Zero voltage switching in CFL ballast half-bridge

[eem2am]

hello

please can you tell me how the circuit on page four of this.....

http://www.irf.com/technical-info/refdesigns/irplcfl5e.pdf

...manages to give zero voltage switching (ZVS) of the two mosfets?

is it due to the capacitor "CDC" which acts with the inductor "LRES" to make the bridge node (node between fets) slew such as to make the respective fet Drain-Source voltage go to zero before the fet is switched ON?

 

[FvM]

CDC, as the name suggests, is for DC blocking purposes, while the considerable smaller CRES is responsible for resonant operation
of the circuit. A better explanation of how ZVS mode is maintained by switching frequency adaption is in the IRF datasheets
(e.g. of IR2520), I think.

 

[phosphor_zhu]

IR2520 to get zvs by frequency jetting.

 

[snafflekid]

IR2520 to get zvs by frequency jetting.

frequency jetting? that is a new term to me. Can you explain?