Circuit arrangement and method for operating at least one electric lamp
View Patent ↗The present invention relates to a circuit arrangement for operating at least one electric lamp (LP) having a drive circuit ( 16 ), which has at least one terminal for a system voltage (U N ) on the input side and at least one terminal for the at least one electric lamp (LP) on the output side; the drive circuit ( 16 ) having a control unit ( 18 ) and a step-up converter having a step-up converter inductor (L 2 ) and a switch (S 1 ), and the control unit ( 18 ) being designed to operate the step-up converter in a discontinuous mode, in which the current (I N ) through the step-up converter inductor (L 2 ) has gaps, the duration (▮t) of these gaps being varied. It also relates to an operating method for at least one electric lamp (LP) using such a circuit arrangement.
1. A circuit arrangement for operating at least one electric lamp (LP) having a drive circuit ( 16 ), which has at least one terminal for a system voltage (U N ) an the input side and at least one terminal for the at least one electric lamp (LP) on the output side;
the drive circuit ( 16 ) having a control unit ( 18 ) and a step-up converter having a step-up converter inductor (L 2 ) and a switch (S 1 );
wherein the control unit ( 18 ) is designed to operate the step-up converter in a discontinuous mode, in which the current (I N ) through the step-up converter inductor (L 2 ) has gaps, the duration (Δt) of these gaps being varied.
2. The circuit arrangement as claimed in claim 1 ,
wherein the step-up converter is designed to bring about a system current harmonic correction ( 12 ).
3. The circuit arrangement as claimed in claim 1 , wherein the control unit ( 18 ) is designed to detect whether an AC voltage and/or a DC voltage is present at the terminal for the system voltage (U N ). the control unit ( 18 ) furthermore being designed to operate the step-up converter in a transition mode when the presence of an AC voltage (U N ) is detected and/or to operate the step-up converter in the discontinuous mode, with a variation in the duration (Δt) of the gaps in the current when the presence of a DC voltage (U N ) is detected.
4. The circuit arrangement as claimed in claim 3 ,
wherein the control unit ( 18 ) is designed to detect a zero crossing of the signal at the terminal for the system voltage (U N ) and to evaluate it for the purpose of driving the step-up converter.
5. The circuit arrangement as claimed in claim 1 ,
wherein the duration of the gaps is between 0.1 μs and 20 μs, preferably between 1 μs and 5 μs.
6. The circuit arrangement as claimed in claim 1 ,
wherein the duration (Δt) of the gaps is varied at a sweep frequency of between 0.1 Hz and 100 kHz, preferably of between 1 Hz and 10 Hz.
7. The circuit arrangement as claimed in claim 1 ,
wherein the step-up converter furthermore comprises a capacitance (C 3 ), it being possible for an intermediate circuit voltage (U ZW ) to be provided at the capacitance (C 3 ) as the output signal of the step-up converter, the control unit ( 18 ) furthermore being designed to determine the switch-on time (t on ) of the switch (S 1 ) such that the intermediate circuit voltage (U ZW ) is within predeteminable limits, in particular is constant.
8. The circuit arrangement as claimed in claim 2 ,
wherein the control unit ( 18 ) is designed to detect whether an AC voltage and/or a DC voltage is present at the terminal for the system voltage (U N ), the control unit ( 18 ) furthermore being designed to operate the step-up converter in a transition mode when the presence of an AC voltage (U N ) is detected and/or to operate the step-up converter in the discontinuous mode, with a variation in the duration (Δt) of the gaps in the current when the presence of a DC voltage (U N ) is detected.
9. The circuit arrangement as claimed in claim 3 , wherein the control unit ( 18 ) is designed to detect a zero crossing of the signal at the terminal for the system voltage (U N ) and to evaluate it for the purpose of driving the step-up converter.
10. The circuit arrangement as claimed in claim 2 ,
wherein the duration of the gaps is between 0.1 μs and 20 μs preferably between 1 μs and 5 μs.
11. The circuit arrangement as claimed in claim 2 ,
wherein the duration (Δt) of the gaps is varied at a sweep frequency of between 0.1 Hz and 100 kHz, preferably of between 1 Hz and 10 Hz.
12. The circuit arrangement as claimed in claim 2 ,
wherein the step-up convener futhermore comprises a capacitance (C 3 ), it being possible for an intermediate circuit voltage (U ZW ) to be provided at the capacitance (C 3 ) as the output signal of the step-up converter, the control unit ( 18 ) furthermore being designed to determine the switch-on time (t on ) of the switch (S 1 ) such that the intermediate circuit voltage (U ZW ) is within predeterminable limits, in particular is constant.
13. An operating method for at least one electric lamp (LP) using a circuit arrangement having a drive circuit ( 16 ), which has at least one terminal for a system voltage (U N ) on the input side and at least one terminal for the at least one electric lamp (LP) on the output side;
the drive circuit ( 16 ) having a control unit ( 18 ) and a step-up converter having a step-converter inductor (L 2 ) and a switch (S 1 ),
wherein the control unit ( 18 ) operates the step-up converter in a discontinuous mode, in which the current (I N ) through the step-up converter inductor (L 2 ) has gaps, the duration (Δt) of these gaps being varied.