Hello there!

I would like to build a nixie watch like this one

I presume that this kind of watch is powered by a lipo 3.7V battery. Do you have any suggestions on how to build a step-up converter in such a small space? The voltage conversion should be from 3.7V to 170V with a maximum current of 2/5mA for example, because i think that the nixie tubes are multiplexed.
I have no experience at all about Nixies and step-up conversion, and this power circuit must be very small, because inside this watch must be a microcontroller to perform RTC functionalities.
I searched for small circuits for this purpose and the MAX1771 could be the answer, but i'm not sure how small could it be the circuit and it's also expensive. How about coupled inductor used as micro-transformer?
Cheers
