Patent Description:
Near Field Communication, NFC, modules can be used for configuring LED drivers or other operating devices for lighting means. Usually, a control circuitry of the LED driver or operating device, such as a microcontroller, can be used in order to communicate with the NFC module.

It is known to use such NFC modules to translate a configuration signal for the LED driver into a pulse-width-modulated signal (e.g., representing an LED current) which can be fed to an integrated control circuit of the LED-driver without the need of further intelligence, such as an extra control circuitry or microcontroller.

Typically, such NFC modules convert a NFC signal into a PWM signal via an integrated circuitry on the NFC module, wherein the duty cycle of the PWM signal reflects the wirelessly received signal.

Moreover, it is known that a control circuitry for operating devices for lighting means can comprise a programming input pin, at which such analog DC voltage may be supplied in order to input a nominal value for the current through the lighting means, especially through an LED load.

Thus, using the NFC communication, the nominal current for LEDs may be programmed.

<CIT> discloses a power regulation for lighting using NFC. A NFC transceiver is used to make the programming of the nominal set-point easier.

Moreover, in some situations, it may be required to perform an LED current selection. However, the previously mentioned solutions make use of NFC modules, which require the presence of a control circuitry such as a microcontroller. This increases the complexity of the NFC modules.

Further, many operating devices have a so-called "DC level feature", which allows to detect and distinguish between an AC and a DC supply voltage. It is, however, difficult to implement such a DC level feature in an operating device without making use of additional intelligence.

Thus, it is an objective to provide for an improved operating device for lighting means.

The object of the present invention is achieved by the solution provided in the enclosed independent claims <NUM> and <NUM>.

According to a first aspect, the invention relates to an operating device for lighting means, comprising: output terminals supplying lighting means, such as e.g. a LED load, a control circuitry for controlling the electrical supply of the lighting means, a NFC module configured to receive NFC signals and output a pulse width modulation, PWM, signal with variable duty cycle, a conversion circuitry arranged for being supplied with the PWM signal and for outputting a DC voltage supplied to an input of the control circuitry. Moreover, the DC voltage is a function of the duty cycle of the PWM signal according to a set conversion rate and the conversion circuitry is configured to be supplied with an internal control signal to set at least two conversion rates.

This provides the advantage that, by making use of the above mentioned NFC module, there is no need for further intelligence within the operating device for lighting means, which is configurable by means of the NFC module. The control circuitry may be a microcontroller. The control signal may comprise an AC or DC voltage signal.

According to the invention, the operating device comprises a detection circuitry configured to detect if a supply voltage of the operating device is a AC or DC voltage and to set the control signal for the conversion rate differently in case of the presence of a AC or DC signal, respectively.

In an implementation form of the first aspect, the control circuitry is configured to map the level of the supplied DC voltage into a nominal current for the LED load and to control the operation of the lighting means, e.g. by controlling a switch operation of at least one switch of a switched converter such that an actual current matches the nominal current.

In an implementation form of the first aspect, the conversion rate can be varied continuously or incrementally in steps by said control signal.

In an implementation form of the first aspect, the conversion circuitry comprises a R-C low pass filter configured to convert the PWM signal into the DC voltage.

According to the first aspect, the operating device comprises a detection circuitry configured to detect if a supply voltage of the operating device is an AC or DC voltage and to set the control signal for the conversion rate differently in case of the presence of an AC or DC signal, respectively.

This provides the advantage that the operating device has a DC level feature, i.e. it can detect whether a mains voltage is an AC or a DC voltage. In case of a detection of a DC signal, such as from a battery inside the operating device, the output current of the operating device for lighting means, e.g., LED driver, can be reduced, so that the battery lasts longer for example in case of an emergency situation.

In an implementation form of the first aspect, the detection circuitry comprises a voltage divider or a R-C low pass filter or a capacitor.

In an implementation form of the first aspect, the operating device comprises a limiting circuitry configured to limit the DC voltage in case the set control signal is a DC signal.

In an implementation form of the first aspect, the limiting circuitry comprises a Zener diode configured to clamp the DC signal.

In an implementation form of the first aspect, the limiting circuitry comprises a switch configured to switch if the control signal is a DC signal.

In particular, the switch is configured to switch on a connection between the detection circuitry and the limiting circuitry.

In an implementation form of the first aspect, the NFC module is configured to program a nominal current of the LED load.

According to a second aspect, the invention relates to a system comprising a NFC transmitting handheld device and an operating device according to the first aspect or any one of the implementation forms thereof.

According to a third aspect, the invention relates to a method for operating a device for lighting means, comprising: supplying lighting means, such as LED load, by output terminals; controlling the electrical supply of the lighting means; receiving NFC signals; outputting a pulse width modulation, PWM, signal with variable duty cycle; supplying a conversion circuitry with the PWM signal; outputting a DC voltage supplied to an input of a control circuitry, wherein the DC voltage is a function of the duty cycle of the PWM signal according to a set conversion rate, wherein the conversion circuitry is configured to be supplied with an internal control signal to set at least two conversion rates, wherein the operating device (<NUM>) comprises a detection circuitry (<NUM>) configured to detect if a supply voltage of the operating device is a AC or DC voltage and to set the control signal for the conversion rate differently in case of the presence of a AC or DC signal, respectively.

Aspects of the present invention are described herein in the context of an operating device for lighting means.

Various aspects of an operating device for lighting means will be presented. However, as those skilled in the art will readily appreciate, these aspects may be extended to aspects of operating devices for lighting means without departing from the invention.

The term "LED luminaire" shall mean a luminaire with a light source comprising one or more LEDs or OLEDs. LEDs are well-known in the art, and therefore, will only briefly be discussed to provide a complete description of the invention.

<FIG> shows a schematic representation of an operating device <NUM> for lighting means <NUM> according to an embodiment.

The operating device <NUM> for lighting means <NUM> can be fed with an AC or DC voltage at the input terminals 401a and 401b. Moreover, the operating device <NUM> for lighting means <NUM> comprises: output terminals 407a, 407b supplying lighting means <NUM>, such as e.g. a LED load, a control circuitry <NUM> for controlling an electrical supply of the lighting means <NUM>; a NFC module <NUM> configured to receive NFC signals and output a pulse width modulation, PWM, signal with variable duty cycle; a conversion circuitry <NUM> arranged for being supplied with the PWM signal and for outputting a DC voltage supplied to an input of the control circuitry <NUM>. The DC voltage is a function of the duty cycle of the PWM signal according to a set conversion rate, and the conversion circuitry <NUM> is configured to be supplied with an internal control signal to set at least two conversion rates.

The internal control signal can comprise an AC or DC voltage signal.

Furthermore, the operating device <NUM> can comprise a detection circuitry <NUM> configured to detect if a supply voltage of the operating device is a AC or DC voltage and to set the control signal for the conversion rate differently in case of the presence of a AC or DC signal, respectively.

Moreover, the operating device <NUM> can comprise a limiting circuitry <NUM> configured to limit the DC voltage in case the set control signal is a DC signal.

The NFC module <NUM> can be configured to translate a current configuration into a pulse-width-modulation (PWM) signal which, then, can be filtered and used as current selection information for a LED control integration circuit or control circuitry <NUM>.

Advantageously, in case of a DC voltage at the input terminals 401a and 401b, the output current of the LED driver or operating device <NUM> can be reduced, so that, for example, a battery inside the LED driver or operating device <NUM> can last longer, for example, in emergency situations.

<FIG> shows a schematic representation of the operating device <NUM> for lighting means <NUM> according to an embodiment.

<FIG> shows a NFC module <NUM> (antenna and processing circuitry) connected to a voltage divider <NUM> which is connected to a low pass R-C filter <NUM>. In this embodiment, the R-C filter <NUM> forms the conversion circuitry <NUM>. In particular, it can be shown that a dim voltage Vdim at the output of the R-C filter <NUM> can depend on the duty cycle of the PWM signal. Moreover, it can be shown that the pulse-width-modulation (PWM) of the input signal of the NFC module <NUM> correlates linearly with the set LED current. The frequency of the PWM signal can be in the range of <NUM> - <NUM>, while the PWM voltage levels can be in the range of <NUM> V - <NUM>,<NUM> V. Moreover, via the R-C low-pass filter <NUM> an analog signal can be obtained.

Furthermore, in <FIG>, an AC/DC signal is provided as input to the limiting circuitry <NUM> and the voltage divider <NUM> comprising two resistors is connected to the NFC module <NUM> and the R-C filter <NUM>. The module <NUM> of the operating device <NUM> can comprise the control circuitry <NUM> (not shown in <FIG>).

In general, the operating device <NUM> can be adapted to operate in different configurations: either a high level of the PWM signal at the output of the NFC module <NUM> can be adapted depending on the supply signal (configuration options 1a and 1b), or a filtered analog signal at the output of the R-C low-pass filter <NUM> can be adapted (configuration option 2a and 2b) depending on the supply signal. Here, the supply signal may refer to the supply voltage of the operating device <NUM>.

For example, according to configuration option 1a, the high level of the PWM signal at the output of the NFC module <NUM> is adapted via the voltage divider <NUM>, which divides the voltage in case of a DC supply signal. In case of an AC supply signal, the voltage is not divided.

<FIG> shows a circuitry similar to the one shown in <FIG>. In particular, instead of a voltage divider <NUM>, a Zener diode <NUM> is added to the circuitry, and an AC/DC voltage is given as input to the Zener diode <NUM>.

In the case of configuration option 1b, the high level of the PWM signal at the output of the NFC module <NUM> is adapted via the Zener diode <NUM>. In case of a DC voltage, the voltage is clamped by the Zener diode <NUM>, while in case of an AC voltage, the voltage is not clamped.

<FIG> shows a circuitry similar to the circuitry of <FIG>, wherein the voltage divider <NUM> is added at the output of the R-C low pass filter <NUM>, instead of at the output of the NFC module <NUM>. In this way, according to configuration option 2a, the analog signal at the output of the R-C filter is adapted by the voltage divider <NUM>. In case of a DC input voltage, the voltage is divided, while in case of an AC voltage, the voltage is not divided.

In particular, <FIG> shows a circuitry similar to the one of <FIG>, wherein a Zener diode <NUM> is added to the circuit at the output of the R-C low pass filter <NUM>. In this case, according to configuration option 2b, the filtered analog signal at the output of the R-C low pass filter is adapted via the Zener diode <NUM>. In case of an input DC voltage, the voltage is clamped, while in case of AC input voltage, the voltage is not clamped.

<FIG> shows a schematic representation of PWM signals and voltage signals in the operating device <NUM> for lighting means <NUM> according to an embodiment.

<FIG> shows the effect of the DC level feature of the operating device <NUM> in case of an AC supply signal.

In particular, the PWM NFC signal at the output of the NFC module <NUM> is shown in case of the configuration options 1a, 1b, 2a and 2b on the upper panel (case "PWM NFC chip out'').

Moreover, the PWM signal at the RC-filter input is shown on the middle panel for the configuration options 1a, 1b, 2a and 2b (case "PWM RC-filter in'').

Finally, a dimmed voltage Vdim or DC voltage, namely the voltage at the output of the R-C low-pass filter <NUM>, is shown as a function of the duty-cycle of the PWM signal on the lower panel for the configuration options 1a, 1b, 2a and 2b (case "Vdim vs. duty-cycle'').

As it can be taken from <FIG>, in case of the AC signal, the voltage Vdim or DC voltage does not change in any configuration option.

In some operating devices <NUM> for lighting means <NUM>, the DC level or conversion rate can be set in the range of <NUM>-<NUM>% dim level, while in other devices it can be fixed at, e.g., <NUM>% of dim level.

<FIG> shows the effect of the DC level feature of the operating device <NUM> in case of a DC supply signal.

In particular, the PWM NFC signal at the output of the NFC module <NUM> is shown for all configuration options 1a, 1b, 2a and 2b on the upper panel (case "PWM NFC chip out'').

Moreover, the PWM signal at the input of the RC-filter <NUM> is shown on the middle panel for the all configuration options 1a, 1b, 2a and 2b (case "PWM RC-filter in''). As it can be taken from <FIG>, in this case, the DC voltage level is lowered at the input of the PWM R-C filter <NUM> for the configuration options 1a and 1b.

Finally, the dimmed voltage Vdim or DC voltage, namely the voltage at the output of the R-C low-pass filter <NUM>, is shown as a function of the duty-cycle of the PWM signal on the lower panel for the configuration options 1a, 1b, 2a and 2b (case "Vdim vs. duty-cycle"). In all the cases, the dimmed voltage or DC voltage as a function of the duty-cycle of the PWM signal reaches its highest value, namely the DC voltage level.

In particular, the voltage Vdim is influenced by connecting a voltage divider <NUM> or a Zener diode <NUM> by a switch if, e.g., a DC mains voltage is applied. Therefore, a circuit can be implemented in order to switch in case of a DC mains, as it will be described with reference to the following figures.

In the embodiment shown in <FIG>, the operating device <NUM> for lighting means <NUM> comprises the detection circuitry <NUM>, the limiting circuitry <NUM> and a rectifying bridge <NUM>.

In particular, the detection circuitry <NUM> comprises two rectifying diodes <NUM>, a voltage divider <NUM>, a R-C filter <NUM> and a capacitor <NUM>. The input voltage comes from the L and N wires, wherein the input voltage is rectified by the rectifying bridge <NUM>. Moreover, the limiting circuit <NUM> comprises a switch <NUM>.

In case of an AC voltage, with e.g. a frequency f=<NUM>, the time constant of the R-C filter is much longer than <NUM> and the switch <NUM>, e.g. FET, does not switch. This can also be seen in the plot of the threshold value th <NUM> which is higher than the voltage value which allows for the switch <NUM> to switch.

<FIG> shows a circuitry which is analogous to the one shown in <FIG>, besides that, in this case, the input voltage is a DC voltage, i.e. with a frequency f=<NUM>. In this case, the capacitor <NUM> is charged according to the time constant of R-C low-pass filter and the switch <NUM> FET switches. This can also be seen in the plot of the threshold value th <NUM> which is lower than the voltage value which allows for the switch <NUM> to switch.

<FIG> shows a circuitry analogous to the one of <FIG> and <FIG>, besides that the detection circuitry <NUM> does not comprise the rectifying diodes <NUM>. Moreover, in this embodiment, only the L wire is sensed. This provides the advantage that sensing only L is cheaper.

In case of an AC supply voltage, e.g. with a frequency f=<NUM>, the time constant of the R-C low-pass filter <NUM> is much longer than <NUM>, and the switch <NUM> FET does not switch. This can also be seen in the plot of the threshold value th <NUM> which is higher than the voltage value which allows for the switch <NUM> to switch.

<FIG> shows a circuitry analogous to the one shown in <FIG>. In the case of a DC voltage signal, i.e. with a frequency f=<NUM>, the capacitor <NUM> is charged according to the time constant of the R-C low-pass filter <NUM> and the switch <NUM> FET switches. This can also be seen in the plot of the threshold value th <NUM> which is lower than the voltage value which allows for the switch <NUM> to switch.

In particular, <FIG> shows a selection of some of the elements which can be comprised in the operating device <NUM> for lighting means <NUM> according to an embodiment.

In particular, the operating device <NUM> in <FIG> comprises the detection circuitry <NUM>, the limiting circuitry <NUM>, the conversion circuitry <NUM>, the NFC module <NUM> and a rectifying bridge <NUM>. The signal coming from the L and N wires is given as input to the detecting circuitry <NUM>.

The detecting circuitry <NUM> can comprise two rectifying diodes <NUM>, a voltage divider <NUM>, a R-C low pass filter <NUM> and a capacitor <NUM>.

Moreover, the limiting circuity <NUM> can comprise a switch <NUM> and a Zener diode <NUM>. The switch <NUM> is configured to switch if the input signal or control signal is a DC signal.

The NFC module <NUM> comprises an NFC antenna which transmits a signal to the unit 406a which, in turn, converts the received signal into a PWM signal. The PWM signal is given as input signal to the conversion circuitry <NUM>. In this embodiment, the conversion circuitry <NUM> comprises the R-C low-pass filter <NUM>. The output signal of the R-C filter <NUM> is given as input to the module <NUM> which comprises the control circuitry <NUM> (not shown in <FIG>).

In particular, <FIG> shows an example of a limiting circuitry <NUM> for a DC level or conversion rate of <NUM>%.

In this embodiment, the configuration option 2b of influencing the Vdim signal or DC voltage via the Zener <NUM> at the R-C low-pass filter <NUM> output and the configuration option 1a and 1b of detecting the DC voltage and switching via sensing L and N are used.

Therefore, by detecting the DC mains voltage with the detection circuit <NUM>, the high level of the PWM signal output of the NFC module <NUM> is influenced in such a way, that the resulting analog signal at the output of the R-C low pass filter <NUM> is relating to a DC dim level relatively to the selected LED current or the current of the operating device <NUM> via the NFC module <NUM>.

<FIG> shows a schematic representation of a method <NUM> for operating a device <NUM> for lighting means <NUM> according to an embodiment.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only and not limitation.

The breadth and scope of the present invention should not be limited by any of the above-described embodiments. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalence.

Claim 1:
Operating device for lighting means (<NUM>), comprising:
- output terminals (407a, 407b) supplying lighting means (<NUM>), such as e.g. a LED load,
- a control circuitry (<NUM>) for controlling an electrical supply of the lighting means (<NUM>);
- a NFC module (<NUM>) configured to receive NFC signals and output a pulse width modulation, PWM, signal with variable duty cycle;
- a conversion circuitry (<NUM>) arranged for being supplied with the PWM signal and for outputting a DC voltage supplied to an input of the control circuitry (<NUM>),
characterized in that the supplied DC voltage is a function of the duty cycle of the PWM signal according to a set conversion rate,
the conversion circuitry (<NUM>) is configured to be supplied with an internal control signal to set at least two conversion rates,
wherein the operating device (<NUM>) comprises a detection circuitry (<NUM>) configured to detect if a supply voltage of the operating device is a AC or DC voltage and to set the internal control signal for the conversion rate differently in case of presence of AC or DC voltage, respectively.