CN111565500A - LED drive circuit with high power factor and low harmonic and LED device - Google Patents

Abstract

The invention belongs to the technical field of LED driving, and discloses an LED driving circuit with high power factor and low harmonic and an LED device, wherein a voltage division circuit divides direct-current voltage to generate reference voltage, and a clamping circuit outputs an analog quantity signal equal to the reference voltage; the constant current circuit controls the output current according to the analog quantity signal so that the output current is in direct proportion to the analog quantity signal, or controls the output current so that the output current is in direct proportion to the reference voltage so that the output current of the constant current circuit is in direct proportion to the direct-current voltage, and therefore harmonic distortion of the LED drive circuit with high power factor and low harmonic is reduced.

Description

LED drive circuit and LED device with high power factor and low harmonics

technical field

The invention belongs to the technical field of LED driving, and in particular relates to an LED driving circuit and an LED device with high power factor and low harmonics.

Background technique

The traditional LED drive circuit generally adopts constant current drive, and the constant current drive realized by operational amplifiers and switching elements generally has the problems of low power factor and excessive harmonic distortion, especially for high-power LED drive circuits, its power The problems of low factor and harmonic distortion are even more pronounced. Therefore, the traditional LED driving circuit is improved to drive the LED by using a segmented driving circuit, thereby improving its power factor, but this driving mode still does not solve the problem of excessive harmonic distortion. Therefore, an LED driving circuit with high power factor and low harmonics is required to solve the problem of excessive harmonic distortion in LED driving.

SUMMARY OF THE INVENTION

In view of this, the embodiments of the present invention provide an LED driving circuit and an LED device with high power factor and low harmonics, aiming to solve the problem of excessive harmonic distortion in the traditional technical solution.

A first aspect of the embodiments of the present invention provides an LED driving circuit with high power factor and low harmonics. The LED driving circuit with high power factor and low harmonics includes a voltage divider circuit, an LED component, N clamping circuits, N +1 constant current circuit and current limiting components;

The voltage dividing circuit is configured to divide the DC voltage to generate a reference voltage when the DC voltage is connected;

The LED assembly includes N+1 loads connected in series in sequence, the N+1 loads include the first load to the N+1th load, the positive pole of the first load is connected to the DC voltage, and the kth load is connected to the DC voltage. The negative pole is connected to the positive pole of the k+1th load; wherein, N is an integer greater than or equal to 1, and k is a positive integer less than or equal to N;

The i-th clamping circuit is connected to the voltage divider circuit, and is configured to be configured when the reference voltage is less than the clamping voltage of the i-th clamping circuit and when the reference voltage is greater than or equal to the i-1-th clamping circuit When the clamping voltage of the clamping circuit is used, an analog signal equal to the reference voltage is output; wherein, i is a positive integer less than or equal to N;

The jth constant current circuit is connected to the jth clamping circuit, the jth load, the j+1th load and the current limiting component, and is configured to control the output current according to the analog signal to Make the output current proportional to the analog signal; wherein, j is a positive integer less than or equal to N;

The N+1 th constant current circuit is connected to the N+1 th load, the voltage dividing circuit and the current limiting component, and is configured to be configured when the reference voltage is greater than or equal to the clamping force of the N th clamping circuit When the reference voltage is less than the upper limit voltage, the output current is controlled so that the output current is proportional to the reference voltage;

The current limiting component is configured to limit the output current of the constant current circuit.

In one embodiment of the first aspect, each of the N clamp circuits includes a clamp component, and the clamp component includes a first operational amplifier, a second operational amplifier, a first field effect transistor, and a first resistor;

The non-inverting input terminal of the first operational amplifier is the reference voltage input terminal of the clamping circuit, the non-inverting input terminal of the second operational amplifier is the clamping voltage input terminal of the clamping circuit, and the inverting phase of the first operational amplifier is The input end, the inverting input end of the second operational amplifier, the source of the first field effect transistor and the first end of the first resistor together form the output end of the clamping circuit, the output end of the first operational amplifier and the second The output end of the operational amplifier is commonly connected to the gate of the first field effect transistor, the drain of the first field effect transistor is connected to the internal power supply, and the second end of the first resistor is connected to the power supply ground.

In one embodiment of the first aspect, each of the N constant current circuits includes a constant current component, and the constant current component includes a third operational amplifier and a second field effect transistor;

The non-inverting input end of the third operational amplifier is the analog signal input end of the constant current component, the output end of the third operational amplifier is connected to the gate of the second field effect transistor, and the negative phase of the third operational amplifier is The input end and the source of the second field effect transistor together form the output current output end of the constant current component, and the drain of the second field effect transistor is the input voltage input end of the constant current component;

The N+1th constant current circuit includes a fourth operational amplifier and a third field effect transistor;

The non-inverting input terminal of the fourth operational amplifier is the upper limit voltage input terminal of the N+1th constant current circuit, the output terminal of the fourth operational amplifier is connected to the gate of the third field effect transistor, and the fourth operational amplifier The negative-phase input terminal of the amplifier and the source of the third field effect transistor together form the output current output terminal of the N+1th constant current circuit, and the drain of the third field effect transistor is the output terminal of the N+1th constant current circuit. Input voltage input terminal.

In one embodiment of the first aspect, the voltage divider circuit includes a second resistor and a third resistor, and the second end of the second resistor and the first end of the third resistor together form a reference voltage output of the voltage divider circuit The first end of the second resistor is the first input end of the DC voltage of the voltage divider circuit, and the second end of the third resistor is the second input end of the DC voltage of the voltage divider circuit.

In an embodiment of the first aspect, the high power factor and low harmonic LED driving circuit further includes:

A rectifier circuit that is connected to alternating current and used to rectify alternating current to generate direct current voltage.

In one embodiment of the first aspect, the rectifier circuit includes a first diode, a second diode, a third diode and a fourth diode; the anode of the first diode is connected to the first diode The positive poles of the four diodes together form the second DC voltage output end of the rectifier circuit, the negative pole of the first diode and the positive pole of the second diode together form the first alternating current input end of the rectifier circuit, the second The cathode of the diode and the cathode of the third diode together constitute the first DC voltage output end of the rectifier circuit, and the anode of the third diode and the cathode of the fourth diode together constitute the second alternating current of the rectifier circuit input.

A second aspect of the embodiments of the present invention provides an LED device, where the LED device includes the LED driving circuit with high power factor and low harmonics according to any embodiment of the first aspect.

The above-mentioned LED drive circuit with high power factor and low harmonics is set by setting N clamping circuits and N+1 constant current circuits; when the reference voltage is less than the clamping voltage of the ith clamping circuit and when the reference voltage is greater than or equal to the ith When the clamping voltage of -1 clamping circuit, the ith clamping circuit outputs an analog signal equal to the reference voltage to the jth constant current circuit, and the jth constant current circuit controls the output current according to the analog signal so that the output current is proportional to the analog signal; when the reference voltage of the N+1th constant current circuit is greater than or equal to the clamping voltage of the Nth clamping circuit and the reference voltage is less than the upper limit voltage, The output current is controlled so that the output current is proportional to the reference voltage; therefore, the N clamp circuits and the N+1 constant current circuits are therefore in so that the output current of the LED driver circuit remains proportional to the DC voltage, minus The harmonic distortion of the LED drive circuit is reduced.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic block diagram of an LED driving circuit with high power factor and low harmonics provided by an embodiment of the present application;

FIG. 2 is a schematic circuit diagram of a clamping component provided by an embodiment of the present application;

FIG. 3 is a schematic circuit diagram of a constant current component provided by an embodiment of the present application;

4 is a circuit schematic diagram of an N+1 th constant current circuit provided by an embodiment of the present application;

FIG. 5 is a circuit schematic diagram of a voltage divider circuit provided by an embodiment of the present application;

6 is a schematic block diagram of an LED driving circuit with high power factor and low harmonics provided by another embodiment of the present application;

FIG. 7 is a circuit schematic diagram of a rectifier circuit provided by an embodiment of the present application;

FIG. 8 is a circuit schematic diagram of an LED driving circuit with high power factor and low harmonics provided by an embodiment of the present application;

FIG. 9 is the output voltage and current waveforms of the LED driving circuit with high power factor and low harmonics of the present application.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in FIG. 1 , an embodiment of the present invention provides an LED driving circuit with high power factor and low harmonics. For the convenience of description, only the parts related to this embodiment are shown. The details are as follows. A high power factor Low harmonic LED drive circuit, high power factor low harmonic LED drive circuit 1 includes a voltage divider circuit 101 , LED components 11 , N clamping circuits, N+1 constant current circuits and a current limiting component 14 .

The voltage dividing circuit 101 is configured to divide the DC voltage to generate a reference voltage when the DC voltage is connected.

The LED assembly 11 includes N+1 loads connected in series in sequence, the N+1 loads include the first load 111 to the N+1 th load 11n+1, the positive pole of the first load 111 is connected to the DC voltage, and the k th load The negative electrode is connected to the positive electrode of the k+1th load; wherein, N is an integer greater than or equal to 1, which means that the LED assembly 11 includes at least two loads; wherein, k is a positive integer not greater than N.

The i-th clamp circuit 12i in the N clamp circuits is connected to the voltage divider circuit 101, the i-th clamp circuit 12i inputs a reference voltage, and the i-th clamp circuit 12i is also configured so that when the reference voltage is lower than the i-th clamp circuit 12i The clamping voltage of the bit circuit 12i and when the reference voltage is greater than or equal to the clamping voltage of the i-1 th clamping circuit, it outputs an analog signal equal to the reference voltage; wherein, the clamping voltage of the i-1 th clamping circuit The voltage is less than the clamping voltage of the ith clamping circuit 12i; among them, i is a positive integer less than or equal to N, because N is an integer greater than or equal to 1, so the minimum value of i is 1; it should be noted that when N is When it is 1, that is, when i is also 1, there is no i-1 th clamp circuit. At this time, the first clamp circuit is configured so that when the reference voltage is less than the clamp voltage of the first clamp circuit 121, the output is An analog signal equal to a reference voltage.

The N+1 constant current circuits include N constant current circuits and an N+1 th constant current circuit. Among them, the jth constant current circuit 13j among the N constant current circuits is respectively connected with the jth clamp circuit, the jth load, the j+1th load and the current limiting component 14; the jth constant current circuit 13j It is also configured to control the output current according to the analog signal so that the output current is proportional to the analog signal; wherein, j is a positive integer less than or equal to N. The output current of the jth constant current circuit 13j is proportional to the analog signal, the analog signal is equal to the reference voltage, and the reference voltage is obtained by dividing the DC voltage, so when the output current of the jth constant current circuit 13j is proportional to the DC voltage Proportional, the LED driver circuit has less harmonic distortion.

The N+1th constant current circuit 13n+1 is respectively connected to the N+1th load 11n+1, the voltage dividing circuit 101 and the current limiting component 14; the N+1th constant current circuit 13n+1 is also configured as a reference When the voltage is greater than or equal to the clamping voltage of the Nth clamping circuit and the reference voltage is smaller than the upper limit voltage, the output current is controlled so that the output current is proportional to the reference voltage. The upper limit voltage is the peak value that the DC voltage of the reference voltage can reach under normal conditions. Because the reference voltage is obtained by dividing the DC voltage, the waveform of the reference voltage is the same as that of the DC voltage, and the output current of the N+1th constant current circuit 13n+1 is proportional to the waveform of the reference voltage, so the Nth The output current of the +1 constant current circuit 13n+1 is proportional to the DC voltage, so when the N+1 th constant current circuit 13n+1 outputs, the harmonic distortion of the LED driving circuit is small.

The current limiting component 14 is configured to limit the output current of the constant current circuit.

As shown in FIG. 2, in one embodiment, each of the N clamping circuits includes a clamping component, and the clamping component includes: a first operational amplifier U1, a second operational amplifier U2, a first field effect transistor Q1 and a first resistor R1; the non-inverting input terminal of the first operational amplifier U1 is the reference voltage input terminal of the clamping circuit; the non-inverting input terminal of the second operational amplifier U2 is the clamping voltage input terminal of the clamping circuit; the inverting input terminal of the first operational amplifier U1 terminal, the inverting input terminal of the second operational amplifier U2, the source of the first field effect transistor Q1 and the first terminal of the first resistor R1 together form the output terminal of the clamping circuit; the output terminal of the first operational amplifier U1 and the first terminal of the first The output terminals of the two operational amplifiers U2 are commonly connected to the gate of the first field effect transistor Q1; the drain of the first field effect transistor Q1 is connected to the internal power supply; the second end of the first resistor R1 is connected to the power supply ground.

As shown in FIG. 3, in one embodiment, the N constant current circuits include constant current components, and the constant current components include a third operational amplifier U3 and a second field effect transistor Q2; the non-inverting input terminal of the third operational amplifier U3 is The analog signal input terminal of the constant current component; the output terminal of the third operational amplifier U3 is connected to the gate of the second field effect transistor Q2; the negative phase input terminal of the third operational amplifier U3 is connected to the source of the second field effect transistor Q2 Together they form the output current output end of the constant current component; the drain of the second field effect transistor Q2 is the input voltage input end of the constant current component.

As shown in FIG. 4, in one embodiment, the N+1th constant current circuit 13n+1 includes a fourth operational amplifier U4 and a third field effect transistor Q3; the non-inverting input terminal of the fourth operational amplifier U4 is the N+th operational amplifier U4. The upper limit voltage input end of a constant current circuit 13n+1; the output end of the fourth operational amplifier U4 is connected to the gate of the third field effect transistor Q3; the negative phase input end of the fourth operational amplifier U4 is connected to the third field effect transistor The source of Q3 together forms the output current output terminal of the N+1th constant current circuit 13n+1; the drain of the third FET Q3 is the input voltage input terminal of the N+1th constant current circuit 13n+1.

As shown in FIG. 5 , in one embodiment, the voltage divider circuit 101 includes a second resistor R2 and a third resistor R3 , and the second end of the second resistor R2 and the first end of the third resistor R3 together form the voltage divider circuit 101 The first end of the second resistor R2 is the first input end of the DC voltage of the voltage divider circuit 101 , and the second end of the third resistor R3 is the second input end of the DC voltage of the voltage divider circuit 101 .

As shown in FIG. 6 , in one embodiment, the LED driving circuit 1 with high power factor and low harmonics further includes a rectifier circuit 105 , which is connected to the alternating current for rectifying the alternating current to generate a direct current voltage.

As shown in FIG. 7, in one embodiment, the rectifier circuit 105 includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4; the first diode D1 The anode of the rectifier circuit 105 and the anode of the fourth diode D4 together form the second output end of the rectifier circuit 105, the cathode of the first diode D1 and the anode electrode of the second diode D2 together form the first input end of the rectifier circuit 105, The cathode of the second diode D2 and the cathode of the third diode D3 together constitute the first output end of the rectifier circuit 105 , and the anode of the third diode D3 and the cathode of the fourth diode D4 together constitute the rectifier circuit 105 of the second input.

The following is a further description of what is shown in FIG. 8 in conjunction with the working principle, wherein, what is shown in FIG. 7 is the circuit schematic diagram of the LED drive circuit with high power factor and low harmonics when N is 2, that is, the high power factor and low harmonics. The LED driving circuit 1 includes a rectifier circuit 105, a voltage divider circuit 101, an LED component 11, two clamping circuits, three constant current circuits and a current limiting component 14. The current limiting component 14 is a resistor R4, wherein the LED component 11 includes a first The light emitting diode L1, the second light emitting diode L2, and the third light emitting diode L3; it should be noted that this embodiment does not limit the LED driving circuit 1 with high power factor and low harmonics, but is an example. Accordingly, it is considered that the N of the LED driving circuit 1 with high power factor and low harmonics can only be set to be 2. The rectifier circuit 105 rectifies the alternating current to output a direct current voltage, and the second resistor R2 and the third resistor R3 divide the direct current voltage and output a reference voltage.

When the reference voltage is not greater than the clamping voltage of the first clamping circuit 121, the non-inverting input terminal of the first operational amplifier U1 of the first clamping circuit 121 inputs the reference voltage, and the non-inverting input terminal of the second operational amplifier U2 inputs the clamping voltage Bit voltage V1, because the negative input terminal of the first operational amplifier U1, the negative input terminal of the second operational amplifier U2, the source of the first field effect transistor Q1 and the first terminal of the first resistor R1 are connected in common, the first The operational amplifier U1 outputs a high level to the gate of the first field effect transistor Q1, so that the first field effect transistor Q1 is turned on, so that the source of the first field effect transistor Q1 outputs an analog signal equal to the reference voltage to the first field effect transistor Q1. The non-inverting input terminal of the third operational amplifier U3, so the output terminal of the third operational amplifier U3 outputs a high level to the gate of the second field effect transistor Q2 of the first constant current circuit 131, so that the first constant current circuit 131 The two field effect transistors Q2 are turned on, and at the same time, because the negative input terminal of the third operational amplifier U3, the source of the second field effect transistor Q2 and the first terminal of the current limiting component 14 (the fourth resistor R4) are connected in common, so that the The current flowing through the first light-emitting diode L1 is proportional to the analog signal, so that the current flowing through the first light-emitting diode L1 is proportional to the DC voltage, so when only the first light-emitting diode L1 is turned on, the output of the LED drive circuit The current is proportional to the DC voltage, and the harmonic distortion is small.

When the reference voltage is greater than the clamping voltage of the first clamping circuit 121 and the reference voltage is not greater than the clamping voltage of the second clamping circuit 122, the negative phase of the third operational amplifier U3 of the first clamping circuit 121 The voltage of the input terminal is greater than that of the non-inverting input terminal, so the output terminal of the third operational amplifier U3 of the first clamping circuit 121 outputs a low level so that the second field effect transistor Q2 of the first constant current module 121 is turned off. The bit circuit 122 outputs an analog quantity equal to the reference voltage to the second constant current module 132 to turn on the second field effect transistor Q2 of the second constant current module 132, so that the first LED L1 and the second LED L2 flow through. The current is proportional to the DC voltage, so when the first LED L1 and the second LED L2 are both turned on, the output current of the LED drive circuit is proportional to the DC voltage, and the harmonic distortion is small.

When the reference voltage is greater than the clamping voltage of the second clamping circuit 122, the voltage of the negative-phase input terminal of the third operational amplifier U3 of the second clamping circuit 122 is greater than the voltage of the positive-phase input terminal, and the third The output terminal of the operational amplifier U3 outputs a low level, so that the second field effect transistor Q2 of the second clamping circuit 122 is turned off, and at the same time, the fourth operational amplifier U4 outputs a high level to the third field effect transistor Q3, so that the third field effect transistor Q3 turn on, so that the current flowing through the first light emitting diode L1, the second light emitting diode L2 and the third light emitting diode L3 is proportional to the reference voltage, so that the first light emitting diode L1, the second light emitting diode L2 and the third light emitting diode The current of the diode L3 is proportional to the DC voltage, so when the first light-emitting diode L1, the second light-emitting diode L2 and the third light-emitting diode L3 are all turned on, the output current of the LED driving circuit 1 with high power factor and low harmonics It is also proportional to the DC voltage, and the harmonic distortion is small. To sum up, the waveforms of the output current and DC voltage of the LED driving circuit 1 with high power factor and low harmonics are as shown in FIG. 9 , and the harmonic distortion is small.

An embodiment of the present invention also provides an LED device, the LED device includes the high power factor and low harmonic LED drive circuit of any of the above embodiments, because the LED device in this embodiment includes any of the above embodiments Therefore, the LED device in this embodiment at least includes the beneficial effects corresponding to the LED driving circuit with high power factor and low harmonics of any one of the above-mentioned embodiments.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. Inside.

Claims (7)

1. An LED drive circuit with high power factor and low harmonic is characterized in that,

the LED drive circuit with high power factor and low harmonic comprises a voltage division circuit, an LED component, N clamping circuits, N +1 constant current circuits and a current limiting component;

the voltage division circuit is configured to divide a direct-current voltage to generate a reference voltage when the direct-current voltage is switched on;

the LED assembly comprises N +1 loads which are sequentially connected in series, the N +1 loads comprise a first load to an N +1 th load, the positive pole of the first load is connected with direct-current voltage, and the negative pole of the kth load is connected with the positive pole of the kth +1 th load; wherein N is an integer greater than or equal to 1, and k is a positive integer less than or equal to N;

the ith clamping circuit is connected with the voltage division circuit and is configured to output an analog quantity signal equal to the reference voltage when the reference voltage is less than the clamping voltage of the ith clamping circuit and when the reference voltage is greater than or equal to the clamping voltage of the (i-1) th clamping circuit; wherein i is a positive integer less than or equal to N;

the jth constant current circuit is connected with the jth clamping circuit, the jth load, the jth +1 load and the current limiting component and is configured to control output current according to the analog quantity signal so that the output current is in direct proportion to the analog quantity signal; wherein j is a positive integer less than or equal to N;

the (N + 1) th constant current circuit is connected with the (N + 1) th load, the voltage division circuit and the current limiting component and is configured to control output current so that the output current is in direct proportion to the reference voltage when the reference voltage is greater than or equal to the clamping voltage of the Nth clamping circuit and is less than the upper limit voltage;

the current limiting component is configured to limit an output current of the constant current circuit.

2. The high power factor low harmonic LED drive circuit of claim 1 wherein each of the N clamping circuits comprises a clamping component comprising a first operational amplifier, a second operational amplifier, a first field effect transistor, and a first resistor;

the non-inverting input end of the first operational amplifier is a reference voltage input end of a clamping circuit, the non-inverting input end of the second operational amplifier is a clamping voltage input end of the clamping circuit, the inverting input end of the first operational amplifier, the inverting input end of the second operational amplifier, the source electrode of the first field effect transistor and the first end of the first resistor jointly form an output end of the clamping circuit, the output end of the first operational amplifier and the output end of the second operational amplifier are connected to the grid electrode of the first field effect transistor in a shared mode, the drain electrode of the first field effect transistor is connected with an internal power supply, and the second end of the first resistor is connected with a power supply ground.

3. The high-power-factor low-harmonic LED driving circuit according to claim 1, wherein each of the N constant current circuits includes a constant current component, and the constant current component includes a third operational amplifier and a second field-effect transistor;

the non-inverting input end of the third operational amplifier is an analog quantity signal input end of the constant current component, the output end of the third operational amplifier is connected with the grid electrode of the second field-effect tube, the negative phase input end of the third operational amplifier and the source electrode of the second field-effect tube jointly form an output current output end of the constant current component, and the drain electrode of the second field-effect tube is an input voltage input end of the constant current component;

the (N + 1) th constant current circuit comprises a fourth operational amplifier and a third field effect transistor;

the non-inverting input end of the fourth operational amplifier is the upper limit voltage input end of the (N + 1) th constant current circuit, the output end of the fourth operational amplifier is connected with the grid electrode of the third field-effect tube, the negative phase input end of the fourth operational amplifier and the source electrode of the third field-effect tube jointly form the output current output end of the (N + 1) th constant current circuit, and the drain electrode of the third field-effect tube is the input voltage input end of the (N + 1) th constant current circuit.

4. The high power factor low harmonic LED drive circuit of claim 1 wherein the voltage divider circuit comprises a second resistor and a third resistor, a second terminal of the second resistor and a first terminal of the third resistor together forming a reference voltage output terminal of the voltage divider circuit; the first end of the second resistor is a direct-current voltage first input end of the voltage division circuit, and the second end of the third resistor is a direct-current voltage second input end of the voltage division circuit.

5. The high power factor low harmonic LED drive circuit of claim 1 further comprising:

and a rectifying circuit electrically connected to the alternating current for rectifying the alternating current to generate a direct current voltage.

6. The high power factor low harmonic LED drive circuit of claim 5 wherein the rectifying circuit comprises a first diode, a second diode, a third diode, and a fourth diode; the positive pole of the first diode and the positive pole of the fourth diode jointly form a second direct current voltage output end of the rectifying circuit, the negative pole of the first diode and the positive pole of the second diode jointly form a first alternating current input end of the rectifying circuit, the negative pole of the second diode and the negative pole of the third diode jointly form a first direct current voltage output end of the rectifying circuit, and the positive pole of the third diode and the negative pole of the fourth diode jointly form a second alternating current input end of the rectifying circuit.

7. An LED device comprising the high power factor low harmonic LED driving circuit according to any one of claims 1 to 6.

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