Minebea Company, Limited

Siemens Aktiengesellschaft

Em Microelectronic-marin Sa

Manfred Schlenk

Mykhaylo Raykhman

Hans Hoffmann

Yves Theoduloz

Robert Weger

Fabien Maupas

Josef Fisch

Daniel N Luthi

Martin Feldtkeller

Michael Herfurth

Masaya Yamashita

Erich Schmidtner

P N Chadwick

Werner Loges

Edwin Hielscher

An adjustable power supply () for light emitting diode arrangements (), with the power supply () being dimensioned for a power class. The power supply () has an adjustable current source () and an adjustable power limitation (), and the power limitation () is adjustable within the limits of the power class. The power supply () further has a control component () that is suitable for running an operating program (). This operating program () uses, as its input parameters (), the number of light emitting diodes () to be controlled and their method of connection and, from these parameters, it calculates the required current and the required power, according to which the current source () and the power limitation () are adjusted and regulated.

Programmable current source for light emitting diode arrangements

An electrical device, particularly having at least one lighting system having light emitting diodes, such as a television having LED backlighting (), which has a stand-by mode (ZPM) with very low power consumption in which only one control unit () is supplied with power via a capacitive voltage divider. For this purpose, alongside parts of the power supply unit (), the interference suppression capacitor () is also switched off.

Electric device having low power consumption in the stand-by state

An electrical device having at least one interference suppression capacitor () that is actively discharged when there is an interruption to the mains voltage () by connecting an electrical load () in parallel. For this purpose, the device has a monitor for the mains voltage () and means for connecting () the electrical load.

Electric device having an interference suppression capacitor circuit

A control circuit () for light emitting diode arrangements (), used particularly for backlighting LC flat screens. The circuit has a plurality of control channels (') in each of which one or more light emitting diode arrangements () are disposed. The circuit has a balancing device () which allows currents in the individual control channels (&#x2032;) to be balanced. Each control channel (&#x2032;) has a separate dimming device () through which a brightness of the light emitting diode arrangements () in this control channel (&#x2032;) can be changed separately from the other control channels (&#x2032;). For this purpose, the control circuit has a compensation device () which allows a flow of current in the individual control channels (&#x2032;) to be balanced when the light emitting diodes have different brightnesses.

Control circuit for light emitting diode arrangements

An electrical appliance, particularly a television or a monitor, having a lighting device () having light emitting diodes (). The light emitting diodes (LED) () are collected in LED strings () and controlled by a balancing network (). The balancing network () has a circuit branch () for each string (), the circuit branches () being connected in parallel to each other. Disposed in each circuit branch (), is a bridge rectifier () to which the LED string () is connected. Moreover, each circuit branch has a balancing transformer (), wherein all the secondary windings () of the balancing transformer () are connected in series in a closed conductor loop (), by which the currents in all circuit branches are balanced.

Electrical appliance having a lighting device having light emitting diodes

A method and a device for controlling gas discharge lamps using a direct current/alternating current inverter (DC/AC inverter) that is operated at a predetermined frequency and that generates an AC output voltage U for operating the gas discharge lamps from a DC input voltage which has a residual ripple. The DC/AC inverter is operated in zero voltage switching (ZVS) mode, wherein the DC input voltage is used as the control variable for the lamp current I, wherein fluctuations in the lamp current Icaused by the residual ripple of the DC input voltage are compensated by a variation in the switch-on times and/or switch-off times of the switching elements Q, Qof the DC/AC inverter.

Method for controlling gas discharge lamps

A resonant circuit successively assumes charging and discharging conditions which form the primary circuit of a transformer in a power pack constructed according to the principle of a resonant converter, and a switch-over pulse is generated after each initiation of the charging condition and depending on the existancee of current and/or voltage values for resonance in the resonant circuit, and the switch-over pulse ends the charging condition by using a switching means and initiates the discharging condition so as to produce an improved resonant converter.

Power pack comprising resonant converter

The invention relates to a fault recognition circuit for at least two power supplies feeding in parallel a user at an output side. The power supplies each have an electronic switch, a power transformer and a rectifier portion with a following filter element. In order to achieve short repair times, the respective down power supply is immediately identified after the outage of one of the parallel power supplies. For this purpose, a current transformer is provided which lies between the electronic switch and the power transformer. The load voltage of the current transformer is supplied to first a rectifier unit and the ac voltage component of the unfiltered dc voltage at the rectifier portion of the power pack units is supplied via a high pass filter to a second rectifier unit. The outputs of the rectifier units are connected to inputs of first and second comparators, and the other inputs of the comparators are connected with comparison voltages. The outputs of the first and second comparators are connected to the inputs of an evaluation circuit. The outputs of all evaluation circuits are connected to an external central power supply control situated, for example, in a data processing system. The central power supply control in turn influences a respective control and regulating unit of the electronic switch in the respective power supply.

Fault recognition circuit for parallel power supply devices feeding a

A startup circuit has an undervoltage monitoring unit and a pulse width modulator PBM with at least one soft start input and one enable input. When switching on the power pack, the undervoltage monitoring unit is disabled until the voltage level at the output has reached a rated value. Outputs of two comparators are connected to the enable input of the pulse width modulator over a NAND gate. A capacitor chargeable via a resistor is applied to the first input of the first comparator with a controllable electronic switch connected in parallel to the capacitor. A first reference voltage is applied to the second input of the first comparator and a second reference voltage equal to or lower than the first reference voltage is connected to the first input of the second comparator. The output voltage of the power pack is connected to the second input thereof. The voltage generated at the capacitor is connected to the soft start input of the pulse width modulator over a biased rectifier whose bias voltage is equal to or lower than the first reference voltage. A control circuit comprising an input for switch-on instructions and an input for switch-off instructions is connected at its output to the control input of the electronic switch. The enable input of the pulse width modulator is also connected to receive the switch-off instruction.

Startup circuit for a switched power supply

A circuit arrangement detects and stores power line faults. The occurrence of sporadic faults as represented, for example, by inadmissibly long network collapses, which could lead to shut-down of a current supply and, therefore, to downtime of a computer are generally difficult to detect because the faults disappear given a return of the network, as does, therefore, the prerequisite for detecting the cause of such faults. For the purpose of detecting the cause of the fault, the rectified power line voltage is supplied to a comparison circuit followed by a signal circuit. The signal circuit is connected to a memory which influences a display. As a result, power line faults remain stored despite the return of the power line input voltage. The circuit arrangement is particularly suitable for use in power supply systems for data processing devices.

Circuit arrangement for identifying and storing power line faults

A control arrangement for the uniform load distribution of at least two power supply devices connected in parallel at their outputs and designed as switch controllers having pulse width modulators provides a common voltage regulator for the power supply devices and a respective non-steady and a steady current regulator per power supply device. The control outputs of three respective regulators are connectred to maximum value selection circuits which precede the pulse width modulators. In three-phase operation having a center conductor of such devices, a uniform load distribution to each device and, therefore, a balancing of the three-phase network is achieved by substituting a proportional-integral controller for the non-steady current regulators and forming the difference of the output currents of the switch controllers with the proportional-integral controller so that the controlling variable at the output thereof is supplied to one maximum value selection circuit via an inverter and is directly supplied to the other maximum value selection circuit.

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Augsburg, Germany

Manfred Schlenk