Patent Description:
Current lighting devices need to control the operation of a big amount of solid-state light sources, such as LEDs. This control is performed by a driver element, which selectively provides electric feed to the LEDs. <CIT> relates to a control circuit including a first light source, a second light source, an input channel for receiving an input signal, at most two output channels each configured to control one of the first light source and the second light source, where the control circuit is configured to use at most two cables, and is capable of permanently powering on one of the first light source and the second light source while, at the same time, flashing on and off the other of the first light source and the second light source. <CIT> relates to a lighting tool for a vehicle including a first power supply, and a lamp for a vehicle operated with electric power supplied from the first power supply, a detection unit that detects a waveform of first electric power, a generation unit that generates a first control signal that is a signal controlling the lamp for a vehicle according to the waveform of the detected first electric power, an output control unit that superimposes the first control signal on the first electric power and wirelessly transmit the signal obtained by the superimposition from a power transmission section, a conversion unit that acquires a second control signal based on the signal received by a power receiving section that receives the signal wirelessly transmitted from the power transmission section, and a lamp control unit that controls the lamp for a vehicle according to the second control signal.

However, these driver elements have limitations in terms of the number of channels, the available current and so on.

Managing the operation of the LEDs using the least number of driver channels would be beneficial for using cheaper drivers and for a better optimization of the automotive lighting device circuitry.

An alternative way of managing the driver's connections is therefore sought.

The invention provides an alternative solution for managing the managing the operation of LEDs by an electronic assembly and an automotive lighting device.

In a first inventive aspect, the invention provides an electronic assembly for an automotive lighting device, the electronic assembly comprising:.

With this structure, the light driver only needs one output to feed two different light groups. Therefore, a channel is saved and a cheaper driver may be used for managing the light functionalities. The signal detector circuit may be installed in the same printed circuit board as the light groups, without affecting the structure of drivers.

The parameter of the output signal is the pulse width modulation rate, the light driver being configured to provide an output signal which has a pulse width modulation rate depending on the first and second signals.

The pulse width modulation (PWM) rate is used in some automotive lighting applications to provide a plurality of customized actual current values from a single nominal current value. By performing a pulse modulation of <NUM>% or <NUM>%, the effective current value, which determines the luminous intensity provided by the LED, is affected, while the nominal amplitude of the current value is not affected.

In some particular embodiments, the light driver is configured to emit an output signal with a pulse width modulation higher than <NUM>% when the first signal is active and is configured to emit an output signal with a pulse width modulation lower than <NUM>% when the second signal is active. In some particular embodiments, the first light group is configured to provide a daytime running light functionality and the second light group is configured to provide a position light functionality.

Some lighting functionalities, such as daytime running lights, use direct current (<NUM>% PWM) or may use <NUM>% or <NUM>% PWM. On the other hand, other lighting functionalities, such as position light, may use the same nominal amplitude value but with <NUM>% PWM.

In some particular embodiments, the discriminator module comprises:.

This particular arrangement detects the level of the PWM and discriminates between a "high" level of PWM (that would correspond to the first light group) and a "low" level of PWM (that would correspond to the second light group).

In some particular embodiments, the signal detector circuit further comprises a CMOS inverter with a P-MOSFET and a N-MOSFET, arranged to control a current received by each one of the light groups.

In the CMOS inverter, the MOSFETs act as switches: depending on the signal received by the transistor, the signal will be forwarded to one of the light groups.

In some particular embodiments, each first and second light group comprises at least one solid-state light source, such as light emitting diodes (LEDs).

The term "solid state" refers to light emitted by solid-state electroluminescence, which uses semiconductors to convert electricity into light. Compared to incandescent lighting, solid state lighting creates visible light with reduced heat generation and less energy dissipation. The typically small mass of a solid-state electronic lighting device provides for greater resistance to shock and vibration compared to brittle glass tubes/bulbs and long, thin filament wires. They also eliminate filament evaporation, potentially increasing the life span of the illumination device. Some examples of these types of lighting comprise semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma or gas.

In a second inventive aspect, the invention provides an automotive lighting device comprising an electronic assembly according to the first inventive aspect.

This lighting device is particularly useful in automotive applications, when many lighting functionalities are required.

In some particular embodiments when each first and second light group comprises at least one solid-state light source, the lighting device further comprises:.

This lighting device provides the advantageous functionality of efficiently managing the colour performance of the light sources.

An optical element is an element that has some optical properties to receive a light beam and emit it in a certain direction and/or shape, as a person skilled in automotive lighting would construe without any additional burden.

In some particular embodiments, the optical element is at least one of a light guide, a lens, a reflector or a collimator.

These optical elements are useful to manage the light produced by the plurality of light sources and provide uniform output.

In these figures, the following reference numbers have been used:.

Accordingly, while embodiment can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.

<FIG> shows an electronic assembly <NUM> according to the invention. This electronic assembly is suitable for being used in an automotive lighting device.

The electronic assembly <NUM> comprises the following elements:.

The body control module <NUM> sends instructions to activate the position light or the daytime running light. These light functionalities are not active at the same time. There are other pairs of light functionalities which are not active at the same time (turning indicator and daytime running light, for example). The body control may send these instructions to the light driver <NUM> in the most suitable mode.

The light driver <NUM> receives the instruction to activate the daytime running light or to activate the position light. It deals internally with these instructions and provide an output signal. This output signal has always the same nominal amplitude, but has a different value of pulse width modulation (PWM). When the daytime running light is to be activated, a continuous signal (<NUM>% PWM) or a high-modulation signal (<NUM>-<NUM>% PWM) is output from the driver. On the contrary, when the position light is to be activated, a low-modulation signal (<NUM>-<NUM>% PWM) is sent. A single output channel is therefore needed to create a signal for two different light groups, intended to provide two different functionalities.

The signal detector circuit <NUM> receives the output signal of the light driver <NUM>. This signal detector circuit comprises a discriminator module, which is configured to receive the output signal of the light driver <NUM> and detect the PWM rate of the output signal. After detecting this PWM rate, the signal detector circuit is configured to provide the electric signal received from the light driver either to the first LED group or to the second LED group, depending on the PWM rate of the output signal detected by the discriminator module.

The signal detector circuit <NUM>, together with the LED groups <NUM>, <NUM> are arranged in the same printed circuit board <NUM>.

<FIG> shows an example of a signal detector circuit <NUM> installed in an electronic assembly according to the invention.

The output signal of the light driver is received by a capacitor <NUM>, which has a different behaviour depending on the PWM rate of the received signal. This behaviour is captured by a comparator element <NUM>, which provides a base signal to a transistor <NUM>, arranged to modulate the output signal from the light driver <NUM>.

This modulated output is received by the current derivator, which comprises a CMOS inverter with a P-MOSFET <NUM> and an N-MOSFET <NUM>, which are configured to switch on or off depending on the received signal. Thus, the signal is sent either to the first LED group <NUM>, configured to provide the daytime running light (if the output signal from the driver has a high PWM rate) or to the second LED group <NUM>, configured to provide the position light (if the output signal from the driver has a low PWM rate).

<FIG> shows an automotive lighting device <NUM> comprising an electronic assembly according to the invention. This lighting device provides the daytime running light and the position light by two different light groups <NUM>, <NUM>.

Claim 1:
Electronic assembly (<NUM>) for an automotive lighting device (<NUM>), the electronic assembly (<NUM>) comprising:
- a first light group (<NUM>), intended to perform a first light functionality;
- a second light group (<NUM>), intended to perform a second light functionality;
- a light driver (<NUM>), configured to receive at least a first signal corresponding to the first light functionality and a second signal corresponding to the second light functionality, and configured to provide an output signal which has a pulse width modulation rate depending on the first signal and the second signal received;
- a signal detector circuit (<NUM>) comprising a discriminator module (<NUM>) configured to receive the output signal of the light driver (<NUM>) and detect the pulse width modulation rate of the output signal, so that the signal detector (<NUM>) is configured to provide a power supply from the output signal either to the first light group (<NUM>) or to the second light group (<NUM>), depending on the pulse width modulation rate of the output signal detected by the discriminator module (<NUM>).