CA1071297A - Device for starting and feeding a discharge lamp - Google Patents
Device for starting and feeding a discharge lampInfo
- Publication number
- CA1071297A CA1071297A CA245,545A CA245545A CA1071297A CA 1071297 A CA1071297 A CA 1071297A CA 245545 A CA245545 A CA 245545A CA 1071297 A CA1071297 A CA 1071297A
- Authority
- CA
- Canada
- Prior art keywords
- lamp
- capacitor
- diode
- voltage
- switching element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/02—Details
- H05B41/04—Starting switches
- H05B41/042—Starting switches using semiconductor devices
- H05B41/044—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes
- H05B41/046—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes using controlled semiconductor devices
Abstract
ABSTRACT
The invention relates to a device for starting a discharge lamp by means of a transistor starter, that starter being provided with an auxiliary transistor for stop-ping the starting procedure if the lamp fails to ignite.
According to the invention a zener diode is included in the control circuit of the auxiliary transistor, while further-more a capacitor is connected in parallel across the lamp, and a self-inductor is included in the connection from the lamp to the main transistor. In a circuit according to the invention, the auxiliary transistor has yet a second func-tion, namely because, by the action of the zener diode, the instants the main transistor is made conductive by means of the auxiliary transistor are delayed, so that a large rise of the voltage between the electrodes of the lamp is produced which is useful for a reliable ignition of the lamp within a large temperature range.
The invention relates to a device for starting a discharge lamp by means of a transistor starter, that starter being provided with an auxiliary transistor for stop-ping the starting procedure if the lamp fails to ignite.
According to the invention a zener diode is included in the control circuit of the auxiliary transistor, while further-more a capacitor is connected in parallel across the lamp, and a self-inductor is included in the connection from the lamp to the main transistor. In a circuit according to the invention, the auxiliary transistor has yet a second func-tion, namely because, by the action of the zener diode, the instants the main transistor is made conductive by means of the auxiliary transistor are delayed, so that a large rise of the voltage between the electrodes of the lamp is produced which is useful for a reliable ignition of the lamp within a large temperature range.
Description
r 7 ,~ ) ~ , r-.
PIIN 7~9~
]~I
9-1-197~
~D71297 .
"Device for starting and feeding a discharge lamp".
The invention relates to a device for starting and feeding a gas - and/or vapour discharge lamp which is provided with two electrodes, the device being provided with two input terminals which are intended for connection to an AC voltage source, whose frequency is less than 100Hz, the two input terminals- during starting and feeding of the lamp- being interconnected by means of a series cir-cuit of at least a stabilizing inductor, and the lamp, whilst the two lamp electrodes are interconnected by a starter comprising a first semiconductor switching element, whilst parallel to a branch which comprises said semiconduc-tor switching element a control circuit of the first semi-conductor switching element is provided, this control cir-cuit comprising at least a first capacitor~ an auxiliary transistor of the starter shunting at least the first ca-~ pacitor, whilst the ~ase of the auxiliary transistor is connected to a control circuit, namely to a junction of a first resistor and a second capacitor which aPe connected in series and which are parallel-to the branch comprising the first ~emiconductor switching element.
A known device of the said type is for example shown in Fig. 1 of United States Patent 3.875.459. An ad-vantage of that k~own device is that, if the lamp refuses to ignite the auxiliary tranqistor stops, after a given time, the efforts to start the lamp. However, a ~isadvantage of that kno~T~ device is that the voltage peaks which are --2~
PlrN 78~2 9~1-1~76 ` 1~71297 generated to start the discharge lamp therewith, show a relatively large and fairly constant amplitude. This en-tails, namely, that the first semiconductor switching element must be able to withstand these voltage peaks in its non-conducting state.
A further disadvantage of that known device is that, if the relatively large amplitude of the voltage peaks is still too small to start the discharge lamp the lamp will not ignite.
- 10 An object of the invention is to provide the possibility for a device of the above mentioned type to rate the first semiconductor switching element for a relatively low, permissible blocking voltage of a somewhat longer duration; but, furthermore, if the lamp is difficult ~ 15 to start to generate one or a few brief voltage peak~:s) of -~ a large amplitude.
A device according to the in~-ention for starting and feeding a gas - and/or vapour discharge lamp which is provided with two electrodes, the device being provided i 20 with two input terminals which are intended for connection .~ to an AC voltage source whose frequency is less than lOOHz, the two input terminals~ during s~tarting and feeding of the ~. lamp - being interconnected by means of a series circuitt7 comprising at least a stabilizing inductor and the lamp,the two lamp electrodes being interconnected by means of a starter comprising a first semiconductor switching element, whilet a control circuit of the first semiconductor switch-ing element is provided~ in parallel to a branch which !.
P~rN 7892 ~-1-1976 ~0712g7 comprises said semiconductor switching element, this con-trol circuit comprising at least a first capacitor~ an auxiliary transistor of the starter, shunting at least the first capacitor, whilst the base of the auxiliary transis-tor is connected to a control circuit, namely to a junction of a resistor and a second capacitor which are connected in series and which are in parallel to the branch comprising the first semiconductor switching element, is characterized in that the base of the auxiliary transistor is connected via a voltage-sensitive threshold element to the junction ! of the resistor and the second capacitor and that the lamp ! electrodes are connected by means of a third capacitor and ¦ that a second inductor is included in the connection of 1 the lamp electrodes to the first semiconductor switching ¦ 1~ element.
~¦ An advantage of this device is that, by means of the voltage-sensitive threshold element incorporated in the control circuit of the auxiliary transistor, the instant at which the first semiconductor switching element ~' 20 starts conducting - a short while a~ter the device has been switched on - can be influenced. This enables in-fluencing the degree to which the voltage between the lamp , electrodes can be raised during the starting of the lamp.
c This in~luence is such that the instant at which the first j 25 semiconductor switching element starts conducting is some-i what delayed, so that the rise in voltage across the serie `' circuit of the third capacitor and the second inductor, -p~ 7892 --~ 9-1-1976 ~7~Z97 and consequently the voltage across the lamp which is made available for starting - is increased.
So the invention i9 in fact based on the idea to use the auxiliary transistor - when the lamp definitely refuses to ignite - not only for stopping the attempts to star$ the lamp by short circuiting the first capacitor, but also to use that auxiliary transistor during the starting procedure of the lamp. This i9 effected by rendering that auxiliary transistor conductive one or more times for a short period before the end of the starting procedure, so that charging the first capacitor in the control circuit of the semiconductor switching element is counteracted. This implies that it lasts longer before the said first capacitor has obtained such a voltage that the se~iconductor switching element can be made conductive therewith. As observed be-fore, this delay results in a larger rise of the voltage across the lamp.
I~owever, it takes some time aft0r the device has been switched on, for the auxiliary transistor to start conducting. The reason is the presence of the voltage-sensitive threshold element in the control Tcircuit of the auxiliary transistor. If, after some time the second capa-citor is charged to such an extent~hatit causes the auxiliary transistor to become conductive, the delay in making the first semiconductor switching element conductive becomes operative.
As far as the rise in voltage across the discharge lamp - in the starting procedure - is concerned, it should l'l~ 78~2 9~1-197~
~6~71Z97 be notod that this is known ~er se from British Patent Specification 1.208.489. In that case, however, the in-stant the semiconductor switching element is made conduc-tive is not variable.
The discharge lamp may, for example, be a lamp which is not provided with preheatable electrodes, for example a high pressure metal vapour discharge lamp.
The discharge lamp is preferably a lamp pro-vided with preheatable electrodes, for example a low-pressure mercury vapour discharge lamp. The current which then flows through the semiconductor switching element during the starting procedure can then also be used to preheat the lamp electrodes.
The first semiconductor switching element con-1~ sist~, ~or example of two thyristors which are connected in anti-parallel. The first semiconduc-tor switching element may also be~ for example, a "triac" i.e. a semiconductor switching element having a bidirectional thyristor character-j istic.
In a preferred embodiment of a device according to the illvention a diode bridge is included between the lamp electrodes and the first semiconductor switching element, -i this semiconductor switching element being a transistor which is located in a centre branch of that diode bridge.
PIIN 7~9~
]~I
9-1-197~
~D71297 .
"Device for starting and feeding a discharge lamp".
The invention relates to a device for starting and feeding a gas - and/or vapour discharge lamp which is provided with two electrodes, the device being provided with two input terminals which are intended for connection to an AC voltage source, whose frequency is less than 100Hz, the two input terminals- during starting and feeding of the lamp- being interconnected by means of a series cir-cuit of at least a stabilizing inductor, and the lamp, whilst the two lamp electrodes are interconnected by a starter comprising a first semiconductor switching element, whilst parallel to a branch which comprises said semiconduc-tor switching element a control circuit of the first semi-conductor switching element is provided, this control cir-cuit comprising at least a first capacitor~ an auxiliary transistor of the starter shunting at least the first ca-~ pacitor, whilst the ~ase of the auxiliary transistor is connected to a control circuit, namely to a junction of a first resistor and a second capacitor which aPe connected in series and which are parallel-to the branch comprising the first ~emiconductor switching element.
A known device of the said type is for example shown in Fig. 1 of United States Patent 3.875.459. An ad-vantage of that k~own device is that, if the lamp refuses to ignite the auxiliary tranqistor stops, after a given time, the efforts to start the lamp. However, a ~isadvantage of that kno~T~ device is that the voltage peaks which are --2~
PlrN 78~2 9~1-1~76 ` 1~71297 generated to start the discharge lamp therewith, show a relatively large and fairly constant amplitude. This en-tails, namely, that the first semiconductor switching element must be able to withstand these voltage peaks in its non-conducting state.
A further disadvantage of that known device is that, if the relatively large amplitude of the voltage peaks is still too small to start the discharge lamp the lamp will not ignite.
- 10 An object of the invention is to provide the possibility for a device of the above mentioned type to rate the first semiconductor switching element for a relatively low, permissible blocking voltage of a somewhat longer duration; but, furthermore, if the lamp is difficult ~ 15 to start to generate one or a few brief voltage peak~:s) of -~ a large amplitude.
A device according to the in~-ention for starting and feeding a gas - and/or vapour discharge lamp which is provided with two electrodes, the device being provided i 20 with two input terminals which are intended for connection .~ to an AC voltage source whose frequency is less than lOOHz, the two input terminals~ during s~tarting and feeding of the ~. lamp - being interconnected by means of a series circuitt7 comprising at least a stabilizing inductor and the lamp,the two lamp electrodes being interconnected by means of a starter comprising a first semiconductor switching element, whilet a control circuit of the first semiconductor switch-ing element is provided~ in parallel to a branch which !.
P~rN 7892 ~-1-1976 ~0712g7 comprises said semiconductor switching element, this con-trol circuit comprising at least a first capacitor~ an auxiliary transistor of the starter, shunting at least the first capacitor, whilst the base of the auxiliary transis-tor is connected to a control circuit, namely to a junction of a resistor and a second capacitor which are connected in series and which are in parallel to the branch comprising the first semiconductor switching element, is characterized in that the base of the auxiliary transistor is connected via a voltage-sensitive threshold element to the junction ! of the resistor and the second capacitor and that the lamp ! electrodes are connected by means of a third capacitor and ¦ that a second inductor is included in the connection of 1 the lamp electrodes to the first semiconductor switching ¦ 1~ element.
~¦ An advantage of this device is that, by means of the voltage-sensitive threshold element incorporated in the control circuit of the auxiliary transistor, the instant at which the first semiconductor switching element ~' 20 starts conducting - a short while a~ter the device has been switched on - can be influenced. This enables in-fluencing the degree to which the voltage between the lamp , electrodes can be raised during the starting of the lamp.
c This in~luence is such that the instant at which the first j 25 semiconductor switching element starts conducting is some-i what delayed, so that the rise in voltage across the serie `' circuit of the third capacitor and the second inductor, -p~ 7892 --~ 9-1-1976 ~7~Z97 and consequently the voltage across the lamp which is made available for starting - is increased.
So the invention i9 in fact based on the idea to use the auxiliary transistor - when the lamp definitely refuses to ignite - not only for stopping the attempts to star$ the lamp by short circuiting the first capacitor, but also to use that auxiliary transistor during the starting procedure of the lamp. This i9 effected by rendering that auxiliary transistor conductive one or more times for a short period before the end of the starting procedure, so that charging the first capacitor in the control circuit of the semiconductor switching element is counteracted. This implies that it lasts longer before the said first capacitor has obtained such a voltage that the se~iconductor switching element can be made conductive therewith. As observed be-fore, this delay results in a larger rise of the voltage across the lamp.
I~owever, it takes some time aft0r the device has been switched on, for the auxiliary transistor to start conducting. The reason is the presence of the voltage-sensitive threshold element in the control Tcircuit of the auxiliary transistor. If, after some time the second capa-citor is charged to such an extent~hatit causes the auxiliary transistor to become conductive, the delay in making the first semiconductor switching element conductive becomes operative.
As far as the rise in voltage across the discharge lamp - in the starting procedure - is concerned, it should l'l~ 78~2 9~1-197~
~6~71Z97 be notod that this is known ~er se from British Patent Specification 1.208.489. In that case, however, the in-stant the semiconductor switching element is made conduc-tive is not variable.
The discharge lamp may, for example, be a lamp which is not provided with preheatable electrodes, for example a high pressure metal vapour discharge lamp.
The discharge lamp is preferably a lamp pro-vided with preheatable electrodes, for example a low-pressure mercury vapour discharge lamp. The current which then flows through the semiconductor switching element during the starting procedure can then also be used to preheat the lamp electrodes.
The first semiconductor switching element con-1~ sist~, ~or example of two thyristors which are connected in anti-parallel. The first semiconduc-tor switching element may also be~ for example, a "triac" i.e. a semiconductor switching element having a bidirectional thyristor character-j istic.
In a preferred embodiment of a device according to the illvention a diode bridge is included between the lamp electrodes and the first semiconductor switching element, -i this semiconductor switching element being a transistor which is located in a centre branch of that diode bridge.
2~ An advantage of this preferred embodiment is that only a simple eemiconductor switc~ing element is re-quired and that furthermore a n~ber of small voltage peaks can be produced across the lamp during each hal~ cycle of .
~ .
PIIN 78~2 :
11~)7~297 .
the supply voltage.
The voltage-sensitive threshold element in the control circuit of the auxiliar-y transistor may, for example, be a neon glow discharge lamp, .5 In a further preferred embodiment of a device according to the invention the voltage-sensitive threshold ; element is a first zener diode.
¦ An advantage of this preferred embodiment is ! that, for example, the threshold voltage of the threshold ~ 10 element varies only little in the course of time.
¦ In a following preferred embodiment according to the invention the control circuit of the auxiliary transis-~ tor comprises a series connection of 7 in this sequence, J the resistor, a first diode, a first zener diode and a i 15 fourth capacitor the pass directions of the first diode ¦ and the zener diode pointing, to one another, the series . circuit of the first diode the first zener diode and the fourth capacitor, being shunted by a series circuit of a second resistor and the second capacitor, whilst the second capacitor and also the fourth capacitor are each shunted by a resistor.
An advantage of the last-mentioned preferred device according to the invention i9 that by means of this special control circuit for the auxiliary transistor it is ensured that the auxiliary transistor can be switched to the conducting and non-conducting state various times dur-ing each half cycle of the supply voltage. This is caused inter alia by the fact that now the second capacitor can ~. .
P~IN 7892 ` 9-1-1976 1C17~;~97 fir9t be charged via the first and the second resistor, whereafter this second capacitor makes the auxiliary transis-tor conductive via the first diode and the blocl~ing direct-ion of the first zener diode. Owing to the fact that the voltage across the branch which comprises the first semi-conductor switching element shows an oscillation the voltage across the series circuit of the second resistor and the second capacitor will fall shortly thereafter to below the threshold voltage of the first zener diode. As a result ~ 10 the auxiliary transistor becomes non-conductive. As the ¦ frequency o~ the ~orementioned voltage across the branch which contains the first semiconductor element is as a rule higher than the frequency of the main supply it is I pos~ible to repeat the procedure9 outlined above, for i 15 switching the auxiliary transistor to the conducting and ~ non-conducting state several times each half cycle of the ! main supply.
¦ The last-mentioned preferred embodiment may be further improviiSd by adding, to the ~ntrol circuit of the auxiliary transistor, a non-capacitive voltage divider which is connected in parallel to the branch which com-prises the first semiconductor switching element~ whilst the tap of a voltage divider is connected via a second diode to the junction of the first diode and the zener diode~ the pass direction of the second diode pointing to-wards the last-mentioned junction.
An advantage of this last improvbment is that if the voltage across the first semiconductor switching _8 ~l~ 7892 9-1-197~
1~71297 element would attain a high value very rapidly, a current will flow via the non-capacitive voltage divider and the second diode into the blocking direction of the zener diode which will rapidly make the auxiliary transistor conductive.
The first capacitor is then practically short-circuited which prevents the first semiconductor ~witching element from becoming conductive again. Namely if the first semi-i conductor switching element, constructed as an auxiliary transistor, would become conductive at that instant, this might be disastrous at such a high voltage across its main electrodes.
In a further preferred embodiment of a device according to the invention a second voltage-sensitive threshold element is connected in the branch which con-tains the first capacitor and which is connected in parallel to the first semiconductor switching element.
An advantage of this preferred embodiment is that, quite irrespectiveof the auxiliary transistor and its control circuit, a delay in the instant the first semicon-ductor switching element becomes conductive is already ob-talned by means of the second voltage~sensitive threshold element, which results in a somewhat higher rise of the voltage across the lamp. A further advantage of the second voltage-sensitive threshold element is that this element is also used to interrupt the starter operation as soon as the lamp has been started. For that purpose the threshold voltage must be above the operating voltage o~ the discharge lamp.
_g_ . .
78~2 ~~ 9-1-1976 ~071297 l`he invention will be further explained with reference to a drawing in which:
Fig. 1 shows an el0ctrie cireuit of a device aeeording to the invention together with a diseharge lamp incorporated in that circuit;
Fig~ 2 shows a graphic representation of the envelope of the voltage peaks between the electrodes of the lamp of Fig. 1 as a function of time.
In Fig. 1 references 1 and 2 are terminals for connection to an AC voltage source of 220V, 50 Hz. An in-ductive stabilization ballast 3 is connected to terminal 1. If desired a capacitive ballast consisting o~ a series circuit of a coil and a capacitor, having in total a capa-citive character may also be used. The other side of ballast
~ .
PIIN 78~2 :
11~)7~297 .
the supply voltage.
The voltage-sensitive threshold element in the control circuit of the auxiliar-y transistor may, for example, be a neon glow discharge lamp, .5 In a further preferred embodiment of a device according to the invention the voltage-sensitive threshold ; element is a first zener diode.
¦ An advantage of this preferred embodiment is ! that, for example, the threshold voltage of the threshold ~ 10 element varies only little in the course of time.
¦ In a following preferred embodiment according to the invention the control circuit of the auxiliary transis-~ tor comprises a series connection of 7 in this sequence, J the resistor, a first diode, a first zener diode and a i 15 fourth capacitor the pass directions of the first diode ¦ and the zener diode pointing, to one another, the series . circuit of the first diode the first zener diode and the fourth capacitor, being shunted by a series circuit of a second resistor and the second capacitor, whilst the second capacitor and also the fourth capacitor are each shunted by a resistor.
An advantage of the last-mentioned preferred device according to the invention i9 that by means of this special control circuit for the auxiliary transistor it is ensured that the auxiliary transistor can be switched to the conducting and non-conducting state various times dur-ing each half cycle of the supply voltage. This is caused inter alia by the fact that now the second capacitor can ~. .
P~IN 7892 ` 9-1-1976 1C17~;~97 fir9t be charged via the first and the second resistor, whereafter this second capacitor makes the auxiliary transis-tor conductive via the first diode and the blocl~ing direct-ion of the first zener diode. Owing to the fact that the voltage across the branch which comprises the first semi-conductor switching element shows an oscillation the voltage across the series circuit of the second resistor and the second capacitor will fall shortly thereafter to below the threshold voltage of the first zener diode. As a result ~ 10 the auxiliary transistor becomes non-conductive. As the ¦ frequency o~ the ~orementioned voltage across the branch which contains the first semiconductor element is as a rule higher than the frequency of the main supply it is I pos~ible to repeat the procedure9 outlined above, for i 15 switching the auxiliary transistor to the conducting and ~ non-conducting state several times each half cycle of the ! main supply.
¦ The last-mentioned preferred embodiment may be further improviiSd by adding, to the ~ntrol circuit of the auxiliary transistor, a non-capacitive voltage divider which is connected in parallel to the branch which com-prises the first semiconductor switching element~ whilst the tap of a voltage divider is connected via a second diode to the junction of the first diode and the zener diode~ the pass direction of the second diode pointing to-wards the last-mentioned junction.
An advantage of this last improvbment is that if the voltage across the first semiconductor switching _8 ~l~ 7892 9-1-197~
1~71297 element would attain a high value very rapidly, a current will flow via the non-capacitive voltage divider and the second diode into the blocking direction of the zener diode which will rapidly make the auxiliary transistor conductive.
The first capacitor is then practically short-circuited which prevents the first semiconductor ~witching element from becoming conductive again. Namely if the first semi-i conductor switching element, constructed as an auxiliary transistor, would become conductive at that instant, this might be disastrous at such a high voltage across its main electrodes.
In a further preferred embodiment of a device according to the invention a second voltage-sensitive threshold element is connected in the branch which con-tains the first capacitor and which is connected in parallel to the first semiconductor switching element.
An advantage of this preferred embodiment is that, quite irrespectiveof the auxiliary transistor and its control circuit, a delay in the instant the first semicon-ductor switching element becomes conductive is already ob-talned by means of the second voltage~sensitive threshold element, which results in a somewhat higher rise of the voltage across the lamp. A further advantage of the second voltage-sensitive threshold element is that this element is also used to interrupt the starter operation as soon as the lamp has been started. For that purpose the threshold voltage must be above the operating voltage o~ the discharge lamp.
_g_ . .
78~2 ~~ 9-1-1976 ~071297 l`he invention will be further explained with reference to a drawing in which:
Fig. 1 shows an el0ctrie cireuit of a device aeeording to the invention together with a diseharge lamp incorporated in that circuit;
Fig~ 2 shows a graphic representation of the envelope of the voltage peaks between the electrodes of the lamp of Fig. 1 as a function of time.
In Fig. 1 references 1 and 2 are terminals for connection to an AC voltage source of 220V, 50 Hz. An in-ductive stabilization ballast 3 is connected to terminal 1. If desired a capacitive ballast consisting o~ a series circuit of a coil and a capacitor, having in total a capa-citive character may also be used. The other side of ballast
3 is connected to a preheatable electrode ~ o~ a low-pressure mercury vapour discharge lamp 5. Reference 6 indicates a , second preheatable electrode of lamp 5. Electrode 6 is ! connected to the input terminal 2. The ends of the electrodes ' -- 4 and 6 nearer to the input terminals 1 and 2 are inter-¦ 20 connected by means of a capacitor 7. The other ends of the eleetrodes ~ and 6 are intereonnected by means of a eapacitor 8, In its turn this capacitor 8 is shunted by a series I eircuit of an induetor 9 and a diode bridge 10 to 13. This i diode bridge comprises four eentre branches:
The first centre branch comprises a series cir-cuit of a resistor 20~ a trans~ormer winding 21 and the main electrodes of an NPN transistor 22. Another winding ~1 .
_ rTIN 7~92 107~L297 9.1 -1976 23 of said transformcr is connected between the base and the emitter of` the transistor 22.
The second centre branch of the diode bridge 10 to 13 comprises a series circuit of a resistor 24~ a ~ener diode 25 and a capacitor 26. A node between the zener diode 25 and the capacitor 26 is connected to a resistor 27. The other side of resistor 27 is connected via a bidirectional breakdown element 28 to the base of the transistor 22. A
resistor 29 is connected between the base and the emitter of the transistor 22. A load between the resistor 27 and the breakdown element 28 is connected to the collector of an NPN-type auxiliary transistor 30. The emitter of this auxilia-ry transistor 30 is connected to the diodes 12 and 13 of the diode bridge.
A third centre branch of' the diode bridge comprises a series circuit of a resistor 31, a first diode 32, a zener diode 33 and a capacitor 34. The capacitor 34 is shunted by a resistor 35. Furthermore~ the series - circuit 32, 33, 35 is shunted by a series circuit of a resistor 36 'in series with a parallel circuit of a capaci-tor 37 and a resistor 3~.
A fourth centre branch of the diode bridge 10 to 13 shows a resistor voltage divider comprising a series circuit of a resistor 39 and a resistor 40. A node between the reslstors 39 and 40 is connected to a diode 41. The other side this diode is connected to a 3unction point be-! tween the diode 32 and the zener diode 33. The pass di-rections of the three diodes 32, 33 and 41 all point to r~N 7892 9-1-i97fi ~712g7 their junction point.
Finally a node between the inductor 9 and diode 10 and a node between the diode 13 and the electrode 6 are interconnected by means of a spike suppressor which is in-dicated by reference 42.
- The circuit described Dperates as follows. When the terminals 1 and 2 are connécted to an AC voltage source of 220~ 50Hz a current will flow when there is a sufficient instantaneous voltage between 1 and 2, depending on the po-larity of the AC voltage source~ in the circuits 1, 3~ 9, 10~
24, 25, 26, 13 to terminal 2 or ~n the circuit~ 2, 6, 11, 24, - 25~ 26~ 12, 9, 3 to terminal 1, ~l0n-as a result the capaci-tor 26 has obtained such a voltage that the breakdown value of the breakdown- or threshold element 28 is exceeded the lg transistor 22 will become fully conductive by means of the transformer 21, 23. Consequently a current will start flowing in the first centre branch of the diode bridge, namely in ; the branch 20~ 21, 22. By means of this current the electrodes
The first centre branch comprises a series cir-cuit of a resistor 20~ a trans~ormer winding 21 and the main electrodes of an NPN transistor 22. Another winding ~1 .
_ rTIN 7~92 107~L297 9.1 -1976 23 of said transformcr is connected between the base and the emitter of` the transistor 22.
The second centre branch of the diode bridge 10 to 13 comprises a series circuit of a resistor 24~ a ~ener diode 25 and a capacitor 26. A node between the zener diode 25 and the capacitor 26 is connected to a resistor 27. The other side of resistor 27 is connected via a bidirectional breakdown element 28 to the base of the transistor 22. A
resistor 29 is connected between the base and the emitter of the transistor 22. A load between the resistor 27 and the breakdown element 28 is connected to the collector of an NPN-type auxiliary transistor 30. The emitter of this auxilia-ry transistor 30 is connected to the diodes 12 and 13 of the diode bridge.
A third centre branch of' the diode bridge comprises a series circuit of a resistor 31, a first diode 32, a zener diode 33 and a capacitor 34. The capacitor 34 is shunted by a resistor 35. Furthermore~ the series - circuit 32, 33, 35 is shunted by a series circuit of a resistor 36 'in series with a parallel circuit of a capaci-tor 37 and a resistor 3~.
A fourth centre branch of the diode bridge 10 to 13 shows a resistor voltage divider comprising a series circuit of a resistor 39 and a resistor 40. A node between the reslstors 39 and 40 is connected to a diode 41. The other side this diode is connected to a 3unction point be-! tween the diode 32 and the zener diode 33. The pass di-rections of the three diodes 32, 33 and 41 all point to r~N 7892 9-1-i97fi ~712g7 their junction point.
Finally a node between the inductor 9 and diode 10 and a node between the diode 13 and the electrode 6 are interconnected by means of a spike suppressor which is in-dicated by reference 42.
- The circuit described Dperates as follows. When the terminals 1 and 2 are connécted to an AC voltage source of 220~ 50Hz a current will flow when there is a sufficient instantaneous voltage between 1 and 2, depending on the po-larity of the AC voltage source~ in the circuits 1, 3~ 9, 10~
24, 25, 26, 13 to terminal 2 or ~n the circuit~ 2, 6, 11, 24, - 25~ 26~ 12, 9, 3 to terminal 1, ~l0n-as a result the capaci-tor 26 has obtained such a voltage that the breakdown value of the breakdown- or threshold element 28 is exceeded the lg transistor 22 will become fully conductive by means of the transformer 21, 23. Consequently a current will start flowing in the first centre branch of the diode bridge, namely in ; the branch 20~ 21, 22. By means of this current the electrodes
4 and 6 of the lamp 5 are preheated. I~hen this current has reached a constant value the drive of the transistor 22 is stopped. Owing to the known delay caused by the draining of charge carriers from the transistar,this transistor becomes non-conductive again a little later. While the transistor 22 is conducting, the capacitor 26 is partly discharged via the resistor 27, the threshold element 28 and the resistor 29. Owing to the fact that the transistor 22 becomes non-conductive the voltage across the capacitors 7 and 8 and co~.~.sequently the voltage across the lamp 5 is raised. This . . ~
.- ~
P]IN 7~92 is a rise in the voltage which is effected in about the same way as specified in the mentioned British Patent Specification 1. 208.489.
However, in the meantime the capacitor 37 is slightly charged via the resistors 31 and 36. When the voltage across capacitor 37 - perhaps after some half cycles of` the supply voltage between the terminals 1 and 2- has attained a certain, relatively largel value a eurrent will thereafter periodically flow, from resistor-31 via diode 32 into the blocking direction of diode 33, which eauses the auxiliary transistor 30 to start eonducting, causing the series circuit of resistor 27 and capacitor 26 to be short-eircuited. This will of course lead to a partial discharge of the capacitor 26. So this actually opposes the eha~ging of this capacitor 26 v~a resistor 24. Owing to this delay in the charging of the eapacitor 26, the instants at which the transistor 22 is made conductive are delayed, so that on the one hand the eircuit of the eapacitor 7 and 8 and~
on the other hand~ the inductor 9 is closed somewh* later by that transistor 22~ This results in a greater rise of the voltage across those two capacitors 7 and 8 and consequent-ly to a corrosponding voltage rise aeross lamp 5.
If the.voltage between the lamp electrodes 4 and 6 would suddenly become very high,current will immediately flow via the voltage divider 39~ 40 and the diode 41 into the blocking direction of the zener diode 33, which switches the transistor 15 very rapidly to the conducting state, thus preventing that the transistor 22 becomes further . ~ - . . - . . . . . ... .
^~ PlIN 7892 9-1-197~
.
conducting. This is favourable because such a transistor should not be more conductive at such a high voltage at its main electrodes as this might have disastrous conse-~uences ~or the transistor. The spike suppressor 42 is a further, additional protection for the starter.
In a practical embodiment, the value of the inductor 3 is approximately 1,2Henry. The lamp 5 is a low-pDessure mercury vapour discharge lamp of approximate-ly 40 Wa~ts. The capacitance value of the capacitor 7 is , 10 approximately 22 nFarad and that of capacitor 8 approxima ¦ tely 2,5 n Farad. The self-inductance of the inductor 9 is approximately 0,2 m Henry. The resistance of the resistor 20 is about 27 Ohm, that of resistor 24 about 18 kOhm, that of resistor 27 about 10 Ohm, that of resistor 29 about 100 Ohm, that of resistor 31 about 390 kOhm, that of resis-tor 35 about 10 kOhm, that of resistor 36 about 6,8 kOhm and that of resistor 38 about 150 kOhm. The resistor 39 has a resistance of about 100 kOhm and resistor 40 of about 3~9 kOhm. The CapacitQrS 26, 34 and 37 have a capacitance of ~espectively 5,6 n Farad; 3~3 n Farad and 6,8/u Farad.
The zener voltage of zener diode 33 is ab~ut 22 volts and that of zéner diode 25 is about 150 volt. The breakdown voltage of the threshold element 28 is about 28 volts, the spike suppressor 42 responds at a voltage of about 680 V at 1 m Ampère.
The arrangement with the two capacitors 7 and 8 is also useful to protect the starter if an electrod~ of the lamp 5 ~ails during the starting procedure.
.
--1 L~_ ' , ~IIN 7S92 9-1-197~
Witll the device described the lamp 5 was started without any flickcring. A reliable ignition was obtained in the temperature range between -20C and ~70~.
If for some reason or another the lamp 5 refuses to igniteJ,the auxiliary transistor 30 blocksJafter some time, the further operation of the starter, owing to the fact that then the voltage across the series circuit of the resistor 36 and the (second capacitor 35) remains per-manently above the zener voltage of the zener diode 33.
A great advantage of this device according to the invention is that this auxiliary transistor 30 also has a second function, namely it opposes, as described above, the charging of the capacitor 26, which enables the higher voltages between the lamp electrodes 4 and 6 during the 6 tarting procedure to be used.
i By way of a further explanation the envelope of the instantaneous voltage e between the electrode 4 and 6 of the lamp 5 of Fig. 1 is plotted as a function of the time ~ in Fig. 7. Three cases will now be considered~
namely:
a) a lamp 5 which is easy to start;
b) a lamp 5 which is difficult to start;
c) a lamp 5 which refuses to start.
Let us assume that the terminals 1 and 2 of Fig. 1 are connected to the supply source at an instant to. Until the instant t1 only that part of the starter designated by 7 to 29~ in Fig. 1 is in operation. This means that the auxiliary transistor 30, with its control p~ 7S92 1~71297 circuit, has as yet no influence on the starting operation.
The time from to to t1 is about 1,2 seconds. The peak voltage between the lamp electrodes is then about 500 V.
From the instant t1 to t2 the auxiliary transis-tor 30 is periodically switched to the conducting and the non-conducting state which results in an increased voltage between the lamp electrodes 4 and 6 as specified in the description of Fig. 1. The time from t1 to t2 is about 0,1 sec. The peak voltage between the lamp electrodes is ; 10 then about 800 Volt.
After the instant t2 the auxiliary transistor 30 blocks the operation of the starter. Then the mains voltage is found between the lamp electrodes.
When the lamp 5 ignites~ the outlined starter procedure will be immediately interr~pted and the voltage between the lamp electrodes 4 and 6 will immediably become equal to the operating voltage of the lamp. The starter is then not actuated by the action of the zener diode ~ whose threshold voltage (150V) is higher than the operating volt-age (100V) o~ the lamp 5.
In the above mentioned case a of the lamp~ which ; easy to ignite, the starting procedure is already interrupt-ed between the instants to and t1~ That means that the voltage between the lamp elec~rodes ~ and 6 will already be equal to the operating voltage B of the lamp (about 100V) at an instant between to and t1~
In the case b of the lamp which is difficult to ignite the start~ng procedure is interrupted between the `~ ~16 A
P]IN 7892 instants tl and t2.
; In the case c of the lamp which refuses to igni~Z the voltage between the lamp electrodes follows the mains voltage (220 Volt) after the instant t2. The auxiliary transistor 30 (see Fig. 1) is then permanentl~ conductive ~o that no ~urther =tarting effort~ are madc.
'i .' Z ~17
.- ~
P]IN 7~92 is a rise in the voltage which is effected in about the same way as specified in the mentioned British Patent Specification 1. 208.489.
However, in the meantime the capacitor 37 is slightly charged via the resistors 31 and 36. When the voltage across capacitor 37 - perhaps after some half cycles of` the supply voltage between the terminals 1 and 2- has attained a certain, relatively largel value a eurrent will thereafter periodically flow, from resistor-31 via diode 32 into the blocking direction of diode 33, which eauses the auxiliary transistor 30 to start eonducting, causing the series circuit of resistor 27 and capacitor 26 to be short-eircuited. This will of course lead to a partial discharge of the capacitor 26. So this actually opposes the eha~ging of this capacitor 26 v~a resistor 24. Owing to this delay in the charging of the eapacitor 26, the instants at which the transistor 22 is made conductive are delayed, so that on the one hand the eircuit of the eapacitor 7 and 8 and~
on the other hand~ the inductor 9 is closed somewh* later by that transistor 22~ This results in a greater rise of the voltage across those two capacitors 7 and 8 and consequent-ly to a corrosponding voltage rise aeross lamp 5.
If the.voltage between the lamp electrodes 4 and 6 would suddenly become very high,current will immediately flow via the voltage divider 39~ 40 and the diode 41 into the blocking direction of the zener diode 33, which switches the transistor 15 very rapidly to the conducting state, thus preventing that the transistor 22 becomes further . ~ - . . - . . . . . ... .
^~ PlIN 7892 9-1-197~
.
conducting. This is favourable because such a transistor should not be more conductive at such a high voltage at its main electrodes as this might have disastrous conse-~uences ~or the transistor. The spike suppressor 42 is a further, additional protection for the starter.
In a practical embodiment, the value of the inductor 3 is approximately 1,2Henry. The lamp 5 is a low-pDessure mercury vapour discharge lamp of approximate-ly 40 Wa~ts. The capacitance value of the capacitor 7 is , 10 approximately 22 nFarad and that of capacitor 8 approxima ¦ tely 2,5 n Farad. The self-inductance of the inductor 9 is approximately 0,2 m Henry. The resistance of the resistor 20 is about 27 Ohm, that of resistor 24 about 18 kOhm, that of resistor 27 about 10 Ohm, that of resistor 29 about 100 Ohm, that of resistor 31 about 390 kOhm, that of resis-tor 35 about 10 kOhm, that of resistor 36 about 6,8 kOhm and that of resistor 38 about 150 kOhm. The resistor 39 has a resistance of about 100 kOhm and resistor 40 of about 3~9 kOhm. The CapacitQrS 26, 34 and 37 have a capacitance of ~espectively 5,6 n Farad; 3~3 n Farad and 6,8/u Farad.
The zener voltage of zener diode 33 is ab~ut 22 volts and that of zéner diode 25 is about 150 volt. The breakdown voltage of the threshold element 28 is about 28 volts, the spike suppressor 42 responds at a voltage of about 680 V at 1 m Ampère.
The arrangement with the two capacitors 7 and 8 is also useful to protect the starter if an electrod~ of the lamp 5 ~ails during the starting procedure.
.
--1 L~_ ' , ~IIN 7S92 9-1-197~
Witll the device described the lamp 5 was started without any flickcring. A reliable ignition was obtained in the temperature range between -20C and ~70~.
If for some reason or another the lamp 5 refuses to igniteJ,the auxiliary transistor 30 blocksJafter some time, the further operation of the starter, owing to the fact that then the voltage across the series circuit of the resistor 36 and the (second capacitor 35) remains per-manently above the zener voltage of the zener diode 33.
A great advantage of this device according to the invention is that this auxiliary transistor 30 also has a second function, namely it opposes, as described above, the charging of the capacitor 26, which enables the higher voltages between the lamp electrodes 4 and 6 during the 6 tarting procedure to be used.
i By way of a further explanation the envelope of the instantaneous voltage e between the electrode 4 and 6 of the lamp 5 of Fig. 1 is plotted as a function of the time ~ in Fig. 7. Three cases will now be considered~
namely:
a) a lamp 5 which is easy to start;
b) a lamp 5 which is difficult to start;
c) a lamp 5 which refuses to start.
Let us assume that the terminals 1 and 2 of Fig. 1 are connected to the supply source at an instant to. Until the instant t1 only that part of the starter designated by 7 to 29~ in Fig. 1 is in operation. This means that the auxiliary transistor 30, with its control p~ 7S92 1~71297 circuit, has as yet no influence on the starting operation.
The time from to to t1 is about 1,2 seconds. The peak voltage between the lamp electrodes is then about 500 V.
From the instant t1 to t2 the auxiliary transis-tor 30 is periodically switched to the conducting and the non-conducting state which results in an increased voltage between the lamp electrodes 4 and 6 as specified in the description of Fig. 1. The time from t1 to t2 is about 0,1 sec. The peak voltage between the lamp electrodes is ; 10 then about 800 Volt.
After the instant t2 the auxiliary transistor 30 blocks the operation of the starter. Then the mains voltage is found between the lamp electrodes.
When the lamp 5 ignites~ the outlined starter procedure will be immediately interr~pted and the voltage between the lamp electrodes 4 and 6 will immediably become equal to the operating voltage of the lamp. The starter is then not actuated by the action of the zener diode ~ whose threshold voltage (150V) is higher than the operating volt-age (100V) o~ the lamp 5.
In the above mentioned case a of the lamp~ which ; easy to ignite, the starting procedure is already interrupt-ed between the instants to and t1~ That means that the voltage between the lamp elec~rodes ~ and 6 will already be equal to the operating voltage B of the lamp (about 100V) at an instant between to and t1~
In the case b of the lamp which is difficult to ignite the start~ng procedure is interrupted between the `~ ~16 A
P]IN 7892 instants tl and t2.
; In the case c of the lamp which refuses to igni~Z the voltage between the lamp electrodes follows the mains voltage (220 Volt) after the instant t2. The auxiliary transistor 30 (see Fig. 1) is then permanentl~ conductive ~o that no ~urther =tarting effort~ are madc.
'i .' Z ~17
Claims (6)
1. A device for starting and feeding a gas- and/or vapour discharge lamp which is provided with two electrodes, the device being provided with two input terminals which are intended for connection to an AC voltage source, whose frequency is less than 100Hz, the two input terminals -during starting and feeding of the lamp - being interconnect-ed by means of a series circuit comprising at least a stabilizing inductor and the lamp, whilst the two lamp electrodes are interconnected by means of a starter com-prising a first semiconductor switching element, whilst parallel to a branch which comprises said semiconductor switching element a control circuit of the first semiconduc-tor switching element is provided, the s control circuit com-prising at least a first capacitor, an auxiliary transis-tor of the starter shunting at least the first capacitors, whilst the base of the auxiliary transistor is connected to a control circuit, namely to a junction of a first resistor and a second capacitor which are connected in series and which are parallel to the branch comprising the first semi-conductor switching element characterized in that the base of the auxiliary transistor is connected via a voltage -sensitive threshold element to the junction of the resistor and the second capacitor and in that the lamp electrodes are connected by a third capacitor and in that a second inductor is included in the connection of the lamp electrodes to the first semiconductor switching element.
2. A device as claimed in Claim 1 characterized in that a diode bridge is included between the lamp electrodes and the first semiconductor switching element, the first semi-conductor switching element being a transistor which is located in a centre branch of that diode bridge.
3. A device as claimed in Claim 2, characterized in that the voltage-sensitive threshold element is a first zener diode.
4. A device as claimed in Claim 3, characterized in that the control circuit of the auxiliary transistor com-prises a series connection of, in this sequence, the resis-tor, a first diode, the first zener diode and a fourth capacitor, whilst the pass directions of the first diode and the zener diode point to one another, the series circuit of the first diode, the first zener diode and the fourth capa-citor being shunted by a series circuit of a second resistor and the second capacitor, whilst the second capacitor and also the fourth capacitor are shunted each by a resistor.
5. A device as claimed in Claim 4, characterized in that the control circuit of the auxiliary transistor also comprises a non-capacitive voltage divider which is connected in parallel to the branch which comprises the semiconductor switching element, the tap of that voltage divider being con-nected via a second diode to the junction of the first diode and the zener diode, whilst the pass direction of the second diode points to last-mentioned junction.
6. A device as claimed in Claim 1 or 5, characterized in that a second voltage-sensitive threshold element is in the branch which contains the first capacitor and which is con-nected in parallel to the first semiconductor switching element.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NLAANVRAGE7502053,A NL179697C (en) | 1975-02-21 | 1975-02-21 | DEVICE FOR IGNITION AND POWERING A GAS AND / OR VAPOR DISCHARGE LAMP. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1071297A true CA1071297A (en) | 1980-02-05 |
Family
ID=19823225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA245,545A Expired CA1071297A (en) | 1975-02-21 | 1976-02-11 | Device for starting and feeding a discharge lamp |
Country Status (12)
| Country | Link |
|---|---|
| JP (2) | JPS51103684A (en) |
| AT (1) | AT364417B (en) |
| AU (1) | AU502466B2 (en) |
| BE (1) | BE838723A (en) |
| CA (1) | CA1071297A (en) |
| CH (1) | CH607536A5 (en) |
| DE (1) | DE2604914C3 (en) |
| ES (1) | ES445327A1 (en) |
| FR (1) | FR2301993A1 (en) |
| GB (1) | GB1529755A (en) |
| NL (1) | NL179697C (en) |
| SE (1) | SE420559B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53105486U (en) * | 1977-01-28 | 1978-08-24 | ||
| GB2173055A (en) * | 1985-03-29 | 1986-10-01 | Philips Electronic Associated | Circuit arrangement for starting discharge lamps |
| DE3628989A1 (en) * | 1986-08-26 | 1988-03-03 | Ceag Licht & Strom | ELECTRONIC BALLAST |
| CN112311223B (en) * | 2020-10-22 | 2022-05-17 | 冠捷电子科技(福建)有限公司 | DC-DC converter with peak delay start notification |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL162814C (en) * | 1967-07-28 | 1980-06-16 | Philips Nv | APPARATUS FOR IGNITION AND OPERATION OF A GAS AND / OR VAPOR DISCHARGE TUBE. |
| CA1026817A (en) * | 1972-05-09 | 1978-02-21 | Michel Remery | Electrical circuit for igniting and supplying a discharge lamp |
-
1975
- 1975-02-21 NL NLAANVRAGE7502053,A patent/NL179697C/en not_active IP Right Cessation
-
1976
- 1976-02-07 DE DE2604914A patent/DE2604914C3/en not_active Expired
- 1976-02-11 CA CA245,545A patent/CA1071297A/en not_active Expired
- 1976-02-18 SE SE7601813A patent/SE420559B/en unknown
- 1976-02-18 AT AT0115576A patent/AT364417B/en not_active IP Right Cessation
- 1976-02-18 GB GB6371/76A patent/GB1529755A/en not_active Expired
- 1976-02-18 AU AU11189/76A patent/AU502466B2/en not_active Expired
- 1976-02-18 CH CH199676A patent/CH607536A5/xx not_active IP Right Cessation
- 1976-02-19 JP JP51016591A patent/JPS51103684A/ja active Pending
- 1976-02-19 BE BE164448A patent/BE838723A/en not_active IP Right Cessation
- 1976-02-19 ES ES445327A patent/ES445327A1/en not_active Expired
- 1976-02-20 FR FR7604763A patent/FR2301993A1/en active Granted
-
1983
- 1983-04-11 JP JP1983052771U patent/JPS5923360Y2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58173197U (en) | 1983-11-19 |
| SE420559B (en) | 1981-10-12 |
| SE7601813L (en) | 1976-08-23 |
| FR2301993B1 (en) | 1981-09-18 |
| DE2604914A1 (en) | 1976-09-02 |
| AU502466B2 (en) | 1979-07-26 |
| JPS51103684A (en) | 1976-09-13 |
| ES445327A1 (en) | 1977-06-01 |
| JPS5923360Y2 (en) | 1984-07-11 |
| DE2604914C3 (en) | 1981-07-23 |
| NL179697C (en) | 1986-10-16 |
| ATA115576A (en) | 1981-03-15 |
| AU1118976A (en) | 1977-09-01 |
| BE838723A (en) | 1976-08-19 |
| AT364417B (en) | 1981-10-27 |
| DE2604914B2 (en) | 1980-10-16 |
| NL7502053A (en) | 1976-08-24 |
| FR2301993A1 (en) | 1976-09-17 |
| GB1529755A (en) | 1978-10-25 |
| CH607536A5 (en) | 1978-12-29 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |