Abstract:
A method is disclosed of controlling a LED, comprising driving the LED with a DC current for a first time, interrupting the DC current for a second time such that the first time and the second time sum to a period, determining at least one characteristic of the LED while the DC current is interrupted, and controlling the DC current during a subsequent period in dependence on the at least one characteristic. The invention thus benefits from the simplicity of DC operation. By operating at the LED in a DC mode, rather than say in a PWM mode, the requirement to be able to adjust the duty cycle is avoided. By including interruptions to the DC current, it is possible to utilize the LED itself to act as a sensor in order to determine a characteristic of the LED. The need for additional sensors is thereby avoided.
Abstract:
The present invention relates to a calibration circuit, computer program product, and method of calibrating a junction temperature measurement of a semiconductor element, wherein respective forward voltages at junctions of the semiconductor element and a reference temperature sensor are measured, and an absolute ambient temperature is determined by using the reference temperature sensor, and the junction temperature of the semiconductor element is predicted based on the absolute ambient temperature and the measured forward voltages.
Abstract:
A damascene process is described using a copper fill process to fill a trench (12). The copper fill (20) is started with a deposited seed layer which includes (5) copper and titanium. Some titanium migrates to the surface during the copper fill process. The structure is annealed in a nitrogen atmosphere which creates a self-aligned TiN barrier (24) at the surface of the copper fill (20). Air gaps (26) may be created in the same annealing process. The process may be used to form a multilayer structure.
Abstract:
A damascene process is described using a copper fill process to fill a trench (12). The copper fill (20) is started with a deposited seed layer which includes (5) copper and titanium. Some titanium migrates to the surface during the copper fill process. The structure is annealed in a nitrogen atmosphere which creates a self-aligned TiN barrier (24) at the surface of the copper fill (20). Air gaps (26) may be created in the same annealing process. The process may be used to form a multilayer structure.
Abstract:
A method of manufacturing a semiconductor device with precision patterning is disclosed. A structure of a small dimension is created in a material, such as a semiconductor material, using a first and a second pattern, the patterns being identical but displaced over a distance with respect to each other. Two mask layers are used, wherein the first pattern is etched into the upper mask layer with a selective etch, and the second pattern is created on the upper mask layer or on the lower mask layer at locations where the upper mask layer has been removed. A part of the lower mask layer and/or the upper mask layer is etched according to the second pattern, resulting in a mask formed by remaining parts of the lower and upper mask layers, the mask having a structure with a dimension determined by a displacement of the second pattern with respect to the first pattern.
Abstract:
A lighting system for exterior lights of an automobile comprises a first lighting unit (10,12,14,16) primarily for outputting a first automotive light signal and a failure detection system (26) for detecting a failure of the first lighting unit (10,12,14,16). A second lighting unit is primarily for outputting a second automotive light signal. The second lighting unit comprises an LED light unit. A controller (30) is adapted to determine if there is failure of the first lighting unit, and if there is failure of the first lighting unit, to use the second lighting unit to generate the first automotive light signal. This is in response to an output request from the first lighting unit (10,12,14,16).
Abstract:
A method of estimating the junction temperature of a light emitting diode comprises driving a forward bias current through the diode, the current comprising a square wave which toggles between high and low current values (Ihigh, llow), the high current value (lhigh) comprising an LED operation current, and the low current value (ILOW) comprising a non-zero measurement current. The forward bias voltage drop (Vf) is sampled and the forward bias voltage drop (Vflow) is determined at the measurement current (ILOW)—The temperature is derived from the determined forward bias voltage drop.
Abstract:
A method of estimating the output light flux of a light emitting diode, comprises applying a drive current waveform to the LED over a period of time comprising a testing period. The forward voltage across the LED is monitored during the testing period, and the output light flux is estimated as a function of changes in the forward voltage.
Abstract:
Apparatus for regulating the temperature of a light emitting diode (LED). The apparatus includes a heat sink, an LED mount, and an LED mounted on the LED mount. The LED mount is configured to change shape in response to a change in temperature. The change in shape alters the position of the LED relative to the heat sink, for adjusting heat transfer between the LED and the heat sink. The LED mount may include a laminated portion such as a bi-metallic strip.
Abstract:
A method is disclosed of controlling a LED, comprising driving the LED with a DC current for a first time, interrupting the DC current for a second time such that the first time and the second time sum to a period, determining at least one characteristic of the LED whilst the DC current is interrupted, and controlling the DC current during a subsequent period in dependence on the at least one characteristic. The invention thus benefits from the simplicity of DC operation. By operating at the LED in a DC mode, rather than say in a PWM mode, the requirement to be able to adjust the duty cycle is avoided. By including interruptions to the DC current, it is possible to utilise the LED itself to act as a sensor in order to determine a characteristic of the LED. The need for additional sensors is thereby avoided.