WO2023014323A1 - Frequency adjustment system and method for in-vehicle lighting - Google Patents

Abstract

A frequency adjustment system for in-vehicle lighting, characterized by comprising a processor (30) which processes the unprocessed PWM signal (20) formed of noisy and square waves with phase difference and transmitted from vehicle control unit, converts the unprocessed PWM signal (20) into a processed PWM signal (40) with increased frequency and stable duty period, transmits the processed PWM signal (40) to a LED strip (50).

Description

FREQUENCY ADJUSTMENT SYSTEM AND METHOD FOR IN-VEHICLE LIGHTING

Field of the Invention

The present invention relates to a system and method for use in systems to adjust color and brightness of light in the context of in-vehicle lighting for passenger transportation vehicles, wherein control signals transmitted from the vehicle are measured in real time by an embedded system software algorithm to control color and brightness of light and eliminate the drawbacks of existing systems.

Prior Art

Today, quality, stability and emission values of the signal that controls the color and brightness of light are among the switch elements of in-vehicle lightning. In prior art applications, as a switching method for in-vehicle lighting, PWM (pulse width modulation) is used to adjust the color and brightness of light.

During this operation, voltage fluctuations happen in light supply due to phase difference and / or irregularity in one or more PWM signals transmitted by the vehicle ECU (electronic control unit) and correspondingly, instability occurs in brightness level of light.

Since this PWM signal works at an audible audio frequency range of 20 to 20000 Hz, an audible-frequency noise is generated in the vehicle audio system. This is solved by selecting filtering elements and a suitable filter, but additional difficulties arise in terms of cost and space occupied on the circuit.

The noise generated in electronic circuits switched at a high frequency (30kHz and above) causes emission. This can further lead to undesired results in vehicle homologation tests.

Application no. 2020/06858 is a prior art application found as a result of literature review, which relates to a lighting assembly for use in illuminating the doors, consoles and I or front panels of motor vehicles, comprising a rectangular lath assembled to the door, console and / or front panel of the vehicle, and a LED light source located inside the channel on the side surface of said lath and giving out different colors of light to ensure in-vehicle illumination.

As can be seen, the abovementioned system relates to an in-vehicle lighting assembly and embodies a configuration that could not provide a solution to the drawbacks explained above.

In conclusion, the drawbacks explained above and the shortcomings in existing solutions to the problems have necessitated improvement in the related technical field.

Object of the Invention

The present invention relates to a system which differs from the embodiments in prior art in having different technical properties and bringing new benefits to the technical field.

The primary object of the invention is to provide a system and method which measures the frequencies and pulse width ratios of PWM signals transmitted from vehicle ECU, calculates by averaging and stabilizes the measured frequencies and pulse width ratios by means of an embedded software, and drives lighting components by regenerating the upconverted, stable PWM signal in a way that stays above conjugate (with no phase difference), audible audio frequency and below emission limits.

Another object of the invention to eliminate the noise problem caused by lighting circuits in audio systems.

In the system and method according to the invention, the PWM transmitted from the vehicle is initially recorded in a proper and stable manner over the processor. PWM is transmitted from processor output to LED driver circuits at 30kHz frequency. By this means, the noise generated in audio systems is blocked without using a separate filter circuit. At the same time, the phase difference generated at the PWM frequency transmitted from the vehicle is detected in a stable manner inside the processor using a software filtering method. Hence, the read PWM value is transmitted to LED drivers with increased frequency (in a way that does not generate noise in audio systems). By the disclosed invention for use in in-vehicle lighting systems, the installed system provides a convenient environment to users in terms of cost and desired working performance.

In order to achieve the objectives described above, the invention relates to a frequency adjustment system for in-vehicle lighting, comprising a processor which processes the unprocessed PWM signal formed of noisy square waves with phase difference transmitted from vehicle control unit, converts it into a processed PWM signal with increased frequency and stable duty period, and transmits it to a LED strip.

The below drawings and the detailed description set out with reference to the accompanying drawings provide for a clearer understanding of the structural and characteristic properties and all benefits of the present invention; therefore, the evaluation needs to take these drawings and the detailed description into account.

Brief Description of the Drawings

Figure 1 is an overall view of the system according to the invention.

Figure 2 is a schematic view of the method according to the invention.

The drawings do not necessarily have to be scaled and details which are not necessary to understand the present invention may be omitted. Furthermore, elements which are at least substantially identical, or which have at least substantially identical functions are designated by the same number.

List of References

10. Vehicle

20. Unprocessed PWM Signal

30. Processor

40. Processed PWM Signal

50. LED Strip

51 . Signal 1

52. Signal 2 Detailed Description of the Invention

In order to facilitate a better understanding of the present invention, this detailed description demonstrates the preferred embodiments of the invention in a nonlimiting manner.

In the in-vehicle lighting control system and method according to the invention, frequencies and pulse width ratios of unprocessed PWM signals transmitted from the vehicle (10) ECU (Electronic control unit) are measured by the processor (30). Frequencies and pulse width values may vary. The processor (30) used on the LED (50) filters the unprocessed PWM signal (20) and stabilizes frequencies and pulse width values.

Unprocessed PWM signals (20) are read on the input channels of the processor (30). Read values are averaged and stabilized. Frequency of stabilized signals are increased from the range of 300Hz-1000Hz to 30kHz level. Therefore, low frequency PWM signal is prevented from creating an audible interference at in-vehicle electronic audio systems. The processor (30) uses the TIMER OC channels to produce a processed PWM signal (40) with increased frequency and stable duty period from the averaged and stabilized PWM signal. The processed PWM signal (40) is transferred to LED drivers on the LED strip (50). Since the frequency and duty period is stable, LED drivers operate at the desired range and duration. Since the same LED brightness signal is transmitted to all LED strip (50) models, the desired level is achieved in the system’s working performance and stability.

The system according to the invention comprises the following process steps:

• Generating PWM signals required by the system from in-vehicle (10) ECU/control unit (1001 );

• Transmitting noisy signals with phase difference generated by in-vehicle (10) ECU/control unit to LED strip (50) side (1002);

• Reading the frequency and duty period of unprocessed PWM signals (20) transmitted from the vehicle by the processor (30) (1003);

• Checking of the frequency and duty period by the processor (30) (1004); • Stabilization of unstable frequency and duty period by the processor (30) (1005);

• Increasing of the frequency by the processor (30) to a level not creating interference on other vehicles and generation of processed PWM signals (40) (1006); • Transmitting the processed PWM signals (40) with stable duty period and frequency to LED drivers on the LED strip (50) (1007).

Claims

CLAIMS A frequency adjustment system for in-vehicle lighting, characterized by comprising

• a processor (30) which o processes the unprocessed PWM signal (20) formed of noisy and square waves with phase difference and transmitted from vehicle control unit, o converts the unprocessed PWM signal (20) into a processed PWM signal (40) with increased frequency and stable duty period, o transmits the processed PWM signal (40) to a LED strip (50). The system according to claim 1 , characterized by comprising the processor (30) which converts the unprocessed PWM signal (20) at the range of 300-1250 Hz to the processed PWM signal (40) at 30 kHz. A frequency adjustment method for in-vehicle lighting, characterized by comprising the process steps of:

• Generating PWM signals required by the system from in-vehicle (10) ECU/control unit (1001);

• Transmitting noisy signals with phase difference generated by in- vehicle (10) ECU/control unit to LED strip (50) side (1002);

• Reading the frequency and duty period of unprocessed PWM signals (20) transmitted from the vehicle by the processor (30) (1003);

• Checking of the frequency and duty period by the processor (30) (1004);

• Stabilization of unstable frequency and duty period by the processor (30) (1005);

• Increasing of the frequency by the processor (30) to a level not creating interference on other vehicles and generation of processed PWM signals (40) (1006); • Transmitting the processed PWM signals (40) with stable duty period and frequency to LED drivers on the LED strip (50) (1007).

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