N1308 1308 NCP1308 SOP-8

The NCP1308 combines a true current mode modulator and a
demagnetization detector to ensure full borderline/
Critical Conduction Mode in any load/line conditions and
minimum drain voltage switching (Quasi-Resonant operation).
Due to its inherent skip cycle capability, the controller enters burst
mode as soon as the power demand falls below a predetermined
level. As this happens at low peak current, no audible noise can be
heard. An internal 10 s timer prevents the free-run frequency to
exceed a high frequency (therefore below the 150 kHz CISPR-22
EMI starting limit), while the skip adjustment capability lets the
user select the frequency at which the burst foldback takes place.
The Dynamic Self-Supply (DSS) drastically simplifies the
transformer design in avoiding the use of an auxiliary winding to
supply the NCP1308. This feature is particularly useful in
applications where the output voltage varies during operation (e.g.
battery chargers). Thanks to its high-voltage technology, the IC is
directly connected to the high-voltage DC rail. As a result, the
short-circuit trip point is not dependent upon any VCC auxiliary
level.