ATX supplies using forward topology with single switch or double switch (half-controlled bridge). Transistors are MOSFETs. Control IC's are UC3842, 3843, 3844, 3845 or other IC's, which are a combo for boht supply and active PFC controll like ML4824, FAN480X and ML4800.
TWO SWITCH FORWARD + PFC, FAN480X
TWO SWITCH FORWARD + PFC WITH ML4800
