CN201967202U

CN201967202U - LED driver without electrolytic capacitors

Info

Publication number: CN201967202U
Application number: CN2011200024205U
Authority: CN
Inventors: 吴志刚
Original assignee: XIAMEN DALAI ELECTRONIC TECHNOLOGY Co Ltd
Current assignee: XIAMEN DALAI ELECTRONIC TECHNOLOGY Co Ltd
Priority date: 2011-01-06
Filing date: 2011-01-06
Publication date: 2011-09-07
Anticipated expiration: 2021-01-06

Abstract

The utility model discloses an LED driver without electrolytic capacitors. The LED driver comprises an alternating current (AC) rectifier circuit, a high-voltage filter circuit, a switch converting circuit, a low-voltage rectifier circuit, a low-voltage filter circuit and a detecting circuit, wherein the detecting circuit is connected with a load and used for acquiring first voltage values of the two ends of the LED load; the switch converting circuit is provided with a switch controller and a sampling module; one terminal of the sampling module is connected between the AC rectifier circuit and the high-voltage filter circuit, so as to acquire second voltage values rectified by the AC rectifier circuit; the other terminal of the sampling module is connected to the switch controller, so as to transmit the second voltage values to the switch controller; the detecting circuit is communicated with the switch controller and transmits the first voltage values to the switch controller; the switch controller compares the first voltage values and the second voltage values and outputs control signals; and an AC following oscillator capable of enabling the working frequency of the switch controller to be variable is arranged in the switch controller. The LED driver dispenses with the electrolytic capacitors, so that the service life of an LED lamp can be greatly prolonged.

Description

A kind of no electrolytic capacitor led driver

Technical field

The utility model relates to the led driver field, relates to a kind of no electrolytic capacitor led driver in particular.

Background technology

LED illumination at present becomes main flow gradually, and has slowly substituted traditional incandescent lamp and fluorescent lamp; LED is with characteristics such as its low-carbon (LC), environmental protection, long-life and high brightness and have bigger illumination advantage; Because LED need utilize constant dc, so LED in use must supporting led driver.

Limited by current techniques, LED can produce about 60% heat when work, and these heats must dispel the heat by light fixture, and led driver 9 major parts all are to be placed on LED light fixture the inside, and promptly led driver 9 all is to work under the condition of high temperature usually.As depicted in figs. 1 and 2, theory diagram and physical circuit figure that it illustrates respectively for existing led driver 9, existing led driver 9 comprises the ac rectifier 91 that links to each other successively, high-pressure filter circuit 92, switch transformed circuit 93, lower pressure rectifier circuit 94 and low-voltage filter circuit 95, this ac rectifier 91 directly inserts civil power 200 and civil power 200 is carried out rectification and makes it become unidirectional pulsating voltage, this high-pressure filter circuit 92 makes the civil power 200 of rectification can be rendered as approximate level and smooth waveform, 93 of this switch transformed circuits are used to regenerate alternating current also simultaneously to its step-down, 95 in this lower pressure rectifier circuit 94 and low-voltage filter circuit carry out rectification and filtering once more to the civil power of handling via step-down 200, form the required direct current of LED thus and supply with LED, this switch transformed circuit 93 also passes through R14, R15 and R16 detect the voltage of output, and send back to the FB pin of on-off controller 931 in the switch change circuit, voltage and the internal signal of FB compare, the MOS switching drive signal is controlled, to obtain constant output.Because it utilizes elementary feedback to control, so can require circuit that bigger AC signal must not be arranged, so must be handy after civil power 200 rectifications big electric capacity carry out filtering, not so led driver 9 will be not can operate as normal in steady state, thereby can not guarantee the output of current constant.

At present, have only the capacity of electrochemical capacitor could satisfy the filtering requirements of power supply, but contain a large amount of electrolyte owing in the electrochemical capacitor, these liquid can slowly volatilize under the baking of high temperature, and make the capacity of electrochemical capacitor slowly diminish and ultimate failure.Even long-life electrochemical capacitor also can only be accomplished about 8000H, and cost an arm and a leg at present.Even if control the working temperature of LED light fixture well, these electrochemical capacitors probably also can only be worked more than 10,000 hour, and the life-span (100,000 hours) of itself and LED itself is far apart.So under the current techniques situation, owing to face bottleneck the useful life of led driver 9, so make that the usefulness of LED load 300 is not fully developed.

In view of this, the inventor has this case to produce at the above-mentioned defective further investigation of existing led driver 9 then.

The utility model content

The purpose of this utility model is to provide a kind of no electrolytic capacitor led driver, makes that because the electrolyte of electrochemical capacitor can volatilize the led driver life-span is short and influences the problem that LED lamp usefulness is fully developed to solve the prior art led driver.

In order to reach above-mentioned purpose, solution of the present utility model is:

A kind of no electrolytic capacitor led driver, comprise the ac rectifier that links to each other successively, high-pressure filter circuit, switch transformed circuit, lower pressure rectifier circuit and low-voltage filter circuit, wherein, this no electrolytic capacitor led driver also comprises for linking to each other with load and obtaining the testing circuit of LED load two ends first magnitude of voltage, this switch transformed circuit has on-off controller and sampling module, this sampling module one termination is gone between ac rectifier and the high-pressure filter circuit and is obtained second magnitude of voltage after the ac rectifier rectification, the other end then inserts on-off controller and second magnitude of voltage is delivered to on-off controller, this testing circuit is connected with on-off controller and first magnitude of voltage is delivered to on-off controller, and this on-off controller compares and utilizes both differences and export control signal first magnitude of voltage and second magnitude of voltage; This on-off controller also is built-in with the interchange that makes the on-off controller operating frequency be in variable condition and follows oscillator.

Further, this testing circuit has first coupling unit, this switch transformed circuit has second coupling unit that links to each other with on-off controller, and this first coupling unit and second coupling unit are coupled and first magnitude of voltage is delivered to on-off controller by second coupling unit.

Further, adopt optical coupling between this first coupling unit and second coupling unit.

Further, this sampling module is first resistance and second resistance of serial connection mutually, and this on-off controller then is connected between first resistance and second resistance.

Further, the electric capacity in this high-pressure filter circuit adopts polyester film capacitor or ceramic condenser.

After adopting said structure, a kind of no electrolytic capacitor led driver that the utility model relates to, it detects LED load two ends first magnitude of voltage by testing circuit, and this first magnitude of voltage is delivered to on-off controller in the switch transformed circuit; Also second magnitude of voltage after the ac rectifier rectification is sampled simultaneously by sampling module, and this second magnitude of voltage is delivered to on-off controller, this on-off controller then compares first magnitude of voltage and second magnitude of voltage, and exports control signal according to both differences; Because being built-in with to exchange, this on-off controller follows oscillator simultaneously, it can allow the operating frequency of on-off controller be operated in non-constant state, thereby can follow control to the pulsating voltage after the rectification, to obtain constant output, thereby voltage must keep level and smooth and stable after also no longer requiring rectification, promptly can allow this moment the capacity of the required electric capacity of high-pressure filter circuit reduce, and then make other non-electrolytic capacitor also can satisfy the demand on the capacity.So the utility model has been by having broken away from electrochemical capacitor to the improvement on the circuit structure, thereby broken through the bottleneck of led driver, and the LED lamp can fully be used.

Description of drawings

Fig. 1 is the theory diagram of existing led driver;

Fig. 2 is the physical circuit figure of existing led driver;

The theory diagram of a kind of no electrolytic capacitor led driver that Fig. 3 relates to for the utility model;

The physical circuit figure of a kind of no electrolytic capacitor led driver that Fig. 4 relates to for the utility model.

Among the figure:

Led driver 100

Ac rectifier 1 high-pressure filter circuit 2

Switch transformed circuit 3 on-off controllers 31

Second coupling unit, 311 sampling modules 32

First resistance, 321 second resistance 322

Lower pressure rectifier circuit 4 low-voltage filter circuit 5

Testing circuit 6 first coupling units 61

Civil power 200 LED loads 300

Led driver 9 ac rectifiers 91

High-pressure filter circuit 92 switch transformed circuits 93

On-off controller 931 lower pressure rectifier circuit 94

Low-voltage filter circuit 95.

Embodiment

In order further to explain the technical solution of the utility model, the utility model is elaborated below by specific embodiment.

As shown in Figure 3 and Figure 4, a kind of no electrolytic capacitor led driver 100 that it relates to for the utility model, it comprises the ac rectifier 1 that links to each other successively, high-pressure filter circuit 2, switch change circuit 3, lower pressure rectifier circuit 4 and low-voltage filter circuit 5, this ac rectifier 1 links to each other with civil power 200, these low-voltage filter circuit 5 outputs are then for linking to each other with LED load 300, wherein, this ac rectifier 1, high-pressure filter circuit 2, the function of lower pressure rectifier circuit 4 and low-voltage filter circuit 5 and principle are all similar with existing led driver 9, event is not done in detail its structure and is specified, and emphatically improvement of the present utility model is described in detail below:

This no electrolytic capacitor led driver 100 also comprises testing circuit 6, and this testing circuit 6 links to each other with LED load 300, and is used to obtain first magnitude of voltage at LED load 300 two ends; This switch change circuit 3 has on-off controller 31 and sampling module 32, these sampling module 32 1 terminations are gone between ac rectifier 1 and the high-pressure filter circuit 2, and be used to obtain second magnitude of voltage after ac rectifier 1 rectification, the other end then inserts on-off controller 31 and second magnitude of voltage is delivered to on-off controller 31, this testing circuit 6 is connected with on-off controller 31, and be used for first magnitude of voltage is delivered to on-off

controller

31,31 of this on-off controllers compare first magnitude of voltage and second magnitude of voltage, and calculate both difference, 31 of this on-off controllers utilize both differences and export control signal, concrete its is to export control signal to on-off controller 31 built-in metal-oxide-semiconductor (not shown), and the switch situation of driven MOS pipe; This on-off controller 31 also is built-in with the interchange that makes on-off controller 31 operating frequencies be in variable condition and follows oscillator.

Like this, the utility model detects by 6 pairs of LED loads of testing circuit, 300 two ends, first magnitude of voltage, and this first magnitude of voltage is delivered to on-off controller 31 in the switch change circuit 3; Also sample simultaneously by 32 pairs of second magnitudes of voltage after ac rectifier 1 rectification of sampling module, and this second magnitude of voltage is delivered to on-off

controller

31,31 of this on-off controllers compare first magnitude of voltage and second magnitude of voltage, and export control signal, thereby can obtain constant output according to both differences; Because being built-in with to exchange, this on-off controller 31 follows the oscillator (not shown) simultaneously, it can allow the operating frequency of on-off controller 31 be operated in non-constant state, thereby can follow control to the pulsating voltage after the rectification, to obtain constant output, thereby voltage must keep level and smooth and stable after also no longer requiring rectification, promptly can allow this moment the capacity of high-pressure filter circuit 2 required electric capacity reduce, and then make other non-electrolytic capacitor also can satisfy the demand on the capacity, promptly adopt not too big polyester film capacitor of capacity or ceramic condenser, just can carry out filtering and satisfy the requirement of elementary filtering high frequency noise.

A kind of specific embodiments as signal transfer mode between this testing circuit 6 and the switch change circuit 3, this testing circuit 6 has first coupling unit 61, this switch change circuit 3 has second coupling unit 311 that links to each other with on-off controller 31, this first coupling unit 61 and second coupling unit 311 are coupled and first magnitude of voltage are delivered to on-off controller 31 by second coupling unit 311, preferably, adopt optical coupling between this first coupling unit 61 and second coupling unit 311.

As the specific embodiments of this sampling module 32, this sampling module 32 is first resistance 321 and second resistance 322 of serial connection mutually, and 31 of this on-off controllers are connected between first resistance 321 and second resistance 322.Can know the size of first magnitude of voltage by the dividing potential drop effect of this first resistance 321 and second resistance 322.

Core of the present utility model is: by changing on-off controller 31 switch inside frequencies of oscillation, and the basic law that is inversely proportional to based on the capacity and the operating frequency of filter capacitor, by promoting operating frequency, can reduce output filter capacitor, thereby make employing polyester film capacitor or ceramic condenser can realize the demand of filtering.In sum, the utility model has been by having broken away from electrochemical capacitor to the improvement on the circuit structure, thereby broken through the bottleneck of led driver 100, and the LED lamp can fully be used.

The foregoing description and graphic and non-limiting product form of the present utility model and style, any person of an ordinary skill in the technical field all should be considered as not breaking away from patent category of the present utility model to its suitable variation or modification of doing.

Claims

1. no electrolytic capacitor led driver, comprise the ac rectifier that links to each other successively, high-pressure filter circuit, switch transformed circuit, lower pressure rectifier circuit and low-voltage filter circuit, it is characterized in that, this no electrolytic capacitor led driver also comprises for linking to each other with load and obtaining the testing circuit of LED load two ends first magnitude of voltage, this switch transformed circuit has on-off controller and sampling module, this sampling module one termination is gone between ac rectifier and the high-pressure filter circuit and is obtained second magnitude of voltage after the ac rectifier rectification, the other end then inserts on-off controller and second magnitude of voltage is delivered to on-off controller, this testing circuit is connected with on-off controller and first magnitude of voltage is delivered to on-off controller, and this on-off controller compares and utilizes both differences and export control signal first magnitude of voltage and second magnitude of voltage; This on-off controller also is built-in with the interchange that makes the on-off controller operating frequency be in variable condition and follows oscillator.

2. a kind of no electrolytic capacitor led driver as claimed in claim 1, it is characterized in that, this testing circuit has first coupling unit, this switch transformed circuit has second coupling unit that links to each other with on-off controller, and this first coupling unit and second coupling unit are coupled and first magnitude of voltage is delivered to on-off controller by second coupling unit.

3. a kind of no electrolytic capacitor led driver as claimed in claim 2 is characterized in that, adopts optical coupling between this first coupling unit and second coupling unit.

4. a kind of no electrolytic capacitor led driver as claimed in claim 1 is characterized in that, this sampling module is first resistance and second resistance of serial connection mutually, and this on-off controller then is connected between first resistance and second resistance.

5. a kind of no electrolytic capacitor led driver as claimed in claim 1 is characterized in that, the electric capacity in this high-pressure filter circuit adopts polyester film capacitor or ceramic condenser.