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US 6,664,743 B2Granted
Low loss operating circuit for a discharge lamp
AssigneeKoninklijke Philips Electronics N.V.
InventorsWilhelmus Hinderikus Maria Langeslag, Arnold Willem Buij, Machiel Antonius Martinus Hendrix, Antonius Henricus Peterus Johannes Habraken
Life of this patent
Estimating the term…
Abstract
In an inverter for operating a discharge lamp by means of an AC current comprising two switching elements, the effect of hard switching is counteracted by means of a snubber comprising two inductive elements and at least two diodes.
Claims20
A circuit arrangement for feeding a lamp comprising
- a first input terminal and a second input terminal which are to be connected to a supply voltage source supplying a DC voltage, an inverter for generating a square-wave periodic voltage from said DC voltage, the inverter including a series arrangement of a first switching element, a first inductive element, a second inductive element and a second switching element, and which inverter interconnects the input terminals,
- a control circuit coupled to a control electrode of the first switching element and to a control electrode of the second switching element, the control circuit generating a control signal for rendering the first and the second switching element alternately conducting and non-conducting,
- a load branch comprising a third inductive element, lamp terminals for connecting the lamp, and a first capacitive element, a first unidirectional element having an anode coupled to the second input terminal and a cathode coupled to a point between the first switching element and the first inductive element,
- a second unidirectional element having a cathode coupled to the first input terminal and an anode coupled to a point between the second switching element and the second inductive element, characterized in that the self-inductances L1′, L2′ and L3′ of, respectively, the first, second and third inductive element, satisfy the following relationship;
- L3′>5*L1′ and L3′>5*L2′.
2 more elements
A circuit for operating a discharge lamp comprising:
- first and second input terminals for connection to a source of DC supply voltage for the circuit,
- an inverter coupled to the first and second input terminals and comprising a series circuit of a first controlled switching element, a first inductive element, a second inductive element and a second controlled switching element,
- a control circuit coupled to respective control electrodes of the first and second controlled switching elements to drive the first and second controlled switching elements alternately conducting and non-conducting,
- a load branch comprising a third inductive element, lamp terminals for connection to the discharge lamp, and a first capacitive element,
- a first unidirectional element coupled between the second input terminal and a circuit point between the first controlled switching element and the first inductive element,
- a second unidirectional element coupled between the first input terminal and a circuit point between the second controlled switching element and the second inductive element, and wherein
- the relationship of the inductances L1′, L2′ and L3′ of the first, second and third inductive elements, respectively, are chosen so as to reduce power dissipation in the first and second controlled switching elements.
4 more elements
A circuit for operating a discharge lamp comprising:
- first and second input terminals for connection to a source of DC supply voltage for the circuit,
- an inverter coupled to the first and second input, terminals and comprising a series circuit of a first controlled switching element, a first inductive element, a second inductive element and a second controlled switching element,
- a control circuit coupled to respective control electrodes of the first and second controlled switching elements to drive the first and second controlled switching elements alternately conducting and non-conducting,
- a load branch comprising a third inductive element, lamp terminals for connection to the discharge lamp, and a first capacitive element,
- a first unidirectional element coupled between the second input terminal and a circuit point between the first controlled switching element and the first inductive element,
- a second unidirectional element coupled between the first input terminal and a circuit point between the second controlled switching element and the second inductive element, and wherein
- the relationship of the inductances L1′, L2′ and L3′ of the first, second and third inductive elements, respectively, are chosen so as to suppress power dissipation in the inverter, and said inductances L1′, L2′ and L3′ satisfy the following relationship
- L3′>10*L1′ and L3′>10*L2′.
5 more elements
Dependencies are inferred from the claim text.