I am looking to power a [phone ringer circuit](https://www.analog.com/en/technical-articles/lt1684-solves-global-ringing-problem.html#) that requires +100 V DC and a -100 V DC. I have found a circuit [here](http://www.circuitstoday.com/12v-to-120v-dc-dc-converter) but this converts it to 120 V DC with a transformer. Is it possible to get +/-100 V DC from 12 V DC without a transformer? If a transformer is the best option then I will use the circuit here and step the voltage down to around 100 V DC (If this circuit is the best way of course!). 

UPDATE: I did find this [instructable](https://www.instructables.com/id/DC-DC-HV-Boost-Converter/), Would this work? (I could use 2 for a +100 and -100 V DC correct?)