Pulsed igniting device comprising a piezoelectric transformer for a high-pressure discharge lamp

1 . An igniting device for igniting the gas discharge in a high pressure discharge lamp (La), the igniting device being embodied as a pulsed igniting device (C, FS, Tr 1 ), characterized in that one piezoelectric transformer (PT) is provided for the voltage supply of the pulsed igniting device (C, FS, Tr 1 ).

2 . The igniting device as claimed in claim 1 , in which the pulsed igniting device has a switching means (FS), a charge storage means (C), and an ignition transformer (Tr 1 ) for generating the ignition voltage required for igniting the gas discharge of the high pressure discharge lamp (La).

3 . The igniting device as claimed in claim 1 , in which a voltage doubling circuit (D 1 , D 2 , C) is connected downstream of the voltage output of the piezoelectric transformer (PT).

4 . The igniting device as claimed in claim 2 , in which the switching means (FS) is a voltage-dependent switching means.

5 . The igniting device as claimed in claim 2 , in which the switching means (FS) has an operating point voltage of greater than 800 V.

6 . The igniting device as claimed in claim 2 , in which the igniting device is fed with a supply voltage of less than 500 V.

7 . The igniting device as claimed in claim 2 , in which the lamp is ignited by means of an auxiliary ignition electrode (ZE).

8 . Igniting device as claimed in claim 1 , in which the input capacitance of the piezoelectric transformer (PT) is part of a resonant circuit that is excited during ignition in order to generate a sufficiently high voltage between the main electrodes of the lamp.

9 . The igniting device as claimed in claim 8 , in which a capacitor (CK) is arranged in series with the inductor (LGes) of the resonant circuit, which ensures a sufficiently high voltage between the main electrodes of the lamp during ignition, and serves for a partial compensation of the inductance (LGes) after the ignition.

10 . The igniting device as claimed in claim 8 , in which components of the igniting device (C, FS, Tr 1 ) or/and the piezoelectric transformer (PT) are accommodated in the lamp base of the high pressure discharge lamp (La).

11 . Operating device for a high pressure discharge lamp (La) having a pulsed igniting device (C, FS, Tr 1 ) and a piezoelectric transformer (PT) for the voltage supply of the pulsed igniting device (C, FS, Tr 1 ).

12 . The operating device as claimed in claim 11 , which supplies the high pressure discharge lamp with a lamp current whose frequency is higher than 0.1 MHz.

13 . The operating device as claimed in claim 11 , in which the input capacitance of the piezoelectric transformer (PT) constitutes a functional component of the voltage transformer that supplies the lamp (La) with energy.

14 . The operating device as claimed in claim 13 , in which the input capacitance of the piezoelectric transformer (PT) serves to relieve the switching load of one or more of the semiconductor switches used.

15 . A method for operating a high pressure discharge lamp, an igniting device embodied as a pulsed igniting device (C, FS, Tr 1 ) serving to ignite the gas discharge in the high pressure discharge lamp (La), characterized in that the pulsed igniting device (C, FS, Tr 1 ) is supplied with voltage with the aid of a piezoelectric transformer (PT).

16 . The method as claimed in claim 15 , the pulsed igniting device (C, FS, Tr 1 ) being switched off by providing at the voltage output of the piezoelectric transformer (PT) a supply voltage for the pulsed igniting device (C, FS, Tr 1 ) that is not sufficient for switching over a voltage-dependent switching means (FS) of the pulsed igniting device (C, FS, Tr 1 ).

17 . The method as claimed in claim 15 , the pulsed igniting device being switched off by varying the frequency spectrum of the voltage exciting the piezoelectric transformer (PT) such that there is generated at the voltage output of the piezoelectric transformer (PT) a supply voltage for the pulsed igniting device (C, FS, Tr 1 ) that is not sufficient for switching over a voltage-dependent switching means (FS) of the pulsed igniting device (C, FS, Tr 1 ).

18 . The method as claimed in claim 15 , in which the piezoelectric transformer (PT) is excited by an amplitude-modulated signal.

19 . The method as claimed in claim 15 , in which the piezoelectric transformer is excited by a harmonic component of one of its resonant frequencies that is included in the frequency spectrum of the voltage present at the voltage input of the piezoelectric transformer (PT).

20 . The igniting device as claimed in claim 2 , in which a voltage doubling circuit (D 1 , D 2 , C) is connected downstream of the voltage output of the piezoelectric transformer (PT).