LED driver with glow suppression

Abstract

The operating device (10) according to the invention includes a rectifier circuit (22) which is connected to a mains AC voltage at its input side in order to provide a rectified mains AC voltage at its outputs “+” and “-”. In a first operating mode (B), this is done by utilizing both mains half-waves by means of a full-wave rectifier. In a second operating mode S (standby mode), the rectifier circuit (22) operates as a half-wave rectifier. In the first operating mode, the rectifier circuit (22) supplies a pulsating DC voltage whose potential relative to the earth conductor may have an AC component. In the second operating mode, the rectifier circuit (22) supplies a DC voltage whose potential relative to earth potential (P) E ) has a negligible or no exchange rate.

Description

[0001] The invention relates to an operating device particularly suitable for operating LED lamps, which reliably suppresses even weak illumination of the connected LED lamps when switched off.

[0002] A known problem with operating LED lamps using electronic control gear is that, when switched off, a small current can flow from the LED lamp to ground potential via the lamp's stray capacitance. This current leads to a glow from the lamp that is noticeable in the dark and is often undesirable. Such a glow can occur even in ungrounded luminaires if a user brings a body part, such as the hand, even close to a lamp connected to an electronic control gear.

[0003] To solve this problem, DE 10 2022 200 431 A1 proposes a circuit in which a diode is connected upstream of the lamp in the positive conduction branch, blocking any reverse current. The other end of the lamp is connected to ground via an electronic switch to safely interrupt the current flow there. In this way, currents flowing through the lamp due to the parasitic capacitances and thus through the lamp are safely suppressed when the control gear is switched off.

[0004] EP 2 823 691 B1 also describes an electronic control device for LED lamps, in which a two-pole switch is placed between the LED lamp and the control device, which interrupts the electrical connection between the LED lamp and the control device when the LED lamp is to be dark, i.e. switched off.

[0005] The arrangement of switches between the operating device and the lamp requires that the switches have extremely high resistance and low capacitance when switched off.

[0006] Against this background, an alternative solution is being sought to suppress unwanted glow from LED lamps on a switched-off control gear.

[0007] To achieve this object, the invention proposes an operating device which, for connection to an AC voltage network, has a rectifier circuit which has a first operating mode in which it operates as a full-wave rectifier and a second operating mode in which it operates as a half-wave rectifier. The first operating mode is intended to supply the lamp with operating current. In the second operating mode, the lamp is unlit and only the control circuit of the operating device is kept energized in order to be able to react to control signals. The rectifier circuit can be configured to output the DC voltage oscillating with respect to earth potential in the first operating mode, but at rest relative to earth potential in the second operating mode.

[0008] A full-wave rectifier is a rectifier circuit that connects both half-waves of the AC mains voltage with the correct polarity to the output of the rectifier circuit. The full-wave rectifier can consist of electronic switches in a so-called Graetz circuit. Such switches can be diodes (self-controlled switches), externally controlled switches (synchronous rectifiers), thyristors, TRIACs, or similar devices.

[0009] Half-wave rectifier circuits, on the other hand, typically consist of only a single diode that acts as a self-controlled electronic switch, or of an externally controlled electronic switch, e.g. a transistor.

[0010] The invention is based on the discovery that in the first operating mode (full-wave operation), the rectifier circuit delivers a DC voltage at its DC output whose potential may have an AC component relative to ground potential, while in its second operating mode (half-wave rectifier), it delivers a DC voltage at its output whose potential has no significant AC component relative to ground potential. Consequently, in this second operating mode, regardless of the specific circuit design of an intermediate voltage converter circuit, it does not deliver an AC potential to the LED light source relative to ground potential.The stray capacitances present there with respect to earth potential cannot therefore carry any capacitive current, which means that the LED lamp remains dark, even if voltage continues to be supplied to the control circuit and possibly also to the voltage converter circuit of the operating device via the rectifier circuit in one-way operation.

[0011] The operating device can be designed so that its control circuit is kept energized by the rectifier circuit in both half-wave and full-wave operation, so that the control circuit can respond to control signals arriving, for example, via a control line in both modes. Such control signals can be switch-on signals, switch-off signals, dimming signals, or other signals carrying information or commands. Thus, the control circuit can activate, deactivate, or, if provided, even modulate the voltage converter circuit.

[0012] The control circuit can be configured to cause the voltage converter circuit to supply the LED lamp with operating current in the first operating mode, in which the rectifier circuit operates as a branch-wave rectifier. This means that the load current, which ultimately belongs to the operation of the LED lamp, is taken from the AC voltage network without any DC component. Furthermore, the control circuit can be configured to shut down the voltage converter circuit and simultaneously operate the rectifier circuit in the second operating mode as a half-wave rectifier. The extremely low current required only to maintain the operation of the control circuit then represents a DC component for the AC voltage network. This current is preferably below 10 mA, more preferably below 1 mA, and is thus completely negligible from a network perspective.

[0013] The control circuit can further be configured to activate the voltage converter circuit, i.e., operate it in its first operating mode, only when the rectifier circuit has also entered its first operating mode. Furthermore, the control circuit can be configured to deactivate the voltage converter circuit (i.e., operate it in the second operating mode) as soon as or shortly before the rectifier circuit leaves its first operating mode. These measures can prevent the voltage converter circuit from becoming active, even briefly, and supplying the lamp with power when the rectifier circuit is not in the first operating mode (two-way operating mode).

[0014] The control circuit can have a control input for remote control, which is configured to receive an operating mode selection signal. The operating mode selection signal can assume at least two states, which are assigned to the two operating modes of the operating device. Additional states for transmitting information can be provided. The different states of the operating mode selection signal can be formed, for example, by different pulse sequences, different analog voltages, or the like.

[0015] In a simple implementation, the rectifier circuit can comprise a two-way rectifier and a half-wave rectifier, as well as a selector switch that selectively feeds the AC mains voltage to the AC input of the two-way rectifier or the half-wave rectifier. Alternatively, a half-wave rectifier can be connected upstream of the two-way rectifier, which can be activated or bypassed. When not bypassed, it only passes one of the two mains half-waves to the two-way rectifier, which is then inactive. The rectifier circuit then operates as a half-wave rectifier. If, however, the diode of the half-way rectifier is bypassed, the two-way rectifier receives both mains half-waves at its input, thus operating in two-way mode.

[0016] The full-wave rectifier, which can be designed, for example, as a Graetz bridge with diodes, can also contain at least one switch that can interrupt and thus deactivate at least one or two diagonally opposite bridge arms. This switches the rectifier circuit from full-wave operation to half-wave operation. If two bridge arms are interrupted, the glow is suppressed even if the L / N polarity is reversed at the input of the operating device.

[0017] Details of advantageous embodiments of the invention are the subject of the drawings and their figures as well as the associated description or subclaims.

[0018] The drawing shows: Fig. 1 An operating device according to the invention, in overview view, Fig. 2 a rectifier circuit for the operating device according to Fig. 1, in a schematic representation and a first embodiment, Fig. 3 a rectifier circuit for the operating device according to Fig. 1, in an alternative version, Fig. 4 a rectifier circuit for the operating device according to Fig. 1, Fig. 5 Voltage conditions on the operating device according to Fig. 1, in the first operating mode and Fig. 6 Voltage ratio at the operating device according to Fig. 1 in the second operating mode, Fig. 7 shows an embodiment of the rectifier circuit according to the invention with a parallel connection of a half-wave rectifier and a full-wave rectifier, Fig. 8 a modified embodiment of the rectifier circuit according to Fig. 7 and Fig. 9 a rectifier circuit designed as a synchronous rectifier with half-wave rectifier and full-wave rectifier function.

[0019] In Fig. 1 illustrates an operating device 10 with a light source 11 connected thereto, which can be configured, in particular, as an LED light source. In this case, it comprises a chain of series-connected LEDs 12, 13, 14, with the two ends 15, 16 of this chain being connected to the output 17 of a voltage converter circuit 18. Any electronic circuit that can generate an output voltage or output current for the light source 11 from a DC voltage, in particular a pulsating DC voltage, applied to its input 19 is suitable as the voltage converter circuit 18.

[0020] For example, the voltage converter circuit 18 can have a so-called PFC circuit on the input side, for example in the form of a flyback converter, which initially generates an intermediate circuit DC voltage. This can be converted by a further converter circuit into an operating current I suitable for operating the lamp 11. BA forward converter circuit, also known in the art as a buck converter, can be provided as such an additional converter circuit. It is designed to provide the required voltage and, at the same time, the operating current I at output 17. B to the lamp 11. However, it should be noted that other DC / DC converters are also suitable for the voltage converter circuit 18.

[0021] Potential-isolating converter circuits can be used to implement the invention. These circuits have in common that they do not have a direct galvanic connection between their input and output. However, they have at least a capacitive coupling between at least one line at their input 19 and a line at their output 17. For example, this can be the Fig. 1 lower lines, which is indicated by a dashed connection. In addition, a capacitive connection can exist between the upper line 15 of the output 17 and the corresponding upper line at the input 19, which is again indicated by a dashed line. To clarify that this is a capacitive, but not galvanic, coupling, corresponding capacitors C1, C2 are shown in the dashed lines. This can, for example, be the coupling capacitance between the primary winding and the secondary winding of a transformer component. The invention is also, and even more so, applicable to a non-galvanically isolated converter circuit 18. In such a circuit, a direct galvanic connection can exist between the "-" and 16 lines. Capacitive or otherwise electrically conductive connections can also exist between the "+" and 15 lines.

[0022] The voltage converter circuit 18 has a control input 20, which is connected to a control circuit 21, which is configured to specify the operating mode of the voltage converter circuit 18. The voltage converter circuit 18 is configured, in a first operating mode, to provide a voltage suitable for operating the lighting device 11 at the output 17 from the voltage received at the input 19 and thus to supply the lighting device 11 with the desired operating current I B Furthermore, the voltage converter circuit 18 is configured to transition to a second operating mode, a sleep mode, upon receipt of a corresponding other control signal. In this second operating mode, the voltage converter circuit 18 generates no output voltage at its output 17 when a voltage is applied to the input 19, and it also outputs no operating current I at the output 17. B to the lamp 11.

[0023] The control circuit 21 is also configured to control a rectifier circuit 22, via which the voltage converter circuit 18 is supplied with DC voltage from an AC voltage network. For this purpose, the rectifier circuit 22 has a mains input W with the terminals L and N. The terminal N is provided for the neutral conductor of the AC voltage network, while the terminal L is provided for the phase conductor of the AC voltage network. In addition, the operating device 10 or a luminaire in which the operating device 10 is used can have a protective conductor terminal P E which is connected to ground potential. This ground potential may largely coincide with the potential at terminal N or may deviate from it, at least briefly.

[0024] The rectifier circuit 22 can be operated in a first operating mode B, in which it works as a full-wave rectifier. For this purpose, the rectifier circuit 22 contains a first rectifier 23, which applies each half-wave of a mains oscillation present at the terminal L as a positive half-wave to the positive line "+" and as a negative wave to the negative line "-" at the rectifier output. The rectifier circuit 22 also contains a half-wave rectifier 24, which is designed to allow only one half-wave of the mains AC voltage to appear at the output of the rectifier circuit 22 when the rectifier circuit 22 is operated in a second operating mode S, in order to generate a voltage between the positive line "+" and the negative line "-". The voltage on the line "+" is then a DC voltage referenced to the neutral conductor N.

[0025] To select the two operating modes (first operating mode or second operating mode) a switching device 25 is used, which in the embodiment according to Fig. 1 is designed as a changeover switch. It is configured to conduct the AC mains voltage present between terminals L and N to the input of the full-wave rectifier 23 in the first operating mode and only to the input of the half-wave rectifier 24 in the second operating mode. The outputs of the two rectifiers 23, 24 are connected in parallel. The switching device 25 is controlled via a control input 26 of the rectifier circuit 22, which is connected to the control circuit 21.

[0026] The protective conductor connection P E may, but need not, have galvanic contact with the rectifier circuit or the voltage converter circuit 18 or the control circuit 21. A Fig. 1 not shown, typically present, for example, the mains filter connected upstream of the rectifier circuit 22, can, for example, via the Y-capacitor customary there, capacitive connection to the protective conductor terminal P E Irrespective of this, the protective conductor connection P E However, it may be connected to metallic parts located near the illuminant 11, so that parasitic capacitances C p1 to C p4 between the light source 11 or its LEDs 12, 13, 14 (etc.) and the corresponding metal part 27.

[0027] For switching the operation of the luminaire 11 on and off, the control circuit 21 has an input E. This can be connected, for example, to a switch provided on the luminaire or, as is preferred, via a bus or a separate control line to a remote control device. The input E can also receive its control signals via the AC mains and, for this purpose, be connected, for example, to the L terminal and / or the N terminal. The input E can also be a wireless input for receiving radio signals, an optical input for receiving light signals, infrared signals, or the like.

[0028] The operating device 10 described so far operates as follows: The operating device 10 has a first operating mode B, in which the lamp 11 is illuminated, and a second operating mode S, in which the lamp 11 does not emit any light and is completely dark. For the first operating mode, reference is made to the Fig. 1 and Fig. 5 is referred to.

[0029] If the first operating mode is to be adopted, ie, light generation by the lamp 11 is to be instructed, a corresponding switch-on signal is sent to input E of the operating device 10. The control circuit 21 then sends corresponding signals to the inputs 20, 26 in order to put both the rectifier circuit 22 and the voltage converter circuit 18 into their first operating mode B.

[0030] In this operating mode, the full-wave rectifier 23 of the rectifier circuit 22 is connected on the input side via the switching device 25 to the mains input W with the terminals L and N. In contrast, the half-wave rectifier 24 is inactive. This leads to the operating mode B in Fig. 5 shown potentials on the lines “+” and “-”. As a reference, the line “+” and “-” is shown in Fig. 5 illustrates the AC mains voltage at input W.

[0031] The peak voltage of the AC mains voltage must be measured between the “+” and “-” lines, for example 325 V at 230 V eff Mains alternating voltage. This voltage Ua is present at an optionally provided capacitor C and is Fig. 5 below. As can be seen, the two lines “+” and “-” have a considerable alternating potential with respect to the protective conductor P Ewhich, via the parasitic capacitances C1, C2 of the voltage converter circuit 18, leads to a current via the parasitic capacitances C p1 to C p4 However, this current is completely irrelevant for the operation of the control gear 10 and the lamp 11, because it is already controlled by the operating current I which is several orders of magnitude larger. B flowed through to shine as desired.

[0032] In the second “dark” operating mode of the operating device 10 and the lamp 11, the control circuit 21 sends a switch-off signal to the input 20 of the voltage converter 18. This will thus stop converting the input voltage of the input 19 into a voltage present at the output 17 or the operating current I Bto implement. Output 17 is de-energized and de-energized. At the same time, control device 21 sends a control signal to control input 26, causing switching device 25 to remove the AC mains voltage from the input of full-wave rectifier 23 and apply it to the input of half-wave rectifier 24.

[0033] In this second operating mode, which is also to be understood as standby mode S, the control circuit 21 is controlled by a Fig. 1 The connection between the "+" and "-" lines (not shown) is still supplied with operating voltage. However, the rectification now takes place according to the Fig. 6. As can be seen, the output of the half-wave rectifier 24 is barely loaded, meaning that a very low current flows, allowing a substantially constant voltage Ua to build up across the capacitor C. Thus, there is no longer any alternating potential of the "+" and "-" lines relative to ground potential. Therefore, no parasitic current can flow through the parasitic capacitances C1, C2, and C p1 to C p4 As a result, the lamp 11 remains completely dark, while the control circuit 21 continues to run in standby mode and can respond to signals at the input E.

[0034] If it is desired to switch back to the first operating mode, the control circuit 21 sends corresponding signals to the control inputs 20, 26 in order to switch both the rectifier circuit 22 and the voltage converter circuit 18 back to the first operating mode B.

[0035] A simple and clear technical implementation of a rectifier circuit 22, which can perform both the functions of a full-wave rectifier and a half-wave rectifier, is described in Fig. 2. The full-wave rectifier 23 consists of a Graetz bridge in a conventional circuit. The half-wave rectifier 24 is formed by a diode D. Functionally, a switch 28 is connected in parallel to this, which forms the switching device 25 and is connected to the control input 26. Unlike in Fig. 1, the full-wave rectifier 23 and the half-wave rectifier 24 are not connected in parallel to each other in this embodiment, but are arranged in series.

[0036] To enter the first operating mode B, switch 26 is closed (made conductive). This deactivates diode D and with it the half-wave rectifier circuit 24. Only the full-wave rectifier 23 operates according to the diagram in Fig. 5.

[0037] To enter the second operating mode, switch 28 is opened (made non-conductive). The half-wave rectifier 24 now only allows one half-wave to pass through to the full-wave rectifier 23. Thus, the current flowing from the mains through the rectifier circuit 22 can only take one path in the full-wave rectifier 23, namely through the diodes D1 and D2. Therefore, the full-wave rectifier 23 is now ineffective. The rectifier circuit 22 is thus in the second operating mode S.

[0038] The switch 28 and the diode D can be formed by a field-effect transistor. The pn junction between the crystal (bulk) and its drain-source channel can be used as diode D, forming a bulk diode Db. An optocoupler 29 can be connected upstream of the gate to enable potential-free control.

[0039] Instead of the Fig. In addition to the MOS enhancement-mode (normally off) field-effect transistor shown in Figure 3, a depletion-mode (normally on) transistor can also be used. Likewise, unlike the ones shown, p-channel field-effect transistors of the depletion-mode or enhancement-mode can be used. Other electronic switches, such as IGBTs, thyristors, triacs, or the like, can also be used.

[0040] In the rectifier circuit 22 according to the Fig. 2 and Fig. 3, a combination of diode and switch is provided only in the line coming from terminal L. However, it should be noted that, particularly in the case of operating devices that are tolerant to reversed polarity at terminals L and N, a corresponding switch 28' can also be provided in the lower branch coming from terminal N, with the cathode of the diode D' connected in parallel then leading to terminal N.

[0041] Fig. Figure 4 illustrates an alternative embodiment of a rectifier circuit 22 that can assume both a first full-wave rectifier mode and a second half-wave rectifier mode. The circuit illustrated therein again comprises, similar to Fig. 2 and Fig. 3, four diodes D1, D2, D3, D4 are arranged in a Graetz circuit. A switch 30, 31 is connected in series with at least the diodes D3 and D4, which together form the switching device 25. The switches 30, 31 can be designed as MOSFET transistors T1, T2. The gates of these transistors T1, T2 can be connected to the control input 26 via suitable control means, for example, potential-isolating optocouplers. Alternatively, other transistors can be used. If the transistors T1, T2 are conductive, the Graetz circuit shown operates as a full-wave rectifier 23. If, however, the transistors T1, T2 are non-conductive (blocked), only the diodes D1 and D2 can conduct current, whereas the current paths for the diodes D3 and D4 are blocked. The rectifier circuit 22 mutates into a half-wave rectifier, consisting of the diodes D1 and D2.

[0042] Numerous other variations are possible. For example, Fig. 7. The rectifier circuit 22 illustrated therein comprises a Graetz bridge consisting of diodes D1, D2, D3, D4 as a full-wave rectifier, whose AC voltage input is connected to terminals N and L. The DC voltage output "+, -" is connected to the voltage converter circuit 18 (not illustrated in any further detail). The circuit concept shown corresponds ideally to the circuit arrangement according to Fig. 1. The half-wave rectifier 24, consisting of a diode D, is connected in parallel with the full-wave rectifier 23 formed by the Graetz bridge with the diodes D1, D2, D3, and D4. The full-wave rectifier 23 can be activated or deactivated via a switch 28 located in the AC path to the full-wave rectifier 23, so that the capacitor C is supplied with DC voltage either via the full-wave rectifier 23 (switch 28 conducting) or via the half-wave rectifier 24 (switch 28 non-conducting).

[0043] The switch 28 can alternatively be arranged at a different location in the rectifier circuit 22. For example, it can be connected to the Fig. 7 must be inserted at the point marked “P” in order to supply the DC voltage output “+, -” either from the full-wave rectifier 23 (switch then closed) or only from the half-wave rectifier 24 (switch then open).

[0044] Instead of influencing the positive branch of the rectifier circuit 22 according to Fig. 7, the diode D of the half-wave rectifier 24 and the associated switch 28 can also be inserted into the negative voltage path of the DC circuit. The diodes D1, D2, D3, D4, in turn, form the full-wave rectifier 23 as a Graetz bridge. The negative output "-" of the Graetz bridge (anodes of diodes D2 and D3) is connected to the negative line "-" of the DC voltage circuit via a switch 28. In addition, the negative line "-" is connected via the half-wave rectifier 24, i.e., the cathode of diode D, to the AC voltage input, in particular terminal N. Here, too, the switch 28 serves to switch the rectifier circuit 22 between full-wave and full-wave operation. The switch 28 can be inserted, as shown, into the DC voltage line or alternatively at point P in the circuit, ie in the line branch between the cathode of the diode D and the AC voltage input of the Graetz bridge connected thereto.

[0045] Alternatively, all rectifier elements of a Graetz circuit, as in Fig.9, controlled electronic switches S1, S2, S3, S4, which can be selectively switched on and off to act in a non-conductive manner and thus blocking current, or in a conductive manner and thus rectifying in time with the mains AC voltage. To control the switches S1, S2, S3, S4, a controller 32 can be provided which is connected to control inputs of the switches S1 to S4. The controller 32 is designed to open and close the switches S1 and S2 in sync with each other. It is also designed to open and close the switches S3 and S4 in sync with each other, but in push-pull with the other switches S1 and S2. Accordingly, the associated control outputs of the controller 32 are labeled "+1" and "-1". If the positive mains half-wave is applied to terminal L, the switches S1 and S2 are conductive, whereas the switches S3 and S4 are blocking.During a negative mains half-wave at terminal L, switches S3 and S4 are conductive, while switches S1 and S2 are blocked. To synchronize the switching signals for switches S1, S2, S3, S4 with the mains frequency, controller 32 is connected to mains input L, N via suitable means (resistors, capacitors, optocouplers, or the like). Controller 32 also has control input 26 for switching from two-way to one-way operation. In one-way operation, for example, switches S3 and S4 are permanently blocked, whereas only switches S1 and S2 become conductive during the positive mains half-wave, thus forming a half-wave rectifier.

[0046] This means that in order to switch the rectifier circuit 22 from the first operating mode to the second operating mode, only one or more of the switches S1 to S4 must be permanently blocked,

[0047] The operating device 10 according to the invention contains a rectifier circuit 22, which is connected on the input side to a mains AC voltage in order to provide a rectified mains AC voltage at its output "+" and "-". In a first operating mode B, this occurs using both mains half-waves by means of a full-wave rectifier. In a second operating mode S (standby operating mode), the rectifier circuit 22 operates as a half-wave rectifier. In the first operating mode B, the rectifier circuit 22 supplies a pulsating DC voltage, the potential of which with respect to the ground conductor can have an AC component. In the second operating mode S, the rectifier circuit 22 supplies a DC voltage, the potential of which with respect to the ground potential P E has a negligible or no exchange rate component. Reference symbol: 10 Operating device 11 light bulbs 12 - 14 LEDs 15 first end of the LED chain 16 second end of the LED chain 17 Output of the voltage converter circuit 18 18 Voltage converter circuit 19 Input of the voltage converter circuit 18 C1 parasitic capacitance of the voltage converter circuit 18 C2 parasitic capacitance of the voltage converter circuit 18 20 Control input of the voltage converter circuit 18 21 Control circuit 22 Rectifier circuit L Connection to the mains input of the rectifier circuit N Connection to the mains input of the rectifier circuit W Mains voltage input P E Protective conductor connection 23 full-wave rectifiers + positive line at the rectifier output - negative line at the rectifier output 24 half-wave rectifiers D, D' diode DbF bulk diode 25 Switching device 26 Control input 27 Metal part 28, 28' switch I B Operating current D1 - D4 diodes 29 optocouplers 30, 31 switches 32 controllers QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 200 431 A1

[0003] EP 2 823 691 B1

[0004]

Claims

[1] Control gear (10) for an LED light source (11) with a circuit arrangement (22, 18) arranged between an input (W) and an output (17), wherein the input (W) has a first terminal (L) and a second terminal (N) and can be connected to an AC voltage supply network, and wherein the output (17) can be connected to the LED light source (11), wherein the circuit arrangement (22, 18) comprises a rectifier circuit (22) connected to the input (W), and a voltage converter circuit (18) connected to the rectifier circuit (22) and connected to the output (17) in order to supply the LED light source (11) with operating current (I B ), with a control circuit (21) for controlling the voltage converter circuit (18), characterized by , that the rectifier circuit (22) is designed to assume a first operating mode (B) in which it operates as a full-wave rectifier, and a second operating mode (S) in which it operates as a half-wave rectifier. [2] Operating device according to claim 1, characterized by that the control circuit (21) is designed to cause the voltage converter circuit (18) in a first operating mode (B) to supply the LED lamp (11) with operating current (I B ) and, in a second operating mode (S), to cause the LED lamp (11) not to be supplied with operating current (I B ) to supply. [3] Operating device according to one of the preceding claims, characterized bythat the control circuit (21) is designed to transfer the rectifier circuit (22) into the first operating mode (B) when it also causes the voltage converter circuit (18) to operate in the first operating mode (B), and that the control circuit (21) is designed to transfer the rectifier circuit (22) into the second operating mode (S) when it also causes the voltage converter circuit (18) to operate in the second operating mode (S). [4] Operating device according to one of the preceding claims, characterized by that the control circuit (21) has a control input (E) which is arranged to receive an operating mode selection signal which can assume at least two states for distinguishing the desired operating modes (B, S). [5] Operating device according to one of the preceding claims, characterized bythat the rectifier circuit (22) comprises a full-wave rectifier (23) and a half-wave rectifier (24) which are connected in parallel or in series with one another. [6] Operating device according to one of the preceding claims, characterized by that the rectifier circuit (22) has a full-wave rectifier (23) with an AC voltage input and a DC voltage output (+, -), wherein a deactivatable half-wave rectifier (24) is arranged between the AC voltage input or the DC voltage output (+, -) on the one hand and the mains-side input (L, N) on the other hand. [7] Operating device according to claim 6, characterized by that the half-wave rectifier (24) includes a diode (D) leading from the input (L) to the full-wave rectifier (23) and bridgeable by a switch (28) and / or a diode (D') leading from the full-wave rectifier (23) to the input (N) and bridgeable by a switch (28'). [8] Operating device according to claim 7, characterized by that the full-wave rectifier (23) is a Graetz bridge rectifier. [9] Operating device according to claim 7, characterized by that the full-wave rectifier (23) is a synchronous rectifier with externally controlled switches (S1, S2, S3, S4). [10] Operating device according to one of claims 7 to 9, characterized by that the deactivatable half-wave rectifier (24) is designed to allow current to pass only in a single flow direction in its activated state, while in the deactivated state it is permeable to current in any flow direction. [11] Operating device according to claim 10, characterized by that the half-wave rectifier (24) is a bridgeable diode (D). [12] Operating device according to claim 11, characterized by that the half-wave rectifier (D) is a MOS transistor whose conduction channel bridges its bulk diode (Db). [13] Operating device according to one of claims 7 to 12, characterized by that the half-wave rectifier (24) is arranged between the first terminal (L) and the full-wave rectifier (23). [14] Operating device according to claim 13, characterized by that a further half-wave rectifier (24) is arranged between the second terminal (N) and the full-wave rectifier (23). [15] Operating device according to claim 1, characterized by that the rectifier circuit (22) has externally controllable switches (30, 31) in order to be operated as a full-wave rectifier (23) in the first operating mode (B) and as a half-wave rectifier (24) in the second operating mode (S).

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