Start auxiliary device, ballast and illumination device

A ballast, comprising:

• a start auxiliary device for driving a gas discharge lamp cluster, the gas discharge lamp cluster comprising n gas discharge lamps that are successively connected in series, wherein n being a natural number greater than or equal to 2, the start auxiliary device comprising:
• a primary start circuit which comprises a primary start capacitor and a primary start inductor that are coupled in series;
• and
• a step-up unit which includes a first terminal, a second terminal, and a third terminal,
• wherein the first terminal of the step-up unit is coupled to one terminal of the primary start capacitor via the filament terminal of the first gas discharge lamp of the gas discharge lamp cluster that is not coupled to other gas discharge lamps of the gas discharge lamp cluster, the second terminal of the step-up unit is coupled to the other terminal of the primary start capacitor via the filament terminal of the nth gas discharge lamp that is not coupled to other gas discharge lamps of the gas discharge lamp cluster, the coupling point of the filament of the first gas discharge lamp and the primary start capacitor is coupled to one terminal of the primary start inductor, and the other terminal of the primary start inductor forms a feeding input terminal of the start auxiliary device, and the third terminal of the step-up unit is coupled to the filament terminals of the mth gas discharge lamp and the (m+1)th gas discharge lamp that are coupled to each other, so that the output voltage at the third terminal of the step-up unit is sufficient to supply start voltage for the respective gas discharge lamps in the gas discharge lamp cluster when the step-up unit is excited by the primary start circuit, wherein m≦n−1 and m is a natural number;
• wherein the ballast further comprises a power supply circuit, the output terminal of the power supply circuit being coupled to the feeding input terminal of the start auxiliary device so as to supply the electric energy necessary for operation of the start auxiliary device.

An illumination device, comprising:

• a ballast, comprising:
• a start auxiliary device for driving a gas discharge lamp cluster, the gas discharge lamp cluster comprising n gas discharge lamps that are successively connected in series, wherein n being a natural number greater than or equal to 2, the start auxiliary device comprising:
• a primary start circuit which comprises a primary start capacitor and a primary start inductor that are coupled in series;
• and
• a step-up unit which includes a first terminal, a second terminal, and a third terminal,
• wherein the first terminal of the step-up unit is coupled to one terminal of the primary start capacitor via the filament terminal of the first gas discharge lamp of the gas discharge lamp cluster that is not coupled to other gas discharge lamps of the gas discharge lamp cluster, the second terminal of the step-up unit is coupled to the other terminal of the primary start capacitor via the filament terminal of the nth discharge lamp that is not coupled to other gas discharge lamps of the gas discharge lamp cluster, the coupling point of the filament of the first gas discharge lamp and the primary start capacitor is coupled to one terminal of the primary start inductor, and the other terminal of the primary start inductor forms a feeding input terminal of the start auxiliary device, and the third terminal of the step-up unit is coupled to the filament terminals of the mth gas discharge lamp and the (m+1)th gas discharge lamp that are coupled to each other, so that the output voltage at the third terminal of the step-up unit is sufficient to supply start voltage for the respective gas discharge lamps in the gas discharge lamp cluster when the step-up unit is excited by the primary start circuit, wherein m≦n−1 and m is a natural number;
• a power supply circuit, the output terminal of the power supply circuit being coupled to the feeding input terminal of the start auxiliary device so as to supply the electric energy necessary for operation of the start auxiliary device;
• and
• an illumination unit, the ballast being configured to drive the illumination unit.