CN202617482U

CN202617482U - Electronic ballast with protection circuit

Info

Publication number: CN202617482U
Application number: CN 201220195554
Authority: CN
Inventors: 谢立山; 杨红敏; 袁青辉
Original assignee: GELINLAI ELECTRONIC TECHNOLOGY Co Ltd SHENZHEN
Current assignee: Guangdong Greenlight Photoelectric Tech Co Ltd
Priority date: 2012-05-02
Filing date: 2012-05-02
Publication date: 2012-12-19
Anticipated expiration: 2022-05-02

Abstract

The utility model provides electronic ballast with a protection circuit. The electronic ballast comprises a half-bridge starting type triggering circuit, a transformer coupling circuit connected with the triggering circuit, a resonance matching circuit connected with the transformer coupling circuit, and a protecting circuit connected with the resonance matching circuit, wherein the protecting circuit is connected with a high pressure gas discharge lamp; the protecting circuit comprises a first diode, a metal-oxide semi-field effect transistor, a clamping diode, a first resistor and a second diode, wherein a positive electrode of the first diode is connected with the resonance matching circuit while a negative electrode thereof is connected with the metal-oxide semi-field effect transistor; a source electrode of the metal-oxide semi-field effect transistor is connected with the positive electrode of the clamping diode; the negative electrode of the second diode is connected with the negative electrode of the clamping diode through the first resistor while the positive electrode thereof is connected with the high pressure gas discharge lamp. With adoption of the electronic ballast with the protection circuit, a tube can be prevented from being broken down due to higher voltage during being started; and the electronic ballast has a simple structure, low cost, high efficiency, and is reliable in work.

Description

A kind of electric ballast with protective circuit

Technical field

The utility model relates to a kind of electric ballast with protective circuit.

Background technology

As everyone knows, (High intensity Discharge HID) is the general designation of mercury, sodium, gold, xenon lamp, i.e. mercury lamp, sodium vapor lamp, Metal halogen lamp, xenon lamp to high-voltage gas discharging light.Wherein the principle of xenon lamp is in the quartzy quartz glass tube of UV-cut uvioresistant; With the number of chemical gas filling; Wherein major part is an xenon (Xenon) and inert gas such as iodide, and then sees through booster (Ballast) low pressure (as 12 volts) direct voltage moment is pressurized to 23000 volts electric current, excites the xenon electronics in the quartz ampoule free through the high pressure amplitude of vibration; Between two electrodes, produce light source, Here it is so-called gas discharge.And, can improve the light color temperature value by the white superpower arclight that xenon produced, and the sunshine in similar daytime, the required magnitude of current is merely 3.5A during HID work, and brightness is three times of traditional based on halogen bulb, and useful life is than long 10 times of traditional based on halogen bulb.

So-called ' high-power ' HID ceramic metal halogen lamp electric ballast it is generally acknowledged that 300W is above just high-power, and so, the high-frequency electronic ballast that we are just adopted with the CDM-TMW ceramic gold-halogen lamp of Philip 315W/930 is as powerful exemplary.Such HID electric ballast uses operating frequency up to more than hundreds of KHz, can develop this series products in the industry away from ' acoustic resonance ' window, and operating frequency is from more than the 650-900KHz, and circuit form has independent-excited that auto-excitation type is also arranged.But quovis modo, because this electron-like ballast is when starting, voltage, current changing rate are big, the dv/dt of transition and di/di often cause the power MOSFET tube damage of the upper and lower arm of half-bridge, so its protective circuit is particularly important.Be not difficult in the street lamp of many use electric ballasts to find that the fault great majority of lamp are that institute caused because electric ballast loses efficacy, and that main cause is a protective circuit is perfect inadequately, causes upper and lower arm MOSFET pipe to puncture.Find out HID electric ballast high-power, big electric current thus, particularly: when lamp loss of ignition, lamp loose contact and open circuit, high voltage causes fluorescent tube to damage through fluorescent tube, and is visible, the importance of its protective circuit.

The utility model content

The utility model proposes a kind of electric ballast with protective circuit, has solved in the prior art when fluorescent tube loss of ignition, fluorescent tube loose contact and when opening a way, high voltage burns out the problem of fluorescent tube.

The technical scheme of the utility model is achieved in that

The utility model discloses a kind of electric ballast with protective circuit; Comprise that the half-bridge that links to each other with the impressed current input current starts the formula circuits for triggering; The transformer-coupled circuit that links to each other with described circuits for triggering, the resonance match circuit that links to each other with described transformer-coupled circuit, the protective circuit that links to each other with described resonance match circuit; Described protective circuit links to each other with high-voltage gas discharging light; Described protective circuit comprises: first diode, metal-oxide half field effect transistor, clamp diode, first resistance, second diode that link to each other successively, and wherein, the positive pole of first diode links to each other with the resonance match circuit; Its negative pole links to each other with described metal-oxide half field effect transistor grid; The metal-oxide half field effect transistor source electrode links to each other with the positive pole of described clamp diode, and the negative pole of described clamp diode links to each other with the negative pole of described second diode through described first resistance, and the positive pole of second diode links to each other with described high-voltage gas discharging light.

In the described electric ballast with protective circuit of the utility model; Described electric ballast with protective circuit also comprises filter circuit; Be connected between described resonance match circuit and the described high-voltage gas discharging light, be used for described resonance match circuit is carried out filtering.

In the described electric ballast with protective circuit of the utility model, the positive pole of described second diode links to each other with described high-voltage gas discharging light through described filter circuit.

In the described electric ballast with protective circuit of the utility model; Described protective circuit also comprises second resistance and first electric capacity; Described second resistance and first electric capacity, one end all are connected between the positive pole of described metal-oxide half field effect transistor source electrode and described clamp diode other end ground connection.

In the described electric ballast with protective circuit of the utility model; Described protective circuit also comprises the 3rd resistance and second electric capacity; Described the 3rd resistance and second electric capacity, one end all are connected between the negative pole and first resistance of described clamp diode, the equal ground connection of the other end.

Implement a kind of electric ballast of the utility model, have following beneficial technical effects with protective circuit:

Bigger voltage breakdown fluorescent tube when avoiding starting, circuit is simple, cost is low, efficient is high, reliable operation.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work property, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is a kind of electric ballast hardware construction sketch map with protective circuit of the utility model;

A kind of electric ballast hardware partial circuit diagram of Fig. 2 the utility model with protective circuit.

Embodiment

To combine the accompanying drawing among the utility model embodiment below, the technical scheme among the utility model embodiment is carried out clear, intactly description, obviously, described embodiment only 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 is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.

See also Fig. 1 and Fig. 2, the preferred embodiment of the utility model, a kind of electric ballast with protective circuit; Comprise that the half-bridge that links to each other with the impressed current input current starts formula circuits for triggering 1; The transformer-coupled circuit 2 that links to each other with circuits for triggering 1, the resonance match circuit 3 that links to each other with transformer-coupled circuit 2, resonance match circuit 3 links to each other with protective circuit 5; Protective circuit 5 links to each other with high-voltage gas discharging light 6; Protective circuit 5 comprises: the first diode VD15 that links to each other successively, metal-oxide half field effect transistor VT5, clamp diode VD17, first resistance R 17, the second diode VD18, and wherein, the positive pole of the first diode VD15 links to each other with resonance match circuit 3; Its negative pole links to each other with metal-oxide half field effect transistor VT5 grid; Metal-oxide half field effect transistor VT5 source electrode links to each other with the positive pole of clamp diode VD17, and the negative pole of clamp diode VD17 links to each other with the negative pole of the second diode VD18 through first resistance R 17, and the positive pole of the second diode VD18 links to each other with high-voltage gas discharging light 6.

In another embodiment of the utility model, the electric ballast with protective circuit also comprises filter circuit 4, is connected between resonance match circuit 3 and the high-voltage gas discharging light 6, is used for resonance match circuit 3 is carried out filtering.The positive pole of the second diode VD18 links to each other with high-voltage gas discharging light 6 through filter circuit 4.

Wherein, protective circuit 5 comprises that also second resistance R 19 and first capacitor C, 19, the second resistance R 19 and first capacitor C, 19 1 ends all are connected between the positive pole of metal-oxide half field effect transistor VT5 source electrode and clamp diode VD17 other end ground connection.

Protective circuit 5 comprises that also the 3rd resistance R 18 and second capacitor C, 20, the three resistance R 18 and second capacitor C, 20 1 ends all are connected between the negative pole and first resistance R 17 of clamp diode VD17 the equal ground connection of the other end.

The protective circuit of HID electric ballast is most important.That the utility model is intended to solve is high-power, the protective circuit of the HID lamp, particularly ceramic gold-halogen lamp of big electric current, makes its operation normal more, reliable.

The local circuit at the protective circuit place among Fig. 2; Wherein, Arrow A is represented outer then resonance match circuit 3; Arrow B representes that outer then half-bridge starts formula circuits for triggering 1, and in fact protective circuit is divided into two protection chains, and first chain is made up of VD18, R17, C20, R18, VD17, C19, R19, VT5 and VD15.This is ' abnormal protection ' circuit; When using as a lamp fire failure, lamp loose contact or open circuit; The VD18 two ends induce higher voltage, and the voltage stabilizing didoe VD17 with 20V after C20 filtering opens, and make small-power FET VT5 conducting; Half-bridge underarm VT3 is through fast diode VD15 (1N4148) shorted to earth, thereby circuit is protected.

The second protection chain is made up of T3, VD16, R24, R20, C21, VD19, VD20, R23, C23, VT4, R22, C22, VD16 and controllable silicon VS1 and miniature relay J1.When loss of ignition repeatedly, when causing electric current, the voltage in heavy-current discharge loop to produce phenomenon such as reflection, standing wave, superposition, cause the possibility of underarm conducting simultaneously maximum, at this moment half-bridge VT2, VT3 could burn because of the electric current infinity! When running into this situation, big electric current flows through the former limit of transformer T3, and level induces high voltage after high speed diode VD16 (1N4148), C21 rectification secondarily; Make the VD20 conducting, VT4 work, source resistance R21 output signal makes controllable silicon VS1 conducting; Electric current flow through temperature switch RT, VS1 through voltage stabilizing didoe VD16 (+12V) over the ground; So relay J 1 action is thoroughly broken off direct current, the half-bridge main switch circuit quits work because of outage.According to the silicon controlled characteristic, anode voltage is cancelled and could be recovered, in other words, circuit gets into has memory protect.Through semifixed resistor R24, can change, control the size of protective current.

What be worth proposition is: T3 is an air-core transformer, and former limit is merely 1.5 circles, available 0.5-1mm line, and secondary (paying the limit) is the 40-60 circle, the wire-wound system below the available 0.1mm.Because the output of the former limit of this transformer string underarm mid point on half-bridge, and voltage is the constant voltage a little less than 400V here, so just induce voltage when having only current break, is a kind of ' current protection '.The coordination that evidence is through ' the first protection chain ' with ' the second protection chain ' is protected, and the circuit reliability of high-power HID electric ballast improves greatly, this also be the utility model the attempt that will reach.

The above is merely the preferred embodiment of the utility model; Not in order to restriction the utility model; All within the spirit and principle of the utility model, any modification of being done, be equal to replacement, improvement etc., all should be included within the protection range of the utility model.

Claims

1. electric ballast with protective circuit; Comprise that the half-bridge that links to each other with the impressed current input current starts formula circuits for triggering, the transformer-coupled circuit that links to each other with described circuits for triggering, the resonance match circuit that links to each other with described transformer-coupled circuit; The protective circuit that links to each other with described resonance match circuit; Described protective circuit links to each other with high-voltage gas discharging light, it is characterized in that, described protective circuit comprises: first diode, metal-oxide half field effect transistor, clamp diode, first resistance, second diode that link to each other successively; Wherein, The positive pole of first diode links to each other with the resonance match circuit, and its negative pole links to each other with described metal-oxide half field effect transistor grid, and the metal-oxide half field effect transistor source electrode links to each other with the positive pole of described clamp diode; The negative pole of described clamp diode links to each other with the negative pole of described second diode through described first resistance, and the positive pole of second diode links to each other with described high-voltage gas discharging light.

2. the electric ballast with protective circuit according to claim 1; It is characterized in that; Described electric ballast with protective circuit also comprises filter circuit; Be connected between described resonance match circuit and the described high-voltage gas discharging light, be used for described resonance match circuit is carried out filtering.

3. the electric ballast with protective circuit according to claim 2 is characterized in that, the positive pole of described second diode links to each other with described high-voltage gas discharging light through described filter circuit.

4. the electric ballast with protective circuit according to claim 1; It is characterized in that; Described protective circuit also comprises second resistance and first electric capacity; Described second resistance and first electric capacity, one end all are connected between the positive pole of described metal-oxide half field effect transistor source electrode and described clamp diode other end ground connection.

5. the electric ballast with protective circuit according to claim 1; It is characterized in that; Described protective circuit also comprises the 3rd resistance and second electric capacity; Described the 3rd resistance and second electric capacity, one end all are connected between the negative pole and first resistance of described clamp diode, the equal ground connection of the other end.