CN211702485U - Passive LED constant current driving device - Google Patents

Abstract

The utility model relates to a passive LED illumination constant current driving device, which comprises a multilayer ceramic capacitor array C1 and an iron core inductor L1, wherein the multilayer ceramic capacitor array C1 and the iron core inductor L1 are connected in series between a driven LED lamp bank and a power frequency alternating current power supply input end; the multilayer ceramic capacitor array C1 has a DC bias effect, and the terminal voltage of the iron core inductor L1 at rated maximum current is not lower than 20% of the effective value of rated power supply voltage. The utility model discloses possess low cost, reliability height, life-span overlength, resistant thunder ability reinforce, have self-healing ability, usable scrap component resource, the usable lamps and lanterns ballast of scrapping, reduce the electric wire netting loss, do not have electromagnetic interference, production simple process environmental protection, tolerate that mains voltage fluctuation ability is strong, be convenient for scintillation or adjust luminance advantages such as operation.

Description

Passive LED constant current driving device

Technical Field

The utility model relates to a LED drive circuit, in particular to passive LED illumination constant current drive arrangement.

Background

The LED light source has long service life and high lighting effect, can adjust light in a large range, and the LED lighting technology is expected to replace the traditional gas discharge lamp and incandescent lamp as a green lighting technology, thereby saving a large amount of energy for the society. The LED is a device with constant voltage characteristic, and a driving circuit is required to be used when commercial power is used for supplying power, however, as for several driving circuits in the prior art, the defects exist, so that the popularization of an LED light source in the field of illumination is influenced, particularly in the field of high-power outdoor or industrial and mining illumination, the market share of LED illumination is not more than 20% so far, and various researches show that the bottleneck of service life reliability of the driving power source is the most fundamental reason for restricting the development of the driving power source.

The most commonly used LED mains driving circuits in the prior art mainly include 3 types: the first is a resistance-capacitance driving circuit, which utilizes the capacitive reactance of a capacitor to step down and limit the current of the alternating voltage of the commercial power and provide a relatively stable current for the connected LED lamp string. The second is a linear constant current driving circuit, which limits the LED current by using a constant current diode device, and has the advantages of low cost and small volume, however, since a resistive element is used as a current limiting device, the efficiency is low, the heat generation is large, the energy saving advantage of the LED light source cannot be exerted, and the high power is difficult to realize. The third type is a high-frequency switching power supply circuit, the control method and the topological structure of the circuit are various, and the circuit has the advantages of high efficiency and good constant current characteristic, but the circuit has a complex structure, the number of elements is as many as 30-60, the lightning protection capability is poor, the reliability and the service life are poor, the actual service life is only 2-4 years, the circuit is used for indoor illumination without problems, but the circuit is used for high-power outdoor or industrial and mining illumination, and the user generally reflects short service life and high early failure rate due to the severe working environment.

With the rapid development of the LED technology, the market penetration rate of the current LED illumination is nearly 50%, a large number of traditional incandescent lamps and energy-saving lamps are replaced by LED light sources, however, in the field of high-power outdoor illumination, the market acceptance of the LED is generally low, and the traditional gas discharge light source still occupies the mainstream, so that the energy-saving progress in the field of high-power outdoor illumination is slow. For this reason, develop a high-power LED drive circuit who really possesses the reliability height, longe-lived, it is significant, the utility model discloses ingenious utilization multilayer ceramic capacitor's bias characteristic, realized the constant current that switching power supply circuit could realize with simple passive circuit scheme, wide input voltage, high power factor, low harmonic performance, still possessed the high reliability that prior art did not possess simultaneously, long-life and low-cost performance, remedied prior art's shortcoming, be expected to promote high-power LED lighting technology's performance and cost index by a wide margin, promote the popularization speed of LED in high-power outdoor lighting field.

SUMMERY OF THE UTILITY MODEL

The utility model discloses to the problem that prior art exists, provide a novel LED constant current drive circuit, can effectively overcome prior art's short slab, possess that the constant current is effectual, the reliability is high, longe-lived, with low costs, impact current is little, the outstanding advantage that power factor is high.

The utility model discloses a passive LED constant current drive device, including a multilayer ceramic capacitor array C1 and an iron core inductance L1, multilayer ceramic capacitor array C1 with iron core inductance L1 connects in series between LED banks that are driven and power frequency AC power supply input; the multilayer ceramic capacitor array C1 is formed by connecting ferroelectric ceramic capacitors in series and parallel, or formed by combining the ferroelectric ceramic capacitors and other types of capacitors in series and parallel; the ferroelectric ceramic capacitor included in the multilayer ceramic capacitor array C1 has negative temperature coefficient characteristic, and the capacitive reactance of the multilayer ceramic capacitor array C1 decreases along with the temperature rise within the temperature range of 50-100 ℃ at the power frequency; the terminal voltage of the iron core inductor L1 at rated maximum current is not lower than 20% of the effective value of rated power supply voltage, and the insulation withstand voltage of the whole multilayer ceramic capacitor array C1 is not lower than the maximum allowable power supply voltage peak value; multilayer ceramic capacitor array C1 welds and adorns in a planar circuit board or encapsulates inside the cuboid casing, weld the planar circuit board of multilayer ceramic capacitor array C1 or encapsulate a surface of multilayer ceramic capacitor array C1's cuboid casing with the laminating of the outside surface of iron core inductance L1 iron core or winding window inside surface. The iron core inductor L1 may have magnetic saturation characteristics, its resistance value at rated maximum current is 40-100% of its initial resistance value, its iron core may be provided with non-equidistant air gaps, and the iron core inductor L1 also includes gas discharge lamp impedance type inductive ballast, etc.

A rectifier bridge D1 can be connected between the driven LED lamp group and the power frequency alternating current power supply, the alternating current side of the rectifier bridge D1 is connected with the multilayer ceramic capacitor array C1 in series and then is connected with the input end of the power frequency alternating current power supply, the direct current side of the rectifier bridge D1 is connected with the driven LED lamp group, and the iron core inductor L1 is connected with the direct current side or the alternating current side of the rectifier bridge D1 in series; the dc side of the rectifier bridge D1 may also be connected in parallel with a filter capacitor C2.

A power frequency transformer T can be connected between the driven LED lamp bank and the input end of the power frequency alternating current power supply, and a voltage reduction capacitor C3 can be connected in series.

The utility model can comprise an overvoltage protector R1, an overvoltage protector R1 is connected with a multilayer ceramic capacitor array C1 in parallel; and the temperature switch S is in contact with the outer surface of the overvoltage protector R1 and is connected with the input end of the power frequency alternating current power supply in series. The utility model discloses can also include an overcurrent protector F, overcurrent protector F establishes ties with power frequency AC power supply input.

The beneficial effects of the utility model reside in that:

1. the cost is low: the utility model discloses ingenious shortcoming that has utilized multilayer ceramic capacitor bias voltage characteristic, turn the harmful into the benefit, change into the automatic control circuit that can automatic constant current with this shortcoming through simple scheme, realized LED's electric current accurate control function with extremely simple passive circuit, avoided the use of active devices such as chip, transistor, therefore the cost is only the fraction of prior art switching power supply constant current scheme.

2. The reliability is high: the whole circuit is completely composed of passive devices such as an inductor, a capacitor and a rectifier bridge, the number of the elements is less than ten, active control devices such as chips and transistors are avoided, the stability of the product can be effectively improved, the adaptability to severe environments such as high temperature and humidity is greatly improved, and under the severe environments of outdoor sun, rain and lightning impact, the inherent firmness and durability characteristics of the circuit can bring extremely high reliability and long service life durability, and experiments prove that the early failure rate of the circuit can reach less than 0.5 per thousand, which is less than one tenth of that of a switching power supply in the prior art.

3. Strong lightning resistance: because passive device's thunder and lightning invasion ripples, heavy current stress endurance are far higher than active semiconductor device, the utility model discloses a resistant thunder performance is far higher than prior art switching power supply, the special method that connects of cooperation iron core inductance, the utility model discloses can reach prior art tens of times's comprehensive lightning protection performance, the annual cumulative failure rate that many thunder areas used can be less than thousandths.

4. The self-healing capability is provided: the utility model is essentially characterized in that the AC current is directly controlled by the capacitor and the inductor series circuit which can automatically change impedance to keep the LED current constant, under the most unfavorable conditions, if the problems of ceramic capacitor breakdown, short circuit inside the reactor, dry filter capacitor and the like are encountered, as long as the selection of the parameters of the resistance-capacitance element is reasonable, the parameters of the impedance element which only controls the current for the LED lamp bank change, the current control capability is reduced, and the LED lamp bank still can maintain the luminous illumination, only the brightness or the stroboscopic index is reduced, therefore, the utility model also has the ingenious fault self-healing capability, when the main elements are broken down, the lamp bank still can emit the luminous illumination, however, the switch power supply in the prior art only damages one dozens of elements, the whole lamp is usually extinguished to lose efficacy immediately, therefore, the utility model has extremely low fault rate, and is adopted in the high tower illumination occasions with difficult maintenance such as highways, airports, railways and, the maintenance and repair cost can be greatly reduced.

5. The scrap element resources can be utilized: ceramic capacitor often is scrapped because bias characteristic test is not up to standard, and the utility model discloses an it is precious that this disadvantage of utilizing ceramic capacitor just changes the waste into, the utility model discloses a reuse a large amount of unqualified discarded ceramic capacitor that can't leave the factory and sell originally, not only make the manufacturing cost of self and cheap, still utilized a large amount of abandonment components and parts resources, especially made the non-waste reuse of rare metal resource among the discarded ceramic capacitor.

6. The recyclable light source electric appliance comprises: along with the LED energy-conservation transformation of a large amount of fluorescent lamps in recent years, a large amount of inductive ballast is abandoned, and inductive ballast stable performance, life-span are extremely long, the utility model discloses an inductive ballast that the iron core inductance can directly utilize gas discharge lamp, like this, but a large amount of original inductive ballast reuse by abandonment not only saved non ferrous metal resources such as a large amount of iron copper, can also constitute LED energy-conservation transformation, old and useless light source electrical apparatus regeneration's green cycle ecology, further exerted the utility model discloses an environmental protection benefit.

7. Ultra-long service life: the utility model discloses the passive device that adopts, self ageing speed is extremely slow, the performance decay is not obvious, including simple structure, can reach very long life-span, even adopt electrolytic capacitor filtering, because the utility model discloses electrolytic capacitor only is used for improving the stroboscopic, even withered inefficacy circuit also can move as usual, LED also can continue luminous illumination, has obvious overlength life-span for hundreds of thousands of hours, is 5-10 times of prior art switching power supply.

8. And (3) reducing the power grid loss: the utility model discloses a ceramic capacitor element can provide perception reactive power for the electric wire netting voluntarily in current control, accounts for about 5-20% of lamps and lanterns active power, can realize certain reactive power compensation to the electric wire netting to reduce the electric wire netting line loss, stabilize electric wire netting voltage, produce indirect energy-conserving benefit.

9. No electromagnetic interference exists: the switch power class drive power supply of prior art, electromagnetic interference is more serious, even adopted good EMI filter circuit, still has a small amount of electromagnetic interference to leak, to special illumination occasions such as military affairs, scientific research, medical treatment, electromagnetic interference produces great influence easily, the utility model relates to a simple impedance circuit, work in the power frequency state, its current-voltage all is continuous power frequency positive ripple or more steady direct current, need not EMI filter circuit and also can not produce any interference to sensitive equipment.

10. The production process is simple and environment-friendly: the utility model discloses there is not active control circuit, production assembly technique is simple, the test is simple, because of the tightness of passive device, the circuit need not the encapsulating, the casing need not to consider sealed heat dissipation, ordinary iron-clad can, simplified production technology, also reduced the essential encapsulating dampproofing chemical solvent emission pollution who causes of prior art.

11. The power supply voltage fluctuation tolerance is extremely strong: the insulating properties of ceramic capacitor can bear the rated voltage of twice not causing the breakdown for the short time, (of course the utility model discloses even breakdown lamps and lanterns also can give out light to throw light on), work as the utility model discloses a ceramic capacitor of 500V voltage can bear 290V's high pressure in short time and be unlikely to damage, and prior art switching power supply voltage surpasses 265V and will lead to damaging, and our country's street lamp supply voltage quality is generally not high, and the night voltage surpasses 270V and often takes place, leads to the frequent damage of LED street lamp, and the utility model discloses can bear nearly 300V's voltage with the help of the outstanding compressive property of ceramic capacitor and not damage.

12. No impact current, and the flash operation: the starting impact current of the reactor is less than 2 times of the rated current and is one tenth of that of a switching power supply in the prior art due to the extremely simple impedance current-limiting principle and the current-limiting effect of the iron core reactor, so that the control contactor is not easy to damage due to centralized starting, the voltage of a power grid is not sunken, the reactor can directly flicker and operate intermittently, and the reactor is used for replacing incandescent lamps in occasions such as signal lamps, barrier lamps and the like to obtain a remarkable energy-saving effect.

13. An extremely inexpensive dimmable drive power supply is provided: LED is fit for adjusting luminance, however because prior art's switching power supply possesses the high price of the function of adjusting luminance, the circuit is complicated, and the fault rate is higher, and the scintillation often appears when the scope of adjusting luminance is big, and the utility model discloses an impedance constant current principle makes it possess natural outside dimming ability, as long as the outside is through series connection impedance, electric capacity or change input voltage, just can conveniently change luminance, also can not lead to the scintillation.

14. The life of the LED element is further improved. The utility model discloses directly utilize the capacitive reactance of ceramic capacitor array to realize lamp current constant current control, if adopt the ceramic capacitor who possesses great temperature coefficient characteristic like this, when equipment temperature or ambient temperature improve, the increase of ceramic capacitor capacitive reactance, corresponding lamp current reduces automatically, through temperature compensation, can further promote the life-span of LED banks, reduce the light decay, prior art possesses temperature compensation and needs to set up special temperature sensor and execution circuit, and the cost is expensive, and the price that ceramic capacitor temperature coefficient is showing more is lower more, the utility model discloses utilize the ceramic capacitor that temperature coefficient is showing more, can realize temperature compensation, life-span under the condition that the economy is not reduce cost.

15. The consistent appearance structure of the inductive ballast can be realized, and the popularization and the installation are facilitated. The utility model discloses can design into the inductance ballast structure with the iron core inductance, also can directly utilize the inductance ballast, ceramic capacitor array pastes at the iron core surface or the internal surface of iron core inductance, and whole outward appearance can be close with the inductance ballast like this, does benefit to the installation, overcomes the non-uniform disadvantage of current LED power appearance structure, and the firm heavy appearance structure of inductance ballast can further strengthen sturdy and durable impression for the user in addition to the popularization of the product of being convenient for.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 is a circuit diagram of a first embodiment of the LED constant current driving circuit of the present invention;

FIG. 2 is a schematic diagram of the current-voltage characteristic of the multilayer ceramic capacitor of the LED constant current driving circuit of the present invention;

fig. 3 is a schematic diagram of the bias characteristic of the multilayer ceramic capacitor of the LED constant current driving circuit of the present invention;

fig. 4 is a circuit diagram of a second embodiment of the LED constant current driving circuit of the present invention;

fig. 5 is a schematic structural diagram of a second embodiment of the LED constant current driving circuit of the present invention;

fig. 6 is a circuit diagram of a third embodiment of the LED constant current driving circuit of the present invention;

fig. 7 is a circuit diagram of a fourth embodiment of the LED constant current driving circuit of the present invention.

Fig. 8 is a circuit diagram of a fifth embodiment of the LED constant current driving circuit of the present invention.

Fig. 9 is a schematic structural diagram of a fifth embodiment of the LED constant current driving circuit of the present invention.

Detailed Description

Referring to fig. 1, it is a circuit diagram of the first embodiment of the present invention, which is the most basic embodiment of the present invention, the circuit structure seems very simple, that is, a multilayer ceramic capacitor array and a core inductor are connected in series between the ac power supply and the LED lamp set, however, in fact, the simple circuit creatively obtains a series of beneficial effects that are difficult to reach by a complex active control circuit through the ingenious combination and selection of components.

The working principle of the circuit is similar to that of the LED resistance-capacitance driving circuit in the prior art, the alternating current is blocked by the capacitance reactance of the capacitor in the alternating current loop, so that the current applied to the LED element is basically stable when the power supply voltage changes, however, because the conventional resistance-capacitance driving technology adopts the common film capacitor, the capacitance reactance of the common film capacitor is fixed, the current change amplitude flowing through the LED can only be controlled when the alternating current power supply voltage changes, and the current cannot be completely constant, for example, when the power supply voltage is higher than 10%, the output current of the resistance-capacitance power supply in the prior art is larger by 12-25%, which affects the service life of the LED element, because the voltage-current distribution relation of each element of the resistance-capacitance power supply obeys the impedance triangular relation, in order to prevent the current from fluctuating too much, only the end voltage of the LED lamp set can be reduced, which greatly reduces the power factor of the whole lamp, so that the power factor of the resistance-capacitance power supply in the prior, cannot be adapted to the existing technical standards. Therefore, the resistance-capacitance driving circuit in the prior art is difficult to realize high power, and the high-power driving power supply has higher requirements on power factor and constant current performance. It is known that the multilayer ceramic capacitor (MLCC capacitor) has the advantages of small volume and reliable operation, but its disadvantage is also obvious, namely, the capacitance is unstable, and due to the special physical properties of the piezoelectric ceramic body, the capacitance of the multilayer ceramic capacitor can be greatly changed due to the change of temperature, direct current voltage and frequency, which brings trouble to the application design of many electrical devices, for example, the capacitance thereof is rapidly reduced with the increase of the applied voltage, as shown in fig. 2, however, the present invention utilizes this disadvantage of the multilayer ceramic capacitor, and a large number of experiments show that the multilayer ceramic capacitor also has obvious bias effect at the power frequency, i.e. the capacitance is rapidly reduced with the increase of the applied voltage, the tested voltammetric characteristic of the typical multilayer ceramic capacitor (as shown in fig. 3) shows that the capacitance thereof is rapidly increased with the increase of the applied voltage, so that when the applied voltage exceeds a certain amplitude, after the voltage is greatly increased, the current is not obviously increased, and a spontaneous constant current effect is generated.

The requirement of the direct current bias effect is that the capacity of the direct current bias effect is not more than 60% of the rated capacity of the direct current bias effect when the direct current bias effect is in a nominal direct current working voltage, so that the direct current bias effect can have a relatively obvious constant current effect, and if the bias effect is relatively weak, the constant current effect is relatively poor; the proportional relation between the rated capacity of the multilayer ceramic capacitor array C1 and the maximum current flowing through the capacitor is 20-110 microfarads/ampere, and experiments prove that the capacity is set according to the proportional relation, the bias effect of the ceramic capacitor is obvious (the working area is close to the vertical section of figure 3), the ceramic capacitor is too small and can be broken down due to overhigh voltage, and the ceramic capacitor is too large and has no constant current effect; in addition, the insulation withstand voltage of the ceramic capacitor array C1 is not lower than the maximum allowable power supply voltage peak value so as not to break down.

The multilayer ceramic capacitor array C1 is formed by connecting ferroelectric ceramic capacitors in series and parallel, or formed by combining the ferroelectric ceramic capacitors and other types of capacitors in series and parallel; the reason is that the single capacity of the ceramic capacitor is smaller, a plurality of capacitors are generally required to be connected in series and in parallel to achieve the required capacity and withstand voltage, and when the overall withstand voltage or capacity or linearity index of the ceramic capacitor array meets the requirement, part of the capacitors can be replaced by other capacitors, so that the cost is reduced.

The ferroelectric ceramic capacitor included in the multilayer ceramic capacitor array C1 has negative temperature coefficient characteristic, and the capacitive reactance of the multilayer ceramic capacitor array C1 decreases with the temperature rise within the temperature range of 50-100 ℃ at the power frequency; the utility model discloses directly utilize the capacitive reactance of ceramic capacitor array to realize lamp current constant current control, if adopt the ceramic capacitor who possesses great temperature coefficient characteristic like this, when equipment temperature or ambient temperature improve, the increase of ceramic capacitor capacitive reactance, corresponding lamp current reduces automatically, through temperature compensation, can further promote the life-span of LED banks, reduce the light decay, prior art possesses temperature compensation and needs to set up special temperature sensor and execution circuit, and the cost is expensive, and the price that ceramic capacitor temperature coefficient is showing more is lower more, the utility model discloses utilize the ceramic capacitor that temperature coefficient is showing more, can realize temperature compensation, life-span under the condition that the economy is not reduce cost.

However, the constant current is far from being insufficient only by using a multilayer ceramic capacitor (the prior art also adopts the capacitor for current limiting), because the constant current performance of the ceramic capacitor is not good enough, the constant current precision performance requirement of an LED power supply can not be achieved, and secondly, the higher harmonic and power factor problems of the circuit can not meet the requirement of high-power lighting, and finally, the multilayer ceramic capacitor has obvious audible noise, so people can not generally endure the lighting lamp which generates the squeak noise, therefore, the utility model discloses a power frequency inductor L1 is connected in series in the ceramic capacitor loop, and by utilizing the smooth current action of the inductor, on one hand, the higher harmonic is restrained, on the other hand, the leading component generated by the ceramic capacitor is also corrected, thereby improving the power factor and enabling the harmonic and power factor indexes of the power supply to reach the standard; in addition, the constant current performance can be further improved by means of the saturation effect of the iron core inductor, when the ceramic capacitor is in a constant current interval, the capacitive reactance of the ceramic capacitor is increased along with the increase of the current, and if the inductive reactance of the inductor L1 is reduced along with the increase of the current, the change rate of the impedance of the whole loop under the unit current increment can be increased, so that the constant current precision is improved. The iron core inductor of the embodiment adopts uneven iron core air gaps, so that a part of the iron core can be quickly saturated to assist constant current, and a part of the iron core maintains a linear state to play the roles of smoothing current and improving power factor. Experiments show that the inductor has a good constant current effect when the impedance value of the inductor is 40-100% of the initial impedance value of the inductor at the rated maximum current; the terminal voltage of the iron core inductor L1 at rated maximum current is not lower than 20% of the effective value of rated power supply voltage, if the terminal voltage is too small, the filtering effect is poor, and the harmonic index can not reach the standard. This core inductance also smoothes the current waveform through the ceramic capacitor array C1, which greatly reduces the audible noise of the ceramic capacitor and the resulting low frequency vibrations, preventing the noise from adversely affecting. In the prior art, a small amount of LED resistance-capacitance driving power supplies also adopt ceramic capacitors, but because the special physical properties of the ceramic capacitors and unreasonable matching and circuit structures cannot be found, the LED resistance-capacitance driving power supplies almost have no constant current effect, and indexes such as harmonic waves, power factors, noise, cost and the like are not good, so that the LED resistance-capacitance driving power supplies are rarely applied.

According to the driving power supply designed by the embodiment, when the voltage of the LED lamp bank reaches 220V, the current fluctuation within the range of +/-20% of the power supply voltage is not more than 8%, at the moment, the power factor can reach more than 0.9, and the driving power supply has good constant current characteristics and higher power factor. Considering that the existing ceramic capacitors are not high in withstand voltage and not large enough in capacity, the ceramic capacitor array of the embodiment can also be formed by connecting a plurality of ceramic capacitors in series and in parallel and respectively connecting discharge resistors in parallel, so that the dual functions of voltage sharing and safety can be achieved, and in case that one ceramic capacitor breaks down, the performance of the whole driving power supply cannot be greatly influenced.

The beneficial effect of this embodiment lies in:

1. the cost is low: the defect of the bias characteristic of the multilayer ceramic capacitor is ingeniously utilized to turn the harmful into the beneficial, the defect is changed into an automatic control circuit capable of automatically controlling the constant current through a simple scheme, the accurate current control function of the LED is realized by using an extremely simple passive circuit, the use of active devices such as a chip and a transistor is avoided, and therefore the cost is only a fraction of that of the constant current scheme of the switching power supply in the prior art.

2. The reliability is high: the whole circuit is completely composed of passive devices such as an inductor and a capacitor, the number of elements is extremely small, active control devices such as chips and transistors are avoided, the stability of a product can be effectively improved, the adaptability to severe environments such as high temperature and humidity is greatly improved, the inherent firmness and durability characteristics of the circuit can bring extremely high reliability and long service life durability under the severe environments of outdoor sun, rain and lightning impact, and experiments prove that the early failure rate of the circuit can reach less than 0.5 per thousand, which is less than one tenth of that of a switching power supply in the prior art.

3. Strong lightning resistance: because the thunder and lightning invasion ripples of passive device, heavy current stress endurance are far higher than active semiconductor device, the utility model discloses a resistant thunder performance is far higher than prior art switching power supply class product.

4. The self-healing capability is provided: the essence of the utility model is that the AC current is directly controlled by adopting a capacitor and inductor series circuit with automatically changing impedance to keep the LED current constant, under the most adverse conditions, if problems such as ceramic capacitor breakdown or internal short circuit of the reactor are encountered, for the LED lamp group, only the parameters of the impedance elements for controlling the current are changed, the current control capability is reduced, however, the luminous illumination can still be maintained, only the brightness or stroboscopic index is reduced, therefore, the utility model also has the ingenious fault self-healing capability, when the main elements are broken down and damaged, the lamp set can still emit light for illumination, however, the whole lamp is usually extinguished and loses efficacy when only dozens of elements are damaged in the switching power supply in the prior art, thus the utility model has extremely low fault rate, adopt in the high tower illumination occasion of maintenance difficulties such as highway, airport pier, mine railway the utility model discloses, will greatly reduce and maintain cost of maintenance.

5. The scrap element resources can be utilized: multilayer ceramic capacitor is that a plurality of rare metal materials form through special technology sintering, suppression, printing, and production technology is complicated, and the defective percentage is high, and a lot of substandaries are exactly because bias characteristic test is not up to standard and scrap to treasure, and the utility model discloses this disadvantage that just utilizes ceramic capacitor is just wasted into valuables, the utility model discloses can reuse a large amount of unqualified discarded ceramic capacitor originally, not only make the manufacturing cost of self extremely cheap, still utilized a large amount of discarded components and parts resources, especially make the unlikely waste reuse of rare metal resource among the discarded ceramic capacitor.

6. Ultra-long service life: the utility model discloses the passive device that adopts, self ageing speed is extremely slow, the performance decay is not obvious, in addition simple structure has obvious overlength life-span for hundreds of thousands of hours, is 5-10 times of prior art switching power supply.

7. And (3) reducing the power grid loss: the utility model discloses a ceramic capacitor element can provide perception reactive power for the electric wire netting voluntarily in current control, accounts for about 5-20% of lamps and lanterns active power, can realize certain reactive power compensation to the electric wire netting to reduce the electric wire netting line loss, stabilize electric wire netting voltage, produce indirect energy-conserving benefit.

8. No electromagnetic interference exists: the switch power class drive power supply of prior art, electromagnetic interference is more serious, even adopted good EMI filter circuit, still has a small amount of electromagnetic interference to leak, to special illumination occasions such as military affairs, scientific research, medical treatment, electromagnetic interference produces great influence easily, the utility model relates to a simple impedance circuit, work in the power frequency state, its current-voltage all is continuous power frequency positive ripple or more steady direct current, need not EMI filter circuit and also can not produce any interference to sensitive equipment.

9. The production process is simple and environment-friendly: the utility model discloses there is not active control circuit, production assembly technique is simple, the test is simple, because of the tightness of passive device, the circuit need not the encapsulating, the casing need not to consider sealed heat dissipation, ordinary iron-clad can, simplified production technology, also reduced prior art must the dampproofing chemical solvent who causes of a large amount of encapsulating and discharged the pollution.

10. The power supply voltage fluctuation tolerance capability is strong: the insulating properties of ceramic capacitor can bear the unlikely breakdown of twice rated voltage for the short time, works as the utility model discloses a 500V voltage's ceramic capacitor can bear the unlikely damage of 290V's high pressure for a short time, and prior art switching power supply voltage surpasses 265V will lead to damaging, and china's street lamp supply voltage quality is generally not high, and the night voltage surpasses 270V and often takes place, leads to the frequent damage of LED street lamp, and the utility model discloses can bear nearly 300V's voltage with the help of the outstanding pressure resistance of ceramic capacitor and not damage.

11. No impact current, and the flash operation: the starting impact current of the reactor is less than 2 times of the rated current and is one tenth of that of a switching power supply in the prior art due to the extremely simple impedance current-limiting principle and the current-limiting effect of the iron core reactor, so that the contactor is not easy to damage when the reactor is started in a centralized manner, the voltage of a power grid cannot be sunken, the reactor can directly flicker and operate intermittently, and the reactor is used for replacing incandescent lamps in occasions such as signal lamps and barrier lamps to obtain a remarkable energy-saving effect.

12. An extremely inexpensive dimmable drive power supply is provided: LED is fit for adjusting luminance, however because prior art's switching power supply possesses the high price of the function of adjusting luminance, the circuit is complicated, and the fault rate is higher, and the utility model discloses an impedance constant current principle makes it possess the outside ability of adjusting luminance of nature, as long as the outside is through series connection impedance, electric capacity or change input voltage, just can conveniently change luminance, can not lead to the scintillation.

Fig. 4 is a circuit diagram of a second embodiment of the present invention, which also comprises a multilayer ceramic capacitor array C1 and an iron core inductor L1, the multilayer ceramic capacitor array C1 and the iron core inductor L1 are connected in series between the driven LED lamp set and the power frequency ac power input end, a rectifier bridge D1 is connected between the LED lamp set and the power frequency ac power, the ac side of the rectifier bridge D1 is connected in series with the multilayer ceramic capacitor array C1 and then connected to the power frequency ac power input end, the dc side of the rectifier bridge D1 is connected to the driven LED lamp set, the iron core inductor L1 is connected in series with the ac side of the rectifier bridge D1 and comprises a gas discharge lamp impedance type inductive ballast; the dc side is connected in parallel with a filter capacitor C2. In addition, an overvoltage protector R1 is connected in parallel with the multilayer ceramic capacitor array C1; and an overcurrent protector F is connected in series with the input end of the power frequency alternating current power supply.

The principle of the embodiment is the same as that of the embodiment, and capacitive reactance change generated by multilayer ceramic capacitor bias effect is matched with iron core inductance to automatically control output current to play a role of providing constant current for the LED. Although this embodiment also adopts the electrolytic capacitor smoothing, because the utility model discloses work in the power frequency, can not produce a large amount of high frequency ripples like prior art switching power supply, consequently the utility model discloses a filtering electrolytic capacitor self generates heat hardly, and consequently the life-span is also very long, can not become the life-span bottleneck like the electrolytic capacitor among the switching power supply. The iron core inductor of the present embodiment is composed of an impedance type inductive ballast of the gas discharge lamp, and we know that the impedance type inductive ballast of the gas discharge lamp is an iron core inductor, and as for 220V grid voltage, the rated end voltage is 140-200V, and the rated current is 0.15-10A, and the impedance parameter can basically and effectively suppress the harmonic wave generated by the circuit, and can make the ceramic capacitor work in the constant current curve section close to the rated voltage, so that the inductive ballast with a certain current specification is adopted to replace the inductance of the present invention, and in recent years, along with the energy-saving transformation of a large number of fluorescent lamps, a large number of inductive ballasts are abandoned, and the inductive ballasts themselves have stable performance and extremely long service life, and the iron core inductor of the present invention can directly utilize the inductive ballast of the gas discharge lamp, so that a large number of the originally abandoned inductive ballasts can be reused, not only saves a large amount of nonferrous metal resources such as iron and copper, but also can form green recycling ecology of LED energy-saving transformation and waste light source electrical appliance recycling, and further exerts the environmental protection benefit of the utility model.

The multilayer ceramic capacitor array C1 of this embodiment is packaged inside the cuboid casing, and one surface of the cuboid casing of the packaged multilayer ceramic capacitor array C1 is attached to the inner surface of the winding window. The appearance structure of the inductive ballast is consistent, so that the whole appearance can be close to the inductive ballast, the installation is facilitated, the defect that the appearance structure of the conventional LED power supply is not uniform is overcome, in addition, the firm, thick and heavy appearance structure of the inductive ballast can further strengthen the firm and durable visual impression for users, and the popularization of products is facilitated.

The embodiment is also provided with an overvoltage protector R1 which is connected with the multilayer ceramic capacitor array C1 in parallel and used for absorbing overvoltage and protecting the ceramic capacitor; the overcurrent protector F is connected with the input end of the power frequency alternating current power supply in series and used for total overcurrent or short circuit protection of the whole driving circuit, and the safety of the power supply is further improved.

Obviously, the embodiment also has the advantages of low cost, high reliability, ultra-long service life, strong lightning resistance, self-healing capability, capability of utilizing scrapped element resources, reduction of power grid loss, no electromagnetic interference, simple and environment-friendly production process, strong power supply voltage fluctuation resistance, convenience in flashing or dimming operation and the like.

Fig. 5 is the circuit diagram of the third embodiment of the present invention, also comprise a multilayer ceramic capacitor array C1 and an iron core inductance L1, multilayer ceramic capacitor array C1 connects between driven LED banks and power frequency ac power supply input, there is rectifier bridge D1 between LED banks and the power frequency ac power supply, rectifier bridge D1's alternating current side and multilayer ceramic capacitor array C1, step-down capacitor C3 connects power frequency ac power supply input after establishing ties, rectifier bridge D1's direct current side is connected with driven LED banks, iron core inductance L1 establishes ties in rectifier bridge D1's direct current side. In addition, an overcurrent protector F is connected with the input end of the power frequency alternating current power supply in series.

The principle of the embodiment is the same as the first and second embodiments, and the output current is automatically controlled by using the capacitive reactance change generated by the multilayer ceramic capacitor bias effect to cooperate with the iron core inductor, so as to provide the constant current for the LED, the iron core inductor of the embodiment is arranged on the direct current side of the rectifier bridge, of course, the iron core inductor can also be composed of a gas discharge lamp impedance type inductive ballast, the iron core inductor is connected on the direct current side, and can also play a role in inhibiting harmonic waves and impact current, but the inductor on the direct current side cannot form a reactive load on the alternating current side, cannot provide capacitive reactive power of the inductive reactive compensation ceramic capacitor array C1, and therefore cannot increase the terminal voltage of the ceramic capacitor, so that the constant current performance of the ceramic capacitor is reduced, but the advantage is that the terminal voltage of the ceramic capacitor array C1 is smaller, and the ceramic capacitor with a lower withstand voltage value can be adopted, so as, in addition, the voltage reduction capacitor C3 connected in series is added, the terminal voltage of the ceramic capacitor array C1 can be further reduced, even if the output end is short-circuited, the voltage at the two ends of the ceramic capacitor can not be greatly increased, so that the low-voltage ceramic capacitor with the withstand voltage of 200-250V can be utilized, and an overvoltage protector is not needed for protection. This embodiment has the additional advantage that the dc side current can be stabilized by the iron core inductor, so that the dc current flowing through the LED lamp set tends to be smooth, thereby avoiding the cost increased by connecting the filter electrolytic capacitor in parallel. This embodiment has still set up overcurrent protector F and power frequency alternating current power supply input and has established ties for whole drive circuit's total overcurrent or short-circuit protection further promotes the security of power.

Obviously, the embodiment also has the advantages of low cost, high reliability, ultra-long service life, strong lightning resistance, self-healing capability, capability of utilizing scrapped element resources, reduction of power grid loss, no electromagnetic interference, simple and environment-friendly production process, strong power supply voltage fluctuation resistance, convenience in flashing or dimming operation and the like.

Fig. 6 is the circuit diagram of the fourth embodiment, also constitute by a multilayer ceramic capacitor array C1 and an iron core inductance L1, it has power frequency transformer T to connect between LED banks and the power frequency ac power input end, power frequency transformer T's secondary winding connects rectifier bridge D1's alternating current side, multilayer ceramic capacitor array C1 establishes ties between power frequency transformer T's secondary winding and rectifier bridge alternating current side, rectifier bridge D1's direct current side and driven LED banks are connected, iron core inductance L1 establishes ties between power frequency transformer T's primary winding and ac power input end. In addition, an overcurrent protector F is connected with the input end of the power frequency alternating current power supply in series.

The principle of the embodiment is the same as that of other embodiments, capacitive reactance change generated by multilayer ceramic capacitor bias effect is matched with iron core inductance, output current is automatically controlled, and constant current is provided for the LED. The iron core inductor can provide a part of inductance due to the short-circuit impedance of the transformer, so the volume and the inductance can be reduced by about 15-30% compared with the iron core inductor without the transformer, and the iron core inductor can also be used for a gas discharge lamp inductive ballast and can also be arranged on the direct current side of a rectifier bridge. This embodiment has also set up overcurrent protector F and power frequency alternating current power supply input end and has established ties equally for whole drive circuit's total overcurrent or short-circuit protection, further promotes the security of power.

It should be noted that, in this embodiment, because of the inductance provided by the short-circuit impedance of the transformer, if the requirement on the harmonic index is not high, the iron core inductance L1 may also be omitted, but the essence is the same, and only the short-circuit impedance of the transformer itself is used to implement the function of the iron core inductance L1, if the harmonic index is to be improved and the volume is to be reduced, the transformer T may also be designed as a leakage transformer, and the larger leakage reactance of the leakage transformer is used to play a role in filtering the iron core inductance L1, so that the harmonic standard may be achieved on the basis of omitting the iron core inductance L1. In addition, the rectifier bridge can also be changed according to the secondary winding characteristics of the transformer, for example, a voltage-doubling rectifier bridge and a double-diode full-wave rectifier circuit are adopted to replace a common rectifier bridge, or a common-cathode common-anode Schottky diode is adopted to form a low-loss rectifier bridge and the like, and the conventional flexible means are completely equivalent to the technical scheme of the utility model.

Obviously, the embodiment also has the advantages of low cost, high reliability, ultra-long service life, strong lightning resistance, self-healing capability, capability of utilizing scrapped element resources, reduction of power grid loss, no electromagnetic interference, simple and environment-friendly production process, strong power supply voltage fluctuation resistance, convenience in flashing or dimming operation and the like.

Fig. 7 is a circuit diagram of the fifth embodiment of the present invention, which also comprises multilayer ceramic capacitor array C1 and iron core inductor L1, multilayer ceramic capacitor array C1 and iron core inductor L1 are connected in series between the driven LED lamp set and the power frequency ac power input end, a rectifier bridge D1 is connected between the LED lamp set and the power frequency ac power, the ac side of rectifier bridge D1 is connected in series with multilayer ceramic capacitor array C1 and then connected to the power frequency ac power input end, the dc side of rectifier bridge D1 is connected to the driven LED lamp set, iron core inductor L1 has two sets of windings, one end of each of the two windings is connected to the power frequency ac power input end, and is connected in series to the ac side of rectifier bridge D1; the dc side is connected in parallel with a filter capacitor C2. In addition, an overvoltage protector R1 is connected in parallel with the multilayer ceramic capacitor array C1; the temperature switch S is in contact with the outer surface of the overvoltage protector R1 and is connected with the input end of the power frequency alternating current power supply in series; in addition, an overcurrent protector F is connected with the input end of the power frequency alternating current power supply in series.

The principle of the embodiment is the same as that of the embodiment, the capacitive reactance change generated by the multilayer ceramic capacitor bias effect is matched with the iron core inductor, the output current is automatically controlled, the constant current is provided for the LED, the iron core inductor of the embodiment is composed of two groups of windings which are connected to the input end of the alternating current power supply, the purpose of better lightening protection can be achieved, the wave head frequency of lightening invasion waves is high, the huge inductance of the iron core inductor can greatly weaken the lightening of the lightening invasion waves, the windings of the iron core inductor are divided into two parts and are respectively connected with the inlet end of the alternating current power supply in series, the lightening invasion waves of overvoltage relative to the ground and zero line to the ground can be effectively absorbed, and if a lightening protection device is matched, the excellent lightening protection effect can be achieved. Although the utility model discloses simple firm structure itself possesses congenital lightning protection ability, but in mountain area, special areas such as thunderstorm district use, then this embodiment can play more outstanding lightning protection effect, through the test, this embodiment can bear in succession looks-ground, zero-50 KV between ground, 1 ms's surge impulse voltage is tens of not damaged, comprehensive lightning protection effect is higher than the tens of times of prior art switching power supply product, the annual thunderbolt spoilage in many thunder district is only thousandth in practical application, the probability of damage is only about one percent of prior art switching power supply. The embodiment is also provided with an overvoltage protector R1 connected with the multilayer ceramic capacitor array C1 in parallel and a temperature switch S contacted with the overvoltage protector for short-circuit protection, and the overcurrent protector F is connected with the input end of the power frequency alternating current power supply in series and used for total overcurrent or short-circuit protection of the whole drive circuit, so that the safety of the power supply is further improved.

Multilayer ceramic capacitor array C1 of this embodiment welds and adorns on a plane circuit board, this circuit board and the laminating of iron core inductance outside surface, simultaneously also can be with rectifier bridge, overvoltage protector, filter capacitor etc. weld the dress on same circuit board, realize the outward appearance structure who is close with inductive ballast, whole outward appearance also can be close with inductive ballast like this, do benefit to the installation, overcome the current non-uniform disadvantage of LED power appearance structure, inductive ballast's sturdy and thick heavy appearance structure in addition, can further strengthen sturdy and durable visual impression for the user, the popularization of the product of being convenient for.

Obviously, the embodiment also has the advantages of low cost, high reliability, ultra-long service life, extremely outstanding lightning resistance, self-healing capability, capability of utilizing scrapped element resources, reduction of power grid loss, no electromagnetic interference, simple and environment-friendly production process, strong power supply voltage fluctuation resistance, convenience in flashing or dimming operation and the like.

It should be noted that the above embodiments are for illustration purposes and not for limitation of the present invention, for example, the multilayer ceramic capacitor array of the present invention may also be composed of other novel capacitors, the multilayer ceramic capacitor array may be connected in parallel with a discharge resistor, the ceramic capacitor and the iron core inductor may be composed of a plurality of series-parallel connections of different or the same specification, the iron core inductor may be made of other iron core materials such as products of other uses or amorphous alloys, the iron core inductor may be composed of an inductive ballast and a special inductive coil, the overvoltage protector may be made of TVS diodes or voltage dependent resistors, the rectifier bridge may be composed of independent diode elements, etc., many technical features of the embodiments of the present invention may be interchanged or omitted, and the parameter settings of many elements may be changed as required; many conventional circuit components also can add as required to the utility model discloses in, for example the condenser both ends add discharge resistance, alternating current power supply input adds lightning protection overvoltage protection device, multilayer ceramic capacitor array C1 sets to multiunit switching and is used for adjusting luminance etc. the utility model discloses "one" or "one" before the component do not exclude to appear a plurality of these kinds of components, and the technical staff in the field can be understanding completely the utility model discloses combine prior art to make a large amount of about on the basis of technical characteristics and principle the utility model discloses a change design, these all should belong to the utility model discloses a protection scope.

Claims (10)

1. A passive LED constant current driving device is characterized by comprising a multilayer ceramic capacitor array (C1) and an iron core inductor (L1), wherein the multilayer ceramic capacitor array (C1) and the iron core inductor (L1) are connected in series between a driven LED lamp bank and a power frequency alternating current power supply input end; the multilayer ceramic capacitor array (C1) is formed by series-parallel connection of ferroelectric ceramic capacitors or by series-parallel connection of the ferroelectric ceramic capacitors and other types of capacitors; the ferroelectric ceramic capacitor included in the multilayer ceramic capacitor array (C1) has negative temperature coefficient characteristics, and the capacitive reactance of the multilayer ceramic capacitor array at the power frequency is reduced along with the temperature rise within the temperature range of 50-100 ℃; the terminal voltage of the iron core inductor (L1) at rated maximum current is not lower than 20% of the effective value of rated power supply voltage, and the insulation withstand voltage of the whole multilayer ceramic capacitor array (C1) is not lower than the maximum allowable power supply voltage peak value; the multilayer ceramic capacitor array (C1) is welded on a planar circuit board or packaged in the cuboid shell, and one surface of the planar circuit board of the multilayer ceramic capacitor array (C1) or the cuboid shell of the multilayer ceramic capacitor array (C1) is welded on and attached to the outer surface of the iron core inductor (L1) or the inner surface of the winding window.

2. The passive LED constant current driving device according to claim 1, wherein the iron core inductor (L1) has a magnetic saturation characteristic with a resistance value at rated maximum current of 40-100% of its initial resistance value.

3. The passive LED constant current driving device according to claim 2, wherein the iron core of the iron core inductor (L1) is provided with an unequal distance air gap.

4. The passive LED constant current driving device according to claim 1, wherein the iron core inductor (L1) comprises a gas discharge lamp impedance type inductive ballast.

5. The passive LED constant-current driving device according to claim 1, wherein a rectifier bridge (D1) is connected between the driven LED lamp set and a power-frequency alternating-current power supply input end, an alternating-current side of the rectifier bridge (D1) is connected with the multilayer ceramic capacitor array (C1) in series and then connected with the power-frequency alternating-current power supply input end, a direct-current side of the rectifier bridge (D1) is connected with the driven LED lamp set, and the core inductor (L1) is connected with the alternating-current side or the direct-current side of the rectifier bridge (D1) in series.

6. The passive LED constant current driving device according to claim 5, characterized in that a filter capacitor (C2) is connected in parallel with the direct current side of the rectifier bridge (D1).

7. The passive LED constant-current driving device according to claim 1, wherein a power frequency transformer (T) is connected between the driven LED lamp set and a power frequency alternating current power supply input end.

8. The passive LED constant-current driving device according to claim 1, wherein a voltage reduction capacitor (C3) is connected in series between the driven LED lamp set and a power frequency alternating current power supply input end.

9. The passive LED constant current driving device according to claim 1, further comprising an overvoltage protector (R1), wherein the overvoltage protector (R1) is connected in parallel with the multilayer ceramic capacitor array (C1); and the temperature switch (S) is in contact with the outer surface of the overvoltage protector (R1) and is connected with the input end of the power frequency alternating current power supply in series.

10. The passive LED constant-current driving device according to claim 1, further comprising an overcurrent protector (F), wherein the overcurrent protector (F) is connected with the input end of the industrial frequency alternating-current power supply in series.

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