ELMOS Semiconductor has been granted a patent for a method of driving a light source using a control signal. The method involves modulating the control signal with PWM pulses and periods, where the frequency of the pulses depends on the duty cycle of the control signal. The patent also covers determining the duty cycle and period based on the desired light intensity. In certain operating states, the duty cycle and pulse frequency vary, with the first duty cycle and pulse frequency being smaller than the second. An illuminant driver supplies the light source with a PWM modulated electric current based on the control signal. GlobalData’s report on ELMOS Semiconductor gives a 360-degree view of the company including its patenting strategy. Buy the report here.

According to GlobalData’s company profile on ELMOS Semiconductor, Photonic quantum communication was a key innovation area identified from patents. ELMOS Semiconductor's grant share as of September 2023 was 49%. Grant share is based on the ratio of number of grants to total number of patents.

Patent granted for pwm modulation of control signal for light source

Source: United States Patent and Trademark Office (USPTO). Credit: ELMOS Semiconductor AG

A recently granted patent (Publication Number: US11751305B2) describes a method and luminaire for driving a light source, particularly an LED, using a control signal. The intensity of light emitted by the light source depends on the value and value progression of the control signal.

The method involves modulating the value progression of the control signal using Pulse Width Modulation (PWM). There are two possible approaches: either determining the duty cycle of the PWM modulation and then determining the PWM period based on the desired light intensity, or determining the PWM period and then determining the duty cycle based on the desired light intensity. The PWM modulation consists of PWM pulses, with each pulse having a PWM period and duty cycle. The PWM period begins with the rising edge of a pulse and ends with the rising edge of the immediately following pulse. The instantaneous frequency of each pulse is the reciprocal of its PWM period, and the duty cycle is the ratio of the pulse duration to the PWM period duration.

The illuminant driver supplies the light source with a PWM modulated electric current that is switched on and off according to the PWM modulation of the control signal. The instantaneous frequency of the PWM pulses depends on the duty cycle of the pulses. In one operating state, the magnitude of the first duty cycle is smaller than the magnitude of the second duty cycle, and correspondingly, the magnitude of the first instantaneous frequency is smaller than the magnitude of the second instantaneous frequency.

The luminaire described in the patent includes an illuminant, an illuminant driver, and a control signal. The illuminant driver generates the control signal and supplies the illuminant with a PWM modulated current based on the control signal. The intensity of light emitted by the illuminant depends on the value and time variation of the control signal. The temporal value progression of the control signal is PWM-modulated in sync with the PWM modulation. The illuminant driver generates or receives a first preset value that determines the PWM duty cycle and/or the PWM pulse instantaneous frequency. For a default value of the first preset value, the PWM pulse instantaneous frequency is a first frequency at a first duty cycle, while for a different value of the first preset value, the PWM pulse instantaneous frequency is a second frequency at a second duty cycle. The magnitude of the first duty cycle is smaller than the magnitude of the second duty cycle, and the magnitude of the first instantaneous frequency is smaller than the magnitude of the second instantaneous frequency.

Overall, this patent presents a method and luminaire for driving a light source using PWM modulation of a control signal, allowing for control of light intensity based on desired values and value progressions.

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GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.