EP0613327A1 - Stromversorgung für Leuchtstofflampen - Google Patents

Stromversorgung für Leuchtstofflampen Download PDF

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Publication number
EP0613327A1
EP0613327A1 EP93102678A EP93102678A EP0613327A1 EP 0613327 A1 EP0613327 A1 EP 0613327A1 EP 93102678 A EP93102678 A EP 93102678A EP 93102678 A EP93102678 A EP 93102678A EP 0613327 A1 EP0613327 A1 EP 0613327A1
Authority
EP
European Patent Office
Prior art keywords
power supply
luminescent
rectifier
input
voltage
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.)
Ceased
Application number
EP93102678A
Other languages
English (en)
French (fr)
Inventor
Nikolai Stukovnin
Anatoli Jakushkin
Vladimir Handogin
Aleksandra Raikova
Taavi Blankin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TALVAKO Ltd
Original Assignee
TALVAKO Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by TALVAKO Ltd filed Critical TALVAKO Ltd
Priority to EP93102678A priority Critical patent/EP0613327A1/de
Publication of EP0613327A1 publication Critical patent/EP0613327A1/de
Ceased legal-status Critical Current

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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
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/295—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps

Definitions

  • the invention can be classified as a source of secondary power supply and may be applied as a power source for luminescent lamps. It ensures necessary modes of switch-on, inflammation and operation of a luminescent lamp.
  • the existent power supply for luminescent lamps includes a starter and a ballast element, which is in series connection with the first outputs of the first and the second luminescent lamp cathode; between the second outputs of the first and the second luminescent lamp cathode, a starter /1/ has been connected.
  • Disadvantages of such devices are - a comparatively low efficiency, heavy weight, the dimensions of electromagnetic elements (due to low frequency of the mains voltage - 50 Hz), and heavy acoustic noises.
  • the use of inductive ballast causes phase difference between the consumption current and the voltage, which considerably overloads the power network.
  • a rather low reliability of the starter limits the reliability of such devices on the whole.
  • a capacitor is connected between the second outputs of the first and the second luminescent lamp cathode, besides, the electronic starter includes a rectifier; a threshold element, its output connected to the output of the rectifier; and a voltage divider, the tap of which is connected to the input of the threshold element /2/.
  • the disadvantage of this device is unreliable mode of expected switch-on. It is connected with the fact that at the moment of switch-on of the power supply by the threshold element, the electronic starter switches on too, which changes the operation mode of the voltage converter to a higher conversion frequency. At the same time the luminescent lamp is affected by the open-circuit voltage Uxx and a Ik current goes through its cathodes. After a certain period of time, the lamp ignition voltage drops (at the expence of cathode warm-up) and it lights up. After that the voltage converter goes to a lower conversion frequency.
  • the present invention is aimed to solve the task of increasing the reliability of the power supply for luminescent lamps.
  • the new technical property achieved by applying the invention, is the provision of necessary modes of ignition, lighting up and operation of the luminescent lamps by forming necessary ignition delay of the luminescent lamp and by ensuring the preliminary warm-up of the cathodes, which promotes the process of ignition and results in the decrease of ignition voltage and starting current, improving thus the operation reliability of the power supply as well as of the luminescent lamp and extending their service life.
  • a capacitor is connected between the second outputs of the first and the second luminescent lamp cathode, besides, the electronic starter includes a rectifier; a threshold element, its output connected to the output of the rectifier; and a voltage divider, the tap of which is connected to the input of the threshold element) is supplied with a ballast capacitor, and the electron starter has been improved with a transformer with three windings, a key element, the second rectifier and n rectifiers according to the number of chains, connected in parallel to one of the arms of the half-bridge circuit of the voltage converter, where the chains are connected in parallel to the arm of the half-bridge circuit of the voltage converter through the first winding of the ballast capacitor, the second winding of which is connected to the rectifier input and the third winding is connected through the second rectifier to the controlling input of the key element, which in its turn is in parallel connection with the joint outputs of the n rectifiers, the input of each of which is connected with the second leads of the first and the second cathode of the corresponding luminescent lamp
  • the threshold element may include two transistors with different conductivity, the base-emitter junctions of which are shunted by parallel RC-circuits, and a series circuit, consisting of a diode and a four-layer diode, connected between the collector of the first transistor and the base of the second transistor; the base of the first transistor and the collector of the second transistor are tied together, the emitters of the transistors are an outlet of the threshold element, and the junction point of the diode and the four-layer diode is an input of the threshold element.
  • the outputs of the voltage divider may be connected to one of the feed circuits of the voltage converter and to one of the input terminals respectively.
  • One of the arms of the voltage divider has been constructed with an additional capacitor from the side of its output, connected to the feed circuit of the voltage converter.
  • the electron starter may contain a second key element with a time-specifying network, which is in parallel connection with one of the arms of the voltage divider from the side of its output, which in its turn is connected to the feed circuit of the voltage converter.
  • the applied elements and their connection in the power supply for luminescent lamps exclude the so-called "cold" switching of the lamp, limit both the no-load voltage amplitude and the starting current, improving thus the operation reliability of the power supply, and especially the reliability of the luminescent lamps, considerably extending their service life.
  • the corresponding accomplishment of the threshold element provides its high noise stability, excludes “cold” switching-on of the luminescent lamp with high noise level in the primary circuit (surges and follows of the circuit).
  • connection of the voltage divider th the input terminal provides quick availability for service of the electron starter and excludes unregulated ignitions of the luminescent lamp.
  • the use of a second key element with a time-specifying circuit in the electronic starter provides the necessary ignition delay of the luminescent lamp with smaller capacitance of the capacitor and enables complete exclusion of the electrolytic capacitors with short service life.
  • Figure 1 presents an example of a conscrete implementation of the power supply for luminescent lamps and figure 2 shows a version of the electonic starter.
  • the electronic starter 1 includes a rectifier 22, a threshold element 23, its output connected to the output of the rectifier 22, and a voltage divider 24, the tap 25 of which is connected to the input of the threshold element 23.
  • the threshold element 23 contains two transistors 35, 36 with different conductivity, the base-emitter junctions of which are shunted by parallel RC chains 37, 38, and a series circuit, consisting of a diode 39 and a four-layer diode 40, connected between the collector of the first 35 and the base of the second 36 transistor; the base of the first 35 and the collector of the second 36 transistor are tied together, the emitters of the transistors 35, 36 are an output of the threshold element 23, and the junction point of the diode 39 and the four-layer diode 40 is an input of the threshold element 23.
  • the voltage dividers 24 outputs are connected to one of the feed circuits of the voltage converter 5 and to one of the input terminals 3 respectively.
  • the one of the arms of the voltage divider 24, wich are connected to the feed circuits of the voltage converter 5, is constructed with an additional capacitor 41.
  • the electron starter 1 may contain (see fig. 2) the second key element 42 with the time-specifying network, which is in parallel connection with one of the arms of the voltage divider 24 from the side of its output, which is connected to the feed circuit of the voltage converter 5.
  • the rectifiers 2, 22, 32 - 34 may be assembled in any known circuit, for example, in half-bridge circuit.
  • the functions of the ballast element 8, 9 may be performed by chokes.
  • the voltage converter 5 (see fig. 1) includes a unijunction transistor oscillator 43, which acts as a starter of the voltage converter 5.
  • the resistors and diodes in the circuit of the voltage converter 5 are for providing the necessary operation modes of its components.
  • the device works as follows: when applying alternating voltage to the input terminals 3, 4 of the power supply (see fig. 1), it is rectified and filtrated by the mains voltage rectifier 2, and after that, it reaches the feed circuits of the voltage converter 5. After starting the converter by the oscillator 43, it generates rectangular form alternating voltage of the type "meander". At the same time, the half-waves of the rectified mains voltage reach the voltage divider 24 of the electronic starter 1. The voltage on the tap 25 of the voltage divider 24 starts to increase. The connection of one of the outputs of the voltage divider 24 to the input terminal 3 (power supply by single half-period pulses of the mains voltage) allows, at the specified delay, to decrease considerably the capacitance of the capacitor 41 of the voltage divider 24.
  • Alternating voltage from the voltage converter 5 reaches the luminescent lamps 14, 15 of the chains 6, 7 through the ballast capacitor 26, the ballast elements 8, 9 and the winding 25 of the transformer 27.
  • the alternating voltage, induced on the winding 30 at the expense of the tie between the windings 28 and 30 of the transformer 27 opens the key element 31 of the electronic starter 1 through the rectifier 32.
  • the key element 31 shorts out the second outputs 16 and 17, 18 and 19 of the first and the second luminescent lamp cathode 14, 15 through the rectifiers 33, 34 and provides the flow of current through the cathodes of the lamps 14, 15.
  • the threshold element 23 When the voltage on the tap 25 of the voltage divider 24 reaches the threshold value of the threshold element 23, the latter opens and with its output shunts the winding 29 of the transformer 27 through the rectifier 22. At the same time, the current, going through the winding 28 and having been transformed before that to the winding 30, is switched to the shunted winding 29. The voltage, induced on the winding 30, decreases and the key element 31 closes.
  • the short circuit of the second outputs 16 and 17, 18 and 19 of the first and the second cathode of the luminescent lamp 14, 15 and the ignition of the latter at a relatively low voltage (at the expense of the preliminary warm-up of the cathodes of the lamps 14, 15) take place.
  • the capacitors 20, 21 provide the flow of additional current through the cathodes, and together with the ballast elements 8, 9, they form a resonant circuit for maintaining the voltage on the lamp 14 (15), when the input voltage decreases (partial stabilization).
  • the key element 31 may commutate analogically any number of luminescent lamps through the corresponding number of rectifiers, connected to the second outputs of their cathodes.
  • the lamps are switched on in the corresponding number of chains, analogical to the chains 6, 7 connected through the ballast capacitor 26 and the winding 28 of the transformer 27 of the electronic starter 1 in parallel with one of the arms of the voltage converter 5.
  • the resistance of the resistor of the voltage divider 24 is determined by starting current of the four-layer diode and the holding time of the luminescent lamp in the mode of preliminary warm-up.
  • the capacitance of the capacitor 41 of the voltage divider 24 is determined only by the holding time. In this connection it is possible to ensure the necessary holding time with considerable values of resistance of the resistor of th voltage divider 24 and small values of capacitance of the capacitor 41 (and also at the expense of the connection of one of the outputs of the voltage divider 24 to the input terminal 3). This enables to exclude the application of electrolytic capacitors, which have higher leakage currents and comparatively high time-instability of the capacitance.
  • the increase of resistance of the resistor of the voltage divider 24 reduces the power of losses and diminishes its dimensions.
  • the threshold element 23 contains a four-layer diode 40, the starting current of which determines (limits) the resistance of the resistor of the voltage divider 24.
  • the transistors 35, 36 open. These transistors shunt the winding 29 of the transformer 27 through the rectifier 22.
  • the flow of the current from the winding 29 through the rectifier 22, the transistor 35, the diode 39, the four-layer diode 40, the resistor 38 and the transistor 36 provides the retention current of the four-layer diode 40.
  • the diode 39 prevents inverted switching of the transistor 35.
  • the transformer 27 is a current transformer, where the current is transformed through the winding 28 either to the circuit of winding 30 or to that of winding 29 after the warm-up of the lamp.
  • the RC chains 37, 38 which are in parallel connection with the base-emitter junctions of the transistors 35, 36, increase the noise stability of the threshold element 23.
  • the second key element 42 with a time-specifying network provides the effect of capacitance multiplication of the capacitor (Miller's circuit) at the expense of the connection to one of the arms of the voltage divider 24, which enables in this type of connection to reduce considerably the capacitance of the time-specifying capacitor, determining the holding time of the lamp (delay time of lamp ignition), providing the required warm-up time of the luminescent lamp (2 - 5 sec.). Reduction of the capacitance allows the microminiaturization of the circuit of the electronic starter 1. As for the rest, then the processes going on in the electronic starter 1 in fig. 2 are similar to those described above for the electronic starter in fig. 1.
  • a failure break may occur with a cathode 10 - 16 (12 - 18); the current through the choke 8 (9) fails, the lamp 14 (15) is not lit.
  • the lamps 14 (15) should be turned round so, that the cathodes 10 - 16 (12 - 18) and 11 - 17 (13 - 19) exchange their places; then the earlier unloaded cathode 11 - 17 (13 - 19) provides current through the choke 8 (9), and the failed cathode 10 - 16 (12 - 18), which is shunted by the capacitor 44 has no influence on the operation of the voltage converter 5, as the alternating current goes through the capacitor 44.
  • the service life of the luminescent lamp increases two times with minimal technical expenditures; every two luminescent lamps 14, 15 require one capacitor 44.
  • the use of a reserve cathode does not disturb the processes going on in the tube of the lamp 14 (15), but the reliability of the power supply with the lamp increases.
  • the proposed device allows to provide algorithmically reliable operation modes for one; two or more luminescent lamps; to exclude the unreliable components from the device, to miniaturize the device and also to increase considerably who reliability of the power supply, to extend the service life of the luminescent lamps and to achieve the reliability indexes of the best specimen in the world: OSRAM, PHILIPS, SIEMENS (10 000 - 16 000 hours).

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  • Circuit Arrangements For Discharge Lamps (AREA)
EP93102678A 1993-02-19 1993-02-19 Stromversorgung für Leuchtstofflampen Ceased EP0613327A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP93102678A EP0613327A1 (de) 1993-02-19 1993-02-19 Stromversorgung für Leuchtstofflampen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP93102678A EP0613327A1 (de) 1993-02-19 1993-02-19 Stromversorgung für Leuchtstofflampen

Publications (1)

Publication Number Publication Date
EP0613327A1 true EP0613327A1 (de) 1994-08-31

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ID=8212619

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93102678A Ceased EP0613327A1 (de) 1993-02-19 1993-02-19 Stromversorgung für Leuchtstofflampen

Country Status (1)

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EP (1) EP0613327A1 (de)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2053592A (en) * 1979-06-26 1981-02-04 Siliani P L Supply and ignition circuit for a fluorescent tube or like device having filaments requiring preliminary heating
DE3938677A1 (de) * 1989-11-22 1991-05-23 Trilux Lenze Gmbh & Co Kg Leuchtstofflampen-vorschaltgeraet

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2053592A (en) * 1979-06-26 1981-02-04 Siliani P L Supply and ignition circuit for a fluorescent tube or like device having filaments requiring preliminary heating
DE3938677A1 (de) * 1989-11-22 1991-05-23 Trilux Lenze Gmbh & Co Kg Leuchtstofflampen-vorschaltgeraet

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