WO2007101835A1

WO2007101835A1 - Circuit arrangement for operating a load and method for operating a load

Info

Publication number: WO2007101835A1
Application number: PCT/EP2007/052047
Authority: WO
Inventors: Jörg LOTT
Original assignee: Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH
Priority date: 2006-03-09
Filing date: 2007-03-05
Publication date: 2007-09-13
Also published as: DE102006010998A1

Abstract

The present invention relates to a circuit arrangement for operating a load (LA) comprising a supply terminal for connecting an AC voltage (UN) for supplying the circuit arrangement; an input circuit, which comprises a rectifier (12), which is coupled on the input side to the supply terminal; an output circuit, which comprises a capacitor (CH) and a bridge circuit (S1, S2) wherein the capacitor (CH) is coupled to the output of the rectifier (12), and wherein the bridge circuit is coupled to the capacitor (CH) for its supply and comprises at least one first and one second switch (S1, S2); a control circuit (14), which drives the first and the second switch (S1, S2) using a signal having a predeterminable frequency, wherein the frequency depends on a characteristic variable (IF) of a signal coupled to a frequency control input (9) of the control circuit (14); and an output terminal, which is coupled to the centre point (HB) of the bridge circuit, for connecting the load (LA); wherein the signal (IF), which is coupled to the frequency control input (9) of the control circuit (14), is a signal which has been coupled out of the input circuit. The invention moreover relates to a method for operating a load using such a circuit arrangement.

Description

description

Circuit arrangement for operating a consumer and method for operating a consumer

Technical area

The present invention relates to a circuit ^arrangement for operating a load, comprising a supply connection for connecting an AC voltage for supplying the circuit arrangement, an input circuit comprising a rectifier, which is coupled on the input side to the supply connection, an output circuit having a capacitor and a Brü ^¬ bridge circuit, wherein the capacitor is coupled to the output of the rectifier, and wherein the-nesting is bridge circuit coupled to their supply to the capacitor and at least a first and a second switch comprises a control circuit supplied to the first and driving the second switch with a signal of a predeterminable frequency, the frequency depending on a characteristic of a signal coupled to a frequency control input of the control circuit, and an output terminal coupled to the center of the bridge circuit for connecting the V erbrauchers. They be ^¬ also applies to a method for operating a consumer to such a circuit arrangement.

State of the art

Although Fig. 1 shows a preferred embodiment of egg ^¬ ner circuit arrangement according to the invention, the constricting the vorlie ^¬ problem underlying the invention can nevertheless be explained with reference to this figure, become. Fig. 1 shows a schematic representation of a circuit arrangement for operating a lamp LA. On the input side, a supply connection for connecting the mains voltage U _{N is} provided. This is followed by a filter device 10, which prevents interference by the circuit arrangement to act on the power grid. After the filter unit 10 is followed by a rectifier 12, which provides at its output a rectified mains voltage U _NG to a capacitor Cl. The voltage dropping across the capacitor C1 is supplied to a step-up converter, which comprises an inductance L _H , a switch S _H , a diode D _H and a capacitor C _H. The voltage dropping across the capacitor C _H is usually referred to as the intermediate circuit voltage U _zw and applied to a bridge circuit, in the present case a half-bridge comprising the switches S 1 and S 2. The half-bridge center HB is coupled to the lamp LA via an inductance L _D. A Kon ^¬ capacitor C _z is used together with the inductance L _D to ignite the lamp LA. Furthermore, coupling capacitors Cκi and C _K 2 are provided.

The switches Sl and S2 are controlled by a control device 14 with a predetermined frequency. By way of example, the control device can be represented by an integrated circuit, for example the Infineon Smart Ballast Control IC ICBlFLOlG module. In this module, the frequency of the signal provided at the outputs A1 and A2 is proportional to the current taken from the terminal 9.

If a constant current is taken from pin 9, then the frequency of the signal provided at the outputs A1 and A2 is constant. This is undesirable because In the spectrum at the corresponding frequency results in a high spectral component, whereby specified EMC regulations can be met only with difficulty or not at all. As a countermeasure, it is known in the art, to the signal present at pin 9 signal to mo ^¬ demodulate - to vary and thus the frequency of the outputs Al and A2 signal provided -. Modulating shown in Figure 2 intermediate circuit U _ZW exploit , In this case, via the series circuit of a decoupling capacitor is selected overall and an ent ^¬ speaking dimensioned Auskoppelwiderstands Ver ^¬ a bond of the block 14 made between the positive terminal of the capacitor C _H and the terminal. 9 A disadvantage of this solution is, on the one hand, that both the decoupling capacitor used and the associated decoupling resistor must be suitable for the high DC load, which is usually more than 400 V.

In this case, frequency 3 shown ^¬ spectrum in which the desired widening is marked with arrows results in Fig.. In addition to the high cost of the ^¬ coupling elements, which result from the fact that they must be designed for such high voltages, on the other is a disadvantage that these two coupling components need a lot of space accordingly. Electronic ballasts, in which such circuits are usually arranged, are characterized by an exceptionally high packing density, which naturally results in the desire to use the smallest possible components for the realization of certain functions. This request can not be met with the known from the prior art solution. -A-

Finally, it is disadvantageous that on the one hand - in view of the constancy of the light emitted by the lamp LA - the intermediate _{circuit voltage} U _zw should be as constant as possible. On the other hand, however, the modulation of the intermediate _{circuit voltage} U _{zw should be used} for the modulation of the signal applied to the input 9 of the control device 14. The smaller the modulation of the intermediate _circuit voltage U _zw and thus the better the constancy of the light emitted by the lamp LA, the greater the decoupling capacitor has to be dimensioned in order to reduce the smaller fluctuation, which is due to the very low frequency of the mains voltage. to pass to the input 9 of the control device 14.

If the intermediate circuit voltage U _{zw is} a DC voltage as in the optimum case, a signal with constant frequency is provided by the control device 14 at the outputs A1 and A2.

Presentation of the invention

The object of the present invention is to further develop the above-mentioned circuit arrangement or the aforementioned method such that it works on the one hand even with a constant ^{DC link} voltage U _zw , on the other hand, can be realized cost-effectively and with minimal space requirements.

This object is achieved by a circuit arrangement having the features of patent claim 1 and by a method having the features of patent claim 10. The present invention is based on the finding that, in order to achieve the above-described object, signals can be tapped which are present in the input circuit of the circuit arrangement The circuit arrangement according to the invention functions even if the intermediate circuit voltage is provided as DC voltage _zw , which is available in the load circuit of the circuit arrangement, is less than 10%, see Fig. 2, the voltage swing of the rectified mains voltage U _NG 100%, see the time course of the rectified mains voltage U _NG in Fig. 4th This opens up the possibility of reducing the voltage across a voltage ^¬ divider. as a result, the voltage reduction can be a capacitor used for the decoupling of the constricting to the connector 9 anzule ^¬ signal that now only for a voltage significantly less than 100 V must be interpreted and therefore can be re ^¬ alisiert as an SMD component. Likewise, the coupling-out can now be dimensioned much smaller, since this also experiences a much lower voltage stress. The design of the decoupling capacitor and the output ^¬ pelwiderstands to a much lower Spannungsbe ^¬ load allows extremely space-saving implementation.

In general, for the purposes of the present invention, any suitable signal can be coupled out of the input circuit of the circuit arrangement. However, it is preferred that the signal coupled to the frequency control input of the control circuit is connected to the output signal of the rectifier is correlated. Particularly preferably, it even corresponds to this.

Preferred embodiments of the inventive circuit arrangement comprises a modification device which the control circuit quenzsteuereingang between the output of the rectifier and the Fre ^¬ coupled. This modification device may, for example, comprise the already mentioned voltage divider, in particular of ohmic resistors. The modification device may preferably comprise a low-pass filter, in particular an RC low-pass filter, and / or a smoothing capacitor. By this measure, the curve shape of the ^¬ coupled signal can be improved, that is a sinusoid is ^¬ are approaching. A sinusoidal variation of the frequency of the signal driving the switches of the bridge circuit is particularly desirable in terms of minimum EMC distortion.

It is furthermore preferred to realize a plurality of components of the modification device, in particular all components of the modification device, as SMD components. Implementation as SMD components results in a minimum space requirement for the entire modification device, whereby at the same time an optimum signal can nevertheless be provided at the input 9 of the control device 14.

It is particularly preferred, however, if the tax advantage ^¬ device having a measuring or supply input which is coupled via a measuring or supply path with the A ^¬ circular gear, wherein the ereingang to the Frequenzsteu- the control circuit coupled signal from DIE sem measuring or supply path is coupled. In particular ^¬ sondere when the control device as an integrated scarf ^¬ processing or ASIC is realized, the to be provided on a measuring or supply input voltage is excluded from the input circuit at the "tapped" voltage already on an integrated circuit or for the ASIC suitable voltage level reduced, so that not to ^¬ additional modification device for generating the be provided to the input 9 of the control device 14 to be guided Sig- staff must or the designated modification device may include a reduced number of components. it is particularly preferred in this case a supply path for a supply input of the control device 14 "tapped", which supplies only in the start-up phase, the integrated circuit or the ASIC with a supply voltage.

In connection with the decoupling of the signal coupled to the frequency control input of the control circuit signal from a measuring or supply path is preferred when a capacitor is arranged seiell between the location of the decoupling and the frequency control input of the control circuit. This eliminates repercussions on the measurement or supply path that could cause, for example, a shift in the startup threshold for the integrated circuit or ASIC.

Further preferred embodiments emerge from the subclaims.

The preferred embodiments and advantages mentioned with reference to the circuit ^arrangement according to the invention apply, as applicable, also for the inventive method.

Short description of the drawing (s)

An ^exemplary embodiment of a circuit ^arrangement according to the invention will now be described in more detail below with reference to the attached drawings. Show it :

Fig. 1 in a schematic representation of an embodiment of a circuit arrangement according to the invention;

Fig. 2 shows the time course of the intermediate _{circuit voltage} U _zw as is usual in the prior art;

3 shows the frequency spectrum of the signal provided at the outputs A1 and A2 in the implementation known from the prior art;

4 shows the time profile of the rectified mains voltage U _NG ;

5 shows the frequency spectrum of the signal provided at the outputs A1 and A2 in a circuit arrangement according to the invention in the embodiment according to FIG. 1; and

6 shows the time profile of the current at the input 9 of the control device 14.

Preferred embodiment of the invention

Einge- components and their function, the write-introduction already loading in ^¬ with reference to Fig. 1 lead and have been described will not be described again in the following in the description of an embodiment of a circuit arrangement according to the invention.

Fig. 1 shows an embodiment of a erfindungsge ^¬ MAESSEN circuit arrangement in which the control device 14 at their outputs Al and A2 provides signals which are used for driving the switches Sl and S2 of the half-bridge. For the sake of clarity, only the inputs 3, 4 and 9 of the control ^device 14 are shown on the input side. The input 4 is connected to a reference potential, in this case with the ground potential verbun ^¬ the. The input 3 represents a supply input, via which the control device 14 is supplied with voltage during the start-up phase. After the start-up phase, the control device 14 is supplied via a charge pump voltage, the charge pump preferably at Halbbrü ^¬ ckenmittelpunkt HB engages.

In the prior art, a single ohmic resistance of the resistors Rl and R2 in place, according to the invention serve as a voltage divider is provided whose resistance value is what the sum of the resistances Rl and R2 ^¬ ent. The output coupling of the frequency to be applied to the control input 9 of the control circuit signal via the series connection of a capacitor C2 and ohmic resistor R3, which together form a RC low-pass bil ^¬. An optional capacitor C3 connected to the coupling-out point between resistors R1 and R2 may be used as a smoothing capacitor to optimize the waveform of the coupled-out signal. The resistors Rl, R2, R3 and the capacitors C2 and C3 are summarized in a modification device 16.

5 shows the frequency spectrum of the signal provided at the outputs A1 and A2 of the control device 14 for the exemplary embodiment of a circuit arrangement according to the invention shown in FIG. As indicated by the arrows, the ge ^¬ desired widening of the frequency spectrum obtained here as well.

Fig. 6 is to illustrate the time course at the input 9 of the control device 14 flow in the embodiment according to Fig. 1. It should be noted that disposed in the control device 14 direct-current source for a sliding Chan ^¬ provides part, said from the Input circuit decoupled alternating component is superimposed.

Although in connection with the presented exemplary embodiment of a circuit arrangement according to the invention the current I _F removed from the input 9 has been modified, embodiments are possible in which, for example, the current flowing into an input, the voltage U present at an input or the one at Input-acting resistance, whether capacitive, in ^¬ duktiv or ohmic, is varied to vary a variation of the frequency of the signal provided at at least one output of the control device.

Claims

claims

1. A circuit arrangement for operating a consumer (LA) comprising:

- A supply terminal for connecting an AC voltage (U _N ) for supplying the circuit arrangement;

- An input circuit comprising a rectifier (12), the input side is coupled to the Versorgungsorg ^¬ circuit;

- An output circuit comprising a capacitor (C _H ) and a bridge circuit (Sl, S2), wherein the

Capacitor (C _H) is coupled to the output of the rectifier (12), and wherein the bridge circuit is pelt for their supply with the capacitor (C _H) gekop ^¬ and at least a first and a two-th switches (Sl, S2) comprises ;

- A control circuit (14) which controls the first and the second switch (Sl, S2) with a signal of a predetermined frequency, wherein the frequency depends on a characteristic (I _F ) of a frequency to a frequency control input (9) of the control circuit ( 14) coupled signal; and

- an output terminal that connects to the center

(HB) of the bridge circuit is coupled to connect the load (LA); characterized in that the coupled to the frequency control input (9) of the control circuit (14) signal (I _F) is decoupled from the A ^¬ circular gear signal.

2. Circuit arrangement according to claim 1, characterized in that the coupled to the frequency control input (9) of the control circuit (14) signal (I _F) with the off ^¬ output signal (U _N G) is correlated of the rectifier (12), in particular corresponding thereto.

3. Circuit arrangement according to one of claims 1 or 2, characterized in that it comprises a modification device (16) which is coupled between the output of the rectifier (12) and the frequency control input (9) of the control circuit (14).

4. Circuit arrangement according to claim 3, characterized in that the modification device (16) comprises a voltage divider (Rl, R2).

5. Circuit arrangement according to one of claims 3 or 4, characterized in that the modification device (16) comprises a low pass (C2, R3), in particular an RC low pass.

6. Circuit arrangement according to one of claims 3 to 5, characterized in that the modification device (16) comprises a smoothing capacitor (C3).

7. Circuit arrangement according to one of claims 3 to 6, characterized in that a plurality of components of the modification device (16), in particular all the components of Modification device (16), re ^¬ alised as SMD components.

8. Circuit arrangement according to one of the preceding claims, characterized in that the control device (14) has a measuring or supply input (3) which is coupled via a measuring o- the supply path to the input circuit, wherein the at the frequency control input (9 ) coupled to the control circuit (14) signal (I _F ) is coupled out of this measurement or supply path.

9. Circuit arrangement according to claim 8, characterized in that a capacitor (C2) is arranged in series between the location of the coupling and the frequency control input (9) of the control circuit.

10. Circuit arrangement according to one of the preceding claims, characterized in that between the output of the rectifier (12) and the capacitor (C _H ), a boost converter (L _H , D _H , S _H ) is coupled.

11. A method of operating a load on a circuit arrangement with a supply connection for connecting an AC voltage (U _N) for the supply of the circuit arrangement, an input circuit comprising a rectifier (12), whose input is coupled to the supply terminal, an off ^¬ transitional circle, one capacitor (C _H ) and one bridge bridge circuit (Sl, S2), wherein the capacitor (C _H ) is coupled to the output of the rectifier (12), and wherein the bridge circuit is coupled to the capacitor (C _H ) and at least a first and a second switch (Sl, S2), a control circuit (14) which controls the first and the second switch (Sl, S2) with a signal of a predeterminable frequency, wherein the frequency depends on egg ^¬ ner characteristic (I _F ) of a frequency to a frequency control input ( 9) coupled to the control circuit (14), and an output terminal coupled to the midpoint (HB) of the bridge circuit for connecting the load (LA), characterized by the steps of: a) coupling out a signal from the input circuit; b) applying the decoupled in step a) signal to the frequency control input (9) of the control circuit (14).