Method for dimming a light-emitting diode arrangement of a motor vehicle
AssigneeHella KGaA Hueck & Co.
InventorMartin Trinschek
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Abstract
The invention concerns a process to dim a light emitting diode device of a motor vehicle. In order to keep changes of the light intensity from being noticeable, they must be appropriately small. Electronic dimmers with pulse width modulation have historically required a microcontroller with a pulse width modulation generator with at least 10 bits. In order to use cheaper controllers, the invention proposes that the pulse width signal be modulated as a function of a variable on-period and a simultaneously variable period length.
Claims9
1-4. (canceled)
A process to dim a light emitting diode device for a motor vehicle, where the brightness of the light emitting diodes is adjusted continuously, said process comprising;
- providing a pulse width signal emitted by a digital pulse width modulator;
- modulating the pulse width signal as a function of a specified target value with a variable on-period (Tein) and a simultaneously variable period length (Tp);
- whereby the brightness of the light emitting diode may be changed without perceptible jumps in light intensity.
A process to dim a light emitting diode device for a motor vehicle, where the brightness of the light emitting diodes is adjusted continuously, said process comprising:
- providing a pulse width signal emitted by a digital pulse width modulator;
- modifying the pulse width signal as a function of a specified target value;
- modifying an on-period (Tein) and a period length (Tp) simultaneously, using a stepwise change in the on-period (Tein) and a saw-tooth plot of the period length (Tp), where each step is represented by a tooth;
- whereby there are no perceptible jumps of the light intensity during a change in the brightness of the light emitting diode.
Dependencies are inferred from the claim text.