CN203071567U - Linear high voltage LED drive protection circuit - Google Patents
Linear high voltage LED drive protection circuit Download PDFInfo
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- CN203071567U CN203071567U CN 201220708512 CN201220708512U CN203071567U CN 203071567 U CN203071567 U CN 203071567U CN 201220708512 CN201220708512 CN 201220708512 CN 201220708512 U CN201220708512 U CN 201220708512U CN 203071567 U CN203071567 U CN 203071567U
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Abstract
The utility model provides a linear high voltage LED drive protection circuit. The linear high voltage LED drive protection circuit comprises drive switches which drive LED light strings to turn on and overvoltage protection circuits which are used for protecting the drive switches. Each overvoltage protection circuit comprises a voltage sampling unit which is used for monitoring the voltage of both ends of each drive switch, a signal processing unit which is used for processing signals collected by the voltage sampling unit, and a control switch unit which is used for controlling a drive switch to turn off when the voltage of both ends of the drive switch exceeds a set value. According to the linear high voltage LED drive protection circuit provided by the utility model, the overvoltage protection circuits which are composed of the voltage sampling units, the signal processing units and the control switch units are designed for the drive switches; and when the power supply voltage exceeds the normal value for a certain range or when short circuit or open circuit of an LED light string occurs, all drive switches turn off, so that no current flows and damage of the drive switches due to large power consumption can be prevented.
Description
Technical field
The utility model belong to light-emitting diode (Light Emitting Diode, hereinafter to be referred as: LED) lighting technical field is specifically related to a kind of linear low density led driver protective circuit.
Background technology
At present, what the LED mains lighting supply mainly adopted is Switching Power Supply, and Switching Power Supply has the little advantage of the high volume of efficient, and the LED illumination has isolated form and non-isolation type with Switching Power Supply.But Switching Power Supply also has the shortcoming that is difficult to overcome, be embodied in: because the Switching Power Supply use is electrolytic capacitor and transformer or inductance, and the disadvantage of electrolytic capacitor is that the life-span is short, and reliability is not high, at most can only reach 5000-8000 hour its useful life yet; And the every raising of the working temperature of aluminium electrolytic capacitor generally can reduce 10% 10 ℃ of its useful lifes, and the working temperature of the Switching Power Supply of LED lamp is generally all about 70 ℃.Therefore, directly determined the useful life of Switching Power Supply the useful life of electrolytic capacitor, but, the life-span of LED lamp pearl generally but can reach 50000 hours, therefore, LED throws light on the life-span of the useful life of Switching Power Supply and LED lamp pearl and does not match, thereby has influenced the useful life of LED lamp pearl, causes the waste of resource.
Some companies have released a kind of linear low density LED and have driven chip now, adopt the LED driving power of this chip manufacturing to be different from Switching Power Supply fully, it need place in circuit be (wherein in turn with the LED lamp string of the LED lamp string of at least 2 sections series connection or series connection and combination in parallel, every section LED lamp string all includes the driving switch of a driving LED lamp string), to be added on the LED lamp string then through the dc pulse moving voltage of over commutation, measure input voltage by driving control chip at last, by the time input voltage reaches after the certain value, and the driving switch connection that drives first section lamp string of control chip control makes the constant current of first section LED lamp string with lower current value; When arriving higher magnitude of voltage, voltage controls the driving switch that first section lamp closed in the driving switch connection of second section lamp string simultaneously later on again, so since two sections lamps be this moment in sequential series first section lamp and second section lamp conducting simultaneously and constant current in higher electric current, after waiting until that at last voltage is higher, connect the 3rd section LED lamp string again, close the driving switch of second section lamp simultaneously, so because three sections lamps are that this moment in sequential series first section lamp, second section and the 3rd section lamp conducting simultaneously and constant current are in the electric current of higher value; If there is more Led lamp string to connect in turn, the working method of follow-up every section LED lamp string by that analogy; Process is just in time opposite when input voltage descends.The driving LED lamp only need drive chip, driving switch and corresponding a small amount of resistance just can be realized like this.Yet, though this linear low density LED drive scheme circuit is simple, but the driving switch of driving LED lamp string will bear very big voltage drop, this is because when after LED lamp string conducting the last period but before back one section LED lamp string also do not have conducting, the switch that drives of conducting is wanted the maximum pressure drop that bear needs when being equivalent to back one section LED lamp conducting, the electric current that flows through driving switch simultaneously is the electric current of current conducting LED lamp string, and driving switch will damage because power consumption is excessive like this.The method that adopts for the power consumption that reduces driving switch has following several at present: first kind, reduce every section corresponding conduction voltage drop of LED lamp string by the hop count that increases LED lamp string, by reducing the power consumption that the corresponding conduction voltage drop of LED lamp string reduces the respective drive switch, but this mode by increase LED lamp string hop count must increase corresponding driving switch number, and its control circuit also can be more complicated; Second kind, the conducting electric current of restriction LED lamp string makes drive scheme only be used for the small-power situation, and general conducting electric current is limited in 40 milliamperes of following gross powers and is limited in below ten watts.
Even if but adopted the method for above-mentioned reduction driving switch power consumption, can not guarantee driving switch safety under special circumstances.For example: when fluctuation takes place supply voltage, the fluctuation range of general civil power is about 20%, supply voltage exceeds at 20% o'clock than normal value, last road driving switch maximum will be born 100 volts voltage, the conducting electric current of last road driving switch is maximum in several roads simultaneously, and driving switch just burns out because power consumption is excessive easily like this; In addition, the high voltage that manys in the time of when a certain LED lamp string is short-circuited or opens a way, also can making its back one road or front one road driving switch bear than operate as normal, driving switch also can burn out because power consumption is excessive, and after one of them driving switch burns out, because other driving switchs need be born bigger pressure drop, at this moment, the driving switch of whole linear led drive circuit will chain-react and is burnt out successively.The power consumption here generally refers to the heating power of device, and the heating power of driving switch is the voltage and the product that flows through the electric current of switch at its two ends here.
The utility model content
The purpose of this utility model is to solve defective that above-mentioned prior art exists, it is a kind of when supply voltage occurs than great fluctuation process or short circuit appears in a certain section LED lamp string or the overvoltage crowbar that can protect the driving switch on each road when opening a way to provide.
For achieving the above object, the utility model adopts following technical scheme:
A kind of linear low density led driver protective circuit comprises for the driving switch of driving LED lamp string conducting, also comprises the overvoltage crowbar for the protection of described driving switch;
The signal processing unit that described overvoltage crowbar comprises for the voltage sample unit of each driving switch both end voltage of monitoring, be used for the signal that the voltage sample unit collects is handled, control the control switch unit of its shutoff when being used for voltage when described driving switch two ends above a certain set point.
Linear low density led driver protective circuit as mentioned above,
Described LED lamp string comprises: at least 2 sections LED lamp strings;
Described driving switch comprises: the driving switch that is used for driving the conducting of every section LED lamp string;
Described protective circuit is protected respectively each road driving switch.
Linear low density led driver protective circuit as mentioned above, described driving switch are NMOS pipe.
Linear low density led driver protective circuit as mentioned above, described voltage sample unit comprises resistance R 1, and signal processing unit comprises resistance R 2, described resistance R 1 and resistance R 2 series connection, one end of series resistance R1 and resistance R 2 is connected after every section LED lamp string, other end ground connection; The NPN triode that described control switch unit is that base stage is connected between resistance R 1 and the resistance R 2, grounded emitter, collector electrode are connected with a described NMOS tube grid.
Linear low density led driver protective circuit as mentioned above, described voltage sample unit comprises resistance R 1, signal processing unit comprises resistance R 2 and signal errors comparator, described resistance R 1 and resistance R 2 series connection, described control switch unit comprises the 2nd NMOS pipe, series resistance R1 and resistance R 2 one ends are connected after every section LED lamp string, other end ground connection; The input anode of described signal errors comparator is connected between resistance R 1 and the resistance R 2, negative pole connects reference voltage, and output is connected with the grid of the 2nd NMOS pipe; The drain electrode of the 2nd NMOS pipe is connected with the grid of a NMOS pipe, the 2nd NMOS manages source ground.
Linear low density led driver protective circuit as mentioned above, described driving switch is NMOS pipe, PMOS pipe, NPN triode, PNP triode.
Linear low density led driver protective circuit as mentioned above, described voltage sample unit can be resistor voltage divider circuit sampling or capacitance partial pressure circuit sampling.
Linear low density led driver protective circuit as mentioned above, described control switch unit is NMOS pipe, PMOS pipe, NPN triode, PNP triode.
Linear low density led driver protective circuit as mentioned above, described overvoltage crowbar can be placed on driving switch and drive outside the control chip, also can adopt the form of integrated circuit to be built in driving switch and drive within the control chip.
Linear low density led driver protective circuit of the present utility model; by the overvoltage crowbar of forming for driving switch design voltage sampling unit, signal processing unit, control switch unit; realized when supply voltage exceeds the normal value certain limit or a certain section LED lamp string turn-offs all driving switchs when short circuit or open circuit occurring and make it not have electric current to flow through; thereby make driving switch just can also not improve the reliability of whole LED drive circuit system work simultaneously owing to power consumption is damaged too greatly.
Description of drawings
Accompanying drawing 1 is for including the linear low density led driver electrical block diagram of the utility model overvoltage crowbar;
Accompanying drawing 2 is for including linear low density led driver embodiment one electrical block diagram of the utility model overvoltage crowbar;
Accompanying drawing 3 is for including linear low density led driver embodiment two electrical block diagrams of the utility model overvoltage crowbar;
Electric current and voltage waveform when accompanying drawing 4 is linear low density led driver operate as normal;
Electric current and voltage waveform when accompanying drawing 5 exceeds thresholding for linear low density led driver input voltage;
Electric current and voltage waveform when accompanying drawing 6 occurs opening circuit for the 3rd section LED lamp string of linear low density led driver;
Circuit and voltage waveform when accompanying drawing 7 occurs opening circuit for second section LED lamp of linear low density led driver string;
Description of reference numerals: the 1-overvoltage crowbar, 11-voltage sample unit 11,12-signal processing unit 12, control switch unit 13,2-drives control chip, 3-driving switch.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with the accompanying drawing in the utility model, technical scheme in the utility model is clearly and completely described, obviously, described embodiment is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that obtains under the creative work prerequisite, all belong to the scope of the utility model protection.
Particularly; though input voltage can not unconfined rising and is caused driving switch to burn out because power consumption is excessive; but in use often having input voltage fluctuation or certain a string LED lamp by a relatively large margin damages; so corresponding driving switch will bear and exceed a lot of voltage than operate as normal and cause driving switch therefrom and burn out; therefore; need provide a kind of can detect the voltage at driving switch two ends and driving switch is turn-offed; thereby make the overvoltage crowbar that this driving switch quits work does not namely have electric current to flow through, driving switch just can not damage because power consumption increases yet.Overvoltage crowbar 1 of the present utility model comprises that (driving switch 3 low-pressure ends have only about 0.5 volt to the pressure drop on ground for voltage for detection of driving switch 3 high voltage end voltage to earths; so high-pressure side voltage over the ground is the voltage at driving switch two ends just) sampling unit 11; handle back (comprise direct transmission, amplification, decay, oppositely or through logical circuit handle) through signal processing unit 12 and be sent to control switch unit 13, drive the operating state that control chip 2 is responsible for three driving switchs of control.Same overvoltage crowbar is formed the overvoltage crowbar to other two driving switchs (Q2, Q3).Control switch of the present utility model unit 13 is connected between the switch control end and driving switch 3 that drives control chip 2, control switch unit 13 and driving control chip 2 are as long as one of them provides the signal that turn-offs driving switch 3, and driving switch 3 just is in closed condition.Voltage sample unit 11 is voltage or the driving switch 3 high voltage ends voltages over the ground at each driving switch 3 two ends of monitoring in real time, drive control switch unit 13 and turn-off driving switchs 3 when this voltage is higher than predefined a certain threshold value.Described driving switch 3 is used for driving described LED lamp string conducting or shutoff, and described driving control chip 2 is used for control driving switch 3 and comes driving LED lamp string.Becoming minimum value behind 220 volts the alternating voltage process full-wave rectification bridge D1 is that 0 peak is the dc pulse moving voltage about 310 volts, when raising from 0 volt, voltage surpasses LED lamp string L1, drive control chip 2 control driving switch Q1 conductings and constant current during the conducting voltage of LED lamp string L2 in a lower current value, voltage continues to be elevated to LED lamp string L3, LED lamp string L4 also drives control chip 2 control driving switch Q2 conductings and constant current during the voltage of conducting in a bigger current value, drive control chip 2 controls simultaneously and turn-off driving switch Q1, at this moment LED lamp string L1, LED lamp string L2, LED lamp string L3, LED lamp string L4 drives conducting by driving switch Q2 simultaneously, voltage continues to be elevated to LED lamp string L5 again, LED lamp string L6 also drives control chip 2 control driving switch Q3 conductings and constant current during the voltage of conducting in a bigger current value, turn-off driving switch Q2 simultaneously, at this moment LED lamp string L1, LED lamp string L2, LED lamp string L3, LED lamp string L4, LED lamp string L5, LED lamp string L6 drives conducting by driving switch Q3 simultaneously, and process is just in time opposite when reducing gradually behind the voltage process peak.
The utility model is by arranging overvoltage crowbar for the driving switch of driving LED lamp string work; realized when the voltage at driving switch two ends surpasses certain limit, making driving switch to close and quit work; namely there is not electric current to flow through; at this moment; driving switch just can not damage because power consumption increases, and then can improve the useful life of using the driving switch that includes the utility model overvoltage crowbar.
Further, on the basis of overvoltage crowbar described above, described LED lamp string comprises: at least 2 sections LED lamp strings; Described driving switch comprises: the driving switch that is used for driving the work of every section LED lamp string; Described protective circuit is protected respectively each road driving switch.Described LED lamp string the serve as reasons series connection of several LED crystal grain or Led lamp pearl or series connection and the LED lamp string that is combined in parallel, his conducting voltage is than high many of single led crystal grain or lamp pearl.
Further, on the basis of overvoltage crowbar described above, described driving switch is NMOS pipe.
Come overvoltage crowbar of the present utility model is described below by specific embodiment.
Particularly, as shown in Figure 2, after 220 volts the alternating voltage process full-wave rectification bridge D1 rectification, its output is connected with and drives control chip 2, LED lamp string L1-L6 and NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3.NPN triode Q4 and resistance R 1, resistance R 2 are formed the overvoltage crowbar of NMOS pipe Q1; NPN triode Q5 and resistance R 3, resistance R 4 are formed the overvoltage crowbar of NMOS pipe Q2, and NPN triode Q5 and resistance R 5, resistance R 6 are formed the overvoltage crowbar of NMOS pipe Q3.The bleeder circuit that resistance R 1, resistance R 2 are formed plays voltage sampling and decay, directly be sent to the base stage of NPN triode Q4 then, when the value after the voltage of the drain electrode of NMOS pipe Q1 is through divider resistance R1, resistance R 2 decay surpasses the conducting voltage (generally being approximately 0.7 volt) of the base stage of NPN triode Q4 and emitter, NPN triode Q4 saturation conduction, NMOS pipe Q1 is because the voltage of grid significantly reduces (being about 100 to 200 millivolts) ends, thereby though the voltage on ground is very high does not have electric current not flow through can to generate heat so NMOS pipe Q1 drains.Same principle NPN triode Q5 and resistance R 3, resistance R 4 protection NMOS pipe Q2 can not cross cause thermal damage, and NPN triode Q6 and resistance R 5, resistance R 6 protection NMOS pipe Q3 can not cross cause thermal damage.
Particularly, as shown in Figure 3, after 220 volts the alternating voltage process full-wave rectification bridge D1 rectification, its output is connected with and drives control chip 2, LED lamp string L1-L6 and NMOS pipe Q1, NMOS pipe Q2, NMOS pipe Q3.NMOS pipe Q4, signal errors comparator U1 and resistance R 1, resistance R 2 are formed the overvoltage crowbar of NMOS pipe Q1; NMOS pipe Q5, signal errors comparator U2 and resistance R 3, resistance R 4 are formed the overvoltage crowbar of NMOS pipe Q2; NMOS pipe Q6, signal errors comparator U3 and resistance R 5, resistance R 6 are formed the overvoltage crowbar of NMOS pipe Q3.The bleeder circuit that resistance R 1, resistance R 2 are formed plays voltage sampling and decay, when sampled voltage is higher than the reference voltage of signal errors comparator U1, signal errors comparator U1 output high level makes NMOS pipe Q4 saturation conduction, NMOS pipe Q1 just quits work and is in cut-off state like this, therefore can not damage because power is excessive.Same; the overvoltage crowbar protection NMOS pipe Q2 that NMOS pipe Q5, signal errors comparator U2 and resistance R 3, resistance R 4 form can not cross cause thermal damage, and the overvoltage crowbar protection NMOS pipe Q3 that NMOS pipe Q6, signal errors comparator U3 and resistance R 5, resistance R 6 form is can be because of its both end voltage not too high and then cause that power is excessive finally to make it cross cause thermal damage.
Further, driving switch described in each embodiment of the utility model can also manage for PMOS, NPN triode, PNP triode.
Further, voltage sample unit described in each embodiment of the utility model can be resistor voltage divider circuit sampling or capacitance partial pressure circuit sampling.
Further, control switch unit described in each embodiment of the utility model is NMOS pipe, PMOS pipe, NPN triode, PNP triode.
Further, the described overvoltage crowbar of above-mentioned arbitrary embodiment can be placed on driving switch and drive outside the control chip, also can adopt the form of integrated circuit to be built within the driving control chip with driving switch.In the time of within overvoltage crowbar of the present utility model being built in the driving control chip, save the space that is used for placing driving switch originally, saved the duty area of whole drive circuit greatly.
Its course of work of drive circuit that includes the utility model overvoltage crowbar is (be that example describe only to contain 3 sections LED lamp strings in the present specification accompanying drawing): when input voltage rises to the voltage that can make the conducting of first section LED lamp string from zero volt, drive control chip 2 and open driving switch Q1, then L2 is luminous for first section LED lamp string L1, LED lamp string, and other sections LED lamp string is not luminous; When input voltage continues to rise to the voltage that can make first section and second section LED lamp string conducting simultaneously, drive control chip 2 and open driving switch Q2, close driving switch Q1 simultaneously, then first section LED lamp string L1, LED lamp string L2 and second section LED lamp string L3, LED lamp string L4 are simultaneously luminous, and other sections LED lamp string is not luminous; By that analogy, voltage continues to rise again, drives control chip 2 and opens driving switch Q3, closes driving switch Q2 simultaneously, and then three sections LED lamp string L1, LED lamp string L2, LED lamp string L3, LED lamp string L4, LED lamp string L5, LED lamp string L6 are simultaneously luminous; Process is just in time opposite when input voltage begins to descend, and repeats no more herein.
Below voltage, the current waveform of the linear low density led driver that includes the utility model overvoltage crowbar described (be example only to contain 3 sections LED lamp strings in the present specification accompanying drawing):
Electric current and voltage waveform when accompanying drawing 4 is linear low density led driver operate as normal, as shown in Figure 4, the 30th, the current waveform, the 31st during linear low density led driver operate as normal, the voltage waveform during linear low density led driver operate as normal.
Particularly, so-called operate as normal refers to that the input voltage of linear low density led driver had not both exceeded the situation appearance (threshold voltage is the upper limit with 340V) of threshold voltage, and the situation that does not also have LED lamp string to open circuit occurs.At this moment, not have voltage, current waveform when protected be the same for the voltage of accompanying drawing 5, current waveform and driver.Wherein, voltage waveform 31 its ceiling voltages are that 310V does not exceed the upper limit, corresponding current waveform 30 has three steps, wherein, first step is to be merely able to satisfy first section LED lamp string L1 when operating voltage, current waveform during LED lamp string L2 conducting, second step is to be merely able to satisfy first section and second section LED lamp string L1 when operating voltage, LED lamp string L2, LED lamp string L3, current waveform during LED lamp string L4 conducting simultaneously, the 3rd step refers to can satisfy first section when operating voltage, second section and the 3rd section LED lamp string L1, LED lamp string L2, LED lamp string L3, LED lamp string L4, LED lamp string L5, current waveform during LED lamp string L6 conducting simultaneously.
Electric current and voltage waveform when accompanying drawing 5 exceeds thresholding for linear low density led driver input voltage; As shown in Figure 5, the 32nd, the voltage waveform, 33rd of linear low density led driver when input voltage exceeds thresholding, the current waveform of linear low density led driver when input voltage exceeds thresholding.
Particularly, as shown in Figure 6, the maximum input voltage of voltage waveform 32 exceeded 340V on be limited to 400V; Current waveform 33 electric current when input voltage is higher than 340V is zero (has one section and be in off-state in the middle of three steps), this is because prescribe a time limit when input voltage surpasses going up of 340V, control switch 4 can cut out by control driving switch Q3, at this moment, the LED lamp string of whole drive circuit does not all have conducting, and therefore, whole LED lamp string does not have electric current to be passed through, the situation that the middle one section disconnection of current waveform in the accompanying drawing 6 will occur at this moment.And when input voltage from the highest toward the falling process, in input voltage falls back to the scope of 340V and voltage when higher, control switch 4 control driving switch Q3 conductings, at this moment, LED lamp string L1, LED lamp string L2, LED lamp string L3, LED lamp string L4, LED lamp string L5, LED lamp string L6 conducting simultaneously, thereby the current waveform of right half of the 3rd step just arranged also in the accompanying drawing 6, and can only satisfy the LED of conducting simultaneously lamp string L1 when input voltage continues to fall back to, LED lamp string L2, LED lamp string L3, during LED lamp string L4, driving control chip 2 control driving switch Q2 opens, Q3 closes, at this moment, the current waveform that second step in the right half of figure just arranged, same principle, when continuing to fall back to again, input voltage can only satisfy conducting LED lamp string L1, during LED lamp string L2, current waveform is just shown in first step in the half of figure in the right side.
Electric current and voltage waveform when accompanying drawing 6 occurs opening circuit for the 3rd section LED lamp string of linear low density led driver; As shown in Figure 6, the 34th, the voltage waveform of linear low density led driver when opening circuit appears in the 3rd section LED lamp string; The 35th, the current waveform of linear low density led driver when opening circuit appears in the 3rd section LED lamp string.
Particularly, as shown in Figure 6, the ceiling voltage of voltage waveform 34 is 310V, current waveform 35 be about the waveform of each 2 step, this is that LED lamp string L5, LED lamp string L6 do not have electric current to pass through because when the 3rd section LED lamp string disconnected, voltage only dropped on LED lamp string L1, LED lamp string L2, LED lamp string L3, the LED lamp string L4, at this moment, the waveform of each two step about just having formed in the accompanying drawing 7.
Circuit and voltage waveform when accompanying drawing 7 occurs opening circuit for second section LED lamp of linear low density led driver string; As shown in Figure 7, the 36th, the voltage waveform, 37th of linear low density led driver when opening circuit appears in second section LED lamp string, the current waveform of linear low density led driver when opening circuit appears in second section LED lamp string.
Particularly, the ceiling voltage of voltage waveform 36 is 310V, do not exceed the upper limit, current waveform 37 be about the waveform of each step, this is that LED lamp string L2, LED lamp string L3, LED lamp string L4, LED lamp string L5 all do not have electric current to flow through, and have only LED lamp string L1, LED lamp string L2 to have electric current to pass through because when opening circuit appears in second section LED lamp string, therefore, can only form about the current waveform figure of each step.
Driving switch of the present utility model is high withstand voltage device can be not breakdown, has good thermal diffusivity and the performance that can bear bigger power consumption.
It should be noted that at last: above embodiment only in order to the technical solution of the utility model to be described, is not intended to limit; Although with reference to previous embodiment the utility model is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of each embodiment technical scheme of the utility model.
Claims (9)
1. a linear low density led driver protective circuit comprises for the driving switch of driving LED lamp string conducting, it is characterized in that, also comprises the overvoltage crowbar for the protection of described driving switch;
The signal processing unit that described overvoltage crowbar comprises for the voltage sample unit of each driving switch both end voltage of monitoring, be used for the signal that the voltage sample unit collects is handled, control the control switch unit of its shutoff when being used for voltage when described driving switch two ends above a certain set point.
2. protective circuit according to claim 1 is characterized in that,
Described LED lamp string comprises: at least 2 sections LED lamp strings;
Described driving switch comprises: the driving switch that is used for driving the conducting of every section LED lamp string;
Described protective circuit is protected respectively each road driving switch.
3. protective circuit according to claim 2 is characterized in that, described driving switch is NMOS pipe.
4. protective circuit according to claim 3 is characterized in that, described voltage sample unit comprises resistance R 1, signal processing unit comprises resistance R 2, described resistance R 1 and resistance R 2 series connection, an end of series resistance R1 and resistance R 2 is connected after every section LED lamp string, other end ground connection; The NPN triode that described control switch unit is that base stage is connected between series resistance R1 and the resistance R 2, grounded emitter, collector electrode are connected with a described NMOS tube grid.
5. protective circuit according to claim 3, it is characterized in that, described voltage sample unit comprises resistance R 1, signal processing unit comprises resistance R 2 and signal errors comparator, described resistance R 1 and resistance R 2 series connection, described control switch unit comprises the 2nd NMOS pipe, and series resistance R1 and resistance R 2 one ends are connected after every section LED lamp string, other end ground connection; The input anode of described signal errors comparator is connected between resistance R 1 and the resistance R 2, negative pole connects reference voltage, and output is connected with the grid of the 2nd NMOS pipe; The drain electrode of described the 2nd NMOS pipe is connected with the grid of a NMOS pipe, the 2nd NMOS manages source ground.
6. protective circuit according to claim 1 is characterized in that, described driving switch is NMOS pipe, PMOS pipe, NPN triode, PNP triode.
7. protective circuit according to claim 2 is characterized in that, described voltage sample unit can be resistor voltage divider circuit sampling or capacitance partial pressure circuit sampling.
8. protective circuit according to claim 2 is characterized in that, described control switch unit is NMOS pipe, PMOS pipe, NPN triode, PNP triode.
9. according to the arbitrary described protective circuit of claim 1-8, it is characterized in that described overvoltage crowbar can be placed on driving switch and drive outside the control chip, also can adopt the form of integrated circuit to be built within the driving control chip with driving switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220708512 CN203071567U (en) | 2012-12-20 | 2012-12-20 | Linear high voltage LED drive protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220708512 CN203071567U (en) | 2012-12-20 | 2012-12-20 | Linear high voltage LED drive protection circuit |
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| CN203071567U true CN203071567U (en) | 2013-07-17 |
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| CN 201220708512 Expired - Lifetime CN203071567U (en) | 2012-12-20 | 2012-12-20 | Linear high voltage LED drive protection circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103582263A (en) * | 2013-11-14 | 2014-02-12 | 上海莱托思电子科技有限公司 | Linear multi-channel LED constant-current drive circuit |
| CN103887769A (en) * | 2012-12-20 | 2014-06-25 | 陕西亚成微电子股份有限公司 | Linear high-voltage LED driver protection circuit |
| CN110545030A (en) * | 2019-10-10 | 2019-12-06 | 上海源微电子科技有限公司 | Boost topology load short-circuit protection circuit |
-
2012
- 2012-12-20 CN CN 201220708512 patent/CN203071567U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103887769A (en) * | 2012-12-20 | 2014-06-25 | 陕西亚成微电子股份有限公司 | Linear high-voltage LED driver protection circuit |
| CN103887769B (en) * | 2012-12-20 | 2017-06-06 | 陕西亚成微电子股份有限公司 | Linear low density LED driver protection circuit |
| CN103582263A (en) * | 2013-11-14 | 2014-02-12 | 上海莱托思电子科技有限公司 | Linear multi-channel LED constant-current drive circuit |
| CN103582263B (en) * | 2013-11-14 | 2015-08-12 | 上海莱托思电子科技有限公司 | A kind of linear multi-channel LED constant-current drive circuit |
| CN110545030A (en) * | 2019-10-10 | 2019-12-06 | 上海源微电子科技有限公司 | Boost topology load short-circuit protection circuit |
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