LED drive circuit

Abstract

The present application discloses an LED driving circuit, which belongs to the field of integrated circuits. The LED driving circuit includes a voltage dividing module, a capacitor charging suppression module, a first capacitor, a ripple current filtering module, and an LED module. The voltage dividing module is used to divide the voltage output by the rectifier module. The voltage dividing module is electrically connected to the capacitor charging suppression module. The first capacitor and the capacitor charging suppression module are connected in series between the rectifier module and the ground. The LED module and the ripple current filtering module are connected in series and in parallel with the first capacitor, so that the power factor of the driving circuit is high, the LED module is compatible with no flicker when it is lit, and the current flowing through the LED is constant.

Description

Technical Field

[0001] The present application belongs to the field of integrated circuits, and specifically relates to an LED driving circuit. Background Art

[0002] With the development of lighting technology, LED lights have entered thousands of households. Before lighting the LED lights, a driving circuit is needed to drive and light the LED lights.

[0003] In the prior art, a multi-segment linear drive circuit is usually used to drive an LED lamp. In the specific driving process, the multi-segment linear drive circuit is turned on in sections according to the input voltage, and the current input to the multi-segment linear drive circuit is approximately a sine waveform with a high power factor value; however, due to the high and low input voltage, the current flowing through the LED and the like is related to the input voltage frequency, which will cause the current flowing through the LED lamp to contain power frequency ripples, thereby causing the LED lamp to flicker when it is in the lit state. If a large-capacity filtering first capacitor is added to the multi-segment linear drive circuit to increase the valley voltage after rectification, so that the total voltage of the LED lamp is lower than the valley voltage after rectification, the LED lamp driving current is not affected by the frequency of the AC input voltage, thereby causing the current flowing through the LED lamp to not contain power frequency ripples, and there is no flicker when the LED lamp is in the lit state; however, since the first filtering capacitor has the characteristics of large capacity, high voltage, and slow discharge, the input voltage can only charge the first filtering capacitor at the peak, and the conduction angle of the input current is very small, resulting in a low power factor of the driving circuit. Therefore, the driving circuit in the prior art has the problem that the process of driving the LED lamp to light up cannot be compatible with the advantages of high power factor and no flicker when the LED lamp is in the lighting state. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide an LED driving circuit that can solve the problem that the driving circuit cannot have the advantages of high power factor and no flicker when the LED lamp is in the lit state during the process of driving the LED lamp to light up.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] An embodiment of the present application provides an LED driving circuit, including a voltage divider module, a capacitor charging suppression module, a first capacitor, a ripple current filtering module, and an LED module. The voltage divider module is used to divide the voltage output by the rectifier module. The voltage divider module is electrically connected to the capacitor charging suppression module. The first capacitor and the capacitor charging suppression module are connected in series between the rectifier module and the ground. The LED module and the ripple current filtering module are connected in series and then connected in parallel with the first capacitor.

[0007] Optionally, the rectification module, the LED module, the ripple current filtering module, and the capacitor charging suppression module are connected in series in sequence.

[0008] Optionally, the rectification module, the ripple current filtering module, the LED module, and the capacitor charging suppression module are connected in series in sequence.

[0009] Optionally, an input end of the voltage divider module is connected between the LED module and the ripple current filtering module, and an output end of the voltage divider module is connected to the capacitor charging suppression module.

[0010] Optionally, the voltage divider module is connected in series between the rectifier module and ground.

[0011] Optionally, the rectifier module, the first capacitor, the capacitor charging suppression module, and the ground are connected in series in sequence.

[0012] Optionally, the rectifier module, the capacitor charging suppression module, the first capacitor, and the ground are connected in series in sequence.

[0013] Optionally, a filtering module is connected in series between the voltage dividing module and the capacitor charging suppression module.

[0014] Optionally, a power regulator is connected in series between the voltage dividing module and the capacitor charging suppression module.

[0015] Optionally, the capacitor charging suppression module includes a first operational amplifier, a first resistor, and a first switch tube. The first switch tube and the first resistor are connected in series between the first capacitor and the ground in sequence. The non-phase input terminal of the first operational amplifier is connected to the voltage divider module, the inverting input terminal of the first operational amplifier is connected between the first resistor and the first switch tube, and the output terminal of the first operational amplifier is connected to the gate of the first switch tube.

[0016] Optionally, the ripple current filtering module includes a second resistor, a second switch tube, and a second operational amplifier. The second switch tube and the second resistor are connected in series between the LED module and the capacitor charging suppression module. The non-phase input terminal of the second operational amplifier is connected to the reference voltage terminal, the inverting input terminal of the second operational amplifier is connected between the second switch tube and the second resistor, and the output terminal of the second operational amplifier is electrically connected to the gate of the second switch tube.

[0017] Optionally, the voltage dividing module includes a third resistor and a fourth resistor connected in series, and the capacitor charging suppression module is connected between the third resistor and the fourth resistor.

[0018] In the embodiment of the present application, the voltage output by the rectifier module is divided by the voltage divider module, the voltage divider module is electrically connected to the capacitor charging suppression module, the first capacitor and the capacitor charging suppression module are connected in series between the rectifier module and the ground, the LED module and the ripple current filtering module are connected in series and in parallel with the first capacitor, the rectifier module rectifies the mains power and outputs it to the voltage divider module and the first capacitor, the first capacitor starts to charge after obtaining the current, the capacitor charging suppression module collects the first divided voltage after the voltage divider module divides the voltage output by the rectifier module and collects the second divided voltage inside itself, and continuously dynamically guides the first divided voltage and the second divided voltage according to the first divided voltage and the second divided voltage. The first capacitor is turned on and off, thereby extending the time from the beginning of charging to full charging of the first capacitor (i.e., the conduction angle of the current output by the rectifier is enlarged), so that the power factor of the drive circuit is high; in addition, the rectifier module will rectify the AC power and output it to the LED module and the ripple current filtering module, so that the LED module is lit and the ripple current filtering module is continuously and dynamically turned on and off, thereby filtering out the industrial frequency ripple in the current input to the LED module, so that there is no flicker when the LED module is lit. The above method achieves the compatibility of a high power factor of the drive circuit and no flicker when the LED module is lit, and the current flowing through the LED is constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a circuit connection block diagram of an LED driving circuit provided by an embodiment of the present application;

[0020] Figure 2 This is a circuit connection block diagram of an LED driving circuit provided by an embodiment of the present application;

[0021] Figure 3 This is a circuit connection block diagram of an LED driving circuit provided by an embodiment of the present application;

[0022] Figure 4 This is a circuit connection block diagram of an LED driving circuit provided by an embodiment of the present application;

[0023] Figure 5 is a circuit diagram of an LED driving circuit provided by an embodiment of the present application;

[0024] Figure 6 This is a circuit diagram of an LED driving circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. In addition, the "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated with each other are in an "or" relationship.

[0027] The LED driving circuit provided in the embodiment of the present application is described in detail below through specific embodiments and application scenarios in conjunction with the accompanying drawings.

[0028] The embodiment of the present application provides an LED driving circuit, which is connected to a rectifier module 100 for rectifying the mains electricity, wherein the rectifier module 100 can be a bridge rectifier module. Specifically, the LED driving circuit includes a voltage dividing module 101, a capacitor charging suppression module 102, a first capacitor C1, a ripple current filtering module 103, and an LED module 105. The voltage dividing module 101 is used to divide the voltage output by the rectifier module 100. The voltage dividing module 101 is electrically connected to the capacitor charging suppression module 102. The first capacitor C1 and the capacitor charging suppression module 102 are connected in series between the rectifier module 100 and the ground. The LED module 105 and the ripple current filtering module 103 are connected in series and connected in parallel with the first capacitor C1.

[0029] The LED driving circuit divides the voltage output by the rectifier module 100 through the voltage divider module 101. The voltage divider module 101 is electrically connected to the capacitor charging suppression module 102. The first capacitor C1 and the capacitor charging suppression module 102 are connected in series between the rectifier module 100 and the ground. The LED module 105 and the ripple current filtering module 103 are connected in series and connected in parallel with the first capacitor C1. The rectifier module 100 rectifies the mains power and outputs it to the voltage divider module 101 and the first capacitor C1 respectively. After the first capacitor C1 obtains the current, it starts to charge. The capacitor charging The electric suppression module 102 will collect the first divided voltage after the voltage divided by the voltage divider module 101 on the voltage output of the rectifier module 100 and collect the second divided voltage inside itself, and will be dynamically turned on and off continuously according to the first divided voltage and the second divided voltage, so as to extend the time from the beginning of charging to the full charging of the first capacitor C1 (i.e., the conduction angle of the current output by the rectifier is enlarged), so that the power factor of the drive circuit is high; in addition, the rectifier module 100 will rectify the AC power and output it to the LED module 105 and the ripple current filtering module 103, so that the LED module 105 is lit and the ripple current filtering module 103 is continuously dynamically turned on and off, so as to filter out the industrial frequency ripple in the current input to the LED module 105, so that there is no flicker when the LED module 105 is lit. In the above manner, the compatibility of the high power factor of the drive circuit and the non-stroboscopic when the LED module 105 is lit is achieved, and the current flowing through the LED is constant.

[0030] Specifically, the specific connection methods of the LED module 105 and the ripple current filtering module 103 include but are not limited to the following two:

[0031] The first type: Figure 1 As shown, the rectifier module 100, the LED module 105, the ripple current filtering module 103, and the capacitor charging suppression module 102 are connected in series in sequence.

[0032] The second type: Figure 2 As shown, the rectifier module 100, the ripple current filtering module 103, the LED module 105, and the capacitor charging suppression module 102 are connected in series in sequence.

[0033] Optionally, specific connection modes of the voltage divider module 101 include but are not limited to the following two:

[0034] The first type: Figure 1 , Figure 2 As shown, the voltage divider module 101 is connected in series between the rectifier module 100 and the ground.

[0035] The second type: Figure 3 As shown, the input end of the voltage divider module 101 is connected between the LED module 105 and the ripple current filtering module 103 , and the output end of the voltage divider module 101 is connected to the capacitor charging suppression module 102 .

[0036] Optionally, specific connection modes of the first capacitor C1 and the capacitor charging suppression module 102 include but are not limited to the following two modes:

[0037] The first type: Figure 1 , Figure 2 As shown, the rectifier module 100, the first capacitor C1, the capacitor charging suppression module 102, and the ground are connected in series in sequence.

[0038] The second type: Figure 4 As shown, the rectifier module 100, the capacitor charging suppression module 102, the first capacitor C1, and the ground are connected in series in sequence.

[0039] Optionally, the voltage dividing module 101 includes a third resistor R3 and a fourth resistor R4 connected in series, and the capacitor charging suppression module 102 is connected between the third resistor R3 and the fourth resistor R4.

[0040] Specifically, Figure 5 As shown in FIG. 1 , as one implementation mode, the third resistor R3 and the fourth resistor R4 are connected in series between the rectifier module 100 and the ground; Figure 6 As shown, as another implementation, the third resistor R3 and the fourth resistor R4 are connected in series between the LED module 105 and the ground.

[0041] Alternatively, if Figure 5 , Figure 6 As shown, the capacitor charging suppression module 102 includes a first operational amplifier U1, a first resistor R1, and a first switch tube Q1. The first operational amplifier U1 has a positive input terminal and a reverse input terminal. The first switch tube Q1 at least includes a gate. The first switch tube Q1 and the first resistor R1 are connected in series between the first capacitor C1 and the ground in sequence. The non-phase input terminal of the first operational amplifier U1 is connected to the voltage divider module 101, the inverting input terminal of the first operational amplifier U1 is connected between the first resistor R1 and the first switch tube Q1, and the output terminal of the first operational amplifier U1 is connected to the gate of the first switch tube Q1.

[0042] Among them, the positive input terminal of the first operational amplifier U1 is used to collect the voltage after the voltage divider module 101 divides the rectifier module 100 (for example, the positive input terminal of the first operational amplifier U1 is connected between the third resistor R3 and the fourth resistor R4, and the voltage between the third resistor R3 and the fourth resistor R4, that is, the first divided voltage, is collected), and the inverting input terminal of the first operational amplifier U1 is used to collect the voltage between the first resistor R1 and the first switch tube Q1 (that is, the second divided voltage inside itself). The first operational amplifier U1 is used to compare the voltage collected at the positive input terminal and the voltage collected at the inverting input terminal. When the voltage collected at the positive input terminal is greater than the voltage collected at the inverting input terminal, the first switch tube Q1 is controlled to be turned on; when the voltage collected at the positive input terminal is less than or equal to the voltage collected at the inverting input terminal, the first switch tube Q1 is controlled to be turned off.

[0043] At the beginning, the positive input terminal collects the voltage after the voltage divider module 101 divides the rectifier module 100; and because the first resistor R1 is grounded, the voltage collected by the inverting input terminal is a low-level signal. Therefore, when the voltage collected by the positive input terminal is greater than the voltage collected by the inverting input terminal, the first operational amplifier U1 controls the first switch tube Q1 to turn on, and the first capacitor C1 starts to charge, so that the voltage collected by the inverting input terminal gradually increases until the voltage collected by the positive input terminal is equal to the voltage collected by the inverting input terminal, and the first switch tube Q1 is controlled to be cut off. Therefore, the voltage collected by the positive input terminal is greater than the voltage collected by the inverting input terminal, and the first operational amplifier U1 controls the first switch tube Q1 to turn on, and the first capacitor C1 starts to charge, and the cycle is dynamically turned on and off, thereby suppressing the time from the beginning of charging to full charge of the first capacitor C1.

[0044] Alternatively, if Figure 5 , Figure 6 As shown, the ripple current filtering module 103 includes a second resistor R2, a second switch tube Q2, and a second operational amplifier U2. The second operational amplifier U2 has a positive input terminal and a reverse input terminal. The second switch tube Q2 at least includes a gate. The second switch tube Q2 and the second resistor R2 are connected in series between the LED module 105 and the capacitor charging suppression module 102. The non-phase input terminal of the second operational amplifier U2 is connected to the reference voltage terminal, the inverting input terminal of the second operational amplifier U2 is connected between the second switch tube Q2 and the second resistor R2, and the output terminal of the second operational amplifier U2 is electrically connected to the gate of the second switch tube Q2.

[0045] Among them, the positive phase input terminal of the second operational amplifier U2 is used to collect the voltage output by the reference voltage terminal, and the negative phase input terminal of the second operational amplifier U2 is used to collect the voltage between the second switch tube Q2 and the second resistor R2. Initially, the positive phase input terminal collects the voltage output by the reference voltage terminal. Since the second resistor R2 is connected to the first switch tube Q1 (the first switch tube Q1 is turned off at the beginning), the second resistor R2 is equivalent to being grounded when the first switch tube Q1 is turned off, so that the voltage between the second switch tube Q2 and the second resistor R2 is a low-level signal. Therefore, the voltage collected by the positive phase input terminal of the second operational amplifier U2 is greater than the voltage collected by the negative phase input terminal, and the second operational amplifier U2 controls the second switch tube Q2 to turn on, and the LED module 105 lights up. When the first operational amplifier U1 controls the first switch tube Q1 to turn on, and the charging of the first capacitor C1 begins, the voltage collected by the negative phase input terminal of the second operational amplifier U2 gradually increases until the voltage collected by the positive phase input terminal is equal to the voltage collected by the negative phase input terminal, and the second switch tube Q2 is controlled to turn off. As a result, the voltage collected at the non-inverting input terminal of the second operational amplifier U2 is greater than the voltage collected at the inverting input terminal. The second operational amplifier U2 controls the second switch tube Q2 to turn on, and the dynamic on-off cycle is repeated, thereby filtering out the industrial frequency ripple in the current input to the LED module 105, so that there is no flicker when the LED module 105 is lit.

[0046] In addition, the first capacitor C1, the ripple current filtering module 103, and the LED module 105 form a loop. When the first capacitor C1 is discharged, it provides a driving current for the LED module 105. The ripple current filtering module 103 can still filter out the industrial frequency ripple in the driving current input to the LED module 105 according to the above working principle.

[0047] Further, considering the instability of the mains, in order to make the capacitor charging suppression module 102 suppress the charging of the first capacitor C1 more accurately, a power regulator 107 can be connected in series between the voltage divider module 101 and the capacitor charging suppression module 102. The power regulator 107 processes the voltage after the rectifier module 100 is divided according to the voltage divider module 101, so that the first divided voltage input to the capacitor charging suppression module 102 after processing changes with the change of the mains. Specifically, the first divided voltage input to the capacitor charging suppression module 102 after processing is inversely proportional to the voltage output by the rectifier module 100 (that is, if the mains voltage becomes lower, the voltage output by the rectifier module 100 also becomes lower, so that the first divided voltage input to the capacitor charging suppression module 102 after processing becomes higher; if the mains voltage becomes higher, the voltage output by the rectifier module 100 also becomes higher, so that the first divided voltage input to the capacitor charging suppression module 102 after processing becomes higher).

[0048] In addition, if Figure 5 , Figure 6 As shown, a filter module 106 may be connected in series between the voltage divider module 101 and the capacitor charging suppression module 102. The filter module 106 may include a second capacitor C2 and a fifth resistor R5 connected in series, the fifth resistor R5 is connected between the third resistor R3 and the fourth resistor R4, the second capacitor C2 is grounded, and the power regulator 107 is connected between the fifth resistor R5 and the second capacitor C2. The filter module 106 is used to filter the current input to the capacitor charging suppression module 102 to remove noise.

[0049] It should be noted that, in this article, the term "comprises", "includes" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the method and device in the embodiment of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0050] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0051] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. An LED driving circuit, characterized in that: It includes a voltage dividing module, a capacitor charging suppression module, a first capacitor, a ripple current filtering module, and an LED module. The voltage dividing module is used to divide the voltage output by the rectifier module. The voltage dividing module is electrically connected to the capacitor charging suppression module. The first capacitor and the capacitor charging suppression module are connected in series between the rectifier module and the ground. The LED module and the ripple current filtering module are connected in series and in parallel with the first capacitor. The ripple current filtering module includes a second resistor, a second switch tube, and a second operational amplifier. The second operational amplifier has a positive input terminal and a reverse input terminal. The second switch tube at least includes a gate. The second switch tube and the second resistor are connected in series between the LED module and the capacitor charging suppression module. The non-phase input terminal of the second operational amplifier is connected to the reference voltage terminal. The inverting input terminal of the second operational amplifier is connected between the second switch tube and the second resistor. The output terminal of the second operational amplifier is electrically connected to the gate of the second switch tube.

2. The LED driving circuit according to claim 1, characterized in that: The rectification module, the LED module, the ripple current filtering module, and the capacitor charging suppression module are connected in series in sequence.

3. The LED driving circuit according to claim 1, characterized in that: The rectification module, the ripple current filtering module, the LED module, and the capacitor charging suppression module are connected in series in sequence.

4. The LED driving circuit according to claim 1, characterized in that: The input end of the voltage divider module is connected between the LED module and the ripple current filtering module, and the output end of the voltage divider module is connected to the capacitor charging suppression module.

5. The LED driving circuit according to claim 1, characterized in that: The voltage divider module is connected in series between the rectifier module and the ground.

6. The LED driving circuit according to claim 1, characterized in that: The rectifier module, the first capacitor, the capacitor charging suppression module, and the ground are connected in series in sequence.

7. The LED driving circuit according to claim 1, characterized in that: The rectifier module, the capacitor charging suppression module, the first capacitor, and the ground are connected in series in sequence.

8. The LED driving circuit according to claim 1, characterized in that: A filter module is connected in series between the voltage dividing module and the capacitor charging suppression module.

9. The LED driving circuit according to claim 1, characterized in that: A power regulator is connected in series between the voltage dividing module and the capacitor charging suppression module.

10. The LED driving circuit according to claim 1, characterized in that: The capacitor charging suppression module includes a first operational amplifier, a first resistor, and a first switch tube. The first switch tube and the first resistor are connected in series between the first capacitor and the ground in sequence. The first operational amplifier has a positive input terminal and a reverse input terminal. The first switch tube at least includes a gate. The positive input terminal of the first operational amplifier is connected to the voltage divider module, the inverting input terminal of the first operational amplifier is connected between the first resistor and the first switch tube, and the output terminal of the first operational amplifier is connected to the gate of the first switch tube.

11. The LED driving circuit according to claim 1, characterized in that: The voltage dividing module includes a third resistor and a fourth resistor connected in series, and the capacitor charging suppression module is connected between the third resistor and the fourth resistor.

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