AT16334U1 - Operating circuit for lamps with PFC control unit - Google Patents

Abstract

An operating circuit for lighting means, in particular for the operation of at least one light-emitting means path with at least one LED, is provided, comprising a preferably integrated control unit. The operating circuit further includes a PFC circuit having a switch clocked by an output signal of the control unit. The control unit may be supplied to at least one input derived from a power supply voltage of the operating circuit input signal. The control unit is configured to change a clocking of the switch depending on the input signal. In addition, a processing circuit may be provided which raises a level of the input signal at least temporarily in the region of the zero crossings of the mains supply voltage before it is fed to the control unit.

Description

description

OPERATING CIRCUIT FOR LUMINAIRES WITH PFC CONTROL UNIT The invention relates to an operating circuit for operating lamps, in particular at least one lamp section with at least one LED or OLED. The operating circuit provides a PFC functionality or has a PFC circuit to provide this function. In particular, the operating circuit is equipped with an integrated control unit (IC, ASIC, microcontroller, ...) which is supplied with a signal which is derived, for example, from an electrical mains supply, in particular from a rectified AC voltage. The control unit controls a switching element, which can be designed as a transistor (field effect transistor FET, MOSFET, ...) in order to provide the PFC functionality. For example, the control unit can be supplied with a signal representing the mains supply voltage.

The switching element or the transistor are referred to below as switches. The switch controlled by the control unit is therefore controlled to achieve a good power factor depending on the signal supplied to the control unit.

A known integrated circuit (IC) can be used as the control unit in the operating circuit, for example a control unit commercially available as an electronic component (off-the-shelf, OTS).

Especially in the field of lighting technology, i.e. Thus, in particular in the case of operating circuits for lamp sections, there is now the problem that such control units cannot be used without further ado, since, although they are suitable in principle for the planned application, they also have disadvantageous properties.

For example, it may be the case that, in the case of certain control units which enable PFC functionality, or which permit appropriate activation of the switch, the switch is activated as a function of a signal supplied to the control unit. In particular, the switch is activated as a function of a voltage signal representing the mains voltage.

The control unit can be designed so that it switches the switch at normal mains voltage values, i.e. if the level of the signal supplied to the control unit is, for example, above (and / or on a threshold value defined in the control unit), or moves in a predetermined range, operates in a first operating mode. If the level of the signal supplied to the control unit is below (and / or at) the threshold value (es) defined in the control unit, or if the level moves in another predetermined range, the control unit can switch the switch to another (second) operating mode operate.

Depending on the level of the signal, the control unit can e.g. Provide at least two modes of operation for the switch. For example, a so-called discontinuous conduction mode (DCM), the switch being controlled so that the current through a PFC inductor can drop to zero, a non-intermittent operation (continuous conduction mode, CCM) and / or an operation in a border area between intermittent operation and non-intermittent operation (borderline conduction mode, BCM).

It can then be provided in the control unit that, for example, at a lower level of the signal supplied to the control unit, the control unit switches to non-intermittent operation (CCM), in which the current through the PFC inductor never drops to zero, while at another level of the signal is triggered according to another operating mode (DCM, BCM).

The problem here is that when the switch is actuated in non-intermittent operation, the switch cannot be switched on again without current. This will heat / 10

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Patent Office generates, which means that the transistor is exposed to a high thermal load and that overall high and undesirable electrical switching losses occur in the operating circuit.

The aim of the invention is now to provide a way to use control units known per se, and yet to avoid these problems, as they are known from the prior art.

[0011] The invention therefore provides an operating circuit and a method according to the independent claims. Further developments of the invention are the subject of the dependent claims.

In a first aspect, an operating circuit for illuminants, in particular for operating at least one illuminant path with at least one LED, is provided, having a preferably integrated control unit. The operating circuit also has a PFC circuit with a switch clocked on the basis of an output signal from the control unit. The control unit can be supplied with an input signal derived from a mains supply voltage of the operating circuit at at least one input. The control unit is set up to change a timing of the switch depending on the input signal. A processing circuit can also be provided which at least temporarily raises a level of the input signal before it is fed to the control unit in the region of the zero crossings of the mains supply voltage.

If the increase takes place selectively and not over the entire course of the sine wave, this can be done via a temporal selection (for example. X%, such as. 20% of the duration of the sine wave centered around the zero crossing), or by a selection , which is done by specifying threshold values for the input signal (for example 10% of the maximum amplitude). In this case, the increase occurs whenever the magnitude of the amplitude of the input signal is less than the predetermined threshold value).

A further signal, preferably a voltage derived from a control unit supply voltage, can be applied to the input signal before it is fed to the control unit.

[0015] The processing circuit can combine the input signal and the further signal. A combined input signal can be fed to the control unit.

The at least one input can be connected to the input for the control unit supply voltage of the control unit, in particular by means of or through the processing circuit.

[0017] The control unit can discriminate the level of the input signal and / or the combined input signal with respect to at least one threshold value. The control unit can control the switch depending on a result of the discrimination, in particular depending on a ratio of the level to the at least one threshold value in one of at least two operating modes.

[0018] The control unit can control the switch in a non-gap operation, a gap operation and / or an operation in a border area between non-gap operation and gap operation.

The control unit can control the switch in only one of the at least two operating modes when the level of the input signal is raised.

The processing circuit can be a resistor. The processing circuitry may include a constant current source and a constant voltage source.

The increase in the level of the input signal can be dependent on the dimensioning of the resistor.

When the level of the input signal is raised, the control unit can control the switch in only one specific operating mode of the at least two operating modes.

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Patent office The resistance can be dimensioned in the megohm range.

[0024] The switch can be switched without current.

The control unit can control the switch in a first operating mode of the at least two operating modes in the intermittent operation. The control unit can control the switch in a second operating mode of the at least two operating modes in the non-intermittent mode.

The control unit can control the switch in the first operating mode when the level of the input signal and / or the combined input signal is above or below the at least one threshold value. The control unit can control the switch in the second operating mode if the level of the input signal and / or the combined input signal is below or above the at least one threshold value.

The control unit can preferably only control the switch in the first operating mode when the input signal is raised.

[0028] In a further aspect, a luminaire is provided, comprising an operating circuit as described above.

In a still further aspect, a method is provided, in particular for operating at least one lamp path with at least one LED, a preferably integrated control unit clocking a switch of a PFC circuit based on an output signal from the control unit, the control unit being connected to at least one Input an input signal derived from a mains supply voltage of the operating circuit is supplied, and the control unit changes a timing of the switch depending on the input signal. In addition, a processing circuit raises a level of the input signal before it is fed to the control unit, at least temporarily, in the region of the zero crossings of the mains supply voltage.

The invention will now be described with reference to the figures. Show:

Fig. 1, Fig. 3 schematically shows an exemplary embodiment of the invention;

schematically a further exemplary embodiment of the invention; and a more specific exemplary embodiment of the solution according to the invention.

The invention therefore provides, in particular, to change the signal representing the mains supply and fed to the control unit such that there is a change in the level of the signal supplied to the control unit at least in the region of the zero crossings of the electrical mains supply or the mains voltage. Thus, in the area of the zero crossings, an actuation of the switch which is actually intended for low signal levels can be avoided in non-intermittent operation, while in particular outside the zero crossings the switch is different, e.g. can be controlled in non-intermittent operation. In particular, in the area of the zero crossings it is thus possible to activate the switch in the intermittent mode, which is provided for higher levels.

The level of the signal supplied to the control unit is thus shifted. For this purpose, a processing circuit is provided in the operating circuit. This processing circuit can be configured such that the signal fed to the control unit is also supplied to it. On the basis of this signal, the processing circuit can track or record the course of the signal and thus in particular the course of the mains voltage and can recognize a zero crossing. In particular, the processing circuit can anticipate a zero crossing on the basis of the signal curve and, if a zero crossing is present or is to be expected, change the level of the signal in such a way that the level lies in particular above a certain threshold value of the control unit for the signal level.

For this purpose, the processing circuit can generate a signal which is combined with the signal VE representing the mains supply, so that the control unit is supplied with the combined signal.

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Patent Office The control unit then discriminates the incoming signal with respect to the predetermined threshold value and determines the type of activation of the switch depending on the ratio of the level value to the threshold value. By changing the level it can be ensured that the input signal at its lowest value during the half-wave of the mains voltage never reaches a value at which the control unit starts operating accordingly, e.g. non-intermittent operation (CCM).

If there is no change in the level supplied to the control unit by the processing circuit according to the invention, then in the area of the zero crossings of the mains voltage there is an operation in the mode actually provided by the control unit, e.g. the non-intermittent operation.

It should be understood that, of course, more than two operating modes can be available in the control unit for operating the switch. In addition to the non-intermittent operation and the intermittent operation, for example, additionally or alternatively, operation in the border area between intermittent and non-intermittent operation (BCM) can be provided.

Overall, the invention can thus be used in order, when a control unit evaluates a level of an input signal in a known manner, to selectively set an operating mode of the control unit by changing the input signal level, in particular for certain sections of the mains voltage signal curve.

It is thus also possible for the processing circuit to adapt the level several times depending on the course of the detected input signal, and in particular for different phases of the detected line voltage course. For example, it can also be provided that the processing circuit selectively reduces the level in order to select a specific operation of the switch by the control unit.

It can of course also be provided that the level is increased to the entire mains half-wave of the mains supply voltage AC.

The LED driver iW3630 from iWatt can serve as an example of a control unit.

Fig. 1 shows a schematic overview of an exemplary operating circuit according to the invention. The operating circuit is accordingly supplied from a mains supply AC via a rectifier G. After the rectifier, a signal VE is tapped at a first connection point 1, which is fed to the control unit SE at an input Vin.

A processing circuit V also provided is e.g. arranged so that it can also detect the input signal VE or a signal derived therefrom. The processing circuit V can then, for example, modify the input signal VE to form a signal Vkomb. Thus, the control unit SE either directly detects at its input Vin the input signal VE representing the mains supply AC and / or a signal Vkomb modified by the processing circuit V at the input Vin.

Furthermore, the control unit SE is equipped with an input for the control unit supply voltage Vcc, via which the control unit is supplied with an operating voltage. The voltage supply for the control unit SE is also tapped downstream of the rectifier at a second connection point 2.

Via an output Out, the control unit SE controls a switch S, which is connected in series with an inductance L. The arrangement of the inductance L and the switch S shown in Fig. 1 represents e.g. is a part of a flyback converter FB or a power factor correction circuit PFC, which is part of the circuit area marked with a dashed border.

Furthermore, the control unit is able to detect a voltage at a measuring winding M of the flyback converter, for example at a measuring input FV. A current through the switch S can also be detected at a further input F1 of the control unit SE.

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Patent Office [0049] A possible connection of an illuminant LED, in particular an LED, to a connection Vout of the circuit arrangement is also indicated schematically.

Fig. 2 shows a substantially identical circuit arrangement to Fig. 1, and the same circuit parts are given the same reference numerals.

In Fig. 2, however, the arrangement of the processing circuit V is chosen differently in that the processing circuit V now no longer necessarily has to detect the input signal VE, but instead can detect the control unit supply voltage VS and, depending on this, the input signal VE another Signal VBias can act to generate the combined signal Vkomb then supplied to the control unit SE. In particular, the processing circuit V can have a constant current and / or constant voltage source in order to generate the further signal VBias.

Since the control unit supply voltage VS is also derived from the mains voltage and in particular reproduces the mains voltage, the processing circuit can also detect a signal here from which zero crossings of the mains voltage can be detected. Accordingly, the processing circuit V can generate a signal based on the control unit supply voltage VS, which is then combined with the input signal VE. Of course, it is alternatively and / or additionally possible that the processing circuit V still detects the input signal VE, or an input signal derived therefrom. This is indicated by the dashed arrow.

FIG. 3 now shows a more specific embodiment of the circuit arrangement from FIG. 1 or FIG. 2.

The circuit arrangement from FIG. 1 is again essentially shown and the same features of the circuit arrangement are identified identically.

It is clearly evident that the supply voltage input of the control unit is now connected to the input Vin via a processing circuit V, V, which is implemented as a resistor RBias.

[0056] This resistance RBias is dimensioned in particular in the mega-ohm range. A further signal Vbias', which is derived from the control unit supply voltage VS, is now applied to the input signal VE via the resistor RBias. Thus, in particular in the area of the zero crossings, the level of the input signal VE at the input Vin of the control unit SE can be raised and thus the switch S can also be controlled accordingly.

Overall, the control unit SE is therefore able to provide at least two operating modes in order to control the switch S. As already mentioned, the operating modes can be a non-intermittent operation, an intermittent operation, and / or an operation in a border area between non-intermittent operation and intermittent operation. Since the control of the switch S is dependent on the level at the input Vin, the control unit SE thus controls the switch S only in one of the provided, at least two operating modes, when the level is changed by the processing circuit V, V.

In the example of FIG. 3, the increase in the level at the input Vin of the input signal VE is dependent on the dimensioning of the resistance RBias. In this respect, the choice of the resistance value can also be used to adapt to different control units SE. Depending on the level at which input Vin changes the operating mode, a suitable resistor RBias can be provided so that it is raised to the desired level.

As an alternative to the resistor RBias, alternative variants would also be possible in order to apply a signal Vbias, for example, a meal with a constant current etc. would also be possible.

Overall, it is a goal to switch the switch S as currentless as possible through 5/10

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Introduce patent office. If the control unit SE discriminates the level at the input Vin with respect to a threshold value, it checks in particular whether the value of the level at the input is above or below the threshold value. This threshold value is generally known from the specification of the control unit SE. Accordingly, the operating circuit can be adapted to a control unit SE to be used in each case.

Of course, the invention also relates to devices equipped with the inventive operating circuit, such as lights, emergency lighting devices, lamps, etc. In principle, the solution according to the invention can be used for all circuits which have (separate) tracking of the mains supply, in particular the mains voltage, by a control unit provide.

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Claims (17)

Expectations 1. Operating circuit for lamps, in particular for operating at least one lamp section with at least one LED, comprising: - A preferably integrated control unit (SE), and - A PFC circuit with a switch (S) clocked on the basis of an output signal (Out) of the control unit (SE), the control unit (SE) having at least one input (Vin) an input signal derived from a mains supply voltage (AC) of the operating circuit ( VE) is supplied, and the control unit (SE) is set up to change a clocking of the switch (S) depending on the input signal (VE), characterized by a processing circuit (V) that a level of the input signal (VE) before it Feed to the control unit (SE) rises at least temporarily in the area of the zero crossings of the mains supply voltage (AC). 2. Operating circuit according to claim 1, wherein a further signal (VBias) is applied to the input signal (VE) before it is fed to the control unit (SE), preferably a voltage derived from a control unit supply voltage (Vcc). 3. Operating circuit according to claim 1 or 2, wherein the processing circuit (V) combines the input signal (VE) and the further signal (VBias) and a combined input signal (Vkomb) is supplied to the control unit (SE). 4. Operating circuit according to one of the preceding claims, wherein the at least one input (Vin) is connected to the input for the control unit supply voltage (Vcc), in particular by means of the processing circuit (V). 5. Operating circuit according to one of the preceding claims, wherein the control unit (SE) discriminates the level of the input signal (VE) and / or the combined input signal (Vkomb) with respect to at least one threshold value and the switch (S) depending on a result of the discrimination, in particular depending on a ratio of the level to the at least one threshold value according to one of at least two operating modes. 6. Operating circuit according to one of the preceding claims, wherein the control unit (SE) the switch (S) in a non-gap operation (CCM), a gap operation (DCM) and / or an operation in a border area (BCM) between non- gapless operation (CCM) and gapless operation (DCM) controls. 7. Operating circuit according to one of the preceding claims, wherein the control unit (SE) to control the switch (S) in only one of the at least two operating modes when the level of the input signal is raised. 8. Operating circuit according to one of the preceding claims, wherein the processing circuit (V) is a resistor (RBias). 9. Operating circuit according to one of the preceding claims, wherein the increase in the level of the input signal (VE) is dependent on the dimensioning of the resistor (RBias). 10. Operating circuit according to one of the preceding claims, wherein when the level of the input signal (VE) is raised, the control unit (SE) controls the switch (S) in only one specific operating mode of the at least two operating modes. 11. Operating circuit according to one of the preceding claims, wherein the resistance (RBias) is dimensioned in the megohm range. 12. Operating circuit according to one of the preceding claims, wherein the switching of the switch (S) takes place without current. 7.10 AT16 334U1 2019-07-15 Austrian Patent Office 13. Operating circuit according to one of the preceding claims, wherein the control unit (SE) controls the switch (S) in a first operating mode of the at least two operating modes in the intermittent operation (DCM) and / or the control unit (SE) switches (S) in a second operating mode which controls at least two operating modes in the non-intermittent operation (CCM). 14. Operating circuit according to one of the preceding claims, wherein the control unit (SE) controls the switch (S) in the first operating mode when the level of the input signal (VE) and / or the combined input signal (Vkomb) above / below the at least one threshold value lies and controls in the second operating mode when the level of the input signal (VE) and / or the combined input signal (Vkomb) is below / above the at least one threshold value. 15. Operating circuit according to one of the preceding claims, wherein the control unit (SE) controls the switch (S) preferably only in the first operating mode when the input signal is raised. 16. Luminaire having an operating circuit according to one of claims 1-15. 17. A method, in particular for operating at least one lamp section with at least one LED, a preferably integrated control unit (SE) clocking a switch (S) of a PFC circuit based on an output signal (Out) from the control unit (SE), the control unit ( SE) an input signal (VE) derived from a mains supply voltage (AC) of the operating circuit is supplied to at least one input (Vin), and the control unit (SE) changes a timing of the switch (S) depending on the input signal (VE), characterized in that that a processing circuit (V) that at least temporarily raises a level of the input signal (VE) before it is fed to the control unit (SE) in the region of the zero crossings of the mains supply voltage (AC). Two sheets of drawings 8.10 AT16 334U1 2019-07-15 Austrian Patent Office 9.10 AT16 334U1 2019-07-15 Austrian Patent Office AC • .......— o FB / PFC! LED I ’ϊ i i i Fig. 3 10/10 L £ ϊ Ö> \ Π, 5, S L 5 ί