EP2092802A1

EP2092802A1 - Circuit arrangement and method for operating a discharge lamp with preheatable electrodes

Info

Publication number: EP2092802A1
Application number: EP06807825A
Authority: EP
Inventors: Bernd Rudolph
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2006-11-22
Filing date: 2006-11-22
Publication date: 2009-08-26
Also published as: US8120270B2; CN101523995A; US20100052541A1; KR20090093988A; WO2008061559A1

Abstract

The invention relates to a circuit arrangement for operating a discharge lamp (LA) with preheatable electrodes with an input terminal for applying an input voltage, an output terminal for providing an output voltage (UA) to a lamp generator (LG) for operating the discharge lamp (LA), a switching unit (14), which is coupled between the input terminal and output terminal, for power factor correction, a monitoring apparatus (20) which is designed to disconnect the lamp generator (LG) in the event of the presence of at least one disconnection criterion, and an integrated circuit (16), which is designed to drive the switching unit (14) for power factor correction, wherein the integrated circuit (16) has a disable input, and wherein the circuit arrangement furthermore comprises a blocking apparatus (18), which is designed to produce a blocking signal at its output when the lamp generator (LG) is disconnected, wherein the output of the blocking apparatus (18) is coupled to the disable input of the integrated circuit (16). It moreover relates to a method for operating a discharge lamp (LA) with preheatable electrodes using such a circuit arrangement.

Description

description

Circuit arrangement and method for operating a discharge lamp with preheatable electrodes

Technical area

The present invention relates to a circuit ^arrangement for operating a discharge lamp with preheatable electrodes with an input terminal for applying an input voltage, an output terminal for providing Stel ^¬ len an output voltage to a lamp generator for operating the discharge lamp, a resistor coupled between the input terminal and the output terminal circuit unit for power factor correction a monitoring device designed to switch off the lamp generator in the presence of at least one switch-off criterion, and an integrated circuit designed to drive the circuit unit for power factor correction, the integrated circuit having a disable input.

State of the art

The present invention relates to the problem that an error case, a circuit arrangement for operating a discharge lamp with preheatable electrodes occurs common in AIl- directly on the lamp generator example ^¬ example during removal of the lamp in a non-ignition lamp or at EOL (end of life). After the detection of an error case, the lamp generator then remains switched off until the normal state is restored. In general, one or more electrodes of the discharge lamp serve to provide information about the proper to achieve proper connection of the discharge lamp to the circuit ^¬ arrangement. If the discharge lamp ge ^¬ exchanged, a current circuit is interrupted, which has maintained these shutdown. This opens up the possibility for a new start attempt of the discharge lamp.

The circuit unit provided in a generic circuit arrangement for effecting the power factor correction is frequently realized by means of a standard PFC (Power Factor Correction) IC (Integrated Circuit), for example with the L6562 from STM. Therefore, measures must be taken that these circuit unit remains until Reset factory ^¬ development of the normal state off, but then becomes operational again Vermei ^¬-making intermittent operation of the switching unit for power factor correction, switch off the lamp generator.

However, a solution that could consist in passing the starting circuit of the power factor correction circuit unit via at least one lamp filament is impossible, because otherwise the so-called active "pull down" of the circuit breaker controlled by the power factor correction circuit unit, which is usually a mosfet, could not be guaranteed under all operating conditions gen and the risk of Zer ^¬ trouble would this circuit breaker.

In the prior art, i. in a generic

Circuitry, the integrated circuit measures the

Input voltage and the output voltage. If the values are within a given value range, a Start sequence triggered. Without load, ie without a lamp used, while the output voltage UA is very high. In intermittent operation, voltages of up to 480 V were measured at the lamp terminals. So that the scarf falls processing arrangement in a safety class that is associated with aufwän ^¬ ended precautions to prevent accidents. The exceeding of a predefinable threshold for the output voltage is detected by the integrated circuit, which then turns off. As a result, the output voltage drops again, which in turn is detected by the integrated circuit, and leads to tripping ^¬ sen a restart sequence. This procedure is repeated, although no lamp is used, and leads to a heavy load on the components involved.

Presentation of the invention

The object of the present invention is to further develop a generic circuit arrangement or a generic method in such a way to avoid with minimal circuit complexity a intermittent forming operation of the circuit unit of the power factor correction and ensure reliable activa ^¬ tion of the circuit unit for power factor correction in desired periods, ,

This object is achieved by a circuit arrangement for operating a discharge lamp having the features of patent claim 1 and by a method for operating a discharge lamp having the features of patent claim 8. The present invention is based on the finding that the above object can be achieved if a blocking device is provided, which is coupled to the lamp generator according to the master-slave principle, wherein the lamp generator is the master and the blocking device is the slave , Thus, once the gate is Lampengenera ^¬ abgeschal ^¬ tet as a result of occurrence of a fault, this automatically causes the Sperrvor ^¬ direction generates a disabling signal, the locking signal is coupled to the disable input of the integrated circuit. Thus, the integrated circuit is abge ^¬ on, a control of the switching unit for power factor correction, which is below remains an intermittent operation. However, as soon as the cancellation of the error is detected, ie the lamp generator is in operation again, the output of a blocking signal is stopped by the locking device, whereby the power factor correction circuit unit resumes its work. The inventive measure is therefore ensured in the simplest way that the Schaltungsein ^{¬ unit} for power ^factor correction in operation, as long as the lamp generator is in operation, and is switched off as soon as the lamp generator is turned off.

By a circuit ^arrangement according to the invention, the intermittent operation and the associated Belas ^¬ tion of the components of the entire circuit unit for power factor correction in the event of lamp failure is avoided. On the other hand, a restart of the circuit arrangement, including the circuit unit for power factor correction after a lamp replacement without problems, ie without further intervention by a user possible. special It is advantageous in this case that, in a circuit arrangement according to the invention, only more voltages of approximately 325 V are produced at the lamp terminals. This is another security class relevant, which goes hand in hand with significantly fewer editions and thus significantly less effort.

A preferred embodiment of a circuit arrangement according to the invention is characterized in that the blocking device is designed to generate an enable signal at its output when the lamp generator is switched on. This ensures that the integrated scarf ^¬ tion is blocked and thus no activation of the scarf ^¬ processing unit performs power factor correction, as long as the lamp generator is turned off. , An enable signal, the circuit unit to effect Leis ^¬ factor correction is reversed as long as the lamp generator is switched on, produces, ie the integrated circuit causes to drive accordingly.

Preferably, it is further provided that the blocking device comprises an electronic switch having a control electrode, the control electrode being connected to a deactivation signal which is designed to deactivate the blocking device in the on state of the lamp generator, and an activation signal , which is designed to acti ^¬ vieren the blocking device in the off state of the lamp generator. It is preferred if the Aktivierungssig ^¬ nal is correlated with a voltage of the circuit arrangement which is sufficient to turn on the electronic switch without pre- handensein the disable signal, said disable signal is correlated with a voltage is that only in the on state of the Lampengenera ^¬ sector has an amplitude which is sufficient to lock the electronic ^¬ nischen switch despite the presence of the activation ^¬ signal. This measure avoids complex gate logic, since the activation and deactivation signals can both be applied to the control electrode of the electronic switch, whereby the deactivation signal, if present, intersperses with the activation signal.

In a preferred development, the lamp generator has a trapezoidal capacitor, wherein the electronic switch is a bipolar transistor, wherein the activation signal is correlated with the input voltage, and wherein the deactivation signal with the voltage across the trapezoidal capacitor, in particular with the voltage rise speed du / dt, is correlated. This offers the advantage that virtually no additional elements, that can be done at no extra cost and without additional assembly plants ^¬ ckungsaufwand, the generation of the activation signal and the deactivation signal.

Particularly preferably, the electronic switch of the blocking device is designed as a transistor, whose reference electrode is connected to ground, wherein the Deacti ^¬ vierungssignal represents a first voltage and the activation signal is a second voltage, wherein the second voltage is designed, the transistor without the presence of the first Voltage to turn on, and wherein the first voltage is designed to disable the transistor despite the presence of the second voltage. In this case, it is further preferred if the first and the second voltage are respectively coupled to the control electrode of the transistor via an ohmic resistor.

Further advantageous embodiments will become apparent from the dependent claims.

The preferred embodiments presented with reference to the circuit ^arrangement according to the invention and their advantages apply, as far as applicable, correspondingly to the method according to the invention.

Short description of the drawing (s)

An exemplary example with reference to the accompanying drawings will now be closer ^¬ written. This shows a schematic representation of the structure of an embodiment of a circuit arrangement according to the invention.

Preferred embodiment of the invention

Fig. 1 shows a schematic representation of an embodiment of an inventive Schaltungsanord ^¬ tion. In this case, between the input terminals El, E2 an input voltage U _E , in this case the mains voltage to. This is followed by a fuse Si and a unit 10, which comprises a capacitor Cl and two coils FIl and F12 coupled to one another, and which serves for radio interference suppression. This is followed by a rectifier 12, which includes the diodes Dl, D2, D3 and D4. The rectified voltage clamping ^¬ is provided to a capacitor C2, a boost converter 14, a step-up converter inductor Ll, a boost converter diode D5 and a boost converter Tl. The output voltage U _{A of} the boost converter 14 is provided to the lamp generator LG on a capacitor C3, in particular as a so-called intermediate circuit voltage. The term of the lamp generator LG is the combination of inverters, designed in particular as half or full bridge circuit, and load circuit to understand. To the lamp generator, the lamp La is coupled and coupled via a coupling capacitor C _κ to the reference potential.

For power factor correction, an integrated circuit 16 is used in addition to the boost converter 14, which controls the switch Tl of the boost converter 14 for effecting a power factor correction via its pin 7 and the ohmic resistance Rl. The integrated circuit 16 may, for example, be a module L6562 from STM. Pin 6 of the integrated circuit 16 is connected to a reference potential, in the present case ground. The voltage supply of the integrated circuit 16 takes place via the pin 8, wherein the starting power supply via the ohmic resistance R2 takes place, while the continuous operating voltage supply with participation of the components C4, R3, D6, Z1, C5 and C6 takes place ^¬ as an inductance L2, which forms a transformer together with the inductance Ll. The output ^¬ voltage U _A is measured with the participation of the components R4, R5 and C7 via the pins 1 and 2 of the integrated circuit 16, wherein the connection of the pins 1 and 2, an integrator is formed. The measurement of the input voltage U _E takes place at pin 3 with the participation of the components R6, R7 and C8. At pin 4, the voltage Waste at ohmic resistance R8, the current monitored by the switch Tl. Pin 5 of the integrated circuit 16 has a double function: the detection of the demagnetization of the storage inductor L1 via the auxiliary winding L2 the so-called disable input. In the normal state, d. h outside of a fault, is at pin 5 via a resistor R9 to a voltage potential, which corresponds to an enable signal. This will si ^¬ chergestellt that the integrated circuit 16 controls the switch Tl via pin 7 of the boost converter 14 for effecting Leistungsfakturkorrektur. However, as soon as an error condition is detected in the lamp generator LG, a blocking device 18 ensures that the potential of the pin 5 of the integrated circuit 16 is changed in such a way that the activation of the switch T 1 via pin 7 of the integrated circuit 16 is blocked , The blocking device 18 comprises a switch T2, two ohmic resistors RIO, RIl, a diode D7 and terminals Sl, S2, to which a negative auxiliary voltage U _{H is} applied. As long as the negative auxiliary voltage U _H , which is obtained for example from a trapezoidal capacitor of Lampenge ^¬ generator LG, is present, the transistor T2 is disabled, so that at pin 5 of the integrated circuit 16 via the resistor R9 a signal is applied, as mentioned , leads to the desired activation of the switch Tl of the boost converter 14 in order to effect a power factor correction. Once the lamp generator LG in case of failure, ie at fixed Ellen least ei ^¬ nes switch-off criterion is deactivated by a monitoring device 20 is omitted, the signal U _H for Deakti ^¬ vation of the locking device 18. Rather, it is now via the resistors R2 and RIO an activation tion signal applied to the switch T2, which causes the switch T2 is turned on, so that at pin 5 is almost the reference potential, in this case ground, to ^¬ , which corresponds to an active low. As a result, the integrated circuit 16 terminates the activation of the switch T 1 of the boost converter 14 via pin 7.

Once the monitoring apparatus 20 determines that no longer exists at least one switch-off criterion for the lamp Gene ^¬ rator LG, the lamp generator LG is again set into operation. As a result, in turn, the auxiliary voltage U _{H is} generated, which leads to a blocking of the scarf ^¬ ters T2. As a result, the integrated circuit 16 resumes its operation and controls the switch Tl via pin 7 to effect the power factor correction.

Claims

claims

1. Circuit arrangement for operating a discharge lamp (LA) with preheatable electrodes with

- An input terminal for applying an input ^¬ voltage (UE); an output terminal for providing an output voltage (U _A ) to a lamp generator (LG) for operating the discharge lamp (LA);

- a between the input terminal and the off ^¬ input terminal coupled circuit unit (14) for power factor correction; a monitoring device (20) which is designed to switch off the lamp generator (LG) in the presence of at least one switch-off criterion; and an integrated circuit (16) which is designed to drive the circuit unit (14) for Leistungsfak ^¬ torkorrektur, wherein the integrated circuit (16) having a disable input, characterized in that the circuit arrangement further comprises a Sperrvor- direction (18) which is designed to generate a blocking signal at its output when the lamp generator (LG) is switched off, the output of the blocking device (18) being coupled to the disable input of the integrated circuit (16).

2. Circuit arrangement according to claim 1, characterized in that the blocking device (18) is designed to generate at its output when the lamp generator (LG) a release signal.

3. Circuit arrangement according to one of claims 1 or 2, characterized in that the blocking device (18) comprises an electronic switch (T2), which has a control electrode ^¬ , wherein the control electrode is connected to a deactivation signal, which is designed to disable the blocking device (18) in the on state of the lamp generator (LG), and an activation signal which is designed to activate the blocking device ^[ 18 ^] in the switched-off state of the lamp generator (LG).

4. A circuit arrangement according to claim 3, characterized in that the activation signal is correlated with a voltage of the circuit arrangement which is sufficient to turn on the electronic switch (T2) without the presence of the deactivation signal, and wherein the de ^¬ activation signal is correlated with a voltage that only in the on state of the Lampengenera ^¬ sector (LG) has an amplitude sufficient to lock the electronic switch (T2) despite the presence of the activation signal.

5. Circuit arrangement according to one of claims 3 or 4, characterized in that the lamp generator (LG) has a trapezoidal capacitor, wherein the electronic switch (T2) a

Bipolar transistor, wherein the activation signal is correlated with the input voltage (U _E ), and where is correlated to the trapezoidal capacitor in the disable signal to the Spannungsan ^¬ increased speed du / dt.

6. Circuit arrangement according to one of claims 3 to 5, characterized in that the electronic switch is a transistor (T2) whose reference electrode is connected to ground, wherein the deactivation signal represents a first voltage and the activation signal is a second voltage, wherein the second voltage is designed to turn on the Transis ^¬ tor (T2) without the presence of the first voltage, and wherein the first voltage is out ^¬ sets to turn off the transistor (T2) despite the presence of the second voltage blocking.

7. Circuit arrangement according to claim 6, characterized in that the first and the second voltage via a respective ohmic resistance (RIO, RIl) to the control electrode of the transistor (T2) are coupled.

8. A method for operating a discharge lamp (LA) having preheatable electrodes on a circuit arrangement having an input terminal for applying an input voltage, an output terminal for providing an output voltage (U _A) to a lamp generator (LG) for operating the discharge lamp (LA), a power factor correction circuit unit (14) coupled between the input terminal and the output terminal, a monitoring device (20) adapted to operate the lamp generator (LG) abschalt ^¬ in the presence of a Abschaltkriteriums, and an integrated circuit (16) which is designed to drive the circuit unit (14) for Lei ^¬ tion factor correction, wherein the integrated circuit (16) has a Disable input, characterized by the following steps: a) generating a blocking signal when the lamp generator (LG) is switched off; b) coupling the inhibit signal to the disable input of the integrated circuit (16) to disable the integrated circuit.