U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Lumileds Lighting B.v.

Johannes E Algra

Joseph A Plagge

Engbert B Nijhof

Marcel J Bucks

Stefan E Roijers

Gerrit Brouwer

Marcel J M Bucks

John E De Clercq

Engbert B G Nijhof

Pieter W Habing

A circuit for receiving electrical power from a switched source such as a solid state relay, and providing power to a semiconductor light source. A rectifier circuit and an interference filter are connected in series between input connections which are connected to the switched source, and a converter which provides the required voltage and current combination for the light source. To prevent improper operation of the switched source, such as oscillation, the portion of the circuit between the input terminals and the rectifier circuit is free from capacitive elements. Preferably the interference filter is connected between the rectifier and the converter. The light source may be used as a signal light, and the circuit may be incorporated in the housing of the signal light.

Power circuit for a semiconductor light source operable from a solid state relay

A circuit arrangement for operating a semiconductor light source includes connection terminals for connecting a control unit, an input filter, a converter comprising a control circuit, output terminals for connecting the semiconductor light source, an apparatus CM for removing a leakage current occurring in the control unit in the non-conducting state, and a self-regulating circuit for deactivating the apparatus CM. The circuit arrangement is also provided with a detection circuit for detecting an incorrect functioning of the converter or the semiconductor light source. For this purpose, preferably a minimum voltage and a maximum voltage are detected at the output terminals.

Circuit arrangement and signalling light provided with the circuit

A self-oscillating power supply circuit comprises a series arrangement of the primary winding (N.sub.1) of a transformer (TR), the main current path of a first semiconductor switch (T.sub.1) and a current measuring resistor (R.sub.1). The first semiconductor switch is driven by a second semiconductor switch (T.sub.2) which in turn is controlled by a comparator (CP). The voltage across the current measuring resistor is applied to the non-inverting input (6) of the comparator and, a reference voltage obtained from a reference voltage source (RS) is applied to the comparator inverting input (5). By arranging a capacitor (C.sub.2) between the output of the second semiconductor switch and the inverting input (5) of the comparator, the first semiconductor switch rapidly turns-off at the end of the forward phase at an accurately determined current through the primary winding. By applying a lower reference voltage to the comparator at a higher mains voltage, an output current is obtained from the transformer secondary winding (N.sub.2) for the load L, which is substantially independent of the mains voltage.

High speed power supply circuit with circuit with positive feedback

A self-oscillating power-supply circuit includes between two power-supply terminals (1, 2), the series arrangement of the primary winding (n1) of a transformer, a first transistor (T1), a first resistor (R1), and a second series arrangement of the secondary winding (n2) and a first diode (D1), with terminals (2, 4) for the connection of a battery (B) and, via a switch (S1), a motor (M). The secondary winding (n2) is connected to the base of the first transistor (T1) via the series arrangement of a second resistor (R2), a first capacitor (C1) and a third resistor (R3), a first zener diode (D2) being arranged between the third resistor (R3) and the first resistor (R1). The ends of the first resistor (R1) are coupled to the inputs (16, 17) of a switching amplifier (15) for turning off the first transistor (T1) at a specific voltage across the first resistor (R1). In order to achieve change-over from a normal charging current to a trickle-charging current at a specific battery voltage and in order to power the motor (M) with a constant voltage which is independent of the load, the circuit further has a switching device including the series arrangement of a fourth resistor (R4), a second transistor (T2) and a fifth resistor (R5), the base of the second transistor (T2) being coupled to the node (6) between the first capacitor (C1) and the second resistor (R2), to which a second diode (D3) is arranged in parallel.

Power-supply circuit having circuitry for switching from a battery

A self-oscillating power supply circuit comprises a series arrangement of the primary winding (N.sub.1) of a transformer (TR), the main current path of a first semiconductor switch (T.sub.1) and a current measuring resistor (R.sub.1). The first semiconductor switch is driven by a second semiconductor switch (T.sub.2) which in turn is controlled by a comparator (CP). The voltage across the current measuring resistor is applied to the non-inverting input (6) of the comparator and, a reference voltage obtained from a reference voltage source (RS) is applied to the comparator inverting input (5). By arranging a capacitor (C.sub.2) between the output of the second semiconductor switch and the inverting input (5) of the comparator, the first semiconductor switch rapidly turns-off at the end of the forward phase at an accurately determined current through the primary winding. By applying a lower reference voltage to the comparator at a higher mains voltage, an output current is obtained from the transformer secondary winding (N.sub.2) for the load (L) which is substantially independent of the mains voltage.

Growing community of inventors

Drachten, Netherlands

Johannes E Algra