Snowflake: USB‑C PD-Powered Air‑Conditioned Clothing Controller with Integrated XL1509‑ADJ Buck Converter (15 V to 9.3 V Peltier Output), NE555 PWM Fan Control, and LM393 Over‑Temperature Cutoff #USBPD #BuckConverter #Peltier #NE555 #LM393 #PWMControl #OverTemperature