农林大学 | Phase-controlled constant-current and high-power LED (light-emitting diode) driving circuit |
| JP2014038826A (en) * | 2012-07-17 | 2014-02-27 | Rohm Co Ltd | Led lighting device |
| JP2014217257A (en) * | 2013-04-30 | 2014-11-17 | 株式会社ブリッジ・マーケット | Power supply circuit, drive load, and led lighting |
| CN105142300A (en) * | 2015-09-23 | 2015-12-09 | 广州硅能照明有限公司 | Strobe-free LED alternating-current driving device and method |
| CN211240189U (en) * | 2019-12-31 | 2020-08-11 | 厦门阳光恩耐照明有限公司 | LED drive circuit and LED lamp |
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