Using a CP2102 USB-Breakout to Program an ESP8266 on an NodeMCU v1
If you are powering the esp8266 directly from the 3.3v pin of the CP2102 board, this one doesn't has the enough current (>200mA) to run the esp8266. You must to connect the esp8266 to an external 3.3V power supply which should  give more than 400mA.