Abstract: Supply circuits (1-3,101-102,201-203) for supplying output current signals to loads (6,106,206) and comprising first circuits (1,101,201) with transistors (11-14,111-112,211-212) for converting input voltage signals into pulse signals and comprising second circuits (2,102,202) with resonance circuits for receiving the pulse signals and for supplying the output current signals to the loads (6,106,206) are provided with third circuits (3,203) for controlling the first circuits (1,101,201), which third circuits (3,203) comprise generators (35-37) for generating control signals for controlling the transistors (11-14,111-112,211-212) for reducing dependencies between the input voltage signals and the output current signals. The third circuits (3,203) supply the control signals in dependence of the input voltage signals and independently from the output current signals. The transistors (11-14,111-112,211-212) may form a full bridge, a full bridge operated in a half bridge mode, or a half bridge.

Abstract: Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to the bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in the supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).

Abstract: A conversion circuit for converting solar power into an alternating 3-phase mains comprises a converter for converting the power from a solar cell into an unipolar converter output voltage provided between a first and a second converter output terminal of the converter, the converter having a constant power output regulation. The conversion circuit further comprises an inverter for cyclically switching one of three 3-phase output terminals to the first converter output terminal, one to the second converter output terminal and one intermittently to the first and second converter output terminal. With this conversion circuit and method, high capacity energy storage components (such as a capacitor having a large capacitance) can be avoided in the conversion circuit.

Abstract: Supply circuits (1-3,101-102,201-203) for supplying output current signals to loads (6,106,206) and comprising first circuits (1,101,201) with transistors (11-14,111-112,211-212) for converting input voltage signals into pulse signals and comprising second circuits (2,102,202) with resonance circuits for receiving the pulse signals and for supplying the output current signals to the loads (6,106,206) are provided with third circuits (3,203) for controlling the first circuits (1,101,201), which third circuits (3,203) comprise generators (35-37) for generating control signals for controlling the transistors (11-14,111-112,211-212) for reducing dependencies between the input voltage signals and the output current signals. The third circuits (3,203) supply the control signals in dependence of the input voltage signals and independently from the output current signals. The transistors (11-14,111-112,211-212) may form a full bridge, a full bridge operated in a half bridge mode, or a half bridge.

Abstract: A conversion circuit for converting solar power into an alternating 3-phase maims (M) comprises a converter (conv) for converting the power from a solar cell (sc) into an unipolar converter output voltage provided between a first and a second converter output terminal of the converter, the converter having a constant power output regulation. The conversion circuit further comprises an inverter (Inv) for cyclically switching one of 3 3-phase output terminals to the first converter output terminal, one to the second converter output terminal and one intermittently to the first and second converter output terminal. With this conversion circuit and method, high capacity energy storage components (such as a capacitor having a large capacitance) can be avoided in the conversion circuit.

Abstract: A circuit arrangement for commutating the AC voltage of a plasma display panel, in which the losses and electro-magnetic interference which occur as a result of the influence of parasitic resistances (coils, supply lines, semiconductor switches) and the attendant hard charging and discharging processes, are substantially avoided. For the charging operation of the capacitor (Cp) of the plasma cells the oscillation circuit is supplied with an auxiliary charging voltage (u1) whose value exceeds 50% of the input voltage (U0). The oscillation circuit for the discharging operation is supplied with an auxiliary discharging voltage (u2) whose value falls short of 50% of the input voltage (U0). The two auxiliary voltages are connected to a DC converter.

Abstract: Recently, the use of class-D audio amplifiers has become more and more widespread. In contrast to the generally employed class-AB linear amplification technology, class-D allows for improved efficiency. However, the class-D principle is known for its poor distortion characteristics. According to the present invention a digital amplifier (18) is provided for converting an audio signal to a power output, comprising a ripple suppression circuit (16) for suppressing voltage ripples in a supply voltage supplied to die bridge circuit with (6) at least one pair of switches. The ripple suppression circuit (16) suppresses ripples in die supply voltage supplied to a switch in the bridge circuit (6), which has been found to cause a major part of the distortions in the output signal of the digital amplifier (18).

Abstract: A method of controlling a circuit arrangement for an AC voltage supply of a plasma display panel, the circuit arrangement comprising at least a transistor bridge constituted by the bridge transistors (T1, T2, T3, T4), an input voltage (U0), a capacitor (Cp) of the plasma cell and a charging circuit comprising an auxiliary voltage (Uh), a first auxiliary transistor (T11) and a first coil (L1) and at the beginning of the charging operation the first auxiliary transistor (T11) is turned on, characterized in that once the first auxiliary transistor (T11) has been turned on, the second bridge transistor (T2) of the half bridge continues to be turned on for a delay time tv and is turned off after the delay time tv has elapsed.

Abstract: A power supply for X-ray generators which includes at least one inverter (11, 12, 13), at least one transformer (111, 121, 131) and at least one voltage cascade (112, 122, 132) for generating a supply voltage for an X-ray tube (15). In order to increase the output power that can be achieved with a comparatively small weight and a low ripple or output capacitance, the voltage cascade is conceived in respect of its capacitances and the stray inductance of the transformers (111, 121, 131) in such a manner that it can be made to operate in the resonance mode by appropriate control of the inverter. In respect of the properties mentioned it is notably advantageous to integrate a two-phase embodiment or three-phase embodiment with an X-ray system so as to form a compact tank generator.

Abstract: A circuit arrangement for commutating the AC voltage of a plasma display panel, in which the losses and electro-magnetic interference which occur as a result of the influence of parasitic resistances (coils, supply lines, semiconductor switches) and the attendant hard charging and discharging processes, are substantially avoided. For the charging operation of the capacitor (Cp) of the plasma cells the oscillation circuit is supplied with an auxiliary charging voltage (u1) whose value exceeds 50% of the input voltage (U0). The oscillation circuit for the discharging operation is supplied with an auxiliary discharging voltage (u2) whose value falls short of 50% of the input voltage (U0). The two auxiliary voltages are connected to a DC converter.

Abstract: A method of controlling a circuit arrangement for an AC voltage supply of a plasma display panel, the circuit arrangement comprising at least a transistor bridge constituted by the bridge transistors (T1, T2, T3, T4), an input voltage (U0), a capacitor (Cp) of the plasma cell and a charging circuit comprising an auxiliary voltage (Uh), a first auxiliary transistor (T11) and a first coil (L1) and at the beginning of the charging operation the first auxiliary transistor (T1) is turned on, characterized in that once the first auxiliary transistor (T11) has been turned on, the second bridge transistor (T2) of the half bridge continues to be turned on for a delay time tv and is turned off after the delay time tv has elapsed.

Abstract: A power supply for X-ray generators which includes at least one inverter (11, 12, 13), at least one transformer (111, 121, 131) and at least one voltage cascade (112, 122, 132) for generating a supply voltage for an X-ray tube (15). In order to increase the output power that can be achieved with a comparatively small weight and a low ripple or output capacitance, the voltage cascade is conceived in respect of its capacitances and the stray inductance of the transformers (111, 121, 131) in such a manner that it can be made to operate in the resonance mode by appropriate control of the inverter. In respect of the properties mentioned it is notably advantageous to integrate a two-phase embodiment or three-phase embodiment with an X-ray system so as to form a compact tank generator.

Abstract: The invention relates to an X-ray examination apparatus in which the X-ray detector 1 and the X-ray source 2 are subject to keeping the temperature constant and to cooling by way of a common cooling circuit. To this end, a cooling medium of constant temperature is applied to the X-ray detector 1 in order to make the X-ray detector 1 operate at uniform ambient temperatures. The temperature of the cooling medium, thus increased a first time, still suffices to perform cooling of the X-ray source 2. Consequently, the heated cooling medium, after application to the X-ray detector 1, is applied to the X-ray source 2 where a second exchange of heat takes place, so that at the same time the X-ray source 2 is cooled without utilizing an additional cooling circuit.

Abstract: The invention relates to a power supply unit for supplying power to a plasma display panel, wherein an active network filter without electrical isolation is provided for the generation of an essentially constant DC voltage from an AC supply voltage, a DC-DC voltage converter being connected to the output of the active network filter with at least one first and one second output and with electrical isolation between the constant DC voltage and the outputs, a regulator being assigned to the DC-DC voltage converter to regulate the voltage at the first output, and a voltage actuator being connected in series at least to the second output.

Abstract: The invention relates to an X-ray examination apparatus in which the X-ray detector 1 and the X-ray source 2 are subject to keeping the temperature constant and to cooling by way of a common cooling circuit. To this end, a cooling medium of constant temperature is applied to the X-ray detector 1 in order to make the X-ray detector 1 operate at uniform ambient temperatures. The temperature of the cooling medium, thus increased a first time, still suffices to perform cooling of the X-ray source 2. Consequently, the heated cooling medium, after application to the X-ray detector 1, is applied to the X-ray source 2 where a second exchange of heat takes place, so that at the same time the X-ray source 2 is cooled without utilizing an additional cooling circuit.

Abstract: In an X-ray device which includes an X-ray tube (12) provided with means (15, 22, 23) for influencing the electron flow through the X-ray tube (12), a control voltage for the means for influencing the electron flow is customarily generated by means of a complex circuit which, because of its size, is not suitable to be accommodated within the protective tube housing. This has the drawback that the control voltage for the X-ray tube, usually of high voltage potential, must be supplied additionally to the high-voltage supply. Therefore, it is desirable to realize a simple generation means the control voltage which is suitable for accommodation in the protective tube housing. To this end, the invention proposes a piezoelectric transformer (21, 24, 25) for generating the control voltage for the X-ray tube. The invention also relates to a piezoelectric transformer which is particularly suitable for generating such a control voltage.

Abstract: The invention relates to a power supply unit which includes an inverter having output connections whereto the primary winding of a transformer is connected via a series capacitor. The rectified secondary voltage of this transformer is applied to a use which requires a high short-time power in a first mode of operation and a lower continuous power in a second mode of operation. The maximum permissible continuous power can be increased by means of an auxiliary inductance Lh which is active in the second mode of operation but inactive in the first mode of operation.

Abstract: A circuit arrangement for powering a load having n terminals includes n branches. One of the terminals of the load is switchably connected to a first or a second terminal of a voltage source by each of the branches resulting in a voltage vector having n components being applied to the load. The vector components can each assume two values based on the voltage of the voltage source. A control circuit sets the n components of the voltage vector to one of the two values. When all n components assume the same value within some portion of a given period of time (referred to as null vector) and provided that at least one of the components of the voltage vector during this given period of time reamins at this same value, the control circuit sets all components of the voltage vector to the other value so as to form a second null vector.The circuit arrangement prevents a voltage on a terminal of the load from being sustained at a given voltage beyond a given period of time without corrective action being taken.

Abstract: A power supply circuit for a two-phase asynchronous motor having two windings at a preset angle there-between. The supply circuit has three nodes at which are respectively supplied three node voltages U1, U2, U3 which are derived as logic combinations of a basic pulse train and a pulsed switching signal having a switching frequency and a duty cycle. The motor windings are respectively connected between the first and second nodes and between the second and third nodes. The voltage U2 at the second node has a rectangular waveform. The voltages U1 and U3 at the first and third nodes alternate between time intervals in which the voltage level is constant and time intervals in which the voltage is pulse modulated, and have a phase angle there-between corresponding to that between the motor windings.

Abstract: An X-ray apparatus, includes a power supply section for powering an X-ray tube (4) with a high-voltage transformer (3) which has two groups of primary and secondary windings provided on the same transformer core, the coupling between the primary windings (16, 26) belonging to different groups being weaker than the coupling between primary and secondary windings (for example, 16, 31) belonging to the same group, the primary windings of the two groups being connected to two inverters (1, 2) which operate at the same frequency. Control of the power at the secondary side is improved in that the inverters are operated at a fixed frequency and with a duty cycle which can be independently controlled.