Electronic ballast for LED lamps

Abstract

Electronic ballast (10) for LED lamps, comprising: a primary-side, first circuit section (10A) with input terminals (11) for connection to a mains supply and a secondary-side, second circuit section (10B), which is galvanically isolated from the first circuit section, with output terminals (12, 14; 13, 15) for supplying LED light sources; a control device (50) for controlling the ballast; wherein the first circuit part (10A) has a converter arrangement (102, 103, 104) with a first transformer (114), preferably an isolation transformer, for galvanic isolation, which provides a DC voltage on the secondary side for the second circuit part (10B); wherein the second circuit part (10B) has a first output channel (32) comprising a first switching converter (302) with a first switching element (304), in particular a power transistor, and at least one energy storage device, in particular a storage inductor (306) or a capacitor, for adjusting the output current at a first output terminal (12) for LED light sources; the second circuit part (10B) has a second output channel (33) comprising a second switching converter (303) with a second switching element (305), in particular a power transistor, and at least one energy storage device, in particular a storage choke (307) or a capacitor, for adjusting the output current at a second output terminal (13) for LED light sources; the control device comprises an integrated control circuit (50) arranged in the second circuit part (10B) and galvanically isolated from the first circuit part (10A), in particular a microcontroller, ASIC, FPGA or the like; and that the integrated control circuit (50) comprises a first driver output (52) which is connected to the switching element (304) of the first switching converter (302), a first control logic which generates a driver signal at the first driver output (52) to actuate this switching element (304), and a second driver output (53) which is connected to the switching element (305) of the second switching converter (303) and includes a second control logic which generates a driver signal at the second driver output (53) to actuate this switching element (305), characterized in that the first circuit part (10A) has primary-side interface connections (120) for signals with control or status information, and a first digital interface circuit (106) which is connected (56) to the integrated control circuit (50) in the second circuit part via a potential-isolating coupler, such as an optocoupler or an electronic coupler, the first interface circuit (106) is designed as a DALI interface module and can be addressed via a separate DALI address for each output channel (32; 33).

Description

[0001] The invention relates to an electronic ballast (ECG) for LED lamps according to the preamble of claim 1. The invention relates in particular to a ballast for connection to a mains voltage, which supplies a lamp with one or more light-emitting diodes with low voltage, in particular safety extra low voltage (SELV) and adjustable output current.

[0002] For safety reasons, electronic ballasts of this type feature galvanic isolation between the primary-side input terminals for the mains connection and the secondary-side output terminals for the light source. Energy transfer thus occurs between a higher-voltage area and a lower-voltage area, which are galvanically isolated from each other. This galvanic isolation is required for safety reasons, among other things, to ensure that user-adjustable or accessible components and connections are safely free of mains voltage.

[0003] A SELV electronic ballast for LED lamps according to the preamble of claim 1 is known from WO 2013 159 131 A1. This ballast comprises a primary-side, first circuit section with input terminals for connection to a mains supply and a secondary-side, second circuit section, which is galvanically isolated from the first circuit section. Thus, the output terminals for supplying LED lamps are galvanically decoupled from the mains-side input terminals.

[0004] In the electronic ballast (EVG) according to WO 2013 159 131 A1, a primary-side control device for controlling the EVG is provided in the first circuit section. This includes, among other things, a converter arrangement in the first circuit section, which has a transformer, e.g., an isolation transformer, and provides a DC voltage on the secondary side of the transformer for the second circuit section, whereby the transformer ensures galvanically isolated energy transfer between the two circuit sections.

[0005] The subsequently published patent application DE 10 2012 220 760 A1 (“Multifunctional ballast for supplying a consumer such as an LED module ...”) describes an LED ballast wherein the secondary-side circuit part has a first and a second output channel for the independent supply of two consumers, in particular light sources.

[0006] Typically, the output stage of an electronic ballast (EVG) for LED lamps comprises a switching converter with a power transistor and at least one energy storage device, such as an inductor or a capacitor. The switching converter is used to adjust the output current at a first output terminal for the LED lamp, thus allowing the luminous flux or brightness of the LED lamp to be adjusted, in particular dimmed as desired.

[0007] In standard SELV ballasts for LED lamps, e.g., according to WO 2013 159 131 A1, with multiple channels for supplying different lamps, the output circuitry typically incorporates separate control logic for each channel, e.g., in the form of a standard switching converter logic or switching converter ICs with an attached high-power transistor, or an encapsulated converter module. The galvanic isolation required to control each switching converter driver or switching converter IC necessitates separate decoupling in each signal path from the control device to the switching converter and back to the control device, e.g., using optocouplers. Consequently, the manufacturing costs of the ballast increase noticeably with the number of output channels.

[0008] Furthermore, a circuit arrangement according to WO 2013 159 131 A1 increases the effort required when adding certain desirable additional functions to the ballast.

[0009] US patent 8,638,045 B2 discloses an LED lighting system in which the color is controlled by activating different colored LED strings. A controller operates the switches with complementary duty cycles, and a transformer provides galvanic isolation. The document thus describes a method for color control of LED lighting.

[0010] German patent DE 10 2010 031 247 A1 discloses an LED lighting system comprising a first module with a DC / DC converter supplied with an input voltage, and a second module with a constant current source that supplies at least one LED module. The first module provides, in parallel with the supply of the second sub-module, at least one low-voltage supply for the second module.

[0011] German patent DE 10 2012 104 898 A1 describes an LED power supply device that has a DALI interface and is powered via an output capacitor voltage. The document focuses on the integration of a DALI interface for controlling LED lighting devices.

[0012] DE 101 63 957 A1 discloses an electronic ballast for fluorescent tubes that can supply several light sources. The ballast has a common rectifier for all connected light sources, but each light source has its own high-frequency generator that can be addressed and controlled.

[0013] One object of the invention is therefore to propose an electronic ballast with SELV protection that can be manufactured cost-effectively even with more than one output channel and preferably can also be cost-effectively equipped and / or retrofitted with additional functions. This object is achieved by a ballast according to claim 1.

[0014] In its simplest embodiment, the invention provides that, in a ballast according to the preamble of claim 1, the mains potential-free second circuit part has a first output channel and a second output channel for separately adjustable supply of an LED light source, wherein the control device comprises an integrated control circuit arranged in the second circuit part and galvanically isolated from the first circuit part, which may in particular be designed as a microcontroller, or as an ASIC, FPGA or the like.

[0015] According to the invention, the secondary-side integrated control circuit has a first driver output which is connected to a switching element of a first switching converter in the first output channel, a first control logic which generates a driver signal at the first driver output to actuate the switching element in the first output channel, and a second driver output which is connected to a switching element of a switching converter in the second output channel and comprises a second control logic which generates a driver signal at the second driver output to actuate this switching element of the second output channel.

[0016] The driver signals are preferably modulated, in particular pulse width modulated, signals, preferably with a fundamental frequency component > 50kHz, which serve to adjust the ratio of the on and off duration of the respective switching element.

[0017] Accordingly, each output channel has a switching converter acting as a power converter, which includes a respective switching element, in particular a power transistor, and at least one energy storage device, in particular a storage inductor or a capacitor, for adjusting the output current at the associated output terminal in order to adjust the power output to the LED light sources.

[0018] The proposed circuit arrangement achieves two key advantages. First, it eliminates the need for separate, complete switching converter modules or ICs for each output channel to control the switching elements. The integrated control circuit, such as a programmable microcontroller, can, in principle, implement any number of independent control logics without incurring additional material costs. Furthermore, while a separate signal path for driver signals from the control circuit to the switching converters of the output channels is still required, these paths, unlike those in known solutions with primary-side control devices, do not need to be decoupled using complex optocouplers or similar components.

[0019] A further advantage is the simplified programming of various functions and parameters, particularly regarding the control of the output channels, which allows for channel-specific and flexible adaptation to the requirements of the respective luminaire or environmental conditions. For example, automatic, adjustable protection functions for temperature monitoring of electronic ballasts and / or LED modules can be provided via an additional secondary-side interface (explained below). With such a design, various types of signal sources can be connected to the secondary side, such as sensors (e.g., light sensors or motion detectors), or passive components like a thermistor for temperature measurement, without their interaction with the control device being subject to limitations regarding galvanic isolation.In this way, it is also possible to set up a self-sufficient operation independent of the first digital interface, which nevertheless allows adjustments to the output power or makes adjustments depending on the sensor.

[0020] In a preferred embodiment, the first circuit section has primary-side interface connections for signals carrying control or status information, as well as a first digital interface circuit, configured as a DALI interface, which is connected to the integrated control circuit of the second circuit section via a potential-isolated coupler, such as an optocoupler or an electronic coupler. Since digital interfaces are generally standardized, there are no limitations regarding decoupling by a potential-isolated coupler. While it is desirable to provide a bidirectional signal path with double decoupling, this does not result in any additional effort compared to a circuit arrangement with a primary-side control device, which also requires double decoupling for each output channel for the driver signal and the measurement signal for control.

[0021] In a particularly preferred embodiment, as mentioned above, an additional interface is provided in the secondary circuit section. For this purpose, the second circuit section preferably has further secondary-side interface connections as well as a second analog and / or digital interface circuit, which is directly connected to the integrated control circuit. No galvanic isolation or complex decoupling is required. The functions can be configured without the limitations of decoupling, for example, by utilizing the ADC inputs of the integrated control circuit, as is typical for a microcontroller. Acquiring analog signals via couplers would only be possible with considerable effort. In contrast, the interaction with a second interface in the secondary-side control circuit can be programmed during manufacturing or use, or retrofitted via an update, according to user requirements.Programming can also be done via the first, digital interface, e.g. through commands to change register memory contents, which are provided for in DALI.

[0022] The integrated control circuit is conveniently configured to specify setpoints for the first and second control logic, particularly depending on control information received via the first and / or second interface circuit. Ideally, a separate setpoint can be specified for each output channel to allow for individual output current adjustment. In addition to the option of individually setting the current values ​​in each output channel, it is also possible, if necessary via programming through the first digital interface, to switch to parallel operation in which both output channels have the same current value.

[0023] In a manner known per se, the first and second switching elements are preferably implemented as separate power transistors. It may be desirable for each switching converter to have a corresponding gate driver circuit for the gate of the power transistor in order to minimize the switching time of the transistor and / or to avoid impermissible switching currents at the driver outputs of the integrated control circuit. The driver outputs then directly control the gate driver circuit with the respective driver signal, which does not require separate control logic, thus allowing the use of cost-effective driver components.

[0024] Depending on the integrated circuit used, it can also directly control the gate of the respective power transistors via its own driver outputs to reduce costs.

[0025] In a preferred embodiment, the integrated circuit generates driver signals which, at least in one operating mode for variable dimming, are doubly modulated: firstly, with a frequency component in the higher frequency range for current control by the switching converters, and secondly, e.g., for so-called PWM dimming, with a frequency component in the lower frequency range for dimming by ratio. The higher frequency range for current control at the output of the switching converters is preferably in the range of a few tens to a few hundred kilohertz (kHz). The lower frequency range for PWM dimming is in a range of a few hundred Hz, typically <1 kHz, which is not perceptible to the human eye.In an operating mode for pure amplitude dimming, however, double modulation is not required; the driver signals are preferably modulated with a fundamental frequency in the range between 50kHz and 500kHz, particularly preferably between 90kHz and 350kHz, especially pulse width modulated.

[0026] In a preferred embodiment, the first circuit section has an auxiliary power supply circuit with an auxiliary converter and a second transformer for providing a secondary-side supply voltage at the second transformer for the integrated control circuit. This allows for an energy-efficient supply of the secondary-side control circuit, and the main power supply or converter arrangement for powering the lamps can be significantly reduced in its power consumption or completely or partially switched off in a power-saving or standby mode.

[0027] For independent output current adjustment in each channel, the driver signals of the first and second control logics can each be set separately via the first interface circuit. This is preferably achieved by designing the first interface circuit as a DALI interface module and addressing each output channel via a separate DALI address. In this way, each output channel can be controlled or set virtually as an independent ballast within a higher-level lighting control system.

[0028] In an advantageous embodiment, the dimming profile during transitions between two power levels is also user-adjustable. For this purpose, preferably in addition to or together with a logarithmic dimming characteristic, e.g., according to the requirements of the DALI standard, which determines the ratio between the percentage setpoint and the output power, at least one dimming curve, programmable via the first or second interface, is stored separately in a memory of the integrated control circuit for each control logic. This dimming curve determines the change behavior of the modulated driver signal during a dimming transition from a first dimming value to a second dimming value. The circuit according to the invention also eliminates limitations, such as propagation delay, on the dynamic behavior through galvanic decoupling. The dimming characteristic itself can also be programmable.

[0029] Furthermore, a bidirectional data connection between the integrated control circuit allows information concerning the ballast to be sent via the first interface circuit and / or information acquired via the second interface circuit, e.g. to a higher-level lighting management system.

[0030] Furthermore, it can readily be provided that the integrated control circuit is configurable via the first interface circuit with regard to the information acquired via the second interface circuit. In particular, the characteristic curves for the different functions, e.g., for the desired output power depending on the acquired sensor signal, can be selectively set.

[0031] The integrated control circuit can acquire virtually any signal via the second interface circuit, such as a push-button signal, a brightness sensor signal, or a motion detector signal. It can also acquire resistance values. Specifically, the integrated control circuit can be connected to a thermal resistor via the second interface circuit and, based on the acquired resistance value, adjust the output current on at least one or both output channels depending on the temperature. A thermistor can thus be used to detect, for example, the operating temperature of the ballast itself and / or one or more light sources. Especially with LEDs, overheating should be avoided to maintain the desired long lifespan of the light source.

[0032] In a practical embodiment, this comprises a converter arrangement with a rectifier that feeds a power factor correction circuit, which in turn feeds a converter, in particular a resonant converter, e.g., an LLC resonant converter. Here, the first transformer for SELV potential isolation can be provided on the output side as part of the resonant converter.

[0033] In a manner known per se, the first and second switching converters can be designed as DC-DC converters, in particular buck converters. The circuit topology according to dependent claim 14 is particularly preferred.

[0034] Further details and advantages of the invention will become apparent below, without limitation, by describing a preferred embodiment with reference to the accompanying drawing. This drawing shows: Fig. 1 An embodiment of a SELV ballast designed according to the invention with two output stages in a schematic circuit diagram.

[0035] Fig. Figure 1 shows an electronic ballast, abbreviated EVG 10, for LED modules with a first and second circuit section 10A, 10B. The first circuit section 10A, connected to the mains lines L, N via the input terminals 11, is galvanically isolated from the second circuit section 10B (see dashed dividing line 105). The primary-side circuit section 10A has a converter arrangement with the following configuration: a rectifier 102 is connected to the output of an input-side EMC filter 101. This rectifier supplies a power factor correction circuit 103 (PFC) and an auxiliary power supply 108. The power factor correction circuit 103 generates a DC voltage in the range of several hundred volts at the intermediate circuit node 111, which supplies an LLC resonant converter 104 of the converter arrangement. The LLC resonant transducer 104 has a first transformer 114 at its output, e.g.an isolation transformer or the like, for power transmission to the second circuit part 10B under galvanic isolation 105.

[0036] As a further main component, the first circuit section 10A comprises, in addition to the converter arrangement 102, 103, 104 and the auxiliary power supply 108, a first DALI interface circuit 106 with primary-side interface connections 120 for communication via a bus according to the DALI standard (primary-side refers here to the first circuit section 10A, secondary-side to the second circuit section 10B). An output voltage regulation of the LLC resonant converter 104 is achieved via a voltage measurement device 301 on the secondary side of the first transformer 114 and an optocoupler 112 with galvanically isolated feedback to the LLC resonant converter 104. To stabilize the regulated voltage, a capacitor is connected in parallel at the output node of the transformer 114, i.e., at the secondary winding in the case of an isolation transformer, in the second circuit section 10B, cf. Fig. 1.

[0037] In the example shown, the transformer 114 feeds two output channels 32, 33 in parallel, whereby three or more output channels in the second circuit part 10B can also be operated according to the same principle. Fig. 1 are feasible.

[0038] Each output channel 32, 33 has its own power converter in the form of a switching converter 302, 303, in Fig. 1. For example, a buck converter. Accordingly, each switching converter 302, 303 comprises a series circuit connected on the secondary side between the first transformer 114 and the ground potential decoupled from the earth connection. This circuit consists of a blocking diode, a power transistor 304, 305, and a shunt resistor. A series circuit consisting of a smoothing capacitor and a storage inductor 306, 307 is connected in parallel to the blocking diode. In this topology, the output terminals 12; 13 and 14, 15 are connected to... Fig. 1 at the node between the smoothing capacitor and the storage choke 306, 307 or at the common node of both series circuits, i.e. at the secondary-side coil tap of the first transformer 114.

[0039] Any switching converter type is within the scope of the invention, provided that each output channel 32, 33 has its own switching converter 302, 303 and the respective output current, i.e., the current through the connected LED module, is adjustable as required.

[0040] A key component of the second circuit section 10B is an integrated control circuit 50, e.g., in the form of a microcontroller, which, among other things, independently controls the switching converters 302 and 303. For this purpose, the integrated control circuit 50 has a first and a second driver output 52 and 53, which are connected to the corresponding power transistors 304 and 305 of the first and second switching converters 302 and 303, respectively. The integrated control circuit 50 incorporates, for example, a first and a second control logic through suitable programming. The first control logic generates a pulse-width modulated driver signal at the first driver output 52 to actuate the first power transistor 304. The same applies to the second control logic, which actuates the second power transistor 305 in the same way. By setting the duty cycle or the relative on-time, the control logic can be adjusted.The integrated control circuit 50 regulates the output current continuously and, if necessary, individually for each output channel 32, 33.

[0041] The integrated control circuit 50 has a signal path 56 to the digital interface circuit 106 for data communication, in which an optocoupler is also provided between the first and second circuit part 10A, 10B for decoupling 105 (not shown in detail).

[0042] The auxiliary power supply 108, e.g., in the form of a flyback converter, has a second transformer 118 for galvanic isolation 105, which provides a secondary supply voltage. This voltage is used to supply the integrated control circuit 50 via a low-voltage supply 202. The integrated control circuit 50 has a control output 58 for controlling the auxiliary power supply 108. This output output, by changing the measured value, interacts with a circuit 201 for voltage measurement to regulate the output voltage of the auxiliary power supply 108. In particular, the integrated control circuit 50 can put the auxiliary power supply 108 into a power-saving mode by changing the voltage in the circuit 201, which is measured via feedback through the optocoupler 107. In the first circuit section 10A a threshold switch 110 is provided for switching off the power factor correction circuit 103 and the LLC resonant converter 104 when the auxiliary supply 108 is in power saving mode.For this purpose, the integrated control circuit 50, with its control output 58, influences the output voltage measurement of the circuit 201 (voltage measurement for the output voltage regulation of the auxiliary supply 108) such that the voltage in the auxiliary supply 108 is reduced to such an extent that it is essentially only sufficient to supply the integrated control circuit 50. At the same time, the voltage provided by a capacitor 109 is reduced to such an extent that the threshold value of the threshold switch 110 is undershot, and the power factor correction circuit 103 and the LLC resonant converter 104 are switched off by this switch.

[0043] The integrated control circuit 50 interacts with an analog / digital interface circuit 400 located in the second circuit section 10B via signal paths 403 and 404. The secondary-side interface connections 401 and 402, unlike signal path 56, are directly connected to the integrated control circuit 50, as the second interface circuit 400 is already galvanically isolated from the first circuit section 10A. The interface circuit 400 is supplied directly from the transformer 118 of the auxiliary power supply 108 via the supply line 405.

[0044] Parameters for setting the functionality of the interface circuit 400 and the electronic ballast 10 are stored in a register memory of the integrated control circuit 50 and can be modified. For example, a programmable dimming curve can be set via the first or second interface circuit 106; 400 for setting dynamic dimming profiles. The integrated control circuit can be configured, for example, via the first interface circuit 106 with regard to the information acquired via the second interface circuit 400, e.g., for detecting a signal from a sensor 412 or a measured resistance value of a thermistor 412 connected to the secondary-side interface terminals 401, 402. For example, the output current of at least one output channel or both output channels 32; 33 can be set to vary depending on the temperature or to be limited to a fixed upper limit.Alternatively, the corresponding setting can also be made exclusively via the second interface 400 itself. Furthermore, the integrated control circuit 50 can send information about the electronic ballast 10 to a higher-level system via the first interface 106, or information acquired via the second interface 400 (e.g., light sensor signal level, temperature, or similar).

[0045] Finally, some functional aspects should be mentioned. The EVG 10 has a separate DALI address for each output channel 32 and 33, thus enabling their independent control in a simple manner. This is achieved by the integrated control circuit 50. For example, the two output channels 32 and 33 can be assigned to different lighting groups. Application examples include white / white-color light control or direct / indirect lighting solutions. For applications where individual control of the EVG output channels 32 and 33 is not required, a so-called single-address mode can be used; that is, the EVG 10 then has only one address within a DALI installation.

[0046] Typically, the nominal current values ​​of the two output channels can be set independently in the range of approximately 200 to 1000 mA. In addition to individual setting of the two output channels 32 and 33, parallel operation with the same current value for both output channels 32 and 33 can also be switched via the interface circuit 400.

[0047] The interface circuit 400 allows the connection of a passive current sink, e.g., a temperature- or light-dependent resistor. The integrated control circuit 50, in conjunction with the interface circuit 400, evaluates the currently applied resistance value and automatically adjusts, e.g., the output currents in the electronic ballast 10, according to an adjustable characteristic curve. This response characteristic is preferably also programmable via the second interface circuit 400, or alternatively via the first interface circuit 106, and stored in the integrated control circuit 50. For example, the output currents of output channels 32 and 33 can be defined via an external ohmic resistor. Reference symbol list

[0048] Fig. 1 10 EVG 10A first circuit section 10B second circuit part 11 input connections 12, 14 first output connections 13, 15 second output connections 32 first output channel 33 second output channel 50 integrated control circuit 52 first driver output 53 second driver output 56 Signal path for DALI interface 58 Control output for auxiliary supply 101 EMC filters 102 rectifiers 103 Power Factor Correction Circuit (PFC) 104 LLC resonant transducer 105 (conceptual) galvanic dividing line 106 DALI interface circuit including optocoupler 107 Optocouplers for voltage feedback to auxiliary power supply 108 Aid provision 109 Primary care support 110 threshold switches for shutdown 111 Intermediate circuit nodes 112 Optocouplers for feedback to LLC resonant transducers 114 first transmitter 118 second transmitter 120 first interface connections 201 Voltage measurement for auxiliary power supply control 202 Low-voltage supply 301 Voltage measurement for LLC output voltage regulation 302 first switching converter 303 second switching converter 304, 305 Power transistor 306, 307 Storage choke (coil) 400 second interface circuit 401, 402 second interface ports 403, 404 Signal paths for second interface circuit 405 Supply line 410 (opt.) Resistor (e.g. thermistor) 412 (opt.) Sensor (e.g. light sensor)

Claims

[1] Electronic ballast (10) for LED lamps, comprising: a primary-side, first circuit section (10A) with input terminals (11) for connection to a mains supply and a secondary-side, second circuit section (10B), which is galvanically isolated from the first circuit section, with output terminals (12, 14; 13, 15) for supplying LED light sources; a control device (50) for controlling the ballast; wherein the first circuit part (10A) has a converter arrangement (102, 103, 104) with a first transformer (114), preferably an isolation transformer, for galvanic isolation, which provides a DC voltage on the secondary side for the second circuit part (10B); wherein the second circuit part (10B) has a first output channel (32) comprising a first switching converter (302) with a first switching element (304), in particular a power transistor, and at least one energy storage device, in particular a storage inductor (306) or a capacitor, for adjusting the output current at a first output terminal (12) for LED light sources; the second circuit part (10B) has a second output channel (33) comprising a second switching converter (303) with a second switching element (305), in particular a power transistor, and at least one energy storage device, in particular a storage choke (307) or a capacitor, for adjusting the output current at a second output terminal (13) for LED light sources; the control device comprises an integrated control circuit (50) arranged in the second circuit part (10B) and galvanically isolated from the first circuit part (10A), in particular a microcontroller, ASIC, FPGA or the like; and that the integrated control circuit (50) comprises a first driver output (52) which is connected to the switching element (304) of the first switching converter (302), a first control logic which generates a driver signal at the first driver output (52) to actuate this switching element (304), and a second driver output (53) which is connected to the switching element (305) of the second switching converter (303) and includes a second control logic which generates a driver signal at the second driver output (53) to actuate this switching element (305), characterized by, that the first circuit part (10A) has primary-side interface connections (120) for signals with control or status information, as well as a first digital interface circuit (106) which is connected (56) to the integrated control circuit (50) in the second circuit part via a potential-isolating coupler, such as an optocoupler or an electronic coupler, the first interface circuit (106) is designed as a DALI interface module and can be addressed via a separate DALI address for each output channel (32; 33). [2] Ballast according to claim 1, characterized by , that the second circuit part (10B) has further secondary-side interface connections (401, 402) as well as a second analog and / or digital interface circuit (400) which is directly connected (403, 404) to the integrated control circuit (50). [3] Ballast according to claim 1 or 2, characterized by, that the integrated control circuit (50) is configured to generate driver signals at the first and second driver outputs (52, 53) which are pulse width modulated, in particular with a fundamental frequency in a frequency range of 50kHz to 500kHz. [4] Ballast according to claim 2 or 3, characterized by , that the integrated control circuit (50) is further configured to specify setpoint values ​​to the first and second control logic, in particular depending on control information obtained via the first interface circuit (106) and / or via the second interface circuit (400), wherein preferably a setpoint is specified separately for each switching converter (302; 303) for individual output current adjustment. [5] Ballast according to any one of claims 1 to 4, characterized by, that the first and second switching elements are each a power transistor (304; 305), the first and second switching converters each have a corresponding gate driver circuit for the gate of the power transistor (304; 305), and the first and second driver outputs (52; 53) of the integrated control circuit (50) directly drive the gate driver circuit with the respective driver signal. [6] Ballast according to any one of claims 1 to 5, characterized by , that the first circuit part (10A) has an auxiliary supply (108) with an auxiliary converter, in particular a flyback converter, and a second transformer (115) to provide a supply voltage on the secondary side of the second transformer for the integrated control circuit. [7] Ballast according to any one of claims 1 to 6, characterized by, the driver signals of the driver outputs (52; 53) can be set separately in the first control logic and the second control logic via the first interface circuit (106). [8] Ballast according to any one of claims 2 to 7, characterized by , that in a memory of the integrated control circuit (50) at least one dimming curve programmable via the first and / or second interface circuit (106; 400) is stored separately for each control logic, which determines the change behavior of the modulated driver signal during a dimming process from a first dimming value to a second dimming value. [9] Ballast according to any one of claims 1 to 8, characterized by , that the integrated control circuit (50) provides information concerning the ballast (10) via the first interface circuit (106). [10] Ballast according to any one of claims 2 to 9, characterized by, that the integrated control circuit (50) is configurable via the first interface circuit (106) with regard to the information acquired via the second interface circuit (400), e.g. for the detection of a button signal, a brightness sensor or motion detector signal or a resistance value of a button, sensor (412) or resistor (410) connected to the secondary-side interface terminals. [11] Ballast according to any one of claims 2 to 10, characterized by , that the integrated control circuit (50) is connected via the second interface circuit to a thermal resistor (410) and adjusts the output current of at least one output channel or both output channels (32; 33) depending on the temperature. [12] Ballast according to any one of claims 1 to 11, characterized by, that the converter arrangement comprises a rectifier (102), a power factor correction circuit (103) and a converter, in particular a resonant converter (104) such as an LLC resonant converter, wherein the first transformer (114) is provided on the output side of the resonant converter (104). [13] Ballast according to any one of claims 1 to 12, characterized by, that the first and the second switching converters (302; 303) are each designed as DC voltage converters, in particular as buck converters, wherein preferably the first and the second switching converters (302; 303) each comprise a series circuit with diode, power transistor (304; 305) and resistor connected on the secondary side between the first transformer (114) and ground and a series circuit with smoothing capacitor and storage inductor (306; 307) connected in parallel to the diode, wherein one output terminal (12, 13) taps off at the node between smoothing capacitor and storage inductor (306; 307) and the other output terminal (14; 15) taps off at the common node of both series circuits on the first transformer (114).

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