Device and method for current equalizer for PWM-dimmed current sources of the lamp

Abstract

Device (V) for controlling at least one light source (LED), comprehensive - a lamp driver (T) with at least two channels (ch), - a measuring device (M) and - a control unit (CU), wherein each channel (ch) is assigned a PWM modulation unit (PWM), and wherein each of the PWM modulation units (PWM) can be controlled separately and individually by the control unit (CU), and wherein each of the PWM modulation units (PWM) is configured to switch exactly one current source (IQ), and wherein each of the current sources (IQ) is designed to be dependent on a PWM period (t PWM ) periodic PWM output signal of its associated PWM modulation unit (PWM) to supply a light source (LED) with electrical energy, whereby an electrical lamp current generated by the associated current source (IQ) flows through the lamp (LED), and / or wherein an electrical lamp voltage applied by the associated current source (IQ) is applied to the lamp (LED) relative to a supply line (VL) of the current sources (IQ), and wherein the respective PWM output signal of each PWM modulation unit (PWM) comprises a PWM pulse with a rising edge and a falling edge, and wherein a switch-on time (t E ) correlates with the rising edge or the falling edge of the PWM pulse, and where the PWM period (t PWM ) corresponds to a time period from the rising edge of the PWM pulse to the rising edge of the immediately following PWM pulse, and where the control unit (CU) is configured to send a control signal (CS) to the PWM modulation units (PWM) in order to determine the respective switch-on time (t E ) of the PWM pulses output by the control unit (CU) addressed PWM modulation units (PWM) per PWM modulation unit (PWM) separately and individually to each other within the PWM period (t PWM ) in such a way that - a resulting total current (i(t)) of the lamp currents and / or a total voltage (V Ges ) of the lamp voltages in the supply line (VL) compared to a reference potential (GND) over the PWM period (t PWM ) corresponds to a nearly constant value and / or - an effective value of an alternating signal component of the resulting total current (i(t)) of the lamp currents and / or the total voltage of the lamp voltages in the supply line (VL) of the current sources (IQ) relative to the reference potential (GND) over the PWM period (t PWM ), wherein the measuring device (M) is designed to record a measured value (MW), wherein the measured value (MW) is a measured value for the resulting total current (i(t)), and / or the measured value (MW) is a measured value for the total voltage (V Ges ) in the supply line (VL) of the current sources (IQ) compared to the reference potential (GND), wherein the control unit (CU) is arranged to send the control signal (CS) depending on the measured value (MW), wherein the control unit (CU) is arranged to send the control signal (CS) when - a deviation of the measured value (MW) from a predetermined and / or calculated mean value (MMW) exceeds a predetermined first threshold value, or - a deviation of a direct signal component (GSA) of the measured value (MW) from a predetermined comparison value is greater than a predetermined second threshold value, and wherein the control unit (CU) is configured to carry out this method until the deviation of the measured value (MW) from the mean value (MMW) is less than or equal to the first threshold value or until the deviation between the direct signal component (GSA) and the comparison value is less than or equal to the second threshold value.

Description

[0001] The invention relates to a device for controlling at least one lighting device, comprising a lighting device driver with at least two channels, a measuring device, and a control unit, wherein each channel is assigned a PWM modulation unit which is configured to switch precisely one current source, wherein each of the current sources is configured to supply a lighting device with electrical energy as a function of a PWM output signal from the PWM modulation unit assigned to it, which PWM output signal is periodic with a PWM period. Each of the PWM modulation units can be controlled separately and individually by the control unit. The control unit is configured to send a control signal to the PWM modulation units in order to shift the respective switch-on time of the PWM pulses output by the control unit.

[0002] Furthermore, the invention relates to a method for a temporal shift of a respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit.

[0003] From US 2011 / 0121761 A1, a method and a device for dynamically controlling an LED system comprising a PWM signal generator and a plurality of LED strings are known, wherein the PWM signal generator is configured to output a plurality of synchronized PWM signals in a phase-shifted manner and thus to reduce visual interference effects of PWM signal-operated LEDs.

[0004] US 2012 / 0098869 A1 discloses an LED control device for a plurality of LEDs, comprising a plurality of LED channels, a pulse width modulator, and an LED control unit. The LEDs are supplied with power by phase signals of different phases.

[0005] US 2008 / 0202312 A1 discloses a device for PWM-modulated control of LED strings, whereby inefficiencies and disturbances in light-emitting diode (LED)-based backlight systems for LCD televisions are reduced.

[0006] From US 2011 / 0267375 A1, an energy management method for a device comprising a plurality of individually controllable LED strings is known, which are dimmed in phase with each other by means of a pulse width modulator

[0007] From the state of the art, lighting devices such as light-emitting diodes and lasers are known in a wide variety of applications, with PWM-controlled constant current sources controlling the lighting devices.

[0008] A constant current source feeds an electric current into the lamp, whereby the electric current is set to a predetermined current value either structurally or by means of a control value signal.

[0009] The light source typically comprises an LED or an LED string comprising one or more LEDs connected in series, or a parallel connection of several LED strings. A constant current source controller switches the constant current source on and off, preferably in a pulse-like manner with a PWM period. The control unit typically controls the constant current source controller. The constant current source controller is preferably part of the respective PWM modulation unit that supplies the LED or LED string with electrical energy. If the constant current source is switched on for a PWM pulse duration during a PWM period, the constant current source thus only feeds this preset current into the light source during the on times for this PWM pulse duration. For the remaining off time of the PWM period outside the PWM pulse duration, the constant current source therefore typically only feeds a lower current or preferably no current into the light source.If the constant current source feeds the preset electrical current into the lamp during the PWM pulse duration, the constant current source supplies the lamp with electrical energy for the duration of the PWM pulse, thus causing the lamp to emit light. During the off-time of the PWM period, the constant current source supplies the lamp with less or preferably no electrical energy, thus causing the lamp to emit no light or only a low light intensity. Preferably, the lamp is dark during the off-time.

[0010] Current lighting drivers use PWM modulation units based on configurable PWM clock modulation units and / or duty cycle timers. The PWM modulation of the lighting power supply by the constant current source has, as defined in this document, PWM periods, each of which is assigned to the PWM pulses. Each PWM pulse has a rising edge and a falling edge, with the rising edge corresponding to an on-time and the falling edge to an off-time. Such a PWM period of a PWM pulse begins, as defined in this document, with the rising edge of the PWM pulse and ends with the rising edge of the immediately following PWM pulse of the PWM modulation.

[0011] Typically, a lamp driver comprises the control unit and a plurality of PWM modulation units, whereby the control unit can address each of the PWM modulation units individually. In a multi-channel lamp driver, a PWM modulation unit switches a current source for each channel, which supplies the lamp with energy according to a PWM output signal from the PWM modulation unit.

[0012] In currently known multi-channel LED drivers, it is common for all addressed PWM modulation units to output a PWM pulse simultaneously, or for the addressed PWM modulation units to emit the PWM pulses at equidistant intervals over the PWM period.

[0013] If all addressed PWM modulation units output a PWM pulse simultaneously, the turn-on times for all corresponding channels are identical. If all PWM pulses have identical PWM pulse durations, the turn-off times for all corresponding channels are also identical.

[0014] If the PWM pulses are shifted from each other by an equidistant amount of time, the switch-on and switch-off times of the addressed channels differ at least partially from each other.

[0015] In particular, the control unit causes the PWM modulation units to shift the PWM pulses relative to each other. Specifically, if the PWM pulses are shifted equidistantly in time, the control unit divides the length of the PWM period, which is identical for all channels of the LED driver, by the number of channels and shifts the PWM pulses relative to each other by the resulting amount of time.

[0016] In an n-channel LED driver, the control unit divides the PWM period t PWM by the number of channels n and then shifts the switching time for the channels relative to each other by an amount of t PWM / n. This division by n can preferably also be predetermined in the design, without the control unit actually having to perform a dividing process step.

[0017] For a k-th channel with 0≤k≤n-1, the switch-on time is correspondingly increased by an amount of k*(t PWM / n shifted to a start time t0 of the PWM period.

[0018] For each of the current sources controlled by the PWM modulation units, and thus for each of the corresponding channels, an inrush current flows through a supply line of the current sources during the duration of the corresponding PWM pulse. The inrush currents of the individual channels are summed in the supply line.

[0019] When the current sources are controlled simultaneously, where the PWM pulses of all addressed PWM modulation units completely overlap in time, the respective inrush currents add up to a summed pulse-shaped inrush current with a high amplitude for the PWM pulse duration, while no current flows in the supply line during the remaining PWM period. This leads to a very uneven load on the supply voltage in the supply line.

[0020] The equidistant temporal shift of the PWM pulses over the PWM period has the advantage that the inrush current for powering the lamps is lower during the on-time. In the special case where the PWM pulses all have an identical PWM pulse duration, this equidistant temporal shift of the PWM pulses over the PWM period leads to a nearly uniform distribution of the current over the PWM period. If the PWM pulses also have at least a nearly identical amplitude, this results in a nearly constant current in the supply line over the PWM period, thus ensuring optimal utilization of the supply voltage in the supply line.

[0021] If the individual PWM pulses have at least partially different PWM pulse durations and / or amplitudes depending on the respective duty cycles of the individual channels, this leads to a suboptimal utilization of the supply voltage in the supply line despite an equidistant temporal shift of the PWM pulses over the PWM period.

[0022] The object of the present invention is therefore to provide a solution for an improved multi-channel lamp driver which enables the most efficient utilization of the supply voltage for individual duty cycles of the individual channels, whereby the solution should be cost-effective and not entail major technical changes to a standard lamp driver.

[0023] The document presented here proposes a device and a method according to the independent claims to solve the problem.

[0024] Further advantageous embodiments of the invention can be found in the dependent claims, the description and the figures.

[0025] The proposed solution provides a device for controlling at least one luminous means, which device comprises a luminous means driver with at least two channels and a control unit, wherein each channel is assigned a PWM modulation unit.

[0026] In particular, each of the PWM modulation units can be controlled separately and individually by the control unit.

[0027] In particular, each of the PWM modulation units is designed to switch exactly one current source.

[0028] In particular, each of the current sources is configured to supply a light source with electrical energy depending on a PWM output signal of the PWM modulation unit assigned to it, which is periodic with a PWM period.

[0029] In particular, an electrical lamp current generated by the associated power source flows through the lamp.

[0030] In particular, additionally or alternatively, an electrical lamp voltage applied by the associated power source is present at the lamp relative to a supply line of the power sources.

[0031] In particular, the respective PWM output signal of each PWM modulation unit comprises a PWM pulse with a rising edge and a falling edge.

[0032] In particular, a turn-on time correlates with the rising edge or the falling edge of the PWM pulse.

[0033] In particular, the PWM period corresponds to a time span from the rising edge of the PWM pulse to the rising edge of the immediately following PWM pulse. In particular, the PWM period begins with the rising edge of the PWM pulse and ends with the rising edge of the immediately following PWM pulse.

[0034] In particular, the control unit is configured to send a control signal to the PWM modulation units in order to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that a resulting total current of the lamp currents and / or a total voltage of the lamp voltages in the supply line of the power sources corresponds to a virtually constant value with respect to a reference potential over the PWM period.

[0035] Additionally or alternatively, the device is configured to shift PWM pulses output by the PWM modulation units separately and individually from one another within the PWM period in such a way that an effective value of an alternating signal component of the resulting total current and / or the total voltage in the supply line of the current sources is reduced compared to the reference potential over the PWM period.

[0036] In particular, the resulting total current and / or the total voltage in the supply line of the current sources with respect to the reference potential over the PWM period corresponds to a nearly constant value if a relative deviation of an amplitude of an alternating signal of the resulting total current and / or a total voltage in the supply line with respect to the reference potential over the PWM period with respect to an associated direct signal is less than or equal to 50%, 30% or 10%.

[0037] In particular, the control unit is configured to use the control signal to individually shift a first switch-on time of a first PWM modulation unit relative to a second switch-on time of a second PWM modulation unit.

[0038] This shift in the switch-on times changes the spectrum of the temporal modulation of the total light amplitude emitted by the lamps as a whole, reducing the alternating component of the emitted light amplitude. This reduces the EMC emissions of the luminaire, including the lamps, as a whole.

[0039] In one embodiment, the device comprises at least one measuring device.

[0040] In one embodiment, the at least one measuring device is configured to record a measured value. In particular, the measured value is a measured value for the resulting total current. In particular, the measured value is a measured value for the total voltage in the supply line of the power sources relative to the reference potential.

[0041] In one embodiment, the control unit is configured to send the control signal depending on the measured value.

[0042] In particular, the measured value is the measured value for the resulting total current.

[0043] In particular, the measured value is the measured value for the total voltage in the supply line of the power sources compared to the reference potential.

[0044] In particular, the control unit is designed to determine the measured value for the resulting total current using the individual current measured values.

[0045] In particular, the control unit is designed to sum the individual current measured values ​​of the measuring devices of all channels.

[0046] In particular, the control unit is designed to determine the total voltage in the supply line of the power sources using the individual voltage measured values.

[0047] In particular, the control unit is designed to sum the individual voltage measured values ​​of the measuring devices of all channels.

[0048] In one embodiment, the control unit is configured to transmit the control signal depending on the alternating signal component of the temporal profile of the measured value (MW). In particular, the control unit is configured to transmit the control signal depending on an alternating signal of the measured value.

[0049] In one embodiment, the control unit is configured to send the control signal when a deviation of the measured value from a predetermined and / or calculated mean value exceeds a predetermined first threshold value.

[0050] In particular, the mean value corresponds to the measured value measured by the measuring device averaged over the PWM period. In particular, the control unit calculates the mean value.

[0051] In one embodiment, the control unit is configured to send the control signal when a deviation of a DC signal component of the measured value from a predetermined comparison value is greater than a predetermined second threshold value.

[0052] In one embodiment, the control unit is configured to divide the PWM pulse of the PWM output signal for at least one of the channels into a plurality of partial pulses. In particular, the control unit is configured to use the control signal to individually and individually shift the respective activation times of the partial pulses output by the PWM modulation units addressed by the control unit relative to one another within the PWM period.

[0053] In one embodiment, the control unit is configured to send the control signal to the PWM modulation units corresponding to individual values ​​predetermined for each channel for a current and / or a voltage for each of the current sources.

[0054] In particular, the control unit sends the control signal in order to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the resulting total current and / or the total voltage in the supply line corresponds to a nearly constant value over the PWM period.

[0055] Additionally or alternatively, the control unit sends the control signal to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the effective value of the alternating signal component of the resulting total current of the lamp currents and / or the total voltage in the supply line of the power sources is reduced compared to the reference potential over the PWM period.

[0056] In particular, at least in part, an individual value of the predetermined individual values ​​is assigned to one of the at least two channels.

[0057] In particular, the predetermined individual values ​​each correspond at least partially to a predetermined value for the lamp current and / or for the lamp voltage for the associated power source.

[0058] In particular, the individual values ​​predetermined for each channel correspond to a predetermined lamp current and / or a predetermined lamp voltage with which the respective power source supplies the respective associated lamp with energy for a predetermined period of time.

[0059] In one embodiment, at least one of the channels has the measuring device.

[0060] In one embodiment, each of the channels has a measuring device.

[0061] In particular, each of the channels of the multi-channel lamp driver is assigned a measuring device.

[0062] In particular, each measuring device is designed to measure an individual current measurement value for a respective lamp current of the respective associated power source.

[0063] In particular, each of the measuring devices assigned to a channel is configured to measure an individual current measurement value for a lamp current of the current source associated with the corresponding channel.

[0064] In particular, each measuring device is designed to measure a single voltage measurement value for a respective lamp voltage, which lamp voltage is applied to the respective lamp relative to the supply line of the power sources.

[0065] In particular, each of the measuring devices assigned to a channel is designed to measure a single voltage measurement value for a lamp voltage of the current source associated with the corresponding channel.

[0066] In particular, the sum of the individual current measured values ​​of all channels corresponds to the measured value for the resulting total current.

[0067] In particular, the sum of the individual voltage measured values ​​of all channels corresponds to the measured value for the total voltage in the supply line of the power sources.

[0068] In particular, the control unit shifts the switch-on times from one another until the deviation of the measured value from the mean value is less than or equal to the first threshold value.

[0069] In one embodiment, the device's integrated circuit automatically adjusts the turn-on time for each channel, with the control unit calculating the comparison value. In particular, the comparison value corresponds to an average value for the DC signal component.

[0070] In particular, the comparator compares the DC signal component with the comparison value. In particular, the comparator sends the comparator signal to the internal control unit if the deviation of the DC signal component from the comparison value is greater than the predefined second threshold.

[0071] In particular, the control unit sends the control signal when the internal control unit receives the comparator signal.

[0072] In particular, the control unit uses the control signal to shift the switching times of the PWM pulses for the respective channels separately and individually.

[0073] In particular, the control unit shifts the switch-on times from one another until the deviation of the DC signal component from the comparison value is less than or equal to the second threshold value.

[0074] In one embodiment, the device comprises a comparator. In particular, the comparator is configured to compare the measured value with the mean value and / or the DC signal component of the measured value with the comparison value.

[0075] In particular, the comparator is configured to send a comparator signal to the control unit when the deviation of the measured value from the mean value exceeds the first threshold value.

[0076] In particular, the comparator is configured to send a comparator signal to the control unit if the deviation of the DC signal component of the measured value from the comparison value is greater than the second threshold value.

[0077] In one embodiment, the control unit is configured to send the control signal depending on the comparator signal sent by the comparator.

[0078] In one embodiment, the control unit is configured to send the control signal in accordance with a manual input.

[0079] In one embodiment, the control unit is configured to send the control signal in accordance with a signal from a higher-level control device.

[0080] In particular, the control signal is sent according to a manual input or a signal from a higher-level control device if the pulse durations and amplitudes of the individual PWM pulses or partial pulses are known for each channel.

[0081] In one embodiment, the device comprises an integrated circuit.

[0082] In particular, the integrated circuit is configured to at least partially automatically shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the resulting total current and / or the total voltage in the supply line, in particular the measured value, corresponds to a virtually constant value over the PWM period.

[0083] In particular, the integrated circuit is configured to at least partially automatically shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the effective value of the alternating signal component of the resulting total current of the lamp currents and / or the total voltage in the supply line of the power sources is reduced relative to the reference potential over the PWM period. In particular, the integrated circuit is configured to automatically shift the second switch-on time for the second PWM modulation unit relative to the first switch-on time for the first PWM modulation unit in such a way that the measured value corresponds to a virtually constant value over the PWM period.

[0084] In one embodiment, the control unit is configured to send the control signal depending on an output signal of a neural network model.

[0085] In a further embodiment, the control unit is configured to execute the neural network model using a feature vector signal.

[0086] Preferably, the feature vector signal is a temporal sequence of preferably several feature vectors.

[0087] In particular, the feature vector signal is determined by a temporal progression of the measured value. The feature vectors of the feature vector signal therefore preferably depend, among other things, on the temporal progression of the measured value. The control unit (CU) can also use additional data to generate the feature vector signal. For example, the additional data can be data such as the measurement data from an EMC sensor or the signals from a higher-level control device.

[0088] In a further embodiment, the control unit is configured to determine the turn-on time of the PWM pulse of the PWM output signal of at least one of the PWM modulation units within the PWM period as a function of the output signal of the neural network model. In particular, the control unit is configured to determine and adjust the turn-on time of the PWM pulse of the PWM output signal of the PWM modulation units for each channel within the PWM period as a function of the output signal of the neural network model. In particular, the control unit is configured to adjust the first turn-on time of the first PWM modulation unit to the second turn-on time of the second PWM modulation unit as a function of the output signal of the neural network model.

[0089] Furthermore, the proposed solution provides a method for setting a resulting total current and / or a total voltage in a supply line of a plurality of current sources of a device described above to a nearly constant value. In particular, the resulting total current and / or the total voltage in the supply line of the current sources relative to the reference potential over the PWM period corresponds to a nearly constant value if a relative deviation of an amplitude of an alternating signal of the resulting total current and / or a total voltage in the supply line relative to the reference potential over the PWM period with respect to an associated direct signal is less than or equal to 50%, 30%, or 10%.

[0090] In particular, the proposed solution provides a method for adjusting an effective value of an alternating signal component of the resulting total current and / or the total voltage in the supply line of the current sources relative to a reference potential, so that the effective value of the alternating signal component is reduced over a PWM period.

[0091] In particular, the device comprises a lamp driver with at least two channels and a control unit.

[0092] In particular, each channel is assigned a PWM modulation unit.

[0093] In particular, the control unit is designed to control each of the PWM modulation units separately and individually.

[0094] In particular, each PWM modulation unit switches exactly one current source.

[0095] In particular, each of the current sources supplies a light source with electrical energy depending on a PWM output signal of the PWM modulation unit assigned to it, which is periodic with the PWM period.

[0096] In particular, an electrical lamp current generated by the associated power source flows through the lamp.

[0097] In particular, an electrical lamp voltage applied by the associated power source is present at the lamp compared to the supply line of the power sources.

[0098] In particular, the respective PWM output signal of each of the PWM modulation units comprises a PWM pulse with a rising edge and a falling edge.

[0099] In particular, a turn-on time correlates with the rising edge or the falling edge of the PWM pulse.

[0100] In particular, the PWM period corresponds to a time span between the rising / falling edges of two consecutive PWM pulses.

[0101] In particular, the control unit sends a control signal to the PWM modulation unit of at least one of the channels.

[0102] In particular, the control unit uses the control signal to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit individually and individually from one another within the PWM period.

[0103] In one embodiment, the control unit divides the PWM pulse of the PWM output signal for at least one of the channels into a plurality of partial pulses.

[0104] In particular, the control unit uses the control signal to shift the respective switch-on time of the partial pulses output by the PWM modulation units addressed by the control unit individually and individually from one another within the PWM period.

[0105] In one embodiment, the control unit sends the control signal to the PWM modulation units according to predetermined individual values ​​in order to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the resulting total current and / or the total voltage in the supply line corresponds to a nearly constant value over the PWM period.

[0106] In one embodiment, the control unit sends the control signal to the PWM modulation units according to predetermined individual values ​​in order to shift the respective switch-on time of the PWM pulses output by the PWM modulation units addressed by the control unit separately and individually from one another within the PWM period in such a way that the effective value of the alternating signal component of the resulting total current of the lamp currents and / or the total voltage in the supply line of the power sources is reduced compared to the reference potential over the PWM period.

[0107] In particular, at least in part, an individual value of the predetermined individual values ​​is assigned to one of the at least two channels.

[0108] In particular, the predetermined individual values ​​each correspond at least partially to a predetermined value for a lamp current and / or for a lamp voltage for the associated power source.

[0109] In one embodiment, the device comprises at least one measuring device.

[0110] In particular, the at least one measuring device records a measured value. In particular, the measured value is a measured value for the resulting total current. In particular, the measured value is a measured value for the total voltage in a supply line of the current sources relative to the reference potential.

[0111] In particular, each channel of the lamp driver has one of the at least one measuring device, wherein each of these measuring devices measures a single current measured value for a lamp current and / or a single voltage measured value for a lamp voltage of the associated current source.

[0112] In particular, the sum of the individual current measured values ​​of all channels corresponds to the measured value for the resulting total current.

[0113] In particular, the sum of the individual voltage measured values ​​of all channels corresponds to the measured value for the total voltage in the supply line.

[0114] In one embodiment, the control unit sends the control signal depending on the measured value. In particular, the control unit sends the control signal depending on the measured value for the resulting total current.

[0115] In particular, the control unit sends the control signal depending on the measured value for the total voltage in the supply line of the power sources relative to the reference potential. In particular, the control unit records the measured value measured by the measuring device. In particular, the control unit determines the measured value for the resulting total current using the individual current measured values.

[0116] In particular, the control unit uses the individual voltage measurements to determine the measured value for the total voltage in the supply line.

[0117] In particular, the control unit calculates the sum of all individual current measured values ​​and / or individual voltage measured values ​​to calculate the measured value.

[0118] In one embodiment, the control unit sends the control signal depending on the alternating signal component of the temporal course of the measured value, in particular depending on an alternating signal of the measured value.

[0119] In one embodiment, the control unit sends the control signal when a deviation of the measured value from a predetermined and / or calculated mean value exceeds a predetermined first threshold value.

[0120] In one embodiment, the control unit sends the control signal if a deviation of a DC signal component of the measured value from a predetermined comparison value is greater than a predetermined second threshold value.

[0121] In one embodiment, the device comprises a comparator. In particular, the comparator compares the measured value with the mean value. In particular, the comparator compares the DC signal component of the measured value with the comparison value.

[0122] In particular, the comparator sends a comparator signal to the control unit when the deviation of the measured value from the mean value exceeds the first threshold.

[0123] In particular, the comparator sends the comparator signal to the control unit if the deviation of the DC signal component of the measured value from the comparison value is greater than the second threshold value.

[0124] In one embodiment, the control unit sends the control signal depending on the comparator signal sent by the comparator.

[0125] In one embodiment, the device comprises a plurality of filters.

[0126] In particular, a first filter filters out a direct signal from the measured value. In particular, the first filter allows an alternating signal from the measured value to pass through. In particular, the alternating signal serves as the input signal for a second filter.

[0127] In particular, the second filter converts the AC signal into a rectifier output signal. In particular, the rectifier output signal serves as the input signal for a third filter. In particular, the third filter outputs the DC signal component of the rectifier output signal. In particular, the comparator compares the DC signal component with the specified comparison value.

[0128] In particular, the comparator sends the comparator signal to an internal control unit of the control unit when a difference between the DC signal component and the comparison value is greater than the second threshold value.

[0129] In particular, the control unit sends the control signal when the internal control unit receives the comparator signal.

[0130] In one embodiment, the control unit sends the control signal in accordance with a manual input.

[0131] In one embodiment, the control unit sends the control signal in accordance with a signal from a higher-level control device.

[0132] In one embodiment, the device comprises an integrated circuit. In particular, the integrated circuit automatically sets the turn-on time for each channel.

[0133] In particular, the control unit calculates the mean value for the measured value over the PWM period using the time course of the measured value.

[0134] In particular, the comparator compares the measured value with the mean value.

[0135] In particular, the comparator sends the comparator signal to the control unit if the deviation of the measured value from the mean value is greater than the specified first threshold value.

[0136] In particular, the control unit sends the control signal to the PWM modulation units when the control unit receives the comparator signal.

[0137] In particular, the control unit uses the control signal to shift the switching times of the PWM pulses for the respective channels separately and individually.

[0138] In one embodiment, a neural network model sets the turn-on times for the respective PWM modulation units.

[0139] In particular, the control unit shifts the switching times for the respective PWM modulation units in relation to each other depending on an output signal of the neural network model.

[0140] In a further embodiment, a temporal course of the measured value serves as an input signal for a feature vector extraction.

[0141] In particular, feature vector extraction yields a feature vector signal. The feature vector signal preferably comprises a temporal sequence of feature vectors. A feature vector preferably comprises an n-tuple of data and data values. A feature vector, as defined in this document, preferably summarizes the parameterizable properties of a temporal pattern in the temporal course of the measured value in a vectorial manner. Various features characteristic of the pattern form the various dimensions of this vector. The totality of the possible feature vectors is the feature space of the temporal course of the measured value. This feature vector signal with its feature vectors enables the automatic classification of the recorded temporal course of the measured value, since the feature vector signal greatly reduces the properties of the temporal course of the measured value to be classified.Preferably, a designer of a proposed device acquires an exemplary data set for exemplary, exemplary feature vector signals or exemplary temporal profiles of the measured value. Said designer of the proposed device typically performs a cluster analysis at the time of design in order to constructively improve the feature extraction and the structure of the neural network model executed by the control device. In particular, the input signal for the neural network model preferably comprises or corresponds to the feature vector signal with its feature vectors.

[0142] In particular, the control unit executes, among other things, the neural network model for evaluating the feature vector signal, preferably to control the PWM control units depending on, among other things, the output signals and / or output values ​​of the neural network model. The neural network model, which the control unit can execute, for example, preferably provides one or more output values ​​and / or output signals. For the sake of simplicity, this document refers to these one or more output values ​​and / or output signals as the output signal of the neural network model.

[0143] In a further embodiment, the control unit determines the switch-on time of the PWM pulse of the PWM output signal of at least one of the PWM modulation units within a PWM period depending on the output signal of the neural network model.

[0144] The use of the invention achieves a uniform current load of the voltage supply of the power sources for supplying energy to the lamps without the need for a costly change in the design of the lamp driver.

[0145] The proposal thus enables an efficient power supply design. At the same time, it avoids EMC problems caused by high inrush currents.

[0146] The proposal also reduces the peak current through uniform current loading. This allows designers to reduce the overall power supply's power consumption.

[0147] In contrast to the prior art, in which the PWM modulation units can only prevent a high starting current at the beginning of a respective PWM period, the device according to the invention and the method according to the invention make it possible to keep the current uniform over the entire PWM period.

[0148] The power supply can thus be designed to be smaller and less robust against power fluctuations. The power supply becomes more efficient through the use of the proposed solution. Furthermore, the invention allows for the reduction of measures against electromagnetic radiation.

[0149] This results in devices with multi-channel lamp drivers that are more cost-efficient.

[0150] The device according to the invention preferably controls a plurality of lighting means, in particular a plurality of LEDs.

[0151] The use of the device according to the invention for controlling other electronic components is conceivable and possible.

[0152] A light source can also be another electrical consumer.

[0153] Further advantageous embodiments, features and functions of the invention are explained in connection with the examples shown in the figures.

[0154] This shows: Fig. 1 resulting total current when all channels are switched on and off simultaneously; Fig. 2 resulting total current for PWM pulses of identical PWM pulse duration that are shifted equidistantly from one another over the PWM period; Fig. 3 resulting total current for PWM pulses of different PWM pulse durations that are shifted equidistantly from one another; Fig. 4 Share of the lamp currents of the respective channels in the resulting total current for two PWM periods, with all channels switched on simultaneously; Fig. 5 Share of the lamp currents of the respective channels in the resulting total current for two PWM periods, with switch-on times of the channels shifted equidistantly from each other; Fig. 6 Share of the luminous element currents of the respective channels in the resulting total current for two PWM periods, with switch-on times of the channels individually shifted from one another in time according to the method according to the invention; Fig. 7 schematic representation of an exemplary embodiment of the device according to the invention; and Fig. 8 schematic representation of a further exemplary embodiment of the device according to the invention.

[0155] A multi-channel lighting driver comprises a plurality of PWM modulation units, each of which switches a current source according to its periodic PWM output signal. The respective PWM modulation unit switches the respective current source on with a rising edge of the output PWM pulse and off with a falling edge of the PWM pulse, so that the current sources are switched on for the duration of the PWM pulse.

[0156] Each current source is assigned to a channel.

[0157] During an on-time corresponding to the respective PWM pulse duration, the associated current source supplies at least one lamp with energy according to the PWM output signal. In the following text, this document refers to the current flowing through the respective channel to supply energy to at least one lamp during the on-time as the lamp current of the respective channel.

[0158] A resulting total current flows through a supply line of the power sources during the on times for the respective channels, whereby the resulting total current in the supply line corresponds to the sum of the lamp currents for the channels.

[0159] Fig. 1 to Fig. 3 shows the lamp currents correlating with the PWM output signals for the respective channels ch and the resulting total current i(t) in the supply line using an example of a 16-channel lamp driver according to the prior art.

[0160] The length of the PWM period t PWM is identical for all PWM modulation units.

[0161] In the Fig. In the configuration shown in Figure 1, the lamp driver outputs a respective lamp current across all 16 channels ch0-ch15 simultaneously over an identical period of time with an identical amplitude, whereby the respective lamp currents correlate with the corresponding PWM output signal.

[0162] In this configuration, the PWM pulse durations, the PWM pulse amplitudes, and the switch-on times t E and switch-off times t A identical for all 16 channels ch. The channels ch0-ch15 thus have a common switch-on time t E and a common switch-off time t A , and thus a common one-time.

[0163] Further shows Fig. 1 the total current i(t) in the supply line resulting from the lamp currents of the channels ch0-ch15.

[0164] Due to the common switch-on time t E and the common switch-off time t AA resulting total current i(t) results in the supply line during the common on-time. During the remaining duration of the PWM period, no total current i(t) flows in the supply line.

[0165] This leads to a very uneven load of a supply voltage in the supply line.

[0166] While in Fig. 1 the 16 channels ch0-ch15 a common switch-on time t E and a common switch-off time t A have, the PWM pulses of the PWM modulation units, and thus the correlating lamp currents, of the individual channels ch in Fig. 2 are shifted in time. The switching times t E for the channels ch by 1 / 16th of the PWM period t PWM shifted relative to each other.

[0167] For the individual channels ch1-ch15, the exemplary 16-channel lamp driver results in a switch-on time tE from t0+k*(tPWM / 16), with 0≤k≤15, where t0 is a start time of the PWM period t PWM corresponds.

[0168] Due to the equidistant time shift of the switch-on times t E for all channels ch0-ch15 over the PWM period t PWM This results in a total current i(t) in the supply line that is almost constant over time.

[0169] This results in a uniform utilization of the supply voltage throughout the power supply. However, this application is very specific.

[0170] As a rule, the individual PWM pulse durations as well as the amplitudes of the PWM pulses of the respective channels differ from each other.

[0171] In the Fig. In the example shown in Figure 3, the PWM pulse durations of channels ch0-ch15 differ from each other as follows: The lamp driver gives in the example of Fig. 3 does not output a PWM signal via channels ch0 and ch1. For channels ch2, ch3 and ch13, the PWM pulse duration is 4 / 16 of the PWM period t PWM . For channels ch4, ch5 and ch12, the PWM pulse duration is 3 / 16 of the PWM period t PWM . For channels ch6, ch11 and ch15 the PWM pulse duration is 2 / 16 of the PWM period t PWM . For channel ch14, the PWM pulse duration is 1 / 16 of the PWM period t PWM . For channels ch7, ch8, ch9 and ch10, the PWM pulse duration corresponds to the PWM period t PWM .

[0172] The switch-on times t E are equivalent to the Fig. 2 example for each channel ch by 1 / 16th of the PWM period t PWM shifted from each other.

[0173] Despite the equidistant shift of the switching times t E over the PWM period t PWMthe differences in the PWM pulse durations and the respective correlating lamp currents of the respective channels ch lead to large fluctuations in the resulting total current i(t) in the supply line and thus to a suboptimal utilization of a supply voltage in the supply line.

[0174] Fig. 4-6 show the total current i(t) resulting in the supply line for two PWM periods t PWM , where for each point in time the respective proportion of the respective luminous fluxes of the respective channels ch is shown.

[0175] In the figures Fig. In the examples shown in Figures 4-6, the PWM output signals of the respective channels ch have at least partially different PWM pulse durations and at least partially different amplitudes.

[0176] According to the respective PWM output signals, the respective lamp currents for the respective channels ch differ in the same way.

[0177] The PWM pulse durations and amplitudes of the respective channels ch0-ch15 are shown in the Fig. The examples shown in 4-6 are identical.

[0178] In the Fig. In the example shown in Figure 4, all channels ch0-ch15 have a common switch-on time t E In this way, the summation of the respective lamp currents of the individual channels results in a resulting total current i(t) in the supply line, which is very uneven over the PWM period t PWM Thus, the resulting total current i(t) decreases gradually over the PWM period t PWM where in the example shown for a quarter of the PWM period t PWM (Range from 12 / 16 to 15 / 16 of the PWM period t PWM) the resulting total current i(t) is zero, so that no current flows in the supply line for this period.

[0179] Fig. 5 shows the Fig. 4 shown summed lamp currents for the respective channels ch0-ch15, where in Fig. 5 the switching times for the 16 channels ch0-ch15 are equidistant in time, i.e. by 1 / 16 of the PWM period t PWM , are shifted relative to each other.

[0180] In this way, at each moment of the PWM period t PWM a resulting total current i(t) in the supply line of the current sources.

[0181] However, due to the at least partially different PWM pulse durations and amplitudes of the respective lamp currents for the respective channels, a very uneven current flow of the resulting total current i(t) in the supply line still results.

[0182] Fig. 6 also shows the Fig. 4 shown summed lamp currents for the respective channels ch0-ch15, where in Fig. 6 the switching times for the 16 channels ch0-ch15 are shifted in time according to the method according to the invention in such a way that an almost uniform over the PWM period t PWM resulting total current i(t).

[0183] By means of the method according to the invention, an average value, in particular the arithmetic mean value, for the resulting total current i(t) over the PWM period t PWM In particular, the device according to the invention calculates the mean value for the resulting total current i(t).

[0184] In particular, a manual input specifies the mean value for the resulting total current i(t).

[0185] In particular, a signal from a higher-level control device specifies the mean value for the resulting total current i(t).

[0186] Subsequently, a control unit of the device according to the invention shifts the switch-on times of the individual channels ch in relation to one another in such a way that a deviation of the total current i(t) resulting from the luminous means currents of the respective channels ch from the calculated mean value is less than or equal to a predetermined first threshold value.

[0187] In this way, the device according to the invention divides the resulting total current i(t) in the supply line at a nearly constant value over the PWM period t by means of the method according to the invention PWM on.

[0188] The method according to the invention can be applied in an equivalent manner to adjust the total voltage in the supply line of the power sources relative to a reference potential. The total voltage in the supply line results from the lamp voltages applied to the respective lamps by the respective power source.

[0189] Fig. 7 shows a schematic representation of an exemplary embodiment of the device V according to the invention.

[0190] The device V comprises a control unit CU and a multi-channel lamp driver T.

[0191] Each channel ch of the multi-channel lamp driver T is assigned exactly one separately configurable PWM modulation unit PWM, which is connected to exactly one current source IQ. Each of the current sources IQ supplies exactly one LED lamp with electrical energy.

[0192] In such a case, exactly one LED lamp in the sense of Fig. 7 It can be a single light source, such as a single LED, or a series connection of several light sources or a parallel connection of the same.

[0193] The control unit (CU) can address each PWM modulation unit (PWM) individually. If the control unit (CU) addresses the PWM modulation unit (PWM), the PWM modulation unit (PWM) generates a PWM output signal. The PWM output signal typically has PWM periods, each of which is assigned to PWM pulses of the corresponding PWM modulation unit (PWM).

[0194] For the purposes of this document, a PWM pulse typically has a rising edge and a falling edge. This approach, for the purposes of this document, neglects any deviations from the actual pulse.

[0195] In the sense of this document, a PWM period of a PWM pulse begins with the rising edge of the PWM pulse and ends with the rising edge of the immediately following PWM pulse of the PWM modulation.

[0196] The PWM output signal switches the current source IQ, which is connected to the corresponding PWM modulation unit. The current source IQ supplies the corresponding LED with electrical energy according to the PWM output signal. The electrical energy supply to the LED is thus PWM-modulated depending on the PWM output signal.

[0197] A voltage converter, such as a switching regulator (SR) or a linear regulator, reduces the voltage drop across the current sources (IQ). The voltage converter can be a buck converter, a boost converter, a multi-quadrant converter, etc. At this point, the present document refers to the extensive literature on voltage converters and power electronics.

[0198] The voltage converter serves to protect the current sources IQ0 to IQn-1 from overloading due to an excessive current source operating voltage, which leads to an unwanted temperature increase of the current source transistors of the current sources IQ0 to IQn-1.

[0199] A measuring device M determines a measured value MW for the resulting total current i(t) and / or for a total voltage V Ges the potential of the supply line VL of the current sources IQ relative to a reference potential GND.

[0200] The measuring device M can be located outside the control unit CU or be part of the control unit CU.

[0201] The device V according to the invention is preferably configured so that the control unit CU can freely and independently set an individual time shift, also called a phase shift, for the activation time of the respective PWM pulses for each channel ch. In particular, the phase shift of the PWM pulses for the individual channels ch is dependent on their PWM pulse duration and / or amplitude.

[0202] In particular, the phase shift of the PWM pulses for the individual channels ch depends on the respective lamp currents of the channels ch.

[0203] Using the measured value MW recorded by the measuring device M, an average value MMW is calculated for the measured value MW over the PWM period.

[0204] In particular, the control unit CU calculates the mean value MMW for the measured value MW over the PWM period.

[0205] If the deviation of the measured value MW from the mean value MMW exceeds the specified first threshold, the control unit CU sends a control signal CS to the addressed channels ch. Using the control signal CS, the control unit CU shifts the activation times of the PWM pulses output by the respective PWM modulation units PWM.

[0206] In one embodiment, the control unit CU transmits the control signal CS in accordance with a manual input or in accordance with a signal from a higher-level control device. In particular, the control unit CU transmits the control signal CS in accordance with a manual input or in accordance with a signal from a higher-level control device if the PWM pulse durations and the amplitudes of the PWM pulses of each channel ch, and thus the corresponding lamp currents of the respective channel ch, are known.

[0207] In particular, the control unit CU sets the switch-on time for each channel ch individually and independently of each other, so that the deviation of the measured value MW from the mean value MMW is less than or equal to the first threshold value.

[0208] This results in an almost constant value for the measured value MW over the PWM period.

[0209] Control via manual input or signaling from a higher-level control device has the advantage of low implementation effort. However, this method is only partially effective due to the manual input.

[0210] In a further embodiment, the individual phase shift of the PWM pulses of the addressed PWM modulation units PWM is carried out by means of an integrated circuit IC, as in Fig. 7 shown.

[0211] The phase shift of the PWM pulses of the addressed PWM modulation units PWM is carried out automatically.

[0212] In particular, the control unit CU shifts the PWM pulses relative to each other in phase with respect to the common temporal start of the common PWM period using the measured value MW as input value by sending a corresponding control signal CS to the respective PWM modulation units PWM.

[0213] In order to ensure this, the control unit CU synchronizes each of the PWM modulation units PWM assigned to this control unit CU in a fixed phase relationship to the beginning of a PWM period, which the control unit CU preferentially uses to control the PWM modulation units PWM.

[0214] In particular, the control unit CU calculates the mean value MMW for the measured value MW over the PWM period using the measured value MW measured by the measuring device M.

[0215] A comparator K compares the measured value MW with the mean value MMW. If the deviation of the measured value MW from the mean value MMW is greater than the specified first threshold, the comparator sends a comparator signal KS to the control unit CU.

[0216] When the control unit CU receives the comparator signal KS, it sends the control signal CS to the PWM modulation units PWM. Using the control signal CS, the control unit CU shifts the activation times of the PWM pulses for the respective channels ch.

[0217] The device V performs this process iteratively until the deviation of the measured value MW from the mean value MMW is less than or equal to the first threshold. For this purpose, the control unit CU preferably checks whether the deviation of the measured value MW from the mean value MMW is less than or equal to the first threshold.

[0218] The comparator K can be located outside the control unit CU or be part of the control unit CU.

[0219] In a special realization of the Fig. 7, the device V comprises a plurality of filters F, as shown in Fig. 8 shown.

[0220] In the Fig. In the example shown in Figure 8, the control unit CU comprises an internal control unit CU', which comprises the control unit CU Fig. 7 replaced.

[0221] The filters F and the comparator K can be located outside the control unit CU, or, as in Fig. 8, be part of the control unit CU.

[0222] In particular, a first filter F1 filters out a DC signal from the measured value MW and allows an AC signal WS of the measured value MW to pass through. Preferably, the first filter F1 is a high-pass or band-pass filter that blocks the DC signal of a measured value MW.

[0223] In particular, the first filter F1 feeds the alternating signal WS directly or indirectly via additional signal processing units, if necessary, into a second filter F2. In particular, the second filter F2 is preferably a rectifier. In particular, a rectifier output signal GA output by the second filter F2 corresponds to an input signal for a third filter F3.

[0224] In particular, the third filter F3 is a low-pass filter. In particular, the output signal of the third filter F3 corresponds to a DC signal component GSA of the rectifier output signal GA. In this example, this DC signal component GSA corresponds to the effective value of the AC signal WS of the measured value signal of the time profile of the measured value MW.

[0225] In particular, the comparator K compares the DC signal component GSA with a comparison value, which corresponds to an average value for the DC signal component GSA calculated by the control unit CU. If the deviation between the DC signal component GSA and the comparison value is greater than a predetermined second threshold, the comparator K sends the comparator signal KS to the internal control unit CU'. If the internal control unit CU' receives the comparator signal KS, the control unit CU sends the control signal CS.

[0226] Using the control signal CS, the control unit CU shifts the switching times of the PWM pulses for the respective channels ch relative to each other.

[0227] The integrated circuit IC performs this process until the deviation between the DC signal component GSA and the comparison value is less than or equal to the second threshold value.

[0228] In particular, the control unit CU is a bus master.

[0229] In the Fig. In the example shown in Figure 8, the control unit CU sends the control signal CS to a plurality of bus slaves BS via interfaces S. Each of the bus slaves BS comprises at least one of the PWM modulation units PWM and at least one of the current sources IQ, wherein each of the at least one PWM modulation unit PWM controls exactly one of the current sources IQ, and each of the current sources IQ supplies an LED with energy in accordance with the PWM output signal of the corresponding PWM modulation unit PWM.

[0230] In the Fig. In the example shown in Figure 8, the control unit CU is integrated into the integrated circuit IC. If the control unit CU is a bus master, the control unit CU can be located outside the integrated circuit IC.

[0231] Furthermore, in the Fig. In the example shown in Figure 8, the current sources IQ are connected to ground. However, a design in which the current sources IQ are connected to a bias voltage is also conceivable.

[0232] In a further embodiment, a neural network model sets the time shift of the switch-on times for the PWM pulses.

[0233] In particular, a time course of the measured value MW recorded by the measuring device M corresponds to a total current i(t) and / or a total voltage V Ges on the supply line VL, an input signal for feature vector extraction. The feature vector extraction provides a feature vector signal, wherein an input signal for the neural network model comprises the feature vector signal. In particular, the feature vector signal corresponds to the input signal for the neural network model.

[0234] The control unit CU preferably comprises a processor that executes the neural network model.

[0235] The processor feeds the feature vector signal of the feature vector extraction into the neural network model and executes the neural network model.

[0236] If the neural network model detects insufficient quality in the distribution of the resulting total current i(t) or the resulting total voltage V Ges in the supply line VL, the neural network model generates a signal whose effect corresponds to the comparator signal KS. The control unit CU can then change the switching times of the PWM pulses within the PWM periods using the PWM modulation units PWM.

[0237] In particular, the control unit CU determines the switching times of the PWM pulses by the PWM modulation units PWM within the PWM periods depending on an output signal of the neural network model.

[0238] Thus, the control unit CU sends the control signal CS depending on the output signal of the neural network model.

[0239] If the neural network model detects insufficient quality in the distribution of a resulting total current i(t) or the resulting total voltage V Ges in the supply line VL and the neural network model generates a signal that corresponds in its effect to the comparator signal KS, the control unit CU then shifts the switch-on times of the PWM pulses of the PWM modulation units PWM depending on the output signal of the neural network model within the PWM period.

[0240] Signals in the sense of this document can also be variables of a processor program.

[0241] Insufficient quality in the distribution of the resulting total current i(t) or the resulting total voltage V Ges in the supply line VL is particularly evident in that the spectrum of the alternating signal component of the time course of the measured value signal from the measured values ​​MW has an amplitude in certain frequency ranges which is above a permitted maximum amplitude and / or that the effective value of the alternating signal component of the time course of the measured value signal from the measured values ​​MW is above a permitted maximum amplitude.

[0242] Preferably, the feature vector signal that the processor of the control unit CU typically uses to feed the neural network model is based on the spectrum and / or the root mean square value of said alternating signal component.

[0243] The individual phase shift of the PWM pulses of the addressed PWM modulation units PWM by means of an integrated circuit IC is more effective than a phase shift which is carried out by a manual input signal.

[0244] However, the implementation effort for an automated design using an integrated circuit (IC) is higher.

[0245] In a further embodiment of the invention, the control unit CU divides each of the PWM pulses for each channel ch into a plurality of partial pulses.

[0246] In particular, in this embodiment, the control unit CU preferably divides the individual PWM pulses for each channel into a plurality of partial pulses with a preferably identical partial pulse duration. For example, if the PWM pulse duration of a PWM pulse of a channel corresponds to 30% of the PWM period, the control unit CU can divide this PWM pulse, for example, into ten partial pulses with a pulse duration of 3% of the PWM period.

[0247] Based on the figures Fig. 4-6, the control unit CU can, for example, divide the PWM pulses for each channel ch in such a way that each partial pulse has a partial pulse duration of 1 / 16th of the PWM period duration t PWM has.

[0248] Instead of shifting the switch-on times for the PWM pulses of the individual channels ch in relation to each other, by dividing the PWM pulses into partial pulses it is possible to shift the switch-on times of the respective partial pulses for each channel ch separately and individually.

[0249] Instead of dividing the PWM pulses into sub-pulses of identical sub-pulse durations, it is also possible to divide the individual PWM pulses for each channel into a plurality of sub-pulses with at least partially different sub-pulse durations.

[0250] The individual phase shifting of the sub-pulses of the PWM pulses of the addressed PWM modulation units using an integrated circuit (IC) is highly effective. However, a corresponding automated design using the integrated circuit (IC) results in a high implementation effort.

[0251] The shift of the switch-on times shifts the PWM pulses or the individual partial pulses of the addressed PWM modulation units PWM of the individual channels ch in phase with each other in such a way that the deviation of the measured value MW from the mean value MMW is less than or equal to the first threshold value or the deviation between the DC signal component GSA and the comparison value is less than or equal to the second threshold value.

[0252] Accordingly, the control unit CU preferably shifts the phase of the activation times of the PWM pulses or the individual partial pulses of the addressed PWM modulation units PWM of the individual channels ch. In particular, the control unit CU or a higher-level unit controlling the control unit CU checks that the deviation of the measured value MW from the mean value MMW is less than or equal to the first threshold. In particular, the control unit CU or a higher-level unit controlling the control unit CU can also check that the deviation between the DC signal component GSA and the comparison value is less than or equal to the second threshold.

[0253] This results in an individual, not necessarily temporally equidistant, shift of the PWM pulses or partial pulses over the PWM period.

[0254] In this way, a nearly constant value is obtained for the measured value MW, in particular for the resulting total current i(t) and / or for the total voltage V Ges , over the PWM period, so that the interventions of the control unit achieve an optimal utilization of a supply voltage in the supply line VL for an individual control of the LED lamps. List of reference symbols ch Channel of the LED driver t E Switch-on time t A Switch-off time t PWM PWM period t0 start time of the PWM period V device T Driver PWM PWM modulation unit IQ power source LED bulbs VL supply line SR switching regulator M measuring device MW measured value i(t) resulting total current in the supply line VL GND reference potential VGes Total voltage relative to the reference potential GND in the supply line VLMMW Average value for the measured value MW over the PWM period t PWM IC Integrated Circuit CU control unit CU' internal control unit CS control signal K Comparator KS comparator signal F Filter F1 first filter F2 second filter F3 third filter WS alternating signal GA rectifier output signal GSA DC signal component S interface BS Bus Slave

Claims

[1] Device (V) for controlling at least one light source (LED), comprehensive - a lamp driver (T) with at least two channels (ch), - a measuring device (M) and - a control unit (CU), wherein each channel (ch) is assigned a PWM modulation unit (PWM), and wherein each of the PWM modulation units (PWM) can be controlled separately and individually by the control unit (CU), and wherein each of the PWM modulation units (PWM) is configured to switch exactly one current source (IQ), and wherein each of the current sources (IQ) is designed to be dependent on a PWM period (t PWM ) periodic PWM output signal of its associated PWM modulation unit (PWM) to supply a light source (LED) with electrical energy, whereby an electrical lamp current generated by the associated current source (IQ) flows through the lamp (LED), and / or wherein an electrical lamp voltage applied by the associated current source (IQ) is applied to the lamp (LED) relative to a supply line (VL) of the current sources (IQ), and wherein the respective PWM output signal of each PWM modulation unit (PWM) comprises a PWM pulse with a rising edge and a falling edge, and wherein a switch-on time (t E ) correlates with the rising edge or the falling edge of the PWM pulse, and where the PWM period (t PWM ) corresponds to a time period from the rising edge of the PWM pulse to the rising edge of the immediately following PWM pulse, and where the control unit (CU) is configured to send a control signal (CS) to the PWM modulation units (PWM) in order to determine the respective switch-on time (t E ) of the PWM pulses output by the control unit (CU) addressed PWM modulation units (PWM) per PWM modulation unit (PWM) separately and individually to each other within the PWM period (t PWM ) in such a way that - a resulting total current (i(t)) of the lamp currents and / or a total voltage (V Ges ) of the lamp voltages in the supply line (VL) compared to a reference potential (GND) over the PWM period (t PWM ) corresponds to a nearly constant value and / or - an effective value of an alternating signal component of the resulting total current (i(t)) of the lamp currents and / or the total voltage of the lamp voltages in the supply line (VL) of the current sources (IQ) relative to the reference potential (GND) over the PWM period (t PWM ), wherein the measuring device (M) is designed to record a measured value (MW), wherein the measured value (MW) is a measured value for the resulting total current (i(t)), and / or the measured value (MW) is a measured value for the total voltage (V Ges ) in the supply line (VL) of the current sources (IQ) compared to the reference potential (GND), wherein the control unit (CU) is arranged to send the control signal (CS) depending on the measured value (MW), wherein the control unit (CU) is arranged to send the control signal (CS) when - a deviation of the measured value (MW) from a predetermined and / or calculated mean value (MMW) exceeds a predetermined first threshold value, or - a deviation of a direct signal component (GSA) of the measured value (MW) from a predetermined comparison value is greater than a predetermined second threshold value, and wherein the control unit (CU) is configured to carry out this method until the deviation of the measured value (MW) from the mean value (MMW) is less than or equal to the first threshold value or until the deviation between the direct signal component (GSA) and the comparison value is less than or equal to the second threshold value. [2] Device (V) according to claim 1, characterized by that the control unit (CU) is designed to divide the PWM pulse of the PWM output signal for at least one of the channels (ch) into a plurality of partial pulses, and to determine the respective switch-on time (t E) of the partial pulses output by the control unit (CU) addressed PWM modulation units (PWM) individually and individually to each other within the PWM period (t PWM ) to be postponed. [3] Device (V) according to one of claims 1 to 2, characterized by , that at least one of the channels (ch) has the measuring device (M), in particular each of the channels (ch) has the measuring device (M), wherein each measuring device (M) is set up to - to measure a single current measurement value for a respective lamp current of the respective associated current source (IQ), and / or - to measure a single voltage measurement value for a respective lamp voltage, which lamp voltage is applied to the respective lamp (LED) with respect to the supply line (VL) of the current sources (IQ), whereby the sum of the single current measurement values ​​of all channels (ch) corresponds to the measurement value for the resulting total current (i(t)), and whereby the sum of the individual voltage measured values ​​of all channels (ch) equals the measured value (VMW) for the total voltage (V Ges ) in the supply line (VL). [4] Device (V) according to one of claims 1 to 3, characterized by that the control unit (CU) is designed to send the control signal (CS) as a function of the alternating signal component of the temporal course of the measured value (MW), in particular in the form of an alternating signal (WS) of the measured value (MW). [5] Device (V) according to one of claims 1 to 4, characterized bythat the device (V) comprises a comparator (K), wherein the comparator (K) is designed to compare the measured value (MW) with the mean value (MMW) and / or the DC signal component (GSA) of the measured value (MW) with the comparison value, and to send a comparator signal (KS) to the control unit (CU) when - the deviation of the measured value (MW) from the mean value (MMW) exceeds the first threshold, or - the deviation of the DC signal component (GSA) of the measured value (MW) from the comparison value is greater than the second threshold value. [6] Device (V) according to claim 5, characterized by that the control unit (CU) is arranged to send the control signal (CS) depending on the comparator signal (KS) sent by the comparator (K). [7] Device (V) according to one of claims 1 or 3 to 6, characterized bythat the control unit (CU) is configured to send the control signal (CS) in accordance with a manual input or a signal from a higher-level control device. [8] Device (V) according to one of the preceding claims, characterized by that the device (V) comprises an integrated circuit (IC), wherein the integrated circuit (IC) is designed to determine the respective switch-on time (t E ) of the PWM pulses output by the control unit (CU) addressed PWM modulation units (PWM) are at least temporarily automatically separated and individually from each other within the PWM period (t PWM ) in such a way that - the resulting total current (i(t)) and / or the total voltage (V Ges ) in the supply line (VL), in particular the measured value (MW), over the PWM period (t PWM ) corresponds to a nearly constant value and / or; - that the effective value of the alternating signal component of the resulting total current (i(t)) of the lamp currents and / or the total voltage (V Ges ) in the supply line (VL) of the current sources (IQ) relative to the reference potential (GND) over the PWM period (t PWM ) is reduced. [9] Device (V) according to one of the preceding claims, characterized by that the control unit (CU) is configured to send the control signal (CS) depending on an output signal of a neural network model. [10] Device (V) according to claim 9, characterized by that the control unit (CU) is configured to execute the neural network model using a feature vector signal, wherein the feature vector signal is determined by the temporal course of the measured value (MW). [11] Device (V) according to one of claims 9 to 10, characterized by that the control unit (CU) is set up to determine the switch-on time (tE ) of the PWM pulse of the PWM output signal of at least one of the PWM modulation units (PWM) within the PWM period (t PWM ) depending on the output signal of the neural network model. [12] Method for setting a resulting total current (i(t)) and / or a total voltage (V Ges ) in a supply line (VL) of a plurality of current sources (IQ) of a device (V) according to one of the preceding claims to a nearly constant value, and / or for setting an effective value of an alternating signal component of the resulting total current (i(t)) and / or the total voltage (V Ges ) in the supply line (VL) of the current sources (IQ) with respect to a reference potential (GND), so that the effective value of the alternating signal component over a PWM period (t PWM ) is reduced, characterized by , that the device (V) comprises a lamp driver (T) with at least two channels (ch), a measuring device (M), and a control unit (CU), wherein each channel (ch) is assigned a PWM modulation unit (PWM), wherein the control unit (CU) is configured to control each of the PWM modulation units (PWM) separately and individually, and wherein each PWM modulation unit (PWM) switches exactly one of the current sources (IQ), whereby each of the current sources (IQ) is dependent on a value corresponding to the PWM period (t PWM ) periodic PWM output signal of its associated PWM modulation unit (PWM) supplies a light source (LED) with electrical energy, whereby an electrical lamp current generated by the associated current source (IQ) flows through the lamp (LED), and / or wherein an electrical lamp voltage applied to the lamp (LED) by the associated current source (IQ) is applied to the supply line (VL) of the current sources (IQ), and the respective PWM output signal of each of the PWM modulation units (PWM) comprises a PWM pulse with a rising edge and a falling edge, wherein a switch-on time (t E ) correlates with the rising edge or the falling edge of the PWM pulse, where the PWM period (t PWM ) corresponds to a time period between the rising / falling edges of two consecutive PWM pulses, where the control unit (CU) sends a control signal (CS) to the PWM modulation unit (PWM) of at least one of the channels (ch), wherein the control unit (CU) uses the control signal (CS) to determine the respective switch-on time (t E) of the PWM pulses output by the control unit (CU) addressed PWM modulation units (PWM) individually and individually to each other within the PWM period (t PWM ), wherein at least one measuring device (M) records a measured value (MW), wherein the measured value (MW) is a measured value for the resulting total current (i(t)), and / or the measured value (MW) is a measured value for the total voltage (V Ges ) in the supply line (VL) of the current sources (IQ) compared to the reference potential (GND), wherein the control unit (CU) sends the control signal (CS) depending on the measured value (MW), wherein the control unit (CU) sends the control signal (CS) when a deviation of the measured value (MW) from a predetermined and / or calculated mean value (MMW) exceeds a predetermined first threshold value, or a deviation of a direct signal component (GSA) of the measured value (MW) from a predetermined comparison value is greater than a predetermined second threshold value, and wherein the control unit (CU) carries out this method until the deviation of the measured value (MW) from the mean value (MMW) is less than or equal to the first threshold value or until the deviation between the direct signal component (GSA) and the comparison value is less than or equal to the second threshold value. [13] Method according to claim 12, characterized by , that the control unit (CU) divides the PWM pulse of the PWM output signal for at least one of the channels (ch) into a plurality of partial pulses and the control unit (CU) uses the control signal (CS) to determine the respective switch-on time (t E ) of the partial pulses output by the control unit (CU) addressed PWM modulation units (PWM) individually and individually to each other within the PWM period (t PWM) shifts. [14] Method according to one of claims 12 to 13, characterized by , that at least one of the channels (ch) has the measuring device (M), in particular each of the channels (ch) has the measuring device (M), wherein each measuring device (M) - measures a single current measurement value for a respective lamp current of the respective associated current source (IQ), and / or - measures a single voltage measurement value for a respective lamp voltage which is applied to the respective lamp (LED) with respect to the supply line (VL) of the current sources (IQ), whereby the sum of the single current measurement values ​​of all channels (ch) corresponds to the measurement value for the resulting total current (i(t)), and whereby the sum of the individual voltage measured values ​​of all channels (ch) equals the measured value (VMW) for the total voltage (V Ges ) in the supply line (VL). [15] Method according to one of claims 12 to 14, characterized by that the control unit (CU) sends the control signal (CS) depending on the alternating signal component of the temporal course of the measured value (MW), in particular in the form of an alternating signal (WS), of the measured value (MW). [16] Method according to one of claims 12 to 15, characterized by , that the device (V) comprises a comparator (K), wherein the comparator (K) compares the measured value (MW) with the mean value (MMW) and / or the comparator (K) compares the DC signal component (GSA) of the measured value (MW) with the comparison value, and wherein the comparator (K) sends a comparator signal (KS) to the control unit (CU) when - the deviation of the measured value (MW) from the mean value (MMW) exceeds the first threshold, or - the deviation of the DC signal component (GSA) of the measured value (MW) from the comparison value is greater than the second threshold value. [17] Method according to claim 16, characterized by that the control unit (CU) sends the control signal (CS) depending on the comparator signal (KS) sent by the comparator (K). [18] Method according to one of claims 16 to 17, characterized by , that the device (V) comprises a plurality of filters (F), wherein a first filter (F1) filters out a direct signal from the measured value (MW) and allows an alternating signal (WS) of the measured value (MW) to pass through, wherein the alternating signal (WS) serves as an input signal for a second filter (F2); the second filter (F2) converts the alternating signal (WS) into a rectifier output signal (GA), whereby the rectifier output signal (GA) serves as an input signal for a third filter (F3); the third filter (F3) outputs the DC signal component (GSA) of the rectifier output signal (GA); the comparator (K) compares the DC signal component (GSA) with the specified comparison value; the comparator (K) sends the comparator signal (KS) to an internal control unit (CU') of the control unit (CU) if a difference between the DC signal component (GSA) and the comparison value is greater than the second threshold value; and when the internal control unit (CU') receives the comparator signal (KS), the control unit (CU) sends the control signal (CS). [19] Method according to one of claims 12 or 14 to 18, characterized by that the control unit (CU) sends the control signal (CS) in accordance with a manual input or a signal from a higher-level control device. [20] Method according to one of claims 16 to 17, characterized by , that the device (V) comprises an integrated circuit (IC), wherein the integrated circuit (IC) determines the switch-on time (t E) for each channel (ch), whereby the control unit (CU) uses the time course of the measured value (MW) over the PWM period (t PWM ) the mean value (MMW) for the measured value (MW) over the PWM period (t PWM ) calculated; the comparator (K) compares the measured value (MW) with the mean value (MMW); the comparator (K) sends the comparator signal (KS) to the control unit (CU) if the deviation of the measured value (MW) from the mean value (MMW) is greater than the predetermined first threshold value; the control unit (CU) sends the control signal (CS) to the PWM modulation units (PWM) when the control unit (CU) receives the comparator signal (KS); the control unit (CU) uses the control signal (CS) to determine the switch-on times (t E ) of the PWM pulses for the respective channels (ch) are shifted separately and individually in time, whereby the control unit (CU) determines the switching times (tE ) are shifted in time until the deviation of the measured value (MW) from the mean value (MMW) is less than or equal to the first threshold value. [21] Method according to one of claims 16 to 18, characterized by , that the integrated circuit (IC) of the device (V) has the switch-on time (t E ) for each channel (ch) automatically, whereby the control unit (CU) calculates the comparison value, wherein the comparison value corresponds to an average value for the direct signal component (GSA); the comparator (K) compares the direct signal component (GSA) with the comparison value; the comparator (K) sends the comparator signal (KS) to the internal control unit (CU') if the deviation of the direct signal component (GSA) from the comparison value is greater than the predetermined second threshold value; the control unit (CU) sends the control signal (CS) when the internal control unit (CU') receives the comparator signal (KS); the control unit (CU) uses the control signal (CS) to determine the switch-on times (t E ) of the PWM pulses for the respective channels (ch) are shifted separately and individually in time, whereby the control unit (CU) determines the switching times (t E ) are shifted in time relative to each other until the deviation of the DC signal component (GSA) from the comparison value is less than or equal to the second threshold value. [22] Method according to one of claims 12 to 21, characterized by that a neural network model can predict the shift in turn-on times (t E ) for the respective PWM modulation units (PWM). [23] Method according to claim 22, characterized by , that a temporal course of the measured value (MW) serves as an input signal for a feature vector extraction; the feature vector extraction provides a feature vector signal, wherein an input signal for the neural network model comprises the feature vector signal or the feature vector signal corresponds to the input signal for the neural network model; and the control unit (CU) executes the neural network model. [24] Method according to claim 23, characterized by that the control unit (CU) determines the switch-on time (t E ) of the PWM pulse of the PWM output signal of at least one of the PWM modulation units (PWM) within a PWM period as a function of an output signal of the neural network model.

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