1. A circuit arrangement for operating at least one low-pressure gas discharge lamp, the circuit arrangement comprising:
an input comprising a first input connection and a second input connection configured to apply a DC supply voltage;
an output comprising a first output connection pair and a second output connection pair configured to connect the at least one low-pressure gas discharge lamp;
an inverter, which is coupled to the first input connection and the second input connection, configured to provide an AC supply voltage from the DC supply voltage;
a control device configured to drive the inverter and thereby to control the frequency of the AC supply voltage, the control device being configured to initiate a preheating phase once a predetermined preheating criterion has been met, in which preheating phase the inverter is operated at a preheating frequency, and to set the frequency of the AC supply voltage to a starting frequency once a predetermined starting criterion has been met;
a resonant circuit comprising a resonant inductor, whose first connection is coupled to the inverter, and whose second connection is coupled to a resonant pole, and comprising a resonant capacitor, which is coupled between the resonant pole and the reference potential of the control device; and
a transformer configured to preheat electrodes of the low-pressure gas discharge lamp, which transformer comprises a primary winding, a first secondary winding, which is coupled to the first output connection pair, and a second secondary winding, which is coupled to the second output connection pair;
wherein the primary winding of the transformer is connected in series with the resonant capacitor and is connected directly to the reference potential of the control device, and an electrical switch is coupled in parallel with the primary winding of the transformer, which switch has a control connection, which is coupled to the control device, the control device further being configured to transfer the electrical switch into its electrically conducting switching state once the starting criterion has been met.
2. The circuit arrangement as claimed in claim 1,
wherein the electrical switch is a bidirectionally blocking or conducting semiconductor switch.
3. The circuit arrangement as claimed in claim 2,
wherein the electrical switch is a bidirectionally blocking or conducting semiconductor MOSFET.
4. The circuit arrangement as claimed in claim 1,
wherein the control device is coupled to a detection pole, which is arranged between the primary winding and the resonant capacitor, and is configured to detect a voltage drop across the primary winding.
5. The circuit arrangement as claimed in claim 4,
wherein the control device is configured to drive the inverter prior to the initiation of the preheating phase and to detect the voltage drop across the primary winding during this driving, the preheating criterion including the fact that this voltage is in a predetermined value range.
6. The circuit arrangement as claimed in claim 4,
wherein the control device is configured to detect the voltage drop across the primary winding during the preheating phase, the starting criterion including the fact that this voltage is in a predetermined value range.
7. The circuit arrangement as claimed in claim 1,
wherein the starting criterion includes the fact that a predetermined time interval has elapsed after initiation of the preheating phase.
8. A method for operating at least one low-pressure gas discharge lamp using a circuit arrangement with an input with a first and a second input connection for applying a DC supply voltage, with an output with a first and a second output connection pair for connecting the at least one low-pressure gas discharge lamp, with an inverter, which is coupled to the first and the second input connection, for providing an AC supply voltage from the DC supply voltage, with a control device, which drives the inverter and which initiates a preheating phase once a predetermined preheating criterion has been met, in which preheating phase the inverter is operated at a preheating frequency, and sets the frequency of the AC supply voltage to a starting frequency once a predetermined starting criterion has been met, with a resonant circuit with a resonant inductor, whose first connection is coupled to the inverter and whose second connection is coupled to a resonant pole, and with a resonant capacitor, which is coupled between the resonant pole and the reference potential of the control device, and with a transformer for preheating electrodes of the low-pressure gas discharge lamp, which transformer comprises a primary winding, a first secondary winding, which is coupled to the first output connection pair, and a second secondary winding, which is coupled to the second output connection pair,
the method comprising:
during the preheating phase: conducting an electrical current flowing via the resonant capacitor via the primary winding of the transformer as well, said primary winding being coupled in series with the resonant capacitor, and being connected directly to the reference potential of the control device; and
once the starting criterion has been met: transferring an electrical switch into its electrically conducting switching state and thereby bridging the primary winding.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A buckle apparatus comprising:
an apparatus main body into which a tongue plate is insertable, the tongue plate being assembled to a webbing belt that restrains a body of a vehicle occupant by being drawn from a predetermined region in the vehicle and fitted over the body of the vehicle occupant;
a latch which is moveable toward and away from the tongue plate inserted into the apparatus main body, the latch engaging with the tongue plate by moving toward the tongue plate, for limiting movement of the tongue plate in a disengaging direction, which is opposite to an insertion direction of the tongue plate;
a giant magnetoresistive element provided at the apparatus main body, the giant magnetoresistive element being structured to include an element main body formed by alternately laminating ferromagnetic substance layers, which are formed by a ferromagnetic substance in thin film form, and non-magnetic substance layers, which are formed by a non-magnetic substance in thin film form;
a permanent magnet which forms a predetermined magnetic field therearound and is provided at the apparatus main body, the permanent magnet forming the predetermined magnetic field therearound and being disposed in the apparatus main body so as to face the giant magnetoresistive element in a direction which is inclined with respect to the insertion direction; and
a shielding member, which interlocks with the tongue plate inserted at the apparatus main body, the shielding member being provided so as to be moveable in conjunction with movement of the tongue plate, such that when the tongue plate moves to a position at which the latch and the tongue plate engage, the shielding member is interposed between the giant magnetoresistive element and the permanent magnet, and shields lines of magnetic force from the permanent magnet toward the giant magnetoresistive element.
2. The buckle apparatus of claim 1, further comprising an ejector provided on a movement path of the tongue plate inserted in the apparatus main body, the ejector being pushed by the tongue plate so as to move, the ejector being subjected to urging force in the disengaging direction, and the ejector pushing to move the tongue plate in the disengaging direction in a state in which engagement of the latch with the tongue plate has been released,
wherein the shielding member is provided at the ejector.
3. The buckle apparatus of claim 1, wherein an orientation of polarities of the permanent magnet intersects both the insertion direction and the direction in which the permanent magnet faces the giant magnetoresistive element.
4. The buckle apparatus of claim 2, wherein an orientation of polarities of the permanent magnet intersects both the insertion direction and the direction in which the permanent magnet faces the giant magnetoresistive element.
5. The buckle apparatus of claim 1, wherein the ferromagnetic substance comprises at least one of cobalt, nickel and permalloy.
6. The buckle apparatus of claim 1, wherein the non-magnetic substance comprises any of copper and chromium.
7. The buckle apparatus of claim 1, wherein the shielding member interlocks with the tongue plate directly.
8. The buckle apparatus of claim 1, wherein the shielding member interlocks with the tongue plate indirectly.
9. A buckle apparatus for fixing a tongue plate which is used at a seat belt apparatus of a vehicle, the buckle apparatus comprising:
an apparatus main body at which the tongue plate is inserted;
a latch disposed in the apparatus main body, the latch engaging with the inserted tongue plate and restricting movement of the tongue plate in a disengaging direction, which is opposite to an insertion direction of the tongue plate;
a permanent magnet disposed on a line extending along a movement path of the tongue plate in the apparatus main body;
a variable resistance element disposed facing the permanent magnet, the variable resistance element being electrically connected to an external current detection element, and exhibiting an electrical resistance value in accordance with an amount of lines of magnetic force penetrating therethrough; and
a plate-like shielding member that shields lines of magnetic force,
wherein, when the tongue plate is fixed at a predetermined insertion position, the shielding member is inserted between the permanent magnet and the variable resistance element and, when the tongue plate is separated from the predetermined insertion position, the shielding member is taken out from between the permanent magnet and the variable resistance element.
10. The buckle apparatus of claim 9, wherein the variable resistance element is formed by alternately laminating thin film-form ferromagnetic substance layers and thin film-form non-magnetic substance layers.
11. The buckle apparatus of claim 9, wherein an orientation of polarities of the permanent magnet intersects both the insertion direction and a direction in which the permanent magnet faces the variable resistance element.
12. The buckle apparatus of claim 9, further comprising an ejector provided on a movement path of the tongue plate inserted in the apparatus main body, the ejector being pushed by the tongue plate so as to move, the ejector being subjected to urging force in the disengaging direction, and the ejector pushing to move the tongue plate in the disengaging direction in a state in which engagement of the latch with the tongue plate has been released,
wherein the shielding member is provided at the ejector.