UC1842, UC2842, UC3842, UC1843, UC2843, UC3843 UC1.
Texas Instruments
UC2842N - Current-Mode PWM Controller
UC1842, UC2842, UC3842, UC1843, UC2843, UC3843 UC1844, UC2844, UC3844, UC1845, UC2845, UC3845 SLUS223G – APRIL 1997 – REVISED JULY 2022 UCx84x Current.