PWM controller for 100Hz, an replacement for the UC3525?

Hi everyone, I'd like to use PWM controller for phase controlled pre-regulator. Such circuit can be found in some of the Agilent's power supplies build around SG/UC3525 PWM controller which switching frequency could go down to 100Hz and be synchronized with the AC mains frequency.

I'm wondering if TI has in its offer some other PWM controller that can be used with such low switching frequency?

Thanks in advance.