Overview: Product Specification Highly-Integrated Green-Mode PWM Controller SG6842J
frequency at l ight-load co nditions. To a void acoustic-noise p roblem, t he m inimum PWM frequency set abo ve 20kHz. T his green-mode f unction e nables t he power supp ly to easily meet in ternational power conservation r equirements. To further re duce p ower consumption, SG 6842J is m anufactured by usi ng the BiCMOS process. This allows the lowest start-up current around 8uA, and the operating current is only 4mA. As a result, large start-up resistance can be used. SG6842J in tegrates freq uency j ittering fun ction internally. The frequency jittering fun ction helps reduce EMI em ission of a power supply wi th minimum line filters. Also, its built-in synchronized slope compensation achieves st able pea k-current-mode c ontrol. The proprietary int ernal line c ompensation ensures c onstant output power limit over a wide AC input voltages, from 90VAC to 264VAC. SG6842J pr ovides many protection f unctions. In addition to cycle-b y-cycle cu rrent limitin g, th e in ternal open-loop protection circuit ensures safety should an open loop or output short-circuit failure occurs. PWM output is disabled till V DD d rops below th e UVLO lo wer lim it. Then, th e co ntroller starts up agai n. As long as VDD exceeds about 24V, the internal OVP circuit is triggered. An exte rnal NTC t hermistor ca n be applied for over-temperature pr otection. For OV P and OTP , the protection m ode can be c hosen t o be l atch o ff or aut o recovery. SG6842J is av ailable in a n 8 -pin DIP o r S OP package.
