Abstract: A photovoltaic assembly is disclosed which comprises a string formed from a plurality of series-connected photovoltaic generators, and a hierarchical structure of power-exchange units, which each exchange power between neighboring photovoltaic generators or groups of photovoltaic generators. The photovoltaic generators may be individual solar cells or a plurality of series-connected solar cells arranged as a segment. To compensate for differences in output between segments for instance due to partial shading, power-exchange units, such as DC-DC converters, are arranged across neighboring segments, such that each power-exchange unit effectively sources or sinks current between neighboring segments to current-match the string. To avoid unnecessary “rippling” of power matching along many power-exchange units and the associated power loss due to many power-exchange units operating at less than 100% efficiency, the power-exchange units are arranged in a hierarchical structure.

Abstract: A supply circuit (1) comprising an inductor (2) coupled to switching means (7) and comprising a capacitor (4) is provided with an impedance (3) located between the inductor (2) and the capacitor (4), with a current injector (5) and with a feedback loop comprising a converter (6) for controlling the current injector (5) for compensating a ripple in an output voltage across the capacitor (4). The impedance (3) allows injection of a compensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor (4). The converter (6) detects a detection signal via the impedance (3) by measuring a voltage across the impedance (3) or across a serial circuit comprising the impedance (3) and the capacitor (4). The impedance (3) comprises a resistor or a further inductor.

Abstract: The present invention relates to a solid state lighting system comprising at least one light emitting semiconductor device, at least one driver for driving a predetermined current through the at least one light emitting semiconductor device. The lighting system furthermore comprises a first voltage supplying unit coupled to provide a first supply voltage to a first side of the at least one light emitting semiconductor device, and a second voltage supplying unit coupled to provide a second supply voltage for the at least one light emitting semiconductor device. The first and the second supply voltages are selected to optimize the voltage drop across the at least one light emitting semiconductor device.

Abstract: The present invention relates to the field of photovoltaic systems with solar cell (s) or modules having insolation differences or mismatch. Each solar module is formed by placing a large number of solar cells in series. The PV system is then formed by placing a number of solar modules in series in a string and sometimes by placing multiple strings of series-connected solar modules in parallel, depending on the desired output voltage and power range of the PV system. In practical cases, differences will exist between output powers of the solar cells in the various modules, e.g. due to (part of) the modules being temporarily shaded, pollution on one or more solar cells, or even spread in solar-cell behaviour that may become worse during aging. Due to the current-source-type behaviour of solar cells and their series connection these differences will lead to a relatively large drop in output power coming from the PV system.

Abstract: A photovoltaic assembly is disclosed which comprises a string formed from a plurality of series-connected photovoltaic generators, and a hierarchical structure of power-exchange units, which each exchange power between neighbouring photovoltaic generators or groups of photovoltaic generators. The photovoltaic generators may be individual solar cells or a plurality of series-connected solar cells arranged as a segment. To compensate for differences in output between segments for instance due to partial shading, power-exchange units, such as DC-DC converters, are arranged across neighbouring segments, such that each power-exchange unit effectively sources or sinks current between neighbouring segments to current-match the string. To avoid unnecessary “rippling” of power matching along many power-exchange units and the associated power loss due to many power-exchange units operating at less than 100% efficiency, the power-exchange units are arranged in a hierarchical structure.

Abstract: The present invention relates to a solid state lighting system comprising at least one light emitting semiconductor device (LEDstr), at least one driving means (LEDdr) for driving a predetermined current through the at least one light emitting semiconductor device (LEDstr). The lighting system furthermore comprises a first voltage supplying unit (PS1) coupled to provide a first supply voltage (Vbus1) to a first side of the at least one light emitting semiconductor device, and a second voltage supplying unit (PS2) coupled to provide a second supply voltage (Vbus2) for the at least one light emitting semiconductor device. The first and the second supply voltages (Vbus1, Vbus2) are selected to optimize the voltage drop across the at least one light emitting semiconductor device (LEDstr).

Abstract: A photovoltaic unit is disclosed comprising a plurality of sub-units connected in series, each sub-unit having a main input and a main output, which main output is connected to the respective main input of a neighbouring sub-unit, each sub-unit further comprising a segment comprising one or more series-connected solar cells, and a supplementary power unit, wherein the supplementary power unit is configured to at least one of receive power from or supply power to the neighbouring sub-unit. The supplementary power unit is preferably a DC-DC converter, and arranged to exchange energy between neighbouring segments, without requiring a high-voltage connection across the complete string (of more than 2 segments). The converter may be inductive or capacitive. A DC-DC converter configured for use in such a unit is also disclosed, as is a method of controlling such a photovoltaic unit.

Abstract: A supply circuit (1) comprising an inductor (2) coupled to switching means (7) and comprising a capacitor (4) is provided with an impedance (3) located between the inductor (2) and the capacitor (4), with a current injector (5) and with a feedback loop comprising a converter (6) for controlling the current injector (5) for compensating a ripple in an output voltage across the capacitor (4). The impedance (3) allows injection of a compensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor (4). The converter (6) detects a detection signal via the impedance (3) by measuring a voltage across the impedance (3) or across a serial circuit comprising the impedance (3) and the capacitor (4). The impedance (3) comprises a resistor or a further inductor.

Abstract: A communication system such as a telephone system has at least a base station and a communication device to communicate with the base station, the communication device comprises an RF power amplifier having an RF output for coupling to an antenna and an RF output power control input, a power supply having a power supply terminal, a control input and a supply output coupled to the RF output power control input for controlling an RF output power on the RF output in dependence on a signal on the control input of the power supply, a data receiver means for coupling to the antenna, the data receiver means having a data output for providing data received from the base station which represents information about said RF output power, and a table means containing a listing of possible power supply control input values related to possible RF output power values, the table means having a table selection input coupled to the data output of the data receiver means and a table output coupled to the control input of the pow

Abstract: A method is described for determining the charge condition of a battery (1), wherein the electromotive force (VEMF) is derived from measurements of the terminal voltage in a loaded condition, and the charge condition (Q) is determined with the aid of a pre-calculated relationship between (VEMF) and the charge condition (Q) on the basis of the (VEMF) thus calculated.

Abstract: A communication system such as a telephone system has at least a base station and a communication device to communicate with the base station, the communication device comprises an RF power amplifier having an RF output for coupling to an antenna and an RF output power control input, a power supply having a power supply terminal, a control input and a supply output coupled to the RF output power control input for controlling an RF output power on the RF output in dependence on a signal on the control input of the power supply, a data receiver means for coupling to the antenna, the data receiver means having a data output for providing data received from the base station which represents information about said RF output power, and a table means containing a listing of possible power supply control input values related to possible RF output power values, the table means having a table selection input coupled to the data output of the data receiver means and a table output coupled to the control input of the pow

Abstract: A communication system such as a telephone system has at least a base station and a communication device to communicate with the base station, the communication device comprises an RF power amplifier having an RF output for coupling to an antenna and an RF output power control input, a power supply having a power supply terminal, a control input and a supply output coupled to the RF output power control input for controlling an RF output power on the RF output in dependence on a signal on the control input of the power supply, a data receiver means for coupling to the antenna, the data receiver means having a data output for providing data received from the base station which represents information about said RF output power, and a table means containing a listing of possible power supply control input values related to possible RF output power values, the table means having a table selection input coupled to the data output of the data receiver means and a table output coupled to the control input of the pow

Abstract: A power supply includes a transformer (TR) having a first winding (N1) for receiving an input signal (U.sub.i) and a second winding (N2) for supplying an output signal (U.sub.o). Switching means (SM) are coupled in series with the first winding (N1) for switching on and switching off a current through the first winding (N1). A parallel arrangement of a freewheel diode (D) and a field effect transistor (T) is coupled in series with the second winding (N2). The gate of the field effect transistor (T) is controlled from an amplifier (AMP). The amplifier (AMP) compares the drain-source voltage of the field effect transistor (T) with the voltage of a reference voltage source (RF1) and ensures that the drain-source voltage is equal to the voltage of the reference voltage source (RF1) as long as an adequate current flows in the second winding (N2).

Abstract: Picture display device comprising a plurality of electron transport ducts or transporting electrons in the form of electron currents, and selection electrodes for withdrawing each electron current at predetermined locations from its transport duct and for directing said current towards a luminescent screen. The selection electrodes are driven by a selection driver comprising integrated driver circuits having outputs which are DC-coupled to the selection electrodes and are cascaded as regards their power supply voltages in such a way that they apply both selection pulses and transport (bias) voltage to the selection electrodes.

Abstract: A switched-mode power supply which uses the primary winding of the isolation transformer as the feedback mechanism for the regulation of the secondary voltage or current. The primary winding voltage and current are used to control the sampling of the primary winding to obtain a measurement signal which is proportional to the secondary voltage or current, and this measurement signal is used to control the switched drive signal. By using the primary winding as the feedback winding, parts can be saved, and the transformer can be of simpler construction.

Abstract: A motor control arrangement including a control circuit for controlling the speed of an electric motor (EM), which control circuit comprises a measurement resistor (MR) and a switching transistor (ST) having a control electrode and a main current path coupled in series with the electric motor (EM) and the measurement resistor (MR), a pulse width control stage (PW) coupled to the control electrode of the switching transistor (ST), a motor current measurement stage (MI) for controlling the pulse width control stage (PW) in response to a motor current of the electric motor (EM), and a motor voltage measurement stage (MV) for controlling the pulse width control stage (PW) in response to a motor voltage (EM) of the electric motor (EM).

Abstract: A sawtooth oscillator includes a current source having an output coupled to a first capacitor for supplying it with a charge current (I). A discharge circuit discharges the first capacitor during a discharge period (TDS) in response to a voltage on the first capacitor. A second capacitor is coupled to the output of the current source. A switch interrupts the supply of charge current to the first capacitor during an interrupt period (TIS). Part of the charge current occurs during the discharge period (TDS). Subsequent to the interrupt period, the first capacitor receives a charge surplus built up by the charge current in the second capacitor. The current supply to the first capacitor is temporarily interrupted at least during a part of the discharge period. The second capacitor operates as an auxiliary capacitor in which a charge is stored which would otherwise have been supplied to the first capacitor.

Abstract: It is possible to limit the voltage across a diode to the level of the pinch-off voltage of a JFET in an integrated circuit by connecting the diode in series with the JFET. As a result, the voltage offered through the JFET can be higher than the breakdown voltage of the diode, which is of particular importance in high-voltage ICs in which a highly doped buried zone is formed below the diode for reducing leakage currents to the substrate. According to the invention, the JFET together with at least one further circuit element is formed in a common island surrounded by an island insulation region. The gate of the JFET extends along the edge of the island and is separated from the relevant portion of the island insulation region substantially only by the source of the JFET. In the pinch-off condition, the gate divides the island into a high-voltage portion and a low-voltage portion which is coupled to the diode.

Abstract: Charge pump including: a capacitor (4) which includes a first capacitor terminal (2) and a second capacitor terminal (8), a discharge switch (20) for discharging the capacitor (4) by the closing and opening of the discharge switch (20) in response to a first or second value respectively, of a clock signal (CS), a first current source (6) for supplying a first current (I1) to the first capacitor terminal (2), a comparator (12) whose first input (10) is connected to the first capacitor terminal (2) and whose second input (14) is connected to a reference voltage source (16) and which comparator generates a comparison signal (Vcomp) of which a first or second value denotes that the voltage (Vc) on the first input (10) is smaller or larger than the voltage on the second input (14), a current switch (24) passing a second current (I2) coming from the second current source (34) to an output terminal (28) once the clock signal (CS) has changed from the first to the second value, and prevents the second current (I2) fl

Abstract: A power transistor switching circuit includes a switching transistor. A switching signal triggers a control device which, via a delay device and a control amplifier applies a first control signal to a control electrode of the switching transistor. A thyristor is coupled to the control electrode of the switching transistor. The thyristor has a first trigger gate and a second trigger gate. A measuring circuit generates a measuring signal proportional to the current in the switching transistor. A comparison device compares the measuring signal with a reference signal for applying a second trigger signal to the thyristor second trigger gate. The control device includes a further control amplifier having an input coupled to the switching signal and an output which applies a further control signal to the first trigger gate. The delay device delays the first control signal with respect to the further control signal.