Stroboscopic elimination LED driving circuit, LED driving chip and lighting system

Abstract

The present invention discloses a stroboscopic removal LED driving circuit, an LED driving chip and an illumination system. The stroboscopic removal LED driving circuit includes a power input terminal, a power output terminal, a ripple sampling circuit and a ripple removal switching tube circuit. The sampling terminal of the ripple sampling circuit is respectively connected to the power input terminal and the power output terminal. The ripple removal switching tube circuit has an input terminal, an output terminal and a controlled terminal. The input terminal of the ripple removal switching tube circuit is connected to the power input terminal, the output terminal of the ripple removal switching tube circuit is connected to the power output terminal, and the controlled terminal of the ripple removal switching tube circuit is connected to the output terminal of the ripple sampling circuit. While achieving the effect of removing the ripple voltage to achieve stroboscopic removal, the cost of the stroboscopic removal LED driving circuit is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of LED lamp lighting drive, and particularly relates to a stroboscopic reduction LED drive circuit, an LED drive chip and a lighting system. Background Art

[0002] Currently, LED lamp loads are generally driven by an AC-to-DC circuit, but the output drive voltage often has a ripple voltage, which easily causes stroboscopic of the LED lamp, resulting in irritation and harm to the human eye. If you want to reduce the ripple voltage, generally, a large-capacitance electrolytic capacitor is connected in parallel at the output end of the AC-to-DC circuit. However, large-capacitance electrolytic capacitors are often expensive, which is not conducive to reducing the production cost of the stroboscopic reduction LED drive circuit. Summary of the Invention

[0003] The main object of the present invention is to propose a stroboscopic reduction LED drive circuit, an LED drive chip and a lighting system, aiming to reduce the production cost of the stroboscopic reduction LED drive circuit.

[0004] To achieve the above object, the present invention proposes a stroboscopic reduction LED drive circuit, and the stroboscopic reduction LED drive circuit includes:

[0005] A power input terminal for connecting to a supply voltage, the supply voltage including a ripple voltage and a DC voltage;

[0006] A power output terminal for connecting to an LED to be driven;

[0007] A ripple sampling circuit, the sampling terminals of the ripple sampling circuit are respectively connected to the power input terminal and the power output terminal;

[0008] An integration filtering circuit, the input terminal of the integration filtering circuit is connected to the output terminal of the ripple sampling circuit;

[0009] A ripple removal switch tube circuit, the ripple removal switch tube circuit has an input terminal, an output terminal and a controlled terminal, the input terminal of the ripple removal switch tube circuit is connected to the power input terminal, the output terminal of the ripple removal switch tube circuit is connected to the power output terminal, and the controlled terminal of the ripple removal switch tube circuit is connected to the output terminal of the integration filtering circuit;

[0010] Wherein, the ripple sampling circuit is used to sample the ripple voltage to obtain a second ripple voltage, and superimpose the second ripple voltage on the voltage output from the power output terminal and then output it to the input terminal of the integration filtering circuit;

[0011] The integration filtering circuit is configured to filter the second ripple voltage and the voltage output from the power supply output terminal together and then output a second DC voltage, and output the second DC voltage to the control terminal of the ripple removal switch tube circuit to control the ripple removal switch tube circuit to operate in an amplification and following state.

[0012] Optionally, the ripple sampling circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to the power supply input terminal, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the power supply output terminal; wherein, the output terminal of the ripple sampling circuit is the first end of the second resistor, and the sampling terminals of the ripple sampling circuit include the first end of the first resistor and the second end of the second resistor.

[0013] Optionally, the integration filtering circuit includes a third resistor and a first capacitor. The first end of the third resistor is connected to the first end of the second resistor, the second end of the third resistor is connected to the first end of the first capacitor, and the second end of the first capacitor is grounded; wherein, the input terminal of the integration filtering circuit is the first end of the third resistor, and the output terminal of the integration filtering circuit is the first end of the first capacitor.

[0014] Optionally, the ripple removal switch tube circuit includes a first switch tube, a fourth resistor, a second capacitor, and a second zener diode. The input terminal of the first switch tube is connected to the power supply input terminal, the control terminal of the first switch tube, the second end of the fourth resistor, and the first end of the second zener diode are respectively connected to the second end of the second capacitor, and the output terminal of the first switch tube, the second end of the second zener diode, and the first end of the second capacitor are respectively connected to the power supply output terminal; wherein, the input terminal of the ripple removal switch tube circuit is the input terminal of the first switch tube, the control terminal of the ripple removal switch tube circuit is the control terminal of the first switch tube, and the output terminal of the ripple removal switch tube circuit is the output terminal of the first switch tube.

[0015] Optionally, the stroboscopic removal LED driving circuit further includes a following acceleration circuit. The input terminal of the following acceleration circuit is connected to the inside of the power supply input terminal, the output terminal of the following acceleration circuit is connected to the output terminal of the integration filtering circuit, and is configured to reduce the integration delay time of the integration filtering circuit.

[0016] Optionally, the stroboscopic removal LED driving circuit further includes a short-circuit protection circuit, an AC-DC conversion circuit, and an electrolytic capacitor;

[0017] The input terminal of the AC-DC conversion circuit is connected to the mains, the output terminal of the AC-DC conversion circuit is connected to the power supply output terminal, and is configured to convert the mains into the supply voltage, and is further configured to stop outputting the supply voltage when the LED is short-circuited;

[0018] The electrolytic capacitor is connected in parallel to the output end of the AC-DC conversion circuit and is used to filter the ripple voltage in the supply voltage;

[0019] The input end of the short-circuit protection circuit is connected to the output end of the ripple-removing switching transistor circuit, and the output end of the short-circuit protection circuit is connected to the power output end, and is used to consume the energy released by the electrolytic capacitor when the LED is short-circuited when the LED is short-circuited.

[0020] There is also proposed an LED driving chip, comprising:

[0021] A packaging housing;

[0022] A mounting substrate, the mounting substrate is encapsulated in the packaging housing, and the anti-flicker LED driving circuit as described in any one of the above is integrated on the mounting substrate.

[0023] Optionally, the LED driving chip further comprises:

[0024] A power supply pin, one end of the power supply pin is fixedly electrically connected to the mounting substrate, and the other end of the power supply pin extends out of the packaging housing, and the power supply pin is the power input end;

[0025] A capacitor setting pin, one end of the capacitor setting pin is fixedly electrically connected to the mounting substrate, and the other end of the capacitor setting pin extends out of the packaging housing;

[0026] A sampling depth setting pin, one end of the sampling depth setting pin is fixedly electrically connected to the mounting substrate, and the other end of the sampling depth setting pin extends out of the packaging housing;

[0027] An output pin, one end of the output pin is fixedly electrically connected to the mounting substrate, and the other end of the output pin extends out of the packaging housing.

[0028] There is also proposed an illumination system, comprising the above-mentioned LED driving chip.

[0029] The present invention constitutes a stroboscopic removal LED driving circuit by setting a power input terminal, a power output terminal, a ripple sampling circuit, and a ripple removal switching circuit. The power input terminal is used to connect to a supply voltage, which includes a ripple voltage and a DC voltage. The ripple sampling circuit is used to sample the ripple voltage to obtain a second ripple voltage, and superpose the second ripple voltage with the voltage output from the power output terminal and then output it to the input terminal of the integrating and filtering circuit. The integrating and filtering circuit is used to filter the second ripple voltage and the voltage output from the power output terminal together and then output a second DC voltage, and output the second DC voltage to the controlled terminal of the ripple removal switching tube circuit to control the ripple removal switching tube circuit to operate in an amplifying and following state. Thus, the switching tube package circuit is kept operating in an amplifying and following state, so that the output DC current does not change and the DC voltage does not change, realizing the removal of ripple, achieving the function of removing stroboscopic when the LED works, and the circuit structure is simple, without the need to use a too large electrolytic capacitor, which is beneficial to reducing the production cost of the stroboscopic removal LED driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0031] Figure 1 It is a schematic diagram of the functional modules of an embodiment of the stroboscopic removal LED driving circuit of the present invention;

[0032] Figure 2 It is a schematic diagram of the circuit of an embodiment of the stroboscopic removal LED driving circuit of the present invention;

[0033] Figure 3 It is a schematic diagram of the circuit of another embodiment of the stroboscopic removal LED driving circuit of the present invention;

[0034] Figure 4 It is a schematic diagram of the structure of an embodiment of the LED driving chip of the present invention.

[0035] Description of the reference numerals in the drawings:

[0036]

[0037] The realization, functional features, and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship, movement conditions, etc. between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0040] In addition, if there are descriptions such as "first" and "second" in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0041] Reference Figure 1 and Figure 2 , in order to reduce the production cost of the stroboscopic-free LED driving circuit, the present invention proposes a stroboscopic-free LED driving circuit.

[0042] In an embodiment of the present invention, the stroboscopic-free LED driving circuit includes a power input terminal, a power output terminal, a ripple sampling circuit 20, an integration filtering circuit 30, and a ripple removal switching tube circuit 10. The sampling terminal of the ripple sampling circuit 20 is respectively connected to the power input terminal and the power output terminal. The power output terminal is used to connect to the LED to be driven. The input terminal of the integration filtering circuit 30 is connected to the output terminal of the ripple sampling circuit 20. The ripple removal switching tube circuit 10 has an input terminal, an output terminal, and a controlled terminal. The input terminal of the ripple removal switching tube circuit 10 is connected to the power input terminal. The output terminal of the ripple removal switching tube circuit 10 is connected to the power output terminal. The controlled terminal of the ripple removal switching tube circuit 10 is connected to the output terminal of the integration filtering circuit 30.

[0043] Among them, the power input terminal is used to connect to a supply voltage, and the supply voltage includes a ripple voltage and a DC voltage. The power output terminal is used to connect to the LED to be driven. The ripple sampling circuit 20 is used to sample the ripple voltage to obtain a second ripple voltage, and superimpose the second ripple voltage on the voltage output from the power output terminal and then output it to the input terminal of the integration and filtering circuit 30. The integration and filtering circuit 30 is used to filter the second ripple voltage and the voltage output from the power output terminal together and then output a second DC voltage, and output the second DC voltage to the controlled terminal of the ripple removal switch tube circuit 10 to control the ripple removal switch tube circuit 10 to operate in an amplification and following state.

[0044] Specifically, during the process of driving an LED lamp, usually, the commercial power or other alternating current used by users is converted from alternating current to direct current through an AC-DC conversion circuit, and then output to drive the LED lamp. However, the supply voltage output by the AC-DC conversion usually has a ripple voltage with alternating current attributes in addition to the direct current voltage. The ripple voltage can be in the form of a sawtooth wave, a sine wave, etc. If the LED lamp is directly driven to work, the LED lamp will flicker. At this time, the AC-DC conversion circuit is connected to the power input terminal and is used to output the supply voltage to the anti-flicker LED driving circuit. The ripple sampling circuit 20 is used to sample the ripple voltage. The first resistor and the second resistor can be used in combination for voltage division. The ripple can be directly sampled by a sampling chip or a sampling circuit to obtain a second ripple voltage, which is then output to the integration filtering circuit 30 together with the output voltage at the power output terminal. After the integration filtering circuit 30 converts the above voltage into a second direct current voltage, it is output to the control end of the ripple removal switching tube circuit 10 to drive the ripple removal switching tube circuit 10 to work in the amplifier follower state. Among them, the ripple removal switching tube can be an NMOS field effect transistor. Taking the NMOS transistor as an example, after the NMOS transistor is driven, it works in the amplifier follower state of the field effect transistor, which is also called the constant current region. At this time, according to the property of the field effect transistor working in the amplifier region, the Vg on the gate (G pole) of the NMOS transistor, that is, the voltage Vg at the control end of the ripple removal switching tube circuit 10, satisfies Vg = Vth + VLED. That is, when entering the amplifier follower state, VLED is the voltage at the power output terminal, and Vth is the threshold voltage of the MOS transistor. At the same time, according to the above content, the second ripple voltage obtained by resistor voltage division sampling can be exactly twice that of Vth, and it is exactly Vth after passing through the integration filtering circuit 30. At this time, the second direct current voltage is exactly equal to Vth + VLED, and the second direct current voltage is also output to the control end of the ripple removal switching tube circuit 10 as the voltage at the control end of the ripple removal switching tube circuit 10, which just meets the condition for the ripple removal switching tube circuit 10 to work in the amplifier follower state. At this time, if the sampling is stable and Vth does not change, then according to the working property of the field effect transistor, when in the amplifier region, the direct current voltage output to the LED driving end will not change either, thus preventing the LED lamp from flickering. Moreover, the circuit structure is simple and there is no need to connect a large electrolytic capacitor in parallel at the power input terminal, which is beneficial to reducing the production cost of the anti-flicker LED driving circuit. At the same time, if the ripple sampling circuit 20 adopts a voltage division circuit combined with, for example, the first resistor and the second resistor, then the adjustment of the ripple acquisition depth can be achieved through the first resistor, which has flexibility and is beneficial to accommodating the user's requirements for different ripple depths in actual situations, and is beneficial to improving the convenience of use.

[0045] The present invention forms a stroboscopic removal LED driving circuit by setting a power input end, a power output end, a ripple sampling circuit 20, a ripple removal switching tube circuit 10, etc. The power input end is used to connect to a supply voltage, and the supply voltage includes a ripple voltage and a DC voltage. The ripple sampling circuit 20 is used to sample the ripple voltage to obtain a second ripple voltage, and superimpose the second ripple voltage on the voltage output from the power output end and then output it to the input end of the integration and filtering circuit 30. The integration and filtering circuit 30 is used to filter the second ripple voltage and the voltage output from the power output end together and then output a second DC voltage, and output the second DC voltage to the controlled end of the ripple removal switching tube circuit 10 to control the ripple removal switching tube circuit 10 to work in an amplification and following state. Thus, the switching tube package circuit is kept working in an amplification and following state, so that the output DC current does not change and the DC voltage does not change, realizing the removal of ripple, playing the function of removing stroboscopic when the LED works, and the circuit structure is simple, without the need to use a large electrolytic capacitor, which is beneficial to reducing the production cost of the stroboscopic removal LED driving circuit.

[0046] Reference Figure 2 and Figure 3 In an embodiment of the present invention, the ripple sampling circuit 20 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the power input end, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the power output end; wherein, the output end of the ripple sampling circuit 20 is the first end of the second resistor, and the acquisition end of the ripple sampling circuit 20 includes the first end of the first resistor R1 and the second end of the second resistor R2. The integration and filtering circuit 30 includes a third resistor R3 and a first capacitor C1. The first end of the third resistor R3 is connected to the first end of the second resistor R2, the second end of the third resistor R3 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is grounded; wherein, the input end of the integration and filtering circuit 30 is the first end of the third resistor, and the output end of the integration and filtering circuit 30 is the first end of the first capacitor C1. The ripple removal switching tube circuit 10 includes a first switching tube Q1, a fourth resistor R4, a second capacitor C2, and a second zener diode ZD1. The input end of the first switching tube Q1 is connected to the power input end, the controlled end of the first switching tube Q1, the second end of the fourth resistor R4, and the first end of the second zener diode ZD2 are respectively connected to the second end of the second capacitor C2, and the output end of the first switching tube Q1, the second end of the second zener diode ZD2, and the first end of the second capacitor C2 are respectively connected to the power output end; wherein, the input end of the ripple removal switching tube circuit 10 is the input end of the first switching tube Q1, the controlled end of the ripple removal switching tube circuit 10 is the controlled end of the first switching tube Q1, and the output end of the ripple removal switching tube circuit 10 is the output end of the first switching tube Q1.

[0047] Specifically, the first resistor R1 can be a variable resistor, the value of the second resistor R2 can be 1K, the first switching transistor Q1 is an NMOS transistor. When the NMOS transistor operates in the amplification and follower state, according to the operating characteristics of the NMOS transistor and the principle of the follower, the voltage output from the source terminal of the NMOS transistor to the load will not change either, and the ripple voltage part in the supply voltage input at the power supply input terminal will all be consumed on Q1.

[0048] Since the first resistor R1 is a variable resistor and the first switching transistor Q1 is an NMOS transistor, according to the working characteristics and principles of the NMOS transistor, when the NMOS transistor operates in the amplification region, Vg = Vth + VLED is satisfied. At the same time, according to the above content, the value of the second ripple voltage needs to be 2 times Vth, that is, 2Vth = Vripple * [R2 / (R1 + R2)], where Vripple is the voltage value of the ripple voltage and Vth is the threshold of the selected NMOS transistor. The user can detect the voltage value of the ripple voltage by using a detection circuit or a detection instrument. If Q1 is to operate exactly in the amplification region, the voltage value of the second ripple voltage should be exactly 2 times Vth. Because the voltage value of the second ripple voltage will be halved after passing through the integration filter circuit 30. When the resistance value of the first resistor R1 is adjusted and satisfies the above formula with the resistance value of the second resistor R2, the NMOS transistor can just operate in the amplification region to remove the input ripple voltage. If the resistance value of the first resistor R1 is adjusted so that the voltage value of the second ripple voltage is greater than 2 times Vth, the NMOS transistor will be in an over-conduction state and cannot completely remove the previously input ripple voltage, but the loss on the NMOS transistor can be reduced, and the value of VLED output to the LED driving end is relatively larger than the previous output LED value. If the LED lamp selected by the customer does not have a very high requirement for the depth of ripple removal, the above settings can be used to reduce the power supply voltage of the loss on the NMOS transistor. At the same time, if the resistance value of the first resistor R1 is adjusted so that the voltage value of the second ripple voltage is less than 2 times Vth, according to the principle of the NMOS transistor operating in the amplification and following state, part of the DC voltage output to the LED will be lost to maintain the driving voltage, that is, the loss on the NMOS transistor will increase. Since it is an ideal state that the ripple is completely removed when 2Vth = Vripple * [R2 / (R1 + R2)], in practice, the resistance value of R1 can be adjusted so that the voltage value of the second ripple voltage is less than 2 times Vth, so as to achieve a smaller output ripple current and meet the requirement for the depth of ripple voltage removal, such as "removing 99% of the ripple voltage". In an embodiment, the breakdown voltage of the NMOS transistor can be 20V to 200V. At the same time, the threshold of the NMOS transistor shall not be greater than half of the ripple voltage. By adjusting the resistance value of the first resistor R1 to change the ratio of the resistance values between the first resistor R1 and the second resistor R2, the resistance value of the first resistor R1 can be freely adjusted to sample and divide the ripple sampling voltage, so as to adjust the depth of ripple removal and meet the customer's requirements for different depths of ripple removal. By using a variable resistor and a fixed-resistance resistor to form a sampling voltage-dividing circuit, the circuit structure is streamlined, and the resistance value of the first resistor R1 can be conveniently and flexibly debugged according to requirements without frequently replacing the resistor, which improves the convenience and compatibility of use, and at the same time has a low cost, effectively reducing the cost of the stroboscopic-free LED driving circuit.In addition, since the ripple voltage can be divided by the voltage divider circuit formed between the first resistor R1 and the second resistor R2, the ripple voltage of any voltage value can be compatible under the condition that the NMOS threshold is not greater than half of the ripple voltage and the withstand voltage of the NMOS tube is satisfied, which is conducive to improving compatibility and has low cost. At the same time, because the NMOS tube works in the amplification follower state, according to the inherent characteristics of the follower, the output current will not overshoot and will not cause damage to the lamp beads, which is conducive to protecting the safety of the LED lamp beads and improving the stability and safety of the de-strobe LED drive circuit.

[0049] Further, in another embodiment, the power input terminal is connected to the output terminal of the AC-DC circuit, and the electrolytic capacitor is connected in parallel to the output terminal of the AC-DC circuit. If the electrolytic capacitor is replaced, for example, the electrolytic capacitor is reduced, the ripple voltage in the power supply voltage output by the AC-DC circuit will become larger. At this time, it is only necessary to adjust the ratio of the resistance between the first resistor R1 and the resistor R2. Specifically, the resistance value of the first resistor R1 is adjusted so that the second ripple voltage value obtained according to the above formula Vripple*[R2 / (R1+R2)] is also equal to 2Vth and the output voltage of the power output terminal is superimposed to the integral filter circuit and then output to the gate of the NMOS tube to meet the condition that the above NMOS tube works in the amplification area, thereby also producing the effect of removing the ripple voltage. For example, in the case of low required current and the switch tube loss is allowed, a smaller electrolytic capacitor can be used, and the resistance value of the first resistor R1 is adjusted to obtain the effect of removing the ripple voltage. Through the above setting, it is beneficial to improve the compatibility of the de-strobe LED drive circuit, and further reduce the cost.

[0050] The integral filter circuit 30 is composed of a resistor and a capacitor, and can smoothly convert the ripple sampling voltage and the superimposed driving circuit into a DC voltage to drive the NMOS tube Q1. The values of the resistor and the capacitor can be configured and selected according to the requirements for the time constant of the integral filter circuit. When the LED driver chip is used, the capacitor with a smaller capacitance value will make the time constant of the filter circuit smaller, so that the filter circuit has a faster response speed so that the LED can be lit faster. The capacitor with a larger capacitance value will make the time constant larger, thereby reducing the increase of ripples, which is conducive to reducing the power consumption of the de-strobe LED driving circuit and reducing the strobe of the driven LED lamp. The values of the resistor and the capacitor can be selected, for example, "R3 is 51K, C1 is 4.7uF", which can be selected according to actual needs, and no excessive restrictions are made here. Through the integral filter circuit 30, the second ripple voltage can be smoothed and superimposed on the voltage output from the power supply output end for filtering and then outputting the second DC voltage to drive the NMOS tube Q1 in the amplification follower state, which is conducive to improving the stability of the de-strobe LED driving circuit.

[0051] Reference Figure 2 In an embodiment of the present invention, the stroboscopic elimination LED driving circuit further includes a following acceleration circuit 40. The input end of the following acceleration circuit 40 is internally connected to the power input end. The output end of the following acceleration circuit 40 is connected to the output end of the integration filtering circuit 30 and is used to reduce the integration delay time of the integration filtering circuit 30.

[0052] Among them, the following acceleration circuit 40 includes a first diode D1 and a first voltage stabilizing diode ZD1. The first pin of the first diode D1 is connected to the power input end. The second pin of the first diode D1 is connected to the first pin of the first voltage stabilizing diode ZD1. The second pin of the first voltage stabilizing diode ZD1 is connected to the first end of a first capacitor C1. The following acceleration circuit 40 is used to, when the stroboscopic elimination LED driving circuit starts to work, directly add the supply voltage VOUT at the power input end minus the voltage of ZD1 to C1, so as to quickly charge C1, avoid the RC integration delay caused by too long RC delay time, and prevent the situation that the VLED climbs too slowly, resulting in the flashing of the LED lamp at the beginning of operation. Through the following acceleration circuit 40, the RC integration delay can be avoided, the situation of LED flashing at the beginning of turning on can be prevented, and the working stability of the stroboscopic elimination LED driving circuit is improved.

[0053] Reference Figure 3 In an embodiment of the present invention, the stroboscopic elimination LED driving circuit further includes a short-circuit protection circuit 50, an AC-DC conversion circuit, and an electrolytic capacitor. The input end of the AC-DC conversion circuit is connected to the mains power supply. The output end of the AC-DC conversion circuit is connected to the power output end and is used to convert the mains power supply into a supply voltage and also used to stop outputting the supply voltage when the LED is short-circuited. The electrolytic capacitor is connected in parallel at the output end of the AC-DC conversion circuit and is used to filter out the ripple voltage in the supply voltage. The input end of the short-circuit protection circuit 50 is connected to the output end of the ripple removal switching tube circuit 10. The output end of the short-circuit protection circuit 50 is connected to the power output end and is used to consume the energy released by the electrolytic capacitor when the LED is short-circuited.

[0054] Among them, the short-circuit protection circuit 50 includes a first protection resistor RW1. The first protection resistor can use a wire-wound resistor, and the resistance value of the wire-wound resistor is much larger than that of Q1. In the normal operation of the LED driving circuit, the power input terminal is often connected to the output terminal of the AC-DC conversion circuit. The AC-DC conversion circuit is used to convert the mains power or other alternating current into a supply voltage. Since an electrolytic capacitor C3 is often connected in parallel at the output terminal of the AC-DC conversion circuit for filtering, when a short circuit occurs in the LED or at the output terminal of the ripple removal module of the stroboscopic LED driving circuit, the AC-DC conversion circuit will perform a protection action. However, the electrolytic capacitor C3 at the output terminal of the AC-DC conversion circuit will discharge the stored charge instantaneously during the short circuit. Q1 is in a fully conducting state. The first protection resistor RW1 selects a wire-wound resistor, and its resistance value is dozens of times that of Q1. Therefore, according to the principle of resistor voltage division, most of the charge stored in the filtering capacitor discharged instantaneously during the short circuit will be consumed on RW1 rather than on Q1. By using a wire-wound resistor as the first protection resistor RW1, it has good current impact resistance, low cost, and is convenient to replace.

[0055] After the energy in the electrolytic capacitor is discharged, the AC-DC conversion circuit starts to restart. If the short-circuit problem is not eliminated, due to the limitation of ZD1 and ZD2, and the sum of their values is less than the minimum load-carrying voltage of the AC-DC conversion circuit, the power supply of the front-stage circuit is insufficient and it restarts again, thus protecting the entire circuit and NMOS from being broken down. It can only be restarted normally after the short-circuit fault is eliminated, which further improves the safety of the overall circuit operation. Further, in terms of the breakdown voltage selection of NMOS, it only needs to be greater than the sum of the breakdown voltages of ZD1 and ZD2, and the breakdown voltage of ZD2, that is, the clamping voltage of Vgs on NMOS, can ensure that NMOS is fully conducting. Because during a short circuit, Vgs of NMOS is pulled to the breakdown voltage by ZD2, resulting in NMOS being fully conducting, and NMOS does not bear voltage. And the sum of the breakdown voltages of ZD1 and ZD2 is less than the minimum load-carrying voltage of the AC-DC conversion circuit, so the front-stage circuit will restart again due to insufficient power supply, thus protecting the MOS tube from being broken down and not being damaged during a short circuit. Therefore, in the selection of the breakdown voltage of the MOS tube, an NMOS tube with a relatively small breakdown voltage can be selected according to the output supply voltage. For example, for a supply voltage of 100V output by the AC-DC conversion circuit, an NMOS with a breakdown voltage of 30V can be used to remove the ripple voltage. And in the case of a load, when a short circuit occurs at the output, the MOS tube with a 30V breakdown voltage will not be damaged due to the output short circuit, improving the stability of the overall circuit operation while reducing the cost of NMOS tube selection.

[0056] In summary, the present invention discloses a stroboscopic removal LED driving circuit, which can adjust the ratio of the first resistor R1 to the second resistor R2, so as to achieve compatible processing of ripple voltages with different voltage values, with good followability, and improve the compatibility of the stroboscopic removal LED driving circuit. At the same time, the depth of ripple removal can be adjusted according to actual usage requirements, improving the convenience of user debugging. In addition, in the case of a short circuit, compared with the prior art, it can prevent the electrolytic capacitor connected in parallel at the output end of the AC-DC circuit from discharging energy and damaging the switching tube during a short circuit, ensuring the stability and safety of the stroboscopic removal LED driving circuit. Further, the circuit structure of the stroboscopic removal LED driving circuit of the present invention is simple and the components selected in the above embodiments are relatively conventional, thus reducing the cost of the stroboscopic removal LED driving circuit.

[0057] Reference Figure 4 , the present invention also proposes an LED driving chip, which includes:

[0058] A packaging shell;

[0059] A mounting substrate, which is arranged inside the packaging shell, and the stroboscopic removal LED driving circuit as described above is arranged on the mounting substrate.

[0060] Among them, the LED driving chip includes a power supply pin, a capacitor setting pin, a sampling depth setting pin, and an output pin. At the same time, the power supply pin is the power input end, and one end of each of the above pins is electrically connected to the mounting substrate, and the other end extends out of the packaging shell for fixing and installing the LED driving chip. In one embodiment, the above pins can be electrically connected to the mounting substrate through wire bonding. The wire bonding method is relatively simple and the structure is not complex. Further, in another embodiment, electrical connection can also be achieved by adopting a method of combining a stacked mounting substrate and metal fillers for wiring. The mounting substrate is electrically connected to the stacked mounting substrate through metal fillers, and the stacked mounting substrate is then electrically connected to multiple pins one by one through the circuit arranged on the mounting substrate, so as to achieve the effects of antioxidation and increased service life. At the same time, the additional mounting substrate can also assist in dissipating heat for multiple electronic components on the mounting substrate, thus being beneficial to improving the working stability of the LED driving chip.

[0061] In addition, in one embodiment, the power supply pin, the capacitor setting pin, the sampling depth setting pin, and the output pin all extend from the inside of the packaging shell to the side of the packaging shell in the form of pins. By adopting this pin setting, it is convenient to electrically connect with the circuits on the external mounting substrate when installing the LED driving chip.

[0062] In another embodiment, in addition to using pins, side pads provided on the side or bottom pads provided on the bottom surface can also be used to electrically connect the LED driving chip to the circuit on the external mounting substrate. The pads used can be immersion gold pads. By using immersion gold pads, the pad pins of the LED driving chip can have good oxidation resistance, preventing the occurrence of soldering defects caused by oxidation of the pad pins during storage after production for too long. At the same time, the good conductivity of the immersion gold pads is more conducive to improving the stability of voltage transmission.

[0063] Specifically, the power pin is the power input terminal of the stroboscopic-free LED driving circuit.

[0064] The capacitor setting pin is connected to the second end of the third resistor. In one embodiment, the original capacitor C1 can be not encapsulated in the LED driving chip. When the LED driving chip is in use, a capacitor with a smaller capacitance value will make the time constant of the filtering circuit smaller, so that the filtering circuit has a faster response speed, enabling the LED to be lit at a faster speed and reducing the stroboscopic situation. A capacitor with a larger capacitance value will make the time constant larger, thereby reducing the increase in ripple, which is beneficial to reducing the power consumption of the stroboscopic-free LED driving circuit and reducing the stroboscopic situation of the driven LED lamp. Users can select an external capacitor with a suitable capacitance value according to the actual driving requirements and electrically connect it to the capacitor setting pin. Through the above settings, the different requirements for driving LED lamps in different usage environments and types can be greatly improved, the compatibility of the LED driving chip is improved, and only by changing the external capacitor connected to the capacitor setting pin, it is convenient to replace, which is beneficial to improving the convenience of use.

[0065] The sampling depth setting pin is connected to the first end of the second resistor. In one embodiment, similar to the above capacitor setting pin, the original first resistor R1 can be not encapsulated in the LED driving chip, and by setting an external resistor, the first end of the external resistor is connected to the sampling depth setting pin, and the second end of the external resistor is connected to the power pin.

[0066] During the use of the LED driving chip, users can, according to the magnitude of the ripple voltage value of the supply voltage input into the LED driving chip in the actual usage application scenario, and based on the above formula content, that is, "2Vth = (Vripple * [R2 / (R1 + R2)])", obtain the resistance value of the external resistor to be set. At the same time, in actual use, if the customer pursues a more thorough ripple removal depth, thereby further reducing the current value of the ripple current, so that the value obtained by Vripple * [R2 / (R1 + R2)] is less than twice of Vth, thus meeting the compatibility of different customer requirements, and the control is flexible and the cost is low.

[0067] Through the above settings, different external resistors can be set to achieve compatibility with the usage and driving requirements of different LED loads, which is beneficial to improving the compatibility of the use of LED driver chips. Further, only the external resistor needs to be replaced, and the circuit structure is simple, with good convenience.

[0068] The output pin is connected to the second end of RW1. During user use, it can be connected to the driving end of the LED lamp.

[0069] In another embodiment, according to the user's selection, the protection resistor RW1 may not be encapsulated in the package of the LED driver chip, and the output pin is directly electrically connected to the source pin of Q1. The user can select a suitable protection resistor according to different requirements of the size of their LED load and connect it in series in the external circuit between the output pin and the driving end of the LED load.

[0070] It can be understood that the package types of the package housing of the LED driver chip include but are not limited to SOP2X3, SOP8, TO-252, etc. The larger the package, the better the heat dissipation effect; the smaller the package, the higher the integration degree, which is more conducive to streamlining the circuit structure. Here, it can be set according to actual needs, or multiple different package versions can be designed to meet the needs of different customers. No more limitations are made here.

[0071] It should be noted that since the LED driver chip of the present invention includes all the embodiments of the above-mentioned stroboscopic elimination LED driver circuit, the LED driver chip of the present invention has all the beneficial effects of the above-mentioned stroboscopic elimination LED driver circuit, which will not be elaborated here.

[0072] The present invention also provides an illumination system, which includes an LED driver chip, and the specific circuit and structure of the LED driver chip refer to the above embodiments.

[0073] It should be noted that since the illumination system of the present invention includes all the embodiments of the above-mentioned LED driver chip, the illumination system of the present invention has all the beneficial effects of the above-mentioned LED driver chip, which will not be elaborated here.

[0074] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A stroboscopic elimination LED driving circuit, characterized in that, The stroboscopic removal LED driving circuit includes: A power input terminal for accessing a supply voltage, where the supply voltage includes a ripple voltage and a DC voltage; A power output terminal for connecting to an LED to be driven; A ripple sampling circuit, where the sampling terminals of the ripple sampling circuit are respectively connected to the power input terminal and the power output terminal; An integration filtering circuit, where the input terminal of the integration filtering circuit is connected to the output terminal of the ripple sampling circuit; A ripple removal switching tube circuit, where the ripple removal switching tube circuit has an input terminal, an output terminal, and a controlled terminal. The input terminal of the ripple removal switching tube circuit is connected to the power input terminal, the output terminal of the ripple removal switching tube circuit is connected to the power output terminal, and the controlled terminal of the ripple removal switching tube circuit is connected to the output terminal of the integration filtering circuit; Among them, the ripple sampling circuit is used to obtain a second ripple voltage after sampling the ripple voltage, and superimpose the second ripple voltage on the voltage output from the power output terminal and then output it to the input terminal of the integration filtering circuit; The integration filtering circuit is used to filter the second ripple voltage and the voltage output from the power output terminal together and then output a second DC voltage, and output the second DC voltage to the controlled terminal of the ripple removal switching tube circuit to control the ripple removal switching tube circuit to operate in an amplification and following state; And, the ripple sampling circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to the power input terminal, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the power output terminal; where, the output terminal of the ripple sampling circuit is the first end of the second resistor, and the sampling terminals of the ripple sampling circuit include the first end of the first resistor and the second end of the second resistor; The integration filtering circuit includes a third resistor and a first capacitor. The first end of the third resistor is connected to the first end of the second resistor, the second end of the third resistor is connected to the first end of the first capacitor, and the second end of the first capacitor is grounded; where, the input terminal of the integration filtering circuit is the first end of the third resistor, and the output terminal of the integration filtering circuit is the first end of the first capacitor; The ripple removal switching tube circuit includes a first switching tube, a fourth resistor, a second capacitor, and a second zener diode. The input terminal of the first switching tube is connected to the power input terminal, the controlled terminal of the first switching tube, the second end of the fourth resistor, and the first end of the second zener diode are respectively connected to the second end of the second capacitor, and the output terminal of the first switching tube, the second end of the second zener diode, and the first end of the second capacitor are respectively connected to the power output terminal; where, the input terminal of the ripple removal switching tube circuit is the input terminal of the first switching tube, the controlled terminal of the ripple removal switching tube circuit is the controlled terminal of the first switching tube, and the output terminal of the ripple removal switching tube circuit is the output terminal of the first switching tube; In addition, the stroboscopic elimination LED driving circuit further includes a following acceleration circuit. The input end of the following acceleration circuit is internally connected to the power input end. The output end of the following acceleration circuit is connected to the output end of the integral filtering circuit and is used to reduce the integral delay time of the integral filtering circuit. The following acceleration circuit includes a first diode and a first voltage stabilizing diode. The first pin of the first diode is connected to the power input end. The second pin of the first diode is connected to the first pin of the first voltage stabilizing diode. The second pin of the first voltage stabilizing diode is connected to the first end of the first capacitor.

2. The stroboscopic-free LED driving circuit according to claim 1, wherein The stroboscopic elimination LED driving circuit further includes a short-circuit protection circuit, an AC-DC conversion circuit, and an electrolytic capacitor. The input end of the AC-DC conversion circuit is connected to the mains power. The output end of the AC-DC conversion circuit is connected to the power output end and is used to convert the mains power into the supply voltage. It is also used to stop outputting the supply voltage when the LED is short-circuited. The electrolytic capacitor is connected in parallel at the output end of the AC-DC conversion circuit and is used to filter out the ripple voltage in the supply voltage. The input end of the short-circuit protection circuit is connected to the output end of the ripple removal switching transistor circuit. The output end of the short-circuit protection circuit is connected to the power output end and is used to consume the energy released by the electrolytic capacitor when the LED is short-circuited during the LED short-circuit.

3. An LED driving chip, characterized in that, The LED driving chip includes: A package housing; A mounting substrate, the mounting substrate is encapsulated in the package housing, and the stroboscopic elimination LED driving circuit as described in any one of claims 1 to 2 is integrated on the mounting substrate.

4. The LED driving chip according to claim 3, wherein The LED driving chip further includes: A power pin, one end of the power pin is fixedly connected to the mounting substrate electrically, and the other end of the power pin extends out of the package housing. The power pin is the power input end. A capacitor setting pin, one end of the capacitor setting pin is fixedly connected to the mounting substrate electrically, and the other end of the capacitor setting pin extends out of the package housing. A sampling depth setting pin, one end of the sampling depth setting pin is fixedly connected to the mounting substrate electrically, and the other end of the sampling depth setting pin extends out of the package housing. An output pin, one end of the output pin is fixedly connected to the mounting substrate electrically, and the other end of the output pin extends out of the package housing.

5. A lighting system, characterized in that, The illumination system includes the LED driving chip as described in claim 3.

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