STR-S6709

The STR-S6707, STR-S6708, and STR-S6709 are specifically designed to meet the requirement for increased integration and reliabil- ity in off-line quasi-resonant flyback converters.  These devices STR-S6709 incorpo- rate the primary control and proportional drive circuit with a third- generation high-voltage bipolar switching transistor.

Crucial system parameters STR-S6709 such as maximum ON time and OFF time are fixed during manufacture.  Local control circuit decoupling and layout are optimized within each device.

Cycle-by-cycle current limiting, under-voltage lock-out with hyster- esis, over-voltage protection, and thermal shutdown protect these devices during all normal and overload conditions.  Over-voltage protection and thermal shutdown are latched after a short delay.  A versatile triple-level inhibit circuit includes the OFF time synchronization required to establish quasi-resonant operation.  The inhibit function has also been expanded to initiate operation in stand-by mode in which the power supply delivers a small fraction of the steady-state output power. The dual requirements of dielectric isolation and low transient thermal impedance and steady-state thermal resistance are satisfied in an over- molded single-in-line power package.

Proven in substantial volumes, these devices STR-S6709 and their fixed- frequency counterparts represent a significant advance in off-line SMPS reliability growth and integration.