Embodiments of the present disclosure disclose a method for improving a performance of a pulsed-ultraviolet (PUV) device. The method includes monitoring an input current across a circuit breaker in communication with a UV lamp, where the input current is delivered by a power signal and is interrupted by the circuit breaker upon exceeding a predefined cut-off current; generating a pulse signal having a set of frequencies based on the power signal for driving the UV lamp, where the pulse signal is associated with a predetermined cut-off frequency that increases the input current beyond the cut-off current; determining a predefined threshold current less than the cut-off current; and configuring the pulse signal with multiple distinct pulse frequencies per second for a predefined configuration period based on the input current exceeding the threshold current. The distinct pulse frequencies per second include at least one pulse frequency greater than the cut-off frequency.

A high-power fast-pulse driver and illumination system for high speed metrology imaging is provided, which includes an illumination source and a driver circuit configured to overdrive the illumination source using high currents and/or high current densities. The high currents are currents higher than manufacturer-recommended currents used to drive the illumination source and the high current densities are current densities higher than manufacturer-recommended current densities used to drive the illumination source. The illumination source is operated using a lifetime preserving technique selected from a first technique of operating the illumination source at low duty cycles of 2% or less or a second technique of operating the illumination source in a burst mode at higher duty cycles for short intervals. The driver and illumination system may be incorporated in a variable focus lens (VFL) system, to define multiple exposure increments for acquiring one or more images focused at one or more focus planes.

A high-power fast-pulse driver and illumination system for high speed metrology imaging is provided, which includes an illumination source and a driver circuit configured to overdrive the illumination source using high currents and/or high current densities. The high currents are currents higher than manufacturer-recommended currents used to drive the illumination source and the high current densities are current densities higher than manufacturer-recommended current densities used to drive the illumination source. The illumination source is operated using a lifetime preserving technique selected from a first technique of operating the illumination source at low duty cycles of 2% or less or a second technique of operating the illumination source in a burst mode at higher duty cycles for short intervals. The driver and illumination system may be incorporated in a variable focus lens (VFL) system, to define multiple exposure increments for acquiring one or more images focused at one or more focus planes.

A control circuit includes: a flip-flop having an output configured to be coupled to a control terminal of a transistor and for producing a first signal; a comparator having an output coupled to an input of the flip-flop, and first and second inputs for receiving first and second voltages, respectively; a transconductance amplifier having an input for receiving a sense voltage indicative of a current flowing through the transistor, and an output coupled to the first input of the comparator; a zero crossing detection (ZCD) circuit having an input configured to be coupled to a first current path terminal of the transistor and to an inductor, where the ZCD circuit is configured to detect a demagnetization time of the inductor and produce a third signal based on the detected demagnetization time; and a reference generator configured to generate the second voltage based on the first and third signals.

A control and/or regulating system is provided for controlling and/or regulating an LED field with n LEDs, with outputs at which control and/or regulating signals for controlling and/or regulating controllable switching elements can be tapped. The control and/or regulating system can be used to define activation times and/or deactivation times of impulses through the control signals and/or regulating signals and one and/or several controllable switching elements can be actuated during the determined impulses for closing or opening. A number of k groups can be specified or has been specified. Each LED is allocated to one of the k groups such that each one of the k groups m.sub.j contains LEDs, where 1≤j≤k and is Σ.sub.j=1.sup.km.sub.j=n and the determined activation times and/or deactivation times of the impulses of every single group has been specified by the control and/or regulating system such that the impulses overlap as little as possible.

A leakage protection circuit and a dimming drive circuit are provided. A leakage detection circuit is configured to detect whether leakage occurs between two input terminals that receive an external signal. When leakage occurs, leakage protection measures are taken. A pulse generation circuit receives the sampling signal characterizing the voltage between the two input terminals to compare the sampling signal with two thresholds to control a detection path of the leakage detection circuit to be turned on or off according to a comparison result. The leakage detection path is enabled to be turned on twice by setting two pulse signals in a power frequency period, which can consider the leakage detection of the front-edge phase-cutting dimming and rear-edge phase-cutting dimming of the dimming drive circuit and has a wide range of applications.

A leakage protection circuit and a dimming drive circuit are provided. A leakage detection circuit is configured to detect whether leakage occurs between two input terminals that receive an external signal. When leakage occurs, leakage protection measures are taken. A pulse generation circuit receives the sampling signal characterizing the voltage between the two input terminals to compare the sampling signal with two thresholds to control a detection path of the leakage detection circuit to be turned on or off according to a comparison result. The leakage detection path is enabled to be turned on twice by setting two pulse signals in a power frequency period, which can consider the leakage detection of the front-edge phase-cutting dimming and rear-edge phase-cutting dimming of the dimming drive circuit and has a wide range of applications.

A method of operating a warning light assembly at a railway crossing, as well as a warning light assembly operable in accordance with such a method, are disclosed. An example method includes receiving a voltage signal at the warning light assembly that corresponds to a railway crossing event. The method includes initiating a warning light flashing sequence that includes, during a first time period, illuminating the warning light during receipt of the voltage signal in a flashing pattern having a flashing frequency. The warning light flashing sequence also includes, during a second time period after the first time period, discontinuing the flashing pattern and illuminating the warning light in accordance with the voltage signal. Upon determining that receipt of the voltage signal at the warning light assembly is discontinued for at least for a predetermined time, the warning light flashing sequence is reinitialized for a next railway crossing event.

A method of operating a warning light assembly at a railway crossing, as well as a warning light assembly operable in accordance with such a method, are disclosed. An example method includes receiving a voltage signal at the warning light assembly that corresponds to a railway crossing event. The method includes initiating a warning light flashing sequence that includes, during a first time period, illuminating the warning light during receipt of the voltage signal in a flashing pattern having a flashing frequency. The warning light flashing sequence also includes, during a second time period after the first time period, discontinuing the flashing pattern and illuminating the warning light in accordance with the voltage signal. Upon determining that receipt of the voltage signal at the warning light assembly is discontinued for at least for a predetermined time, the warning light flashing sequence is reinitialized for a next railway crossing event.

A light emitting device includes: a resonant circuit that is provided with an electric accumulator accumulating electric charge and generates resonance; a light emitting element that emits light in a case where a current in the resonant circuit is supplied; and a first switching unit that is connected to a circuit between a power supply that supplies electric charge to the electric accumulator and the resonant circuit, and switches between a conduction state in which a circuit from the power supply to the resonant circuit is conductive and a non-conduction state in which the circuit is not conductive.