in this topology there is no high voltage supplied by a boost converter the q factor needs to be high enough to obtain the proper voltage across the lamp in an exemplary embodiment with a 22 nf resonant capacitor 600 uh resonant inductor and a lamp resistance of about 520 u03c9 the q factor is about 3 15 and the circulation current is about 3 times the load current this high circulation current is one of the main drawbacks of this circuit for this reason the circuit is preferably used with a 220v ac input with a 110v input the q factor needs to be twice as high and the circulation current will then be too high by operating at a higher frequency the inductor and capacitor can be reduced in size saving cost and maintaining the q factor at the same time higher q factor helps in obtaining better thd and power factor on the other hand when q factor is lowered the input capacitor can not be discharged all the way to zero during the cycle and thus causes a deteriorated thd and power factor once the design power rating is fixed the lamp should be chosen to place in the circuit the circuit according to the described embodiments will power a 40w lamp the dc bus capacitor value determines the.