230 V ac input, current feedback 350 ma power led driver?

hi all. how do people produce small size power led drivers? i think they dont use transformers. how can i find power led driver s schamatic diagram? i search a driver which has like these properties:

Input Voltage :170-230 VAC
Outpu Voltage:3-5 Volt
Output Current: 350 ma

i will connect to driver just one power led.1 watt, 350 ma, 3 volt.

They use a SMPS IC such as the SSL2101.

Many more examples can be found using Google.

https://www.electro-tech-online.com/custompdfs/2009/08/SSL2101_3.pdf
https://www.electro-tech-online.com/custompdfs/2009/08/AN10754_1.pdf