CN201700073U - Electronic ballast with function of overvoltage protection - Google Patents
Electronic ballast with function of overvoltage protection Download PDFInfo
- Publication number
- CN201700073U CN201700073U CN2010202158229U CN201020215822U CN201700073U CN 201700073 U CN201700073 U CN 201700073U CN 2010202158229 U CN2010202158229 U CN 2010202158229U CN 201020215822 U CN201020215822 U CN 201020215822U CN 201700073 U CN201700073 U CN 201700073U
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- inductor
- electronic switch
- circuit
- output
- voltage
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Abstract
The utility model provides an electronic ballast with the function of overvoltage protection. The overvlotage condition of the electronic ballast is judged through the monitoring on the electrical parameters of an inductor. The electronic ballast has the advantages of small area of high-voltage compartment of a printed circuit board, high safety factor, easy wiring, and strong disturbance resisting capacity.
Description
Technical field
The utility model relates to a kind of electric ballast, relates in particular to a kind of electric ballast with over-voltage protecting function.
Background technology
Gaseous discharge lamp as fluorescent lamp, high-pressure sodium lamp, metal halide lamp etc., needs electric ballast that AC drive voltage is provided so that its operate as normal usually.Usually, electric ballast as power supply, is a direct current input voltage with ac grid voltage or the dc-battery voltage transitions that receives with electrical network or battery, by inverter circuit this DC input voitage is converted to required AC drive voltage again.
The driving voltage difference that gaseous discharge lamp needs at different working stages, it needs higher driving voltage (characteristic and the different of application scenario according to lamp are not waited to several ten thousand volts by several hectovolts), the operating voltage under stable state then lower (for example less than 200 volts) at ignition phase.The terminal voltage of gaseous discharge lamp can not be too high, in order to avoid cause the damage of lamp and other components and parts.Over-voltage protection method commonly used is the terminal voltage of sample gas discharge lamp and produces a voltage sampling signal.There is over-voltage condition if this voltage sampling signal greater than a preset value, then is judged as, and takes corresponding overvoltage protection measure.Adopt the electric ballast of this method to need high-voltage capacitor or high voltage resistor to sample, the area of its printed circuit board (PCB) high-pressure section is big, and coefficient of safety is low, and the insulation distance between device is had higher requirements, and is unfavorable for the miniaturization of electric ballast.
The utility model content
The technical problems to be solved in the utility model provides a kind of coefficient of safety height and connects up and is easy to have the electric ballast of over-voltage protecting function.
In order to solve the problems of the technologies described above, the utility model provides a kind of electric ballast with over-voltage protecting function, comprising: inverter circuit, comprise at least one electronic switch, and wherein each electronic switch all possesses first end, second end and the 3rd end; Inductor, the one end is electrically coupled to the output of described inverter circuit, and the other end is electrically coupled to gaseous discharge lamp; Capacitor is connected in parallel with described gaseous discharge lamp; Control circuit possesses an input and at least one output, and wherein each output all is electrically coupled to the 3rd end of a described electronic switch; Sample circuit, its input is coupled to described inductor, and its output provides the sampled signal of the described inductor electrical quantity of representative; And comparison circuit, possess first input end, second input and output, wherein first input end is electrically coupled to the output of described sample circuit, second input receives a threshold value, output is electrically coupled to the input of described control circuit, indicates the voltage at described gaseous discharge lamp two ends whether to have overvoltage; Wherein if there is overvoltage, then described control circuit cuts out described inverter circuit.
According to embodiment of the present utility model, the electrical quantity of described inductor is the voltage at described inductor two ends, and described sample circuit comprises: coupling inductor, with described inductor magnetic coupling; And rectification circuit, its input is electrically coupled to described coupling inductor, and its output provides described sampled signal.
According to embodiment of the present utility model, the electrical quantity of described inductor is the electric current that flows through described inductor, and described sample circuit comprises that series electrical is coupled to the sampling resistor in described inductor loop.
According to embodiment of the present utility model, the electrical quantity of described inductor is the electric current that flows through described inductor, and described sample circuit comprises: current transformer, and its former limit coupled in series is to described inductor; Rectification circuit, its input is electrically coupled to the secondary of described current transformer; And resistor, being electrically connected to the output of described rectification circuit, the voltage at described resistor two ends is described sampled signal.
According to embodiment of the present utility model, described inverter circuit adopts half-bridge topology, comprise first electronic switch and second electronic switch, first termination of described first electronic switch is received supply voltage, second end of described first electronic switch is electrically connected to first end of described second electronic switch, the second end ground connection of described second electronic switch.
According to embodiment of the present utility model, close described inverter circuit and comprise described first and second electronic switches of shutoff.
According to embodiment of the present utility model, close described inverter circuit and comprise described first electronic switch of shutoff and described second electronic switch of conducting.
Electrical quantity by monitoring inductor two ends judges whether to exist overvoltage, and its sample circuit need not high-voltage capacitor or resistor, thereby the area of the printed circuit board (PCB) high-pressure section of electric ballast is little, the coefficient of safety height, and wiring is easily, and antijamming capability is strong.
Description of drawings
Below in conjunction with accompanying drawing embodiment of the present utility model is further described:
Fig. 1 is the block diagram of the utility model electric ballast;
Fig. 2 is the circuit diagram of first execution mode of the utility model electric ballast;
Fig. 3 is the circuit diagram of second execution mode of the utility model electric ballast;
Fig. 4 is the circuit diagram of the 3rd execution mode of the utility model electric ballast;
Fig. 5 is the circuit diagram of the 4th execution mode of the utility model electric ballast.
Embodiment
To describe specific embodiment of the utility model in detail below, should be noted that the embodiments described herein only is used to illustrate, be not limited to the utility model.
Fig. 1 is the block diagram of the utility model electric ballast, comprises voltage conversion circuit 100, inverter circuit 101, control circuit 102, series capacitor C
s, shunt capacitor C
p, inductor L and over-voltage detection circuit 110.Voltage conversion circuit 100 receives the input voltage V that comes from electrical network or battery
In, and be converted into DC input voitage V
DcVoltage conversion circuit 100 can comprise or wherein several combinations in rectifier bridge, DC circuit, the ac/dc translation circuit.Inverter circuit 101 is electrically coupled to voltage conversion circuit 100, comprises at least one electronic switch, the conducting by electronic switch with turn-off DC input voitage V
DcBe converted to alternating voltage.This alternating voltage is by series capacitor C
s, shunt capacitor C
pThe resonant network that constitutes with inductor L produces AC drive voltage at the lamp two ends.Inverter circuit 101 can adopt any AC/DC transformation topology structure, for example full-bridge, half-bridge topology etc.Control circuit 102 is electrically coupled to inverter circuit 101, controls the conducting and the shutoff of this at least one electronic switch.Over-voltage detection circuit 110 is coupled to inductor L, judges whether to exist overvoltage by the electrical quantity of monitoring inductor L.If there is overvoltage, then control circuit 102 cuts out inverter circuit 101.In one embodiment, inverter circuit 101 adopts half-bridge topology, comprise first electronic switch and second electronic switch that are connected in series, close inverter circuit 101 and can be first and second electronic switches are all turn-offed, also can be and turn-off first electronic switch and conducting second electronic switch.
In one embodiment, over-voltage detection circuit 110 comprises sample circuit 103 and comparison circuit 104.Sample circuit 103 is coupled to inductor L, the electrical quantity of sampling inductor L, and produce the sampled signal SENSE that represents this electrical quantity.The electrical quantity of inductor L comprises the voltage at inductor L two ends or flows through the electric current of inductor L.Comparison circuit 104 is electrically coupled to sample circuit 103, a sampled signal SENSE and a threshold value is compared, and produce overvoltage signal OV.If sampled signal SENSE is greater than this threshold value, overvoltage signal OV effectively (low level " 0 " or high level " 1 ") then.Control circuit 102 receives overvoltage signal OV, if overvoltage signal OV is effective, then control circuit 102 cuts out inverter circuit 101, realizes overvoltage protection.
When discharge lamp was not lighted or do not insert, lamp presented open-circuit condition.Because series capacitor C
s, shunt capacitor C
pL is in resonance condition with inductor, and when the amplitude increase of voltage of both ends of lamp, the amplitude that flows through the electrical quantity of inductor L also increases, and vice versa.Thereby need not high-voltage capacitor or resistor by the electrical quantity of sample circuit of the present utility model monitoring inductor L, thereby the area of the printed circuit board (PCB) high-pressure section of electric ballast is little, the coefficient of safety height, and wiring is easily, and antijamming capability is strong.
Control circuit 202 comprise error amplifier ERR_AMP, voltage controlled oscillator, not gate NOT1, with door AND1 and AND2.The in-phase input end of error amplifier ERR_AMP receives reference voltage Ref, and inverting input is electrically connected to current sampling circuit 205 with received current sampled signal I
Sense, the output signal COMP that affords redress.Voltage controlled oscillator is electrically coupled to the output of error amplifier ERR_AMP, regulates the frequency of the control signal of its output according to compensating signal COMP, and the duty ratio of this control signal is generally 50%.Be electrically connected to the output of comparator C OM1 to receive overvoltage signal OV with the input of door AND1 and AND2.Be electrically connected to voltage controlled oscillator to receive control signal with another input of door AND1, output is electrically coupled to conducting and the shutoff of the gate pole of electronic switch S1 with control electronic switch S1.Be electrically coupled to voltage controlled oscillator with another input of door AND2 by not gate NOT1, output is electrically coupled to conducting and the shutoff of the gate pole of electronic switch S2 with control electronic switch S2.
If there is overvoltage in the voltage at gaseous discharge lamp two ends, the corresponding increase of voltage meeting at inductor L two ends makes sampled signal SENSE greater than threshold value V
Th1, then overvoltage signal OV is effective, is low level.With door AND1 and the equal output low level of AND2, electronic switch S1 and S2 are turn-offed, realize overvoltage protection.
Fig. 3 is the circuit diagram of second execution mode of the utility model electric ballast, and wherein inverter circuit 301, comparison circuit 304 and current sampling circuit 305 are all identical with appropriate section in the circuit shown in Figure 2.The voltage at sample circuit 303 sampling inductor L two ends comprises coupling inductor L
CoupleHalf-wave rectifying circuit with diode D5 formation.Coupling inductor L
CoupleMagnetic coupling is to inductor L.Half-wave rectifying circuit is electrically coupled to coupling inductor L
Couple, to coupling inductor L
CoupleThe voltage at two ends carries out halfwave rectifier, and produces sampled signal SENSE.
If there is overvoltage in the voltage at gaseous discharge lamp two ends, the corresponding increase of voltage meeting at inductor L two ends makes sampled signal SENSE greater than threshold value V
Th1, then overvoltage signal OV is effective, is low level.With door AND1 output low level, electronic switch S1 is turn-offed, realize overvoltage protection, and this moment or door OR1 output high level, with electronic switch S2 conducting.In one embodiment, electronic switch S1 and S2 are NMOS (n channel metal field oxide semiconductor field effect transistor).For the normally that guarantees electronic switch S1 with close, between its drive circuit and source electrode, be provided with one usually from opening capacitor.This opens capacitor certainly and is recharged when electronic switch S2 conducting, and discharges when electronic switch S1 conducting.After detecting overpressure situation, turn-off electronic switch S1 and conducting electronic switch S2; can reach the purpose of overvoltage protection; can make again and keep, make electronic switch S1 energy operate as normal when electric ballast is restarted, guarantee reliably restarting of electric ballast from opening the voltage at capacitor two ends.
Fig. 4 is the circuit diagram of the 3rd execution mode of the utility model electric ballast, and wherein inverter circuit 401, control circuit 402 and current sampling circuit 405 are all identical with appropriate section in the circuit shown in Figure 2.Sample circuit 403 sample streams are crossed the electric current of inductor L, and the current sampling circuit 405 multiplexing sampling resistor R that are connected electrically between electronic switch S2 and the ground
SenseComparison circuit 404 comprises comparator C OM2.The in-phase input end of comparator C OM2 receives a threshold value V
Th2, inverting input is electrically connected to sampling resistor R
SenseWith reception sampled signal SENSE, output output overvoltage signal OV, wherein this overvoltage signal OV is that low level is effective.
If there is overvoltage in the voltage at gaseous discharge lamp two ends, flow through the corresponding increase of electric current meeting at inductor L two ends, make sampled signal SENSE greater than threshold value V
Th2, then overvoltage signal OV is effective, is low level.With door AND1 and the equal output low level of AND2, electronic switch S1 and S2 are turn-offed, realize overvoltage protection.In great-power electronic ballast, excessive for fear of power consumption, sampling resistor R
SenseResistance generally less, thereby the value of sampled signal SENSE is also less, is subject to disturb.
Fig. 5 is the circuit diagram of the 4th execution mode of the utility model electric ballast, and wherein inverter circuit 501, control circuit 502 and current sampling circuit 505 are all identical with appropriate section in the circuit shown in Figure 3.Sample circuit 503 sample streams are crossed the electric current of inductor L, comprise current transformer T1, diode D6 and resistor R 1.The former limit coupled in series of current transformer T1 is to the loop at inductor L place.The half-wave rectifying circuit that diode D6 constitutes is connected to the secondary of current transformer T1, and the electric current of convection current overcurrent instrument transformer T1 secondary carries out halfwave rectifier.Resistor R 1 is connected in series with diode D6, and the current signal after the halfwave rectifier is converted to sampled signal SENSE, sends into comparison circuit 504.Resistor R 1 also can directly be connected in parallel to the secondary of current transformer T1, and half-wave rectifying circuit carries out the voltage at resistor R 1 two ends to produce sampled signal SENSE after the halfwave rectifier.Comparison circuit 504 comprises comparator C OM2.The in-phase input end of comparator C OM2 receives a threshold value V
Th3, inverting input is electrically connected to half-wave rectifying circuit with reception sampled signal SENSE, output output overvoltage signal OV, and wherein this overvoltage signal OV is that low level is effective.
If there is overvoltage in the voltage at gaseous discharge lamp two ends, flow through the corresponding increase of electric current meeting at inductor L two ends, make sampled signal SENSE greater than threshold value V
Th3, then overvoltage signal OV is effective, is low level.With door AND1 output low level, electronic switch S1 is turn-offed, realize overvoltage protection.At this moment, or door OR1 output high level, with electronic switch S2 conducting.
Though described the utility model with reference to several exemplary embodiments, should be appreciated that used term is explanation and exemplary and nonrestrictive term.The spirit or the essence that do not break away from utility model because the utility model can specifically be implemented in a variety of forms, so be to be understood that, the foregoing description is not limited to any aforesaid details, and should be in the spirit and scope that claim limited of enclosing explain widely, therefore fall into whole variations in claim or its equivalent scope and remodeling and all should be the claim of enclosing and contain.
Claims (7)
1. electric ballast with over-voltage protecting function comprises:
Inverter circuit comprises at least one electronic switch, and wherein each electronic switch all possesses first end, second end and the 3rd end;
Inductor, the one end is electrically coupled to the output of described inverter circuit, and the other end is electrically coupled to gaseous discharge lamp;
Capacitor is connected in parallel with described gaseous discharge lamp;
Control circuit possesses an input and at least one output, and wherein each output all is electrically coupled to the 3rd end of a described electronic switch;
Sample circuit, its input is coupled to described inductor, and its output provides the sampled signal of the described inductor electrical quantity of representative; And
Comparison circuit, possess first input end, second input and output, wherein first input end is electrically coupled to the output of described sample circuit, second input receives a threshold value, output is electrically coupled to the input of described control circuit, indicates the voltage at described gaseous discharge lamp two ends whether to have overvoltage;
Wherein if there is overvoltage, then described control circuit cuts out described inverter circuit.
2. electric ballast as claimed in claim 1 is characterized in that, the electrical quantity of described inductor is the voltage at described inductor two ends, and described sample circuit comprises:
Coupling inductor is with described inductor magnetic coupling; And
Rectification circuit, its input is electrically coupled to described coupling inductor, and its output provides described sampled signal.
3. electric ballast as claimed in claim 1 is characterized in that, the electrical quantity of described inductor is the electric current that flows through described inductor, and described sample circuit comprises that series electrical is coupled to the sampling resistor in described inductor loop.
4. electric ballast as claimed in claim 1 is characterized in that, the electrical quantity of described inductor is the electric current that flows through described inductor, and described sample circuit comprises:
Current transformer, its former limit coupled in series is to described inductor;
Rectification circuit, its input is electrically coupled to the secondary of described current transformer; And
Resistor is electrically connected to the output of described rectification circuit, and the voltage at described resistor two ends is described sampled signal.
5. as each described electric ballast in the claim 1 to 4, it is characterized in that, described inverter circuit adopts half-bridge topology, comprise first electronic switch and second electronic switch that are connected in series, first termination of described first electronic switch is received supply voltage, second end of described first electronic switch is electrically connected to first end of described second electronic switch, the second end ground connection of described second electronic switch.
6. electric ballast as claimed in claim 5 is characterized in that, closes described inverter circuit and comprises described first and second electronic switches of shutoff.
7. electric ballast as claimed in claim 5 is characterized in that, closes described inverter circuit and comprises described first electronic switch of shutoff and described second electronic switch of conducting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202158229U CN201700073U (en) | 2010-05-28 | 2010-05-28 | Electronic ballast with function of overvoltage protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202158229U CN201700073U (en) | 2010-05-28 | 2010-05-28 | Electronic ballast with function of overvoltage protection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201700073U true CN201700073U (en) | 2011-01-05 |
Family
ID=43401319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010202158229U Expired - Fee Related CN201700073U (en) | 2010-05-28 | 2010-05-28 | Electronic ballast with function of overvoltage protection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201700073U (en) |
-
2010
- 2010-05-28 CN CN2010202158229U patent/CN201700073U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: ZHEJIANG DABONG TECHNOLOGY CO., LTD. Free format text: FORMER NAME: HANGZHOU DABONG TECHNOLOGY CO., LTD. |
|
| CP03 | Change of name, title or address |
Address after: Hangzhou City, Zhejiang province 311100 Yuhang District Canal Town Road No. 3 Building 2 pole Patentee after: Zhejiang Dabang Technology Co.,Ltd. Address before: 311100, No. 37 East Street, East Lake street, Yuhang District, Zhejiang, Hangzhou Patentee before: Hangzhou Dabang Technology Co., Ltd. |
|
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110105 Termination date: 20170528 |