CN116963347A - LED drive circuit, drive device and lighting device - Google Patents
LED drive circuit, drive device and lighting device Download PDFInfo
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- CN116963347A CN116963347A CN202311215863.6A CN202311215863A CN116963347A CN 116963347 A CN116963347 A CN 116963347A CN 202311215863 A CN202311215863 A CN 202311215863A CN 116963347 A CN116963347 A CN 116963347A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/345—Current stabilisation; Maintaining constant current
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/36—Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
Abstract
An LED driving circuit, driving equipment and lighting equipment comprises a rectifying module, a first constant current source and a second constant current source. The first constant current source is used for adjusting the on-resistance of the first constant current source according to the first reference voltage and the voltage of a first voltage feedback point in the first constant current source so as to generate and output a first driving current; the second constant current source is used for adjusting the on-resistance of the second constant current source according to the second reference voltage and the voltage of a second voltage feedback point in the second constant current source when the second driving voltage is larger than the on threshold of the second constant current source so as to generate and output a second driving current; the second driving current is used for driving the first load to work together with the first driving current and is used for increasing the voltage of the first voltage feedback point so as to reduce the first driving current. The effect of constant current can be achieved through the first constant current source and the second constant current source, and when the first load is an LED light-emitting device, the problem of stroboscopic effect of the LED light-emitting device can be eliminated.
Description
Technical Field
The application belongs to the technical field of LED illumination, and particularly relates to an LED driving circuit, driving equipment and illumination equipment.
Background
At present, the LED illumination is an energy-saving and environment-friendly illumination mode, and has become a mainstream illumination mode at present, and meanwhile, requirements of stroboscopic, low cost and various environment-friendly authentications on subharmonics have become important attention indexes of the LED illumination.
Because the LED light emitting diode load used in LED lighting needs to be driven by using direct current, and the brightness of the LED light emitting diode is determined by the current flowing through the LED light emitting diode load, in the LED driving control process, the low-frequency ripple wave band in the input ac mains supply is often put into the LED light emitting diode load, so that the light fluctuation occurs in the LED light emitting diode load, and the stroboscopic phenomenon occurs due to the light fluctuation. Meanwhile, the requirement of various environmental protection authentications on subharmonics causes that the traditional circuit can not better solve the stroboscopic phenomenon.
Disclosure of Invention
The application aims to provide an LED driving circuit, driving equipment and lighting equipment, and aims to solve the problem that the traditional LED lighting equipment working based on alternating current has a stroboscopic phenomenon.
A first aspect of an embodiment of the present application provides an LED driving circuit, including: a rectification module for generating a first driving voltage and a second driving voltage based on an input alternating current; the input end of the first constant current source is connected with the rectifying module, the output end of the first constant current source and the reference ground of the first constant current source are both used for being connected with a first load, and the first constant current source is configured to adjust the on-resistance of the first constant current source according to a first reference voltage and the voltage of a first voltage feedback point in the first constant current source so as to generate and output a first driving current based on a first driving voltage; the first constant current source comprises a first sampling resistor, and the first sampling resistor is connected between the first voltage feedback point and the output end of the first constant current source; the input end of the second constant current source is connected with the rectifying module, the output end of the second constant current source and the reference ground of the second constant current source are connected with the first voltage feedback point, and the second constant current source is configured to adjust the conduction impedance of the second constant current source according to the second reference voltage and the voltage of the second voltage feedback point in the second constant current source when the second driving voltage is larger than the conduction threshold value of the second constant current source so as to generate and output a second driving current based on the second driving voltage; the second driving current is used for driving the first load to work together with the first driving current and is used for increasing the voltage of the first voltage feedback point through the first sampling resistor so that the first constant current source generates a third driving current, and the sum of the second driving current and the third driving current is equal to the first driving current.
In one embodiment, the first constant current source comprises a first switching tube and a first operational amplifier unit; the first end of the first switch tube is the input end of the first constant current source, the second end of the first switch tube is connected with the first end of the first sampling resistor, the first end of the first sampling resistor is a first voltage feedback point of the first constant current source, and the second end of the first sampling resistor is the output end of the first constant current source and the reference ground of the first constant current source; the first operational amplifier unit is configured to adjust the on-resistance of the first switching tube based on the voltage of the first voltage feedback point of the first constant current source and the voltage of the first constant current source with reference to the ground so that the voltage on the first sampling resistor is equal to the first reference voltage.
In one embodiment, the first operational amplifier unit includes a first operational amplifier, a non-inverting input terminal of the first operational amplifier is configured to receive the first reference voltage, an inverting input terminal of the first operational amplifier is connected to a first terminal of the first sampling resistor, a ground terminal of the first operational amplifier is connected to a second terminal of the first sampling resistor, and an output terminal of the first operational amplifier is connected to a controlled terminal of the first switching tube.
In one embodiment, the second constant current source includes a second switching tube, a second sampling resistor and a second operational amplifier unit; the first end of the second switching tube is the input end of the second constant current source, the second end of the second switching tube is connected with the first end of the second sampling resistor, the first end of the second sampling resistor is a second voltage feedback point of the second constant current source, and the second end of the second sampling resistor is the output end of the second constant current source and the reference ground of the second constant current source; the second operational amplifier unit is configured to adjust the on-resistance of the second switching tube based on the voltage of the second voltage feedback point of the second constant current source and the voltage of the reference ground of the second constant current source so that the voltage on the second sampling resistor is equal to the second reference voltage.
In one embodiment, the second operational amplifier unit includes a second operational amplifier, a non-inverting input terminal of the second operational amplifier is configured to receive the second reference voltage, an inverting input terminal of the second operational amplifier is connected to a first terminal of the second sampling resistor, a ground terminal of the second operational amplifier is connected to a second terminal of the second sampling resistor, and an output terminal of the second operational amplifier is connected to a controlled terminal of the second switching tube.
In one embodiment, the first reference voltage is greater than the second reference voltage, and the resistances of the first sampling resistor and the second sampling resistor are equal; or the first reference voltage is not larger than the second reference voltage, and the ratio of the resistance values of the first sampling resistor and the second sampling resistor is equal to the ratio of the first reference voltage and the second reference voltage.
In one embodiment, the rectifier module further comprises a third constant current source, wherein the input end of the third constant current source is connected with the rectifier module, the output end of the third constant current source is used for being connected with a second load, and the third constant current source is configured to adjust the impedance of the third constant current source according to a third reference voltage and the voltage of a third voltage feedback point in the third constant current source so as to generate a fourth driving current based on the first driving voltage; and a third voltage feedback point in the third constant current source is also connected with the grounding end of the first load.
In one embodiment, the rectifying module includes a rectifying unit, a unidirectional conductive device and an energy storage capacitor; the input end of the rectifying unit is used for accessing the input alternating current, and the rectifying unit is used for generating the second driving voltage based on the input alternating current; the positive electrode of the unidirectional conductor is connected with the output end of the rectifying unit, and the negative electrode of the unidirectional conductor is used for outputting the first driving voltage; the first end of the energy storage capacitor is connected with the negative electrode of the unidirectional conductor, and the second end of the energy storage capacitor is grounded.
A second aspect of an embodiment of the present application provides a driving apparatus including; the LED driving circuit comprises a main control device and the LED driving circuit, wherein the main control device and the LED driving circuit are used for controlling the LED driving circuit to work.
A third aspect of an embodiment of the present application provides a lighting device, including: the LED driving circuit is connected with the first load and used for driving the first load to work.
Compared with the prior art, the embodiment of the application has the beneficial effects that: when the second driving voltage is smaller than the conduction threshold value, the first constant current source drives the first load to work with a fixed first driving current. When the second driving voltage is larger than the conducting threshold value, the second driving current generated by the second constant current source can influence the first constant current source to work, and as the second driving current needs to be transmitted to the first voltage feedback point of the first constant current source and is transmitted to the first load through the first sampling resistor, the second driving current can raise the voltage of the first voltage feedback point, finally the first constant current source can output the third driving current according to the raised voltage of the first voltage feedback point, the effect of constant current supplied to the first load is achieved, and when the first load is an LED light-emitting device, the stroboscopic problem of the LED light-emitting device can be eliminated. Meanwhile, compared with using only a single constant current source, the harmonic wave of the input current of the LED driving circuit can be optimized by the second constant current source.
Drawings
Fig. 1 is a schematic structural diagram of an LED driving circuit according to an embodiment of the present application;
FIG. 2 is a schematic waveform diagram of a second driving voltage;
fig. 3 is a schematic circuit diagram of an LED driving circuit according to an embodiment of the present application;
FIG. 4 is a schematic waveform diagram of the driving current when the first reference voltage is not less than the second reference voltage;
FIG. 5 is a schematic diagram of waveforms of the driving current when the first reference voltage is smaller than the second reference voltage;
FIG. 6 is a schematic waveform diagram of an input voltage and an input current;
FIG. 7 is a schematic diagram of another embodiment of an LED driving circuit according to the present application;
fig. 8 is a schematic structural diagram of a driving apparatus according to an embodiment of the present application;
fig. 9 is a schematic structural diagram of a lighting device according to an embodiment of the present application.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Fig. 1 shows a schematic structural diagram of an LED driving circuit according to an embodiment of the present application, and for convenience of explanation, only the portions related to the present embodiment are shown in detail as follows:
an LED driving circuit 10, comprising: a rectifying module 100, a first constant current source 200, and a second constant current source 300.
The rectifying module 100 is configured to generate a first driving voltage and a second driving voltage based on an input alternating current.
It should be noted that, as shown in fig. 2, the second driving voltage V2 may be obtained after the input ac VAC is rectified by the rectifying module 100, and the rectifying module 100 may obtain the first driving voltage based on the second driving voltage V2, where the waveform of the second driving voltage V2 is a steamed bread wave as shown in fig. 2.
The input terminal of the first constant current source 200 is connected to the rectifying module 100, and the output terminal of the first constant current source 200 and the reference ground of the first constant current source 200 are both used to be connected to the first load 20, and the output terminal of the first constant current source 200, that is, the reference ground of the first constant current source 200, the first constant current source 200 is configured to adjust the on-resistance of the first constant current source 200 according to the first reference voltage and the voltage of the first voltage feedback point in the first constant current source 200, so as to generate and output the first driving current based on the first driving voltage. The first load 20 may be an LED lamp group composed of light emitting diodes, and an output end of the first constant current source 200 is connected to a positive electrode of the first load 20, and a negative electrode of the first load 20 is grounded. The first constant current source 200 includes a first sampling resistor, and the first sampling resistor is connected between the first voltage feedback point and the output end of the first constant current source.
It may be understood that the voltage of the reference ground of the first constant current source 200 may be used as a reference voltage, the voltage difference between the first voltage feedback point and the reference ground of the first constant current source 200 may be obtained by collecting the voltage of the first voltage feedback point, that is, the voltage difference between the first voltage feedback point and the output terminal of the first constant current source 200 may be obtained, the first constant current source 200 may adjust its on-resistance according to the obtained voltage difference between the first voltage feedback point and the output terminal of the first constant current source 200, so that the voltage difference between the first voltage feedback point and the output terminal of the first constant current source 200 is equal to the first reference voltage, and the voltage applied to the first sampling resistor is controlled to be stable, thereby ensuring stable output of the first driving current, which is the current input by the input terminal of the first constant current source 200 and output by the output terminal of the first constant current source 200. When only the first constant current source 200 is operated, the first driving current is the actual current transmitted to the first load 20, so that the first reference voltage and the first sampling resistor can be adjusted according to the actual requirement, and the actual current transmitted to the first load is controlled.
The input end of the second constant current source 300 is connected to the rectifying module 100, and the output end of the second constant current source 300 and the reference ground of the second constant current source 300 are both connected to the first voltage feedback point, and the second constant current source 300 is configured to adjust the on-resistance of the second constant current source 300 according to the second reference voltage and the voltage of the second voltage feedback point in the second constant current source 300 to generate and output the second driving current based on the second driving voltage V2 when the second driving voltage V2 is greater than the on-threshold of the second constant current source 300. In some embodiments, the on threshold of the first constant current source 200 is equal to the on threshold of the second constant current source 300, and the on threshold is smaller than the minimum value of the first driving voltage, and the on threshold is larger than the minimum value of the second driving voltage V2.
It may be appreciated that the voltage of the reference ground of the second constant current source 300 may be used as a reference, and the voltage difference between the second voltage feedback point and the reference ground of the second constant current source 300 may be obtained by collecting the voltage of the second voltage feedback point, that is, the voltage difference between the second voltage feedback point and the output end of the second constant current source 300 may be obtained, the second constant current source 300 may adjust its on-resistance according to the obtained voltage difference between the first voltage feedback point and the output end of the second constant current source 300, so that the voltage difference between the second voltage feedback point and the output end of the second constant current source 300 is equal to the second reference voltage, thereby ensuring stable output of the second driving current, which is the current input by the input end of the second constant current source 300 and output by the output end of the second constant current source 300.
The second driving current is used for being transmitted to the first load 20 through the first sampling resistor to work and increasing the voltage of the first voltage feedback point, so that the first constant current source 200 generates a third driving current based on the voltage of the first voltage feedback point after the second driving current is increased, and the sum of the second driving current and the third driving current is equal to the first driving current.
It should be noted that, when the second driving voltage V2 is smaller than the on threshold of the second constant current source 300, the first constant current source 200 supplies power to the first load 20 only, and the first constant current source 200 may adjust the on resistance of the first constant current source 200 according to the voltage of the first voltage feedback point, so that the voltage of the first voltage feedback point is equal to the first reference voltage, and finally may provide a stable first driving current to the first load 20 based on the voltage of the stable first voltage feedback point.
When the second driving voltage V2 is greater than the on threshold of the second constant current source 300, such that the second constant current source 300 outputs the second driving current, the second driving current increases the voltage of the first voltage feedback point, and the first constant current source 200 may increase the on resistance of the first constant current source 200 according to the increased voltage of the first voltage feedback point, and finally still maintain the voltage of the first voltage feedback point stable, so as to provide a stable third driving current to the first load 20 based on the first reference voltage, and at this time, the first load 20 is driven by the second driving current and the third driving current. When the first load 20 is an LED lamp, then the strobe of the LED lamp can be eliminated.
For example, let the first reference voltage be 1V, the first sampling resistor be 10Ω, and when the second driving voltage V2 is less than the on-threshold of the second constant current source 300, the first driving current be 0.1A. When the second driving voltage V2 is greater than the on threshold of the second constant current source 300, such that the second constant current source 300 outputs a second driving current of 0.08A, the second driving current will raise the voltage of the first voltage feedback point by 0.8V, the first constant current source 200 will correspondingly adjust its own impedance to generate and output a third driving current of 0.02A instead of the first driving current, so that the voltage of the first voltage feedback point reaches 1V, and at this time, the sum of the second driving current and the third driving current is still equal to the first driving current, and the current received by the first load 20 remains constant.
In an embodiment, as shown in fig. 3, the first constant current source 200 further includes a first switching tube Q1 and a first operational amplifier unit 210. The first switching tube Q1 may be a MOS (Power MOSFET) tube or an IGBT (insulated gate bipolar transistor) tube, and may be specifically set according to actual requirements.
The first end of the first switching tube Q1 is an input end of the first constant current source 200, the second end of the first switching tube Q1 is connected with the first end of the first sampling resistor R1, the first end of the first sampling resistor R1 is a first voltage feedback point of the first constant current source 200, and the second end of the first sampling resistor R1 is an output end of the first constant current source 200 and a ground GND1 of the first constant current source 200. The first operational amplifier unit 210 is configured to adjust the on-resistance of the first switching tube Q1 (i.e., adjust the on-resistance of the first end of the first switching tube Q1 to the second end of the first switching tube Q1) based on the voltage of the first voltage feedback point of the first constant current source 200 and the voltage of the ground GND1 of the first constant current source 200, so that the voltage across the first sampling resistor R1 is equal to the first reference voltage REF1.
It can be understood that the on-resistance of the first switching tube Q1 can be adjusted by controlling the voltage provided to the controlled end of the first switching tube Q1 by the first operational amplifier unit 210, so as to achieve the effect of adjusting the on-resistance of the first constant current source 200. When the first constant current source 200 operates normally, the following first formula is possible:calculating to obtain a specific value of the first driving current I1, wherein +_1>Is the actual current actually delivered to the first load 20.
In an embodiment, the first operational amplifier unit 210 includes a first operational amplifier U1, a non-inverting input terminal of the first operational amplifier U1 is configured to receive the first reference voltage REF1, an inverting input terminal of the first operational amplifier U1 is connected to a first terminal of the first sampling resistor R1, a ground terminal GND1 of the first operational amplifier U1 is connected to a second terminal of the first sampling resistor R1, and an output terminal of the first operational amplifier U1 is connected to a controlled terminal of the first switching tube Q1.
The first operational amplifier U1 may adjust the output voltage according to the voltage difference between the non-inverting input terminal and the inverting input terminal, thereby controlling the on-resistance of the first switching tube Q1.
In an embodiment, the second constant current source 300 includes a second switching transistor Q2, a second sampling resistor R2, and a second operational amplifier unit 310. The second switching transistor Q2 may be a MOS transistor (Power MOSFET) or an IGBT transistor (insulated gate bipolar transistor).
The first end of the second switching tube Q2 is an input end of the second constant current source 300, the second end of the second switching tube Q2 is connected with the first end of the second sampling resistor R2, the first end of the second sampling resistor R2 is a second voltage feedback point of the second constant current source 300, and the second end of the second sampling resistor R2 is an output end of the second constant current source 300 and a ground GND2 of the second constant current source 300. The second operational amplifier unit 310 is configured to adjust the on-resistance of the second switching tube Q2 based on the voltage of the second voltage feedback point of the second constant current source 300 and the voltage of the ground GND2 of the second constant current source 300 so that the voltage across the second sampling resistor R2 is equal to the second reference voltage REF2.
It can be understood that the on-resistance of the second switching transistor Q2 can be adjusted by controlling the voltage supplied to the controlled terminal of the second switching transistor Q2, thereby achieving the effect of adjusting the on-resistance of the second constant current source 300. When the second constant current source 300 operates normally, the following second formula is possible:a specific value of the second drive current I2 is calculated. Meanwhile, when the second driving current I2 is transmitted to the first load 20 through the first sampling resistor R1, the voltage of the first voltage feedback point is increased, and the third driving current I3 lower than the first driving current I1 is generated due to the constant current characteristic of the first constant current source 200, and may be expressed by a third formula: />The reduced third driving current I3 is obtained, and finally, the fourth formula can be passed:the actual current ILED output to the first load 20 is obtained.
By adjusting the first reference voltage REF1, the second reference voltage REF2, the first sampling resistor R1 and the second sampling resistor R2, the sum of the second driving current I2 and the third driving current I3 is equal to the first driving current I1, and constant current output is realized.
In an embodiment, the second operational amplifier unit 310 includes a second operational amplifier U2, a non-inverting input terminal of the second operational amplifier U2 is configured to receive the second reference voltage REF2, an inverting input terminal of the second operational amplifier U2 is connected to a first terminal of the second sampling resistor R2, a ground terminal GND2 of the second operational amplifier U2 is connected to a second terminal of the second sampling resistor R2, and an output terminal of the second operational amplifier U2 is connected to a controlled terminal of the second switching tube Q2.
The second operational amplifier U2 may adjust the output voltage according to the voltage difference between the non-inverting input terminal and the inverting input terminal, thereby controlling the on-resistance of the second switching tube Q2.
In an embodiment, the first reference voltage REF1 is greater than the second reference voltage REF2, and the resistances of the first sampling resistor R1 and the second sampling resistor R2 are equal.
It can be understood that, as shown in fig. 4, when the resistance of the first sampling resistor R1 is equal to the resistance of the second sampling resistor R2, if the second driving voltage V2 is smaller than the on threshold of the second constant current source 300, the first load 20 is only powered by the first constant current source 200, and the actual current ILED is equal to the first driving current I1. If the second driving voltage V2 is greater than the on threshold of the second constant current source 300, at this time, since the resistances of the first sampling resistor R1 and the second sampling resistor R2 are equal, the fifth formula can be simplified according to the fourth formula:the first driving current I1 before the second constant current source 300 is turned on at this time, the actual current ILED is always stable, which is obtained by the fifth formula.
If the first reference voltage REF1 is equal to the second reference voltage REF2, the first driving current I1 is zero, and the second constant current source 300 only drives the first load 20.
In an embodiment, the first reference voltage REF1 is not greater than the second reference voltage REF2, and the ratio of the resistances of the first sampling resistor R1 and the second sampling resistor R2 is equal to the ratio of the first reference voltage REF1 and the second reference voltage REF2.
It will be appreciated that when the first reference voltage REF1 is smaller than the second reference voltage REF2, as shown in fig. 5, if the second driving voltage V2 is smaller than the on threshold of the second constant current source 300, the second driving current I2 is zero, and the actual current ILED is equal to the first driving current I1. If the second driving voltage V2 is greater than the on threshold of the second constant current source 300, since the ratio of the resistances of the first sampling resistor R1 and the second sampling resistor R2 is equal to the ratio of the first reference voltage REF1 to the second reference voltage REF2, the voltage drop generated by the second driving current I2 on the first sampling resistor R1 is equal to the first reference voltage REF1, and finally the third driving current I3 is zero, and the actual current ILED remains constant.
In an embodiment, as shown in fig. 3, the rectifying module 100 includes a rectifying unit 110, a unidirectional current collector D1, and a storage capacitor C1.
An input terminal of the rectifying unit 110 is for inputting an alternating current VAC, the rectifying unit 110 is for generating and outputting a second driving voltage V2 from an output terminal of the rectifying unit 110 based on the input alternating current VAC, and an input terminal of the second constant current source 300 is connected to the output terminal of the rectifying unit 110. The rectifying unit 110 may include a full-bridge rectifying circuit composed of diodes for rectifying the input alternating current VAC to output the second driving voltage V2.
The positive pole of the unidirectional conduction device D1 is connected with the output end of the rectifying unit 110, the first end of the energy storage capacitor C1 and the first constant current source 200 are both connected with the negative pole of the unidirectional conduction device D1, and the second end of the energy storage capacitor C1 is grounded. By charging and discharging the energy storage capacitor C1, the first driving voltage can be generated and output, and meanwhile, according to the actual situation, the parameters of the energy storage capacitor C1 can be configured so that the voltage on the energy storage capacitor C1 is always greater than the conduction threshold of the first constant current source 200, so that the first constant current source 200 can be kept in a conduction state all the time. Wherein the unidirectional conductor D1 may be a diode.
It should be noted that, when the second driving voltage V2 is greater than the voltage on the energy storage capacitor C1, the energy storage capacitor C1 may be charged through the unidirectional current collector D1, and when the second driving voltage V2 is less than the conduction threshold of the first constant current source 200, the energy storage capacitor C1 may discharge to provide the first driving voltage to supply power to the first constant current source 200, at this time, the unidirectional current collector D1 is turned off reversely, and the electric energy output by the energy storage capacitor C1 cannot be transmitted to the second constant current source 300 through the unidirectional current collector D1, so that the second constant current source 300 is turned off.
As shown in fig. 6, waveforms of the input voltage Vin and the input current Iin received by the rectifying module 100 are shown, it should be noted that, in a period from T0 to T1, the second driving voltage V2 obtained by rectifying the input voltage Vin is greater than the on threshold of the second constant current source 300, the second constant current source 300 outputs the second driving current I2, and meanwhile, the unidirectional current conductor D1 can provide the first constant current source 200 with the first driving voltage and generate the third driving current I3, and at this time, the input current Iin is equal to the sum of the second driving current I2 and the third driving current I3. In the period from T1 to T2, the second driving voltage V2 is greater than the voltage on the energy storage capacitor C1, so the input current Iin needs to be supplied to the first constant current source 200 and the second constant current source 300 and the energy storage capacitor C1 needs to be charged at the same time, so that the input current Iin increases rapidly until the time T2 is reached. In the period from T2 to T3, since the voltage difference between the second driving voltage V2 and the energy storage capacitor C1 reaches the maximum value, the input current Iin reaches the peak current, and then the input current Iin starts to decrease until reaching the time T3, the energy storage capacitor C1 is full, the voltage on the energy storage capacitor C1 (i.e., the first driving voltage) is equal to the second driving voltage V2, the energy storage capacitor C1 is not recharged, the second constant current source 300 outputs the second driving current I2 based on the second driving voltage V2, the first constant current source 200 outputs the third driving current I3 based on the first driving voltage, so that the input current Iin remains stable, and the input current Iin is equal to the actual current ILED. Under the condition that the second driving voltage V2 is larger than the conduction threshold value of the second constant current source 300, the input current Iin is always not smaller than the second driving current I2, and further according to actual conditions, the input current Iin is enabled to be more than or equal to 5% of peak current before the voltage conduction angle is 60 degrees by adjusting the parameters of the energy storage capacitor C1 and the conduction threshold value of the second constant current source 300; before the voltage conduction angle is 65 degrees, the input current Iin reaches the maximum value; when the voltage conduction angle is 90 degrees, the input current Iin is more than or equal to 5 percent of peak current, so that the harmonic wave of the input current Iin is optimized, and the requirements of authentication standards such as CCC, CE and the like are met.
In an embodiment, as shown in fig. 7, the LED driving circuit 10 further includes a third constant current source 400, an input terminal of the third constant current source 400 is connected to the rectifying module 100, an output terminal of the third constant current source 400 is used to be connected to the second load 30, and the third constant current source 400 is configured to adjust an impedance of the third constant current source 400 according to the third reference voltage REF3 and a voltage of a third voltage feedback point in the third constant current source 400 to generate a fourth driving current based on the first driving voltage. The structure of the third constant current source 400 may be equal to that of the first current source 200.
The third voltage feedback point in the third constant current source 400 is also connected to the ground terminal of the first load 20.
The third constant current source 400 can realize wide voltage input of the LED driving circuit 10, and when the input average voltage is high, both the first and second constant current sources 200 and 300 are turned on to drive the first and second loads 20 and 30 to operate simultaneously. When the input average voltage is low, only the third constant current source 400 may be turned on, and only the second load 30 may be driven to operate.
The third constant current source 400 includes a third switching transistor Q3, a third sampling resistor R3, and a third operational amplifier unit 410. The third switching transistor Q3 may be a MOS transistor (Power MOSFET) or an IGBT transistor (insulated gate bipolar transistor).
The first end of the third switching tube Q3 is an input end of the third constant current source 400, the second end of the third switching tube Q3 is connected with the first end of the third sampling resistor R3, the first end of the third sampling resistor R3 is a first voltage feedback point of the third constant current source 400, and the second end of the third sampling resistor R3 is an output end of the third constant current source 400 and a ground GND3 of the third constant current source 400. The third operational amplifier unit 410 is configured to adjust the on-resistance of the third switching tube Q3 based on the voltage of the third voltage feedback point of the third constant current source 400 and the voltage of the ground GND3 of the third constant current source 400 so that the voltage across the third sampling resistor R3 is equal to the third reference voltage REF3.
It can be understood that the on-resistance of the third switching tube Q3 can be adjusted by controlling the voltage provided to the controlled end of the third switching tube Q3 by the third operational amplifier unit 410, so as to achieve the effect of adjusting the on-resistance of the third constant current source 400.
In an embodiment, the third operational amplifier unit 410 includes a third operational amplifier U3, a non-inverting input terminal of the first operational amplifier U1 is configured to receive the third reference voltage REF3, an inverting input terminal of the third operational amplifier U3 is connected to a first terminal of the third sampling resistor R3, a ground terminal of the third operational amplifier U3 is connected to a second terminal of the third sampling resistor R3, and an output terminal of the third operational amplifier U3 is connected to a controlled terminal of the third switching tube Q3.
The third operational amplifier U3 may adjust the output voltage according to the voltage difference between the non-inverting input terminal and the inverting input terminal, thereby controlling the on-resistance of the third switching transistor Q3.
Fig. 8 shows a schematic structural diagram of a driving apparatus according to an embodiment of the present application, and for convenience of explanation, only the portions related to the present embodiment are shown, and the following details are given:
the driving apparatus 40 includes; the main control device 50 and the LED driving circuit 10 according to any one of the above embodiments, the main control device 50 and the LED driving circuit 10 are used to control the operation of the LED driving circuit 10. The master control device 50 may be a single chip, a microprocessor, or other electronic devices.
The main control device 50 can output corresponding first reference voltage REF1 and second reference voltage REF2 to control the operation of the LED driving circuit 10.
Fig. 9 shows a schematic structural diagram of a lighting device according to an embodiment of the present application, and for convenience of explanation, only the portions related to the present embodiment are shown, which are described in detail below:
the lighting device 60 includes: the first load 20 and the LED driving circuit 10 according to any one of the above embodiments, the LED driving circuit 10 is connected to the first load 20 for driving the first load 20 to operate. Wherein the first load 20 comprises an LED light group consisting of light emitting diodes.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, the specific names of the functional units and modules are only for distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. An LED driving circuit, comprising:
a rectification module for generating a first driving voltage and a second driving voltage based on an input alternating current;
the input end of the first constant current source is connected with the rectifying module, the output end of the first constant current source and the reference ground of the first constant current source are both used for being connected with a first load, and the first constant current source is configured to adjust the on-resistance of the first constant current source according to a first reference voltage and the voltage of a first voltage feedback point in the first constant current source so as to generate and output a first driving current based on a first driving voltage; the first constant current source comprises a first sampling resistor, and the first sampling resistor is connected between the first voltage feedback point and the output end of the first constant current source;
the input end of the second constant current source is connected with the rectifying module, the output end of the second constant current source and the reference ground of the second constant current source are connected with the first voltage feedback point, and the second constant current source is configured to adjust the conduction impedance of the second constant current source according to the second reference voltage and the voltage of the second voltage feedback point in the second constant current source when the second driving voltage is larger than the conduction threshold value of the second constant current source so as to generate and output a second driving current based on the second driving voltage;
the second driving current is used for being transmitted to the first load through the first sampling resistor to work and increasing the voltage of the first voltage feedback point, so that the first constant current source generates a third driving current, and the sum of the second driving current and the third driving current is equal to the first driving current.
2. The LED driving circuit according to claim 1, wherein the first constant current source further includes a first switching tube and a first operational amplifier unit;
the first end of the first switch tube is the input end of the first constant current source, the second end of the first switch tube is connected with the first end of the first sampling resistor, the first end of the first sampling resistor is a first voltage feedback point of the first constant current source, and the second end of the first sampling resistor is the output end of the first constant current source and the reference ground of the first constant current source;
the first operational amplifier unit is configured to adjust the on-resistance of the first switching tube based on the voltage of the first voltage feedback point of the first constant current source and the voltage of the first constant current source with reference to the ground so that the voltage on the first sampling resistor is equal to the first reference voltage.
3. The LED driving circuit of claim 2, wherein the first operational amplifier unit comprises a first operational amplifier having a non-inverting input for receiving the first reference voltage, an inverting input connected to the first terminal of the first sampling resistor, a ground connected to the second terminal of the first sampling resistor, and an output connected to the controlled terminal of the first switching tube.
4. The LED driving circuit according to claim 2, wherein the second constant current source includes a second switching tube, a second sampling resistor, and a second operational amplifier unit;
the first end of the second switching tube is the input end of the second constant current source, the second end of the second switching tube is connected with the first end of the second sampling resistor, the first end of the second sampling resistor is a second voltage feedback point of the second constant current source, and the second end of the second sampling resistor is the output end of the second constant current source and the reference ground of the second constant current source;
the second operational amplifier unit is configured to adjust the on-resistance of the second switching tube based on the voltage of the second voltage feedback point of the second constant current source and the voltage of the reference ground of the second constant current source so that the voltage on the second sampling resistor is equal to the second reference voltage.
5. The LED driving circuit of claim 4, wherein the second operational amplifier unit comprises a second operational amplifier having a non-inverting input for receiving the second reference voltage, an inverting input connected to the first terminal of the second sampling resistor, a ground connected to the second terminal of the second sampling resistor, and an output connected to the controlled terminal of the second switching tube.
6. The LED driving circuit of claim 4, wherein the first reference voltage is greater than the second reference voltage, and the first sampling resistor and the second sampling resistor have equal resistance values;
or the first reference voltage is not larger than the second reference voltage, and the ratio of the resistance values of the first sampling resistor and the second sampling resistor is equal to the ratio of the first reference voltage and the second reference voltage.
7. The LED driving circuit of claim 1, wherein the rectifying module comprises a rectifying unit, a unidirectional current transformer, and an energy storage capacitor;
the input end of the rectifying unit is used for accessing the input alternating current, and the rectifying unit is used for generating the second driving voltage based on the input alternating current;
the positive electrode of the unidirectional conductor is connected with the output end of the rectifying unit, and the negative electrode of the unidirectional conductor is used for outputting the first driving voltage;
the first end of the energy storage capacitor is connected with the negative electrode of the unidirectional conductor, and the second end of the energy storage capacitor is grounded.
8. The LED driving circuit according to claim 1, further comprising a third constant current source having an input connected to the rectifying module, an output for connection to a second load, the third constant current source configured to adjust an impedance of the third constant current source according to a third reference voltage and a voltage of a third voltage feedback point in the third constant current source to generate a fourth driving current based on the first driving voltage;
and a third voltage feedback point in the third constant current source is also connected with the grounding end of the first load.
9. A driving apparatus, characterized by comprising; a master device and an LED driving circuit according to any one of claims 1 to 8, the master device and the LED driving circuit being arranged to control operation of the LED driving circuit.
10. A lighting device, comprising: a first load and an LED driving circuit as claimed in any one of claims 1 to 8, the LED driving circuit being connected to the first load for driving the first load into operation.
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| CN202311215863.6A CN116963347B (en) | 2023-09-20 | 2023-09-20 | LED drive circuit, drive device and lighting device |
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| CN202311215863.6A CN116963347B (en) | 2023-09-20 | 2023-09-20 | LED drive circuit, drive device and lighting device |
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| CN110933798A (en) * | 2019-07-24 | 2020-03-27 | 深圳市晟碟半导体有限公司 | LED drive circuit and drive device |
| CN210670677U (en) * | 2019-08-20 | 2020-06-02 | 深圳市晟碟半导体有限公司 | High-power-factor stroboflash-free LED dimming circuit and device |
| CN211959628U (en) * | 2020-03-26 | 2020-11-17 | 上海源微电子科技有限公司 | LED constant current drive circuit with high PF does not have stroboscopic |
| US11202146B1 (en) * | 2020-09-03 | 2021-12-14 | Algo Communication Products Ltd. | IP speaker system |
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| CN106851911A (en) * | 2017-02-20 | 2017-06-13 | 深圳市明微电子股份有限公司 | The LED linear constant-current control circuit and LED light emission device of a kind of self adaptation clamper |
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| US11202146B1 (en) * | 2020-09-03 | 2021-12-14 | Algo Communication Products Ltd. | IP speaker system |
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| CN116963347B (en) | 2024-01-19 |
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