U.S. Philips Corporation

Manfred Albach

Hubert C Raets

Armin F Wegener

Hans-Peter Stormberg

Thomas Durbaum

Fritz A Wegener

Ralf Schafer

Theo Husgen

A transformer, particularly for a voltage converter, has a primary winding having a predeterminable leakage inductance and at least one secondary winding magnetically coupled to the primary winding with a predetermined voltage-transformation ratio. The (primary) leakage inductance is increased as compared with a conventional transformer without violating the limits for implementing an appropriately functioning transformer, and without choosing an additional coil or a larger core than is required for the power transformation, in that the primary winding comprises at least two winding sections whose magnetic couplings to the at least one secondary winding are implemented such that they operate in mutually opposite senses and are arranged such that they are at least substantially magnetically decoupled from one another.

High leakage inductance transformer

Switched-mode power supply

A circuit arrangement for generating at least a DC output voltage (at 18, 19) from an at least substantially sine-shaped AC input voltage (at 2, 3) of a first frequency by a first rectifier arrangement (1) to which the AC input voltage can be applied (at 2, 3) and which has a DC output (4, 5) from which a rectified voltage is obtainable, a first inductance (6), a second rectifier arrangement (7) and a first filter capacitance (8) which, in this order, constitute a series arrangement connected parallel to the DC output (4, 5), a switched-mode power supply (9) having two input terminals (10, 11) with which it is arranged parallel to the first filter capacitance (8) and between which it includes a series arrangement of a second inductance (12) and a switching device (13) which is alternately switchable in the conducting state and in the blocked state at a second frequency and from which the DC output voltage(s) is (are) obtainable (at 18, 19), as well as a first control capacitance (23) by which the junction point (22) between the first inductance (6) and the second rectifier arrangement (7) is combined with the junction point (24) between the second inductance (12) and the switching device (13), as well as the series arrangement of a second control capacitance (28) and a second switching device (29) which is arranged parallel to the first control capacitance (23) between the junction points (22) and (24), the first inductance (6) and the first control capacitance (23) being dimensioned in such a way that a resonance frequency determined thereby is larger than the second frequency and the last-mentioned frequency is chosen to be large with respect to the first frequency, while the second control capacitance (28) is chosen to be large with respect to the first control capacitance (23). While using a small number of components, both the voltage rise at the switching device and thus the high-frequency interference originating therefrom can be reduced under all occurring circumstances, and the harmonics of the line current can also be reduced. Moreover, the maximum voltage occurring at the switching elements may be limited to a predetermined value without any additional losses.

Circuit arrangement for generating a DC-separated output voltage

A description is given of a circuit arrangement for producing at least an output direct voltage (at 18, 19) from an at least significantly sinusoidal input a.c. voltage (at 2, 3) of a first frequency, comprising a first rectifier device (1), to which the input a.c. voltage (at 2, 3) can be applied and from which from a direct voltage output (4, 5) a rectified voltage can be taken, a first inductance (6), a second rectifier device (7) and a first filter capacitor (8), which, interconnected in the above sequence, form a series arrangement arranged in parallel with the direct voltage output (4, 5), a switched-mode power supply (9) having two input terminals (10, 11) arranged parallel to a first filter capacitor (8) and between which there is a series arrangement including a second inductance (12) and a switching device (13), a second frequency can alternately be switched to the conductive and the non-conductive state and from which the output direct voltage(s) (at 18, 19) can be supplied, the junction point (22) between the first inductance (6) and the second rectifier device (7) is linked to the junction point (24) between the second inductance (12) by a control capacitor and the switching device (13), the first inductance (6) and the control capacitor (23) being rated such that a resonant frequency determined thereby exceeds the second frequency and the latter is chosen to be high compared to the first frequency. Thereby, with little design effort and cost for the components both the voltage increase at the switching device and consequently the high-frequency interferences originating therefrom and also the harmonics of the mains current are reduced.

Circuit arrangement for producing a direct voltage with reduction of

A circuit arrangement for driving an inductive load (M) having a first (1) and a second sub-winding (2), which sub-windings can be connected to an energy source (5) via switch devices (9, 10) periodically driven by a controller (16). The source produces a DC voltage (U5) to supply energy to the load (M). Alternatively, the sub-windings are coupled electrically (3) and magnetically (6) like an autotransformer, while voltages (for example U8) for feeding the controller (16) can be tapped from the transformer end terminals (7,8) which are formed by non-interconnected terminals of the sub-windings (1,2). In this circuit arrangement start and operation is ensured with the least possible additional circuitry even if the DC voltage taken from the energy source is less than the supply voltage necessary for the controller.

Circuit arrangement for powering control circuitry and driving an

A very inexpensive and compact circuit arrangement having low electrical losses and which supplies a load with energy from an AC voltage source by means of a switch-mode power supply unit (22). The load includes at least two partial loads (3, 4) and electric energy is supplied to one of the partial loads (3 or 4) through the switch-mode power supply unit (22) and, as desired, also to at least a second one of the partial loads (4 or 3) directly from the AC voltage source.

Circuit for supplying plural loads via a SMPS and/or directly from an AC

In a circuit arrangement for the operation of high-pressure gas discharge lamps by means of a pulsatory supply current having a pulse recurrence frequency between 50 and 2000 Hz and a duty cycle between 0.2 and 0.8, a current having a high-frequency between 20 and 200 kHz is superimposed on the current pulses and with a modulation ratio beween 0.3 and 1. The high-frequency is an integral multiple of the pulse recurrence frequency. Thus, flickering of the lamps is avoided.

Circuit arrangement for the operation of high-pressure gas discharge

A circuit arrangement for supplying a load (15) with energy from a power supply mains (1 to 5; 21, 22, 23) conveying at least one alternating voltage (UW; R, S, T) includes a simple network to ensure both a uniform energy supply of the load (15) and a reliable suppression of interference from the load to the power supply mains and in the reverse direction by means of a rectifier arrangement (7 to 10) which for each terminal (4, 5; 21, 22, 23), of the power supply mains includes a rectifier stage (7, 8; 9, 10; 24, 25; 26, 27; 28, 29) constituted as a first branch of a bridge rectifier. For each rectifier stage an energy storage device (11; 12; 30; 31; 32) can be charged by and is connected to said stage in accordance with a complementary branch of the bridge rectifier. For each stage a switching element (13; 14; 33; 34; 35) is provided for connecting each energy storage device to the load. A control circuit (18; 36; 191, 192) switches the switching elements-- cyclically following the charge of the energy storage devices from the power supply mains, via the rectifier stages. The switching elements are switched to conduct outside of the charge time intervals of the storage devices (i.e. the conducting phases of the rectifier stages).

Circuit arrangement for supplying a load

A circuit arrangement for feeding a load (3) from a low voltage energy source (1) via a direct-voltage conversion circuit (2). The direct-voltage conversion circuit periodically takes energy from the energy source by means of a main switching element (10) and supplies this energy as an increased supply voltage (at 12) to the load via an inductive element (9) and a rectifier (11). A starting switching element (15) takes energy for generating the supply voltage (at 12) from the energy source during a starting phase. The circuit arrangement is simple and compact and the energy losses produced are so low that it is economic to use it for energizing a small appliance particularly a small domestic appliance, from a battery or a rechargeable accumulator. A main control circuit (13) is supplied with energy directly from the supply voltage (at 12) and periodically controls the main switching element. A starting control circuit (16) is fed directly and exclusively from the energy source and periodically controls the starting switching element (15) so that is switching periods are shorter than those of the main switching. The starting control circuit, and thus the starting switching element, are switched off when the supply voltage reaches a predetermined value.

Battery operated power supply with low voltage start circuit

A power-supply circuit receives its power from an a.c. source (1) which, in specific time intervals is connected to a power-storage device (6) to feed power thereto. The power supply circuit includes a switch (10) which is periodically actuated by a control circuit (13) to take power from the power-storage device. Interference is suppressed in a simple, space-saving and cheap manner in that the control circuit (13) turns on the switch (10) only at times outside the time intervals (t2-t1) in which the a.c. source is connected to the power-storage device.

Power-supply circuit

A circuit for operating high-pressure gas discharge lamps comprises a full-wave rectifier (2) which is connected to an alternating voltage supply source and supplies an output direct voltage to a combinatorial circuit part comprising a switching transistor (3), a choke coil (4), a fly-wheel diode (5) and a storage capacitor (6), from which the lamp is energized. A further combinatorial circuit part (7, 8, 10, 11) comprises at least one electronic circuit element (7) coupled between the storage capacitor (6) and the lamp (9) and is controlled by a control device (12). The control device compares an instantaneous lamp current of higher frequency with a nominal-value signal composed of a sinusoidal voltage component having double the supply frequency and a d.c. voltage component having a value of at least the maximum amplitude of the sinusoidal voltage.

Circuit arrangement for operating high-pressure gas discharge lamps

A circuit arrangement for reducing an interference current produced by a load (2). The frequency of the interference current is considerably higher than the frequency of a supply voltage source (1) which is coupled to the load. In order to reduce the interference current, a compensation circuit is provided comprising at least one connection branch connected in the leads between the load and the supply voltage source and having each time a series-combination of a capacitor and a controlled signal source. Each signal source supplies a current dependent upon a control signal. The control signals are derived from the current flowing in a lead to the connection branch or away from it. The magnitude and the phase of the currents supplied by the signal sources are proportioned so that the interference current flows for the major part through the connection branch.

Load current interference reducing apparatus

A circuit arrangement for driving a capcitive load comprises a control circuit (1), whose output is the collector of an output transistor (2). The collector is coupled through the gatesource path of a junction field effect transistor (5) and a resistor (6) connected parallel thereto to the capacitive load (8). The drain connection of the J-FET is connected to the supply voltage (Ub). The circuit permits rapid switching of the load while maintaining the current consumption relatively low.

Circuit for driving a capacitive load which provides low current

A circuit arrangement for producing a direct voltage from a sinusoidal input voltage comprising a filter for suppressing interference voltages, a rectifier, a switched mode power supply part and a pulse generator. The pulse generator produces from the rectified input signal switching pulses for the switched mode power supply part. The frequency of these pulses is varied so that it is a minimum at the maximum value of the rectified input voltage and is a maximum at the minimum value and is varied between the extreme values so that the second derivative of the frequency with respect to time is always zero or negative. A switching pulse is terminated when a signal proportional to the output current of the rectifier exceeds the difference between a signal proportional to the rectified input voltage and an integrated signal proportional to the output current of the rectifier.

AC-DC converter triggered by variable frequency pulses

A circuit arrangement for producing a direct voltage from a sinusoidal input voltage comprising a filter required for suppressing interference voltages, a rectifier, a switched mode power supply part and a pulse generator. The pulse generator produces, from the rectified input signal, switching pulses for the combinatorial circuit part, whose frequency is varied so that it is a minimum at the maximum value of the rectified input voltage and is a maximum at the minimum value and is varied between the extreme values so that the second derivative of the frequency with respect to time is invariably zero or negative. A switching pulse is terminated when a signal proportional to the rectified input voltage is smaller than an integrated signal proportional to the output current of the rectifier.

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Aachen, Germany

Manfred Albach