CN202262008U - Discharge lamp protection circuit, electronic ballast and discharge lamp - Google Patents
Discharge lamp protection circuit, electronic ballast and discharge lamp Download PDFInfo
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- CN202262008U CN202262008U CN2011203518264U CN201120351826U CN202262008U CN 202262008 U CN202262008 U CN 202262008U CN 2011203518264 U CN2011203518264 U CN 2011203518264U CN 201120351826 U CN201120351826 U CN 201120351826U CN 202262008 U CN202262008 U CN 202262008U
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Abstract
The utility model discloses a discharge lamp protection circuit, an electronic ballast and a discharge lamp. The discharge lamp protection circuit comprises a comparison module for receiving a lamp voltage detection signal and comparing the lamp voltage detection signal with reference lamp voltage to generate an overvoltage detection signal and a modulation module for modulating a power control signal according to the overvoltage detection signal and outputting a modulated power control signal. Compared with the conventional driving circuit for the discharge lamp, the discharge lamp protection circuit determines whether the discharge lamp is run out according to the lamp voltage of the discharge lamp; and when the discharge lamp runs out, the protection circuit can reduce driving current of the discharge lamp quickly to limit the run-out power of the discharge lamp. Therefore, heat of the discharge lamp in the run-out state is reduced effectively, and the driving circuit of the discharge lamp is protected effectively; and the use safety is improved.
Description
Technical field
The utility model relates to lighting technical field, more specifically, relates to a kind of discharge lamp protection circuit, electric ballast and discharge lamp light fixture.
Background technology
Discharge lamp is widely used in the occasion of various needs illuminations.Usually, discharge lamp comprises with air tight manner and is sealed in the luminous tube in the discharge space, ionizable fill and the pair of electrodes in the discharge space.When work, be loaded driving voltage on the electrode of discharge lamp, correspondingly, gas discharge takes place and forms lamp current meeting in the electric discharge between electrodes space in this, thereby makes discharge lamp luminous.
Yet; For many discharge lamps; For example (High Intensity ischarge HID) phenomenons such as discharge instability and modulating voltage be unusual can occur in its working life later stage (or be called " dying of old age ") to high-intensity discharge lamp, and the temperature of discharge lamp might significantly raise.The rising of discharge lamp temperature can cause the heating of lamp socket and electric wire and possibly cause problems such as plastics or other insulating material thawings wherein.
Therefore, need provide a kind of protective circuit to avoid discharge lamp to generate heat because of dying of old age.
The utility model content
The basic thought of the utility model is to utilize the lamp of discharge lamp to press to judge whether it dies of old age, and reduces its power of dying of old age through the drive current that reduces discharge lamp, thereby reduces the heating of discharge lamp when dying of old age.
In order to address the above problem, an aspect according to the utility model provides a kind of discharge lamp protection circuit, comprising: comparison module, and be used to receive lamp and press detection signal, and more said lamp presses detection signal and reference lamp to press to generate the overvoltage detection signal; Modulation module is used for coming power control signal is modulated with said overvoltage detection signal, and exports modulated power control signal.
Another aspect according to the utility model; A kind of discharge lamp protection circuit also is provided, has comprised first switch, timing capacitor, comparator and modulation module, wherein; Said first switch and said timing capacitor coupled in series; The control end of said first switch is couple to lamp and presses detection signal, and when said first switch closure, said timing capacitor is recharged; An input of said comparator is couple to first end of said timing capacitor, and another input is couple to threshold voltage, its output output overvoltage comparison signal; An input of said modulation module is couple to the output of said comparator, and another input is couple to power control signal, the modulated power control signal of its output output.
According to the another aspect of the utility model, a kind of electric ballast that is used to drive discharge lamp also is provided, comprise voltage transformation module, light module, the discharge lamp protection circuit described in inversion module and the aforementioned aspect.
According to the utility model more on the one hand, a kind of discharge lamp light fixture also is provided, comprise discharge lamp and according to the electric ballast described in the aforementioned aspect.
Than the drive circuit of conventional discharge lamps, the discharge lamp protection circuit of the utility model presses to confirm through the lamp of discharge lamp whether it is in the state of dying of old age.When discharge lamp was died of old age, this protective circuit can promptly reduce the drive current of discharge lamp, thus the power of dying of old age of restriction discharge lamp.The heating that this had both reduced the state discharge lamp of dying of old age effectively makes the drive circuit of discharge lamp to be effectively protected again, has improved safety in utilization.
The above characteristic of the utility model and other characteristics are partly set forth embodiment hereinafter clearly.
Description of drawings
Through with reference to the detailed description of being done below the advantages, can more easily understand characteristic, purpose and the advantage of the utility model to non-limiting example.Wherein, same or analogous Reference numeral is represented same or analogous device.
Fig. 1 shows the block diagram of application according to the electric ballast 100 of the protective circuit of an embodiment of the utility model;
Fig. 2 shows the block diagram according to the discharge lamp protection circuit 200 of an embodiment of the utility model;
Fig. 3 shows the circuit diagram of the electric ballast 100 of Fig. 1;
Fig. 4 shows the circuit diagram of comparison module in the discharge lamp protection circuit 200 of Fig. 2;
Fig. 5 shows the circuit diagram of comparison module of the protective circuit 200 of the Fig. 2 that adopts bipolar transistor;
Fig. 6 shows the circuit diagram of comparison module of the protective circuit 200 of the Fig. 2 that adopts field-effect transistor;
Fig. 7 shows the protective circuit 700 according to another embodiment of the utility model;
Fig. 8 shows the comparison module and the circuit diagram of lighting detection module of the protective circuit 700 of the Fig. 7 that adopts bipolar transistor;
Fig. 9 shows the comparison module and the circuit diagram of lighting detection module of the protective circuit 700 of the Fig. 7 that adopts field-effect transistor;
Figure 10 shows the flow chart according to the driving method that is used for discharge lamp of an embodiment of the utility model.
Embodiment
Go through enforcement and the use of embodiment below.Yet, should be appreciated that the specific embodiment discussed only exemplarily explanation implement and use the ad hoc fashion of the utility model, and the scope of unrestricted the utility model.
Fig. 1 shows the block diagram of application according to the electric ballast 100 of the protective circuit of an embodiment of the utility model.
As shown in Figure 1, this electric ballast 100 comprises voltage transformation module 101, inversion module 103, lights module 105, control module 107 and protective circuit 109, wherein:
Particularly; Voltage transformation module 101 comprises rectification unit and Active PFC unit; Wherein this rectification unit is used for converting AC supply voltage into dc pulse moving voltage; The dc pulse moving voltage that the Active PFC unit then further generates rectification unit carries out filtering and Active PFC, dc pulse moving voltage is converted into the basicly stable DC power supply voltage that is suitable for late-class circuit module in the electric ballast 100.Should be realized that the circuit structure of above-mentioned voltage transformation module 101 is illustrative rather than restrictive, any other can all can be applicable to the utility model with the circuit that AC supply voltage converts DC power supply voltage into.
Need to prove that according to the difference of practical application, electric ballast of the utility model and protective circuit both can be used for high-intensity discharge lamp, also can be used for other discharge lamp, should not limit its scope.
Fig. 2 shows the block diagram according to the discharge lamp protection circuit 200 of an embodiment of the utility model.As shown in Figure 2, this protective circuit 200 comprises:
In practical application; When discharge lamp is under the normal operating conditions, promptly it can set up electric arc and when stably luminous, the lamp between two electrodes of discharge lamp is pressed and maintained usually below 150 volts in luminous tube; For example for high-intensity discharge lamp, its lamp is pressed big in 70 to 150 volts scope; And when discharge lamp was died of old age, promptly it can not be set up electric arc and continue when luminous in luminous tube, and the lamp between two electrodes of discharge lamp is pressed and can be jumped to more than 150 volts usually.Therefore, the lamp of discharge lamp is pressed to change and can be used for promptly confirming whether it is in the state of dying of old age.Be appreciated that the discharge lamp for dissimilar or specification, the lamp of its die of old age state and the normal operating conditions scope of pressing may be different, and above-mentioned lamp pressure scope is merely example, should not limit its scope.
On the other hand, as aforementioned,, can control by power control signal by its amplitude that is provided at the driving voltage between two electrodes of discharge lamp for the inversion module in the electric ballast.For example, for the inversion module that adopts switching power circuit, it controls wherein switch opens or closure through the power control signal that different duty and different frequency are provided.Particularly, high more corresponding to the duty ratio of the power control signal of each switch, inversion module the driving power that can provide also just big more usually.Therefore, for the discharge lamp that is under the normal operating conditions, modulation module 203 need not change normal power control signal; And for the discharge lamp that is in the state of dying of old age, need to reduce or limit its power below preset limit value, correspondingly, modulation module 205 need be modulated power control signal, so that the duty ratio of the power control signal after modulated significantly reduces.
Fig. 3 shows the circuit diagram of the electric ballast 100 of Fig. 1.
As shown in Figure 3, this electric ballast 100 comprises voltage transformation module 101, inversion module 103, lights module 105, control module 107 and protective circuit 109.
Particularly, voltage transformation module 101 comprises rectification unit 301 and power factor correction unit 302, and wherein, rectification unit 301 comprises four diodes that bridge-type connects, and it converts the AC supply voltage that AC power 303 provides into dc pulse moving voltage.Power factor correction unit 302 comprises inductance 303 and switch 304; Wherein an end of inductance 303 couples with the output of rectification unit 301 mutually; Its other end couples with an end of switch 304 mutually, and the other end of switch 304 is coupled to reference potential, for example earth potential.
In practical application, under the control of the Active PFC signal that control module provides, the closure of switch 304 and open mode change, thereby make the equivalent resistance of switch 304 change.This makes this Active PFC unit 302 act as a low-pass filter circuit, and it can carry out LPF to the dc pulse moving voltage of rectification unit 301 outputs, thereby generates basicly stable DC power supply voltage and offer the late-class circuit module.
In practical application; The first dividing potential drop electric capacity 306 has the capacitance that equates usually with the second dividing potential drop electric capacity 307; This makes the common port (Section Point 309) of win the dividing potential drop electric capacity 306 and the second dividing potential drop electric capacity 307 form the intermediate potential that is between DC power supply voltage and the reference potential; And the first dividing potential drop electric capacity 306 cooperates with inversion module 103 with the second dividing potential drop electric capacity 307, has formed two loops of symmetry.These two symmetrical circuits are conducting respectively periodically, to exchange the ground power supply to discharge lamp 111.
Light that module 105 comprises voltage transformation unit 318, lights switch 319, boost capacitor 320 and boost resistor 321.Wherein, this voltage transformation unit 318 comprises elementary winding 318a and secondary winding 318b, and this elementary winding 318a has much smaller than the coil number of secondary winding 318b.Boost resistor 321 and boost capacitor 320 are coupled in series between first node 308 and the 3rd node 310; The common port of this boost resistor 321 and boost capacitor 320 is couple to the end of elementary winding 318a, and the other end of this elementary winding 318a is couple to the 3rd node 310 through lighting switch 319.Secondary winding 318b is coupled between discharge lamp 111 and the inductance 313.When operation; Lighting switch 319 periodically opens under the signal controlling or closed lighting of providing of control module 107; So that the DC power supply voltage cycle property that voltage transformation module 101 provides ground charges to boost capacitor 320 through boost resistor 321, and the voltage on this boost capacitor 320 further amplifies through voltage transformation unit 318.Like this, the secondary winding 318b of voltage transformation unit 318 can periodically provide the voltage of lighting of amplitude in response to the variation of lighting switch 319 to discharge lamp 111, is lighted until discharge lamp 111.After discharge lamp 111 is lighted, light switch 319 and stay open, thereby make voltage transformation unit 318 only act as the inductance with discharge lamp 111 coupled in series.
In one embodiment, inductance 313 is coupled with detecting winding 322 through iron core, so that the voltage at inductance 313 two ends is proportional to the voltage that detects winding 322 two ends.In application because the voltage that the voltage at inductance 313 two ends and the lamp of discharge lamp 111 are pressed and equal Section Point 309 basically and the 3rd node 310 between potential difference, and this potential difference is definite by substantially invariable DC power supply voltage.Therefore, the change in voltage at detection winding 322 two ends is associated with the lamp pressure variation of discharge lamp 111.Like this, the voltage that detects winding 322 outputs can reflect the variation of discharge lamp 111 lamps pressure, can press detection signal as lamp with it.Particularly, than the discharge lamp 111 of operate as normal, when being in when dying of old age state, the lamp of discharge lamp is pressed higher, and correspondingly, lamp presses detection signal lower.
Fig. 4 shows the circuit diagram of comparison module in the discharge lamp protection circuit 200 of Fig. 2.
As shown in Figure 4, comparison module comprises timing capacitor 401 and comparator 403.Timing capacitor 401 is recharged under the control of lamp pressure detection signal; And comparator 403 is used to receive the voltage and the threshold voltage of timing capacitor 401, and presses detection signal based on the voltage of timing capacitor 401 and the comparative result output lamp of threshold voltage.
Particularly, comparison module also comprises first switch 405, and it is used to receive lamp and presses detection signal, and controls the charging of timing capacitor 401 in response to the variation of lamp pressure detection signal.The timing capacitor 401 and first switch 405 are coupled in series in the first current potential V
DdWith the second current potential V
CcBetween, and the control end of this first switch 405 is couple to lamp pressure detection signal.Wherein, first end of first switch 405 is couple to the first current potential V
Dd, second end of first switch 405 is couple to first end of timing capacitor 401, and second end of timing capacitor 401 is couple to the second current potential V
Cc
In application, first switch 405 is corresponding opening or closure in response to the variation of this lamp pressure detection signal.When first switch, 405 closures, the first current potential V
DdWith the second current potential V
CcBetween electrical potential difference make timing capacitor 401 be recharged.For example, press detection signal for the lamp that the aforesaid voltage instrument transformer is detected, when lamp pressed detection signal higher, for example lamp was pressed the detection signal and the first current potential V
DdCooperate the switch 405 of winning is opened, timing capacitor 401 can not be recharged; And when lamp pressed detection signal low, for example lamp was pressed the detection signal and the first current potential V
DdCooperate to make switch 405 closures of winning, timing capacitor 403 promptly is coupled in the first current potential V
DdWith the second current potential V
CcBetween, thereby it is recharged.
Particularly, uncharged or when just having begun to charge, its voltage is lower than threshold voltage when timing capacitor 401, in this case, the overvoltage detection signal of comparator 403 outputs first state for example is a logic ' 1 '.And after timing capacitor 401 continued charging a period of times, the voltage on it surpassed threshold voltage, and this makes the overvoltage detection signal of comparator 403 outputs and second state of first opposite states, for example is logic ' 0 '.
As aforementioned, the modulation module of protective circuit is used for coming power control signal is modulated with the overvoltage detection signal, and exports modulated power control signal.Wherein, modulation module generally includes two inputs, and one of them input is couple to the output of comparator 403 with reception overvoltage detection signal, and another input is couple to power control signal, and the pin of power control signal promptly is provided in the control module; Modulation module is at the modulated power control signal of its output output.
In one embodiment, modulation module comprise multiplier or with door, perhaps other logic circuit components.With modulation module for door be example; When it receives the overvoltage detection signal of logic ' 1 '; Its output signal depends on power control signal, so the output signal of modulation module is identical with the power control signal of its said reception, and for example its duty ratio remains unchanged.When modulation module received the overvoltage detection signal of logic ' 0 ', its output signal remained logic ' 0 ', does not receive the influence of power control signal, and this makes the duty ratio of power control signal change.In application, the change of power control signal duty ratio can make the electric current that flows through discharge lamp change, and further changes the driving power that electric ballast offers discharge lamp.
It will be understood by those skilled in the art that the differences of the different or modulation module logic of difference according to the overvoltage detection signal, reference potential, the structure of this comparison module can respective change, should not limit its scope.
In the protective circuit 200 of reality, first switch 405 can adopt bipolar transistor or field-effect transistor, perhaps other constructions of switch.Next, be example to adopt bipolar transistor and field-effect transistor, the physical circuit of protective circuit 200 is further described.
Fig. 5 shows the circuit diagram of comparison module of the protective circuit 200 of the Fig. 2 that adopts bipolar transistor.
As shown in Figure 5, comparison module comprises first input resistance 501, input capacitance 502, first biasing resistor 503, first bipolar transistor 504, current-limiting resistance 505, timing capacitor 506 and comparator (not shown).Wherein, this first bipolar transistor 504 is a PNP transistor, is appreciated that in practical application, and it can also use for NPN transistor and as switch.
Particularly, first input resistance 501 is coupled in series in the first node 511 and the second current potential V with input capacitance 502
CcBetween, this first node 511 is coupled to lamp and presses detection signal.The common port (Section Point 512) of first input resistance 501 and input capacitance 502 is couple to the base stage of first bipolar transistor 504.
First biasing resistor 503, first bipolar transistor 504, current-limiting resistance 505 and timing capacitor 506 in series are coupled in the first current potential V
DdWith the second current potential V
CcBetween.Wherein an end of first biasing resistor 503 is coupled to the first current potential V
Dd, its other end is coupled to the emitter of first bipolar transistor 504.The collector electrode of first bipolar transistor 504 then is couple to an end (the 3rd node 513) of timing capacitor 506 through current-limiting resistance 505, and the other end of timing capacitor 506 is couple to the second current potential V
CcSimultaneously, the 3rd node 513 further is couple to an input of comparator, so that the voltage on the timing capacitor 506 is exported.
In an optional embodiment, all right further coupled in series diode between the collector electrode of first bipolar transistor 504 and the 3rd node 513, the N utmost point of this diode is couple on the timing capacitor 506.Through inserting diode, can avoid discharging via first bipolar transistor 504 because of the overtension of timing capacitor 506.
Be in operation, when the discharge lamp operate as normal, the lamp of discharge lamp forces down in reference lamp and presses, and this makes lamp press detection signal to be higher than certain predetermined value.Correspondingly, the voltage on the Section Point 512 is higher, and this ends the bipolar transistor 504 of winning, and timing capacitor 506 can not be recharged, and the voltage of the 3rd node 513 is lower than threshold voltage.Therefore, after comparator compares the voltage and threshold voltage on the 3rd node 513, export the overvoltage detection signal of first state.Correspondingly, modulation module does not change power control signal after receiving the overvoltage detection signal of this first state.
When discharge lamp is in when dying of old age state, the lamp of discharge lamp is pressed and is higher than reference lamp and presses, and this makes lamp press detection signal to be lower than certain predetermined value.Correspondingly, the voltage on the Section Point 512 is lower, cooperates the first higher current potential V that loads on first bipolar transistor, 504 emitters
Dd, making bipolar transistor 504 conductings of winning, timing capacitor 506 is recharged, so that the voltage of the 3rd node 513 is higher than threshold voltage.Therefore, after comparator compares the voltage and threshold voltage on the 3rd node 513, export the overvoltage detection signal of second state.Correspondingly, modulation module is understood corresponding change power control signal after receiving the overvoltage detection signal of this second state, for example reduce the duty ratio of power control signal.
Need to prove because power control signal periodic signal normally, so the overvoltage detection signal also to require be the periodic signal that is suitable for this power control signal.For generating this periodic overvoltage detection signal, timing capacitor 506 is discharge periodically, for example through the timing switch of coupled in parallel at its two ends.Like this, press detection signal lower and make when winning the bipolar transistor conducting when lamp, timing capacitor 506 is charge and discharge periodically, thereby exports periodic overvoltage detection signal.
It will be appreciated by those skilled in the art that; The charging interval of timing capacitor 506 (for example being charged to above the time more than the threshold voltage from 0) is depended on the capacitance of charging current and timing capacitor 506, and this charging current is relevant with the resistance value of first biasing resistor 503 and current-limiting resistance 505.Through regulating first biasing resistor 503, current-limiting resistance 505 and/or timing capacitor 506, can realize control, and then the duty ratio of power control signal is modulated the charging interval of timing capacitor 506.
Fig. 6 shows the circuit diagram of comparison module of the protective circuit 200 of the Fig. 2 that adopts field-effect transistor.As shown in Figure 6, this comparison module comprises first input resistance 601, input capacitance 602, first MOS transistor 604, current-limiting resistance 605, timing capacitor 606 and comparator (not shown).Wherein, this first MOS transistor 604 is the PMOS transistor, is appreciated that in practical application, and it can also use for nmos type transistor and as switch.
In an optional embodiment, all right further coupled in series diode between the drain electrode of first MOS transistor 604 and the 3rd node 613, the N utmost point of this diode is couple on the timing capacitor 606.Through inserting diode, can avoid discharging via first MOS transistor 604 because of the overtension of timing capacitor 606.
Be in operation, when the discharge lamp operate as normal, the lamp of discharge lamp forces down in reference lamp and presses, and this makes lamp press detection signal to be higher than certain predetermined value.Correspondingly, the voltage on the Section Point 612 is higher, and this ends the MOS transistor 604 of winning, and timing capacitor 606 can not be recharged, and the voltage of the 3rd node 613 is lower than threshold voltage.Therefore, after comparator compares the voltage and threshold voltage on the 3rd node 613, export the overvoltage detection signal of first state.
When discharge lamp is in when dying of old age state, the lamp of discharge lamp is pressed and is higher than reference lamp and presses, and this makes lamp press detection signal to be lower than certain predetermined value.Correspondingly, the voltage on the Section Point 612 is lower, cooperates the first higher current potential V that loads on first MOS transistor, 604 source electrodes
Dd, make MOS transistor 604 conductings of winning, the first current potential V
DdTiming capacitor 606 is charged so that the voltage of the 3rd node 613 is higher than threshold voltage.Therefore, after comparator compares the voltage and threshold voltage on the 3rd node 613, export the overvoltage detection signal of second state, explain that promptly timing capacitor 606 voltages are higher than threshold voltage.Correspondingly, modulation module is understood corresponding change power control signal after receiving the overvoltage detection signal of second state, for example reduce the duty ratio of power control signal.
In practical application, when light module to discharge lamp provide amplitude light voltage the time, lamp between two electrodes of discharge lamp is pressed also higher, but this moment, discharge lamp was not to be in the state of dying of old age.Therefore, be necessary to confirm the illuminating state of discharge lamp, so that when electric ballast is lighted discharge lamp, protective circuit can be to not pressing detection signal based on different lamps and power control signal being modulated.
Fig. 7 shows the protective circuit 700 according to another embodiment of the utility model.
As shown in Figure 7, protective circuit 700 comprises comparison module 701, modulation module 703 and lights detection module 705.Wherein, this is lighted detection module 705 and is used for receiving and lights signal, and makes 701 pairs of lamps of comparison module press the reception of detection signal invalid in response to effectively lighting signal.
Particularly, this is lighted detection module 705 and comprises second switch 707, an end of this second switch 707 and comparison module 703 coupled in parallel; Wherein the control end of second switch 707 is couple to and lights signal; Lighting signal when effective, second switch 707 closures, thus make comparison module 703 by bypass.
In the protective circuit 700 of reality, similar with first switch, second switch 707 can adopt bipolar transistor or field-effect transistor, perhaps other constructions of switch.Next, be example to adopt bipolar transistor and field-effect transistor, the physical circuit of protective circuit 700 is further described.
Fig. 8 shows the comparison module and the circuit diagram of lighting detection module of the protective circuit 700 of the Fig. 7 that adopts bipolar transistor.
As shown in Figure 8, this comparison module comprises first input resistance 801, input capacitance 802, first biasing resistor 803, first bipolar transistor 804, current-limiting resistance 805, timing capacitor 806 and comparator (not shown).Light detection module and comprise second bipolar transistor 807, second input resistance 808, second biasing resistor 809 and comparator (not shown).Wherein, this first bipolar transistor 804 and PNP transistor, and second bipolar transistor 807 is a NPN transistor.Be appreciated that in practical application these two transistors can also use for the transistor of opposite types and as switch.
First biasing resistor 803, first bipolar transistor 804, current-limiting resistance 805 and timing capacitor 806 in series are coupled in bias potential V
bWith the second current potential V
CcBetween, this bias potential V
bBy first biasing resistor 903, second biasing resistor 809 and the first current potential V
DdConfirm.One end of first biasing resistor 803 is coupled to the first current potential V
Dd, its other end is coupled to the emitter of first bipolar transistor 804.The collector electrode of first bipolar transistor 804 then is couple to an end (the 3rd node 813) of timing capacitor 806 through current-limiting resistance 805, and the other end of timing capacitor 806 is couple to the second current potential V
CcSimultaneously, the 3rd node 813 further is couple to an input of comparator, with the voltage output with timing capacitor 806.
The collector electrode of second bipolar transistor 807 is couple to the emitter of first bipolar transistor 804; The base stage of second bipolar transistor 807 receives through second input resistance 808 and lights signal, and the emitter of second bipolar transistor 807 is couple to the second current potential V
CcOne end of second biasing resistor 809 and the collector electrode of second bipolar transistor 807 couple, and the other end of second biasing resistor 809 is couple to the second current potential V
Cc
Be in operation, when second bipolar transistor 807 receives low level when lighting signal (invalid light signal), second bipolar transistor 807 ends.Therefore, first bipolar transistor 804 still can be pressed variation and the corresponding conducting of detection signal or ends in response to lamp, changes and power control signal is modulated thereby press based on the lamp of discharge lamp.
Yet, when second bipolar transistor 807 receive high level light signal the time (effectively lighting signal), 807 conductings of second bipolar transistor, its emitter with first bipolar transistor 804 is couple to the second current potential V
CcThereby, the bipolar transistor 804 of winning is ended, it is no longer pressed variation and the conducting of detection signal in response to lamp or ends, and also just stops the modulation to power control signal.
Fig. 9 shows the comparison module and the circuit diagram of lighting detection module of the protective circuit 700 of the Fig. 7 that adopts field-effect transistor.
As shown in Figure 9, this comparison module comprises first input resistance 901, input capacitance 902, first MOS transistor 904, current-limiting resistance 905, timing capacitor 906 and comparator (not shown); Comprise second MOS transistor 907 and light detection module.Wherein, this first MOS transistor 904 is the PMOS transistor, and second MOS transistor is a nmos pass transistor.Be appreciated that in practical application these two MOS transistors can also use for the MOS transistor npn npn of opposite types and as switch.
The drain electrode of second MOS transistor 907 is couple to the source electrode of first MOS transistor 904, and the source electrode of second MOS transistor 907 is couple to the second current potential V
Cc, the grid of second MOS transistor 907 is used for receiving lights signal.
Be in operation, when second MOS transistor 907 receives low level when lighting signal (invalid light signal), second MOS transistor 907 ends, and the source electrode of first MOS transistor 904 is couple to the first current potential V
DdTherefore, first MOS transistor 904 still can be pressed variation and the corresponding conducting of detection signal or ends in response to lamp, changes and power control signal is modulated thereby press based on the lamp of discharge lamp.
Yet, when second MOS transistor 907 receive high level light signal the time (effectively lighting signal), 907 conductings of second MOS transistor, its source electrode with first MOS transistor 904 is couple to the second current potential V
CcThereby, the MOS transistor 904 of winning is ended, and no longer press variation and the conducting of detection signal or end in response to lamp, also just stop modulation to power control signal.
Figure 10 shows the flow chart according to the driving method that is used for discharge lamp of an embodiment of the utility model.Shown in figure 10, this driving method comprises:
Execution in step S1002 receives lamp and presses detection signal, and more said lamp presses detection signal and reference lamp to press to generate the overvoltage detection signal; Execution in step S1004 comes power control signal is modulated based on said overvoltage detection signal, and exports modulated power control signal.
Particularly, when discharge lamp is under the normal operating conditions, the lamp between two electrodes of discharge lamp is pressed and is maintained usually below 150 volts, for example in 70 to 150 volts the scope; And when discharge lamp was died of old age, promptly it can not be set up electric arc and continue when luminous in luminous tube, and the lamp between two electrodes of discharge lamp is pressed and can be jumped to more than 150 volts usually.Therefore, the variation of the lamp of discharge lamp pressure can be used to promptly judge whether it is in the foundation of dying of old age.
On the other hand, as aforementioned,, can control by power control signal by its amplitude that is provided at the operating voltage between two electrodes of discharge lamp for the inversion module in the electric ballast.For example, for the inversion module that adopts switching power circuit, it controls wherein opening or closure of switch through the power control signal that different duty and frequency are provided.Particularly, high more corresponding to the duty ratio of the power control signal of each switch, inversion module the operating power that can provide also just big more usually.Therefore, for the discharge lamp that is under the normal operating conditions, need not change normal power control signal; And for the discharge lamp that is in the state of dying of old age; Need to reduce or limit it and die of old age power below preset limit value; Correspondingly, make the duty ratio of the power control signal after modulated significantly reduce through power control signal is modulated, thereby reduce the power that offers discharge lamp.
Need to prove, when light module to discharge lamp provide amplitude light voltage the time, lamp between two electrodes of discharge lamp is pressed also higher, but this moment, discharge lamp was not to be in the state of dying of old age.Therefore, in a preferred embodiment, before execution in step S1002, also comprise and whether detect discharge lamp,, then stop execution in step S1002 and S1004 if this discharge lamp is in illuminating state from illuminating state; And if discharge lamp is not in illuminating state, then continue execution in step S1002 and S1004.Like this, when electric ballast is lighted discharge lamp, can not modulate power control signal.
Although in accompanying drawing and aforesaid description sets forth in detail with the utility model has been described, should think that this is illustrated and describes is illustrative and exemplary, rather than restrictive; The utility model is not limited to above-mentioned execution mode.
The those skilled in the art in those present technique fields can be through research specification, disclosed content and accompanying drawing and appending claims, and understanding and enforcement are to other changes of the execution mode of disclosure.In claim, word " comprises " element and the step of not getting rid of other, and wording " one " is not got rid of plural number.In the practical application of utility model, the function of a plurality of technical characterictics of being quoted during a part possibility enforcement of rights requires.Any Reference numeral in the claim should not be construed as the restriction to scope.
Claims (15)
1. discharge lamp protection circuit comprises:
Comparison module is used to receive lamp and presses detection signal, and more said lamp presses detection signal and reference lamp to press to generate the overvoltage detection signal;
Modulation module is used for coming power control signal is modulated with said overvoltage detection signal, and exports modulated power control signal.
2. discharge lamp protection circuit according to claim 1 is characterized in that said comparison module comprises timing capacitor and comparator, wherein:
Said timing capacitor is recharged under the control of said lamp pressure detection signal;
Said comparator is used to receive the voltage and the threshold voltage of said timing capacitor, and presses detection signal based on the voltage of said timing capacitor and the comparative result output lamp of said threshold voltage.
3. discharge lamp protection circuit according to claim 2 is characterized in that said comparison module also comprises first switch, itself and said timing capacitor coupled in series, and the control end of wherein said first switch is couple to said lamp and presses detection signal.
4. discharge lamp protection circuit according to claim 3; It is characterized in that; First end of said first switch is couple to first current potential, and second end of said first switch is couple to first end of said timing capacitor, and second end of said timing capacitor is couple to second current potential; An input of said comparator is couple to first end of said timing capacitor, and another input is couple to said threshold voltage.
5. according to each described discharge lamp protection circuit in the claim 1 to 4; It is characterized in that; Also comprise and light detection module, be used for receiving and light signal, and light signal and make said comparison module press the reception of detection signal invalid said lamp in response to effectively said.
6. discharge lamp protection circuit according to claim 5; It is characterized in that; The said detection module of lighting comprises second switch, said second switch and said comparison module coupled in parallel, and the control end of wherein said second switch is couple to the said signal of lighting; When effective, said second switch is closed at the said signal of lighting.
7. discharge lamp protection circuit according to claim 1 is characterized in that, said modulation module comprise multiplier or with door.
8. discharge lamp protection circuit according to claim 1 is characterized in that, also comprises lamp pressure detection module, is used to detect the lamp pressure of said discharge lamp and generates lamp press detection signal.
9. discharge lamp protection circuit according to claim 8; It is characterized in that; Said lamp presses detection module to comprise voltage transformer; Said voltage transformer has elementary winding and the secondary winding that intercouples, wherein said elementary winding and said discharge lamp coupled in series, and said secondary winding is exported said lamp and is pressed detection signal between its two ends.
10. a discharge lamp protection circuit comprises first switch, timing capacitor, comparator and modulation module, wherein,
Said first switch and said timing capacitor coupled in series, the control end of said first switch are couple to lamp and press detection signal, and when said first switch closure, said timing capacitor is recharged;
An input of said comparator is couple to first end of said timing capacitor, and another input is couple to threshold voltage, its output output overvoltage comparison signal;
An input of said modulation module is couple to the output of said comparator, and another input is couple to power control signal, the modulated power control signal of its output output.
11. discharge lamp protection circuit according to claim 10; It is characterized in that; Also comprise second switch, first switch and the timing capacitor coupled in parallel of itself and said coupled in series, the control end of said second switch is couple to lights signal; When effective, said second switch is closed at the said signal of lighting.
12. discharge lamp protection circuit according to claim 10 is characterized in that, said modulation module comprise multiplier or with door.
13. discharge lamp protection circuit according to claim 10; It is characterized in that; Also comprise voltage transformer; Said voltage transformer has elementary winding and the secondary winding that intercouples, wherein said elementary winding and said discharge lamp coupled in series, and said secondary winding is exported said lamp and is pressed detection signal between its two ends.
14. an electric ballast that is used to drive discharge lamp comprises voltage transformation module, lights module, each described discharge lamp protection circuit in inversion module and the aforementioned claim.
15. a discharge lamp light fixture comprises discharge lamp and according to the electric ballast described in the claim 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203518264U CN202262008U (en) | 2011-09-07 | 2011-09-07 | Discharge lamp protection circuit, electronic ballast and discharge lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203518264U CN202262008U (en) | 2011-09-07 | 2011-09-07 | Discharge lamp protection circuit, electronic ballast and discharge lamp |
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| Publication Number | Publication Date |
|---|---|
| CN202262008U true CN202262008U (en) | 2012-05-30 |
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|---|---|---|---|
| CN2011203518264U Expired - Fee Related CN202262008U (en) | 2011-09-07 | 2011-09-07 | Discharge lamp protection circuit, electronic ballast and discharge lamp |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113824097A (en) * | 2021-09-30 | 2021-12-21 | 深圳慧能泰半导体科技有限公司 | Protection circuit and charging cable |
-
2011
- 2011-09-07 CN CN2011203518264U patent/CN202262008U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113824097A (en) * | 2021-09-30 | 2021-12-21 | 深圳慧能泰半导体科技有限公司 | Protection circuit and charging cable |
| CN113824097B (en) * | 2021-09-30 | 2024-03-12 | 深圳慧能泰半导体科技有限公司 | Protection circuit and charging cable |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: PHILIPS LIGHTING LUMINAIRES (SHANGHAI) CO., LTD. Effective date: 20120912 |
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| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20120912 Address after: 200233 Shanghai, Tianlin Road, Lane No. 888, No. 10, No. Patentee after: Philips (China) Investment Co., Ltd. Patentee after: Philips Lamp (Shanghai) Co., Ltd. Address before: 200233 Shanghai, Tianlin Road, Lane No. 888, No. 10, No. Patentee before: Philips (China) Investment Co., Ltd. |
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| 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: 20120530 Termination date: 20200907 |