The TOP234YN is a design flexible, EcoSmart®, Integrated Off-line Switcher with 45W open frame at 85 to 265VAC. TOPSwitch-FX uses the proven TOPSwitch topology and cost effectively integrates many new functions that reduce system cost and at the same time, improve design flexibility, performance and energy efficiency. Like TOPSwitch, the high voltage power MOSFET, PWM control, fault protection and other control circuitry are all integrated onto a single CMOS chip, but with two added terminals. The first one is a MULTIFUNCTION (M) pin, which implements programmable line OV/UV shutdown and line feed forward/DC (max) reduction with line voltage. The same pin can be used instead to externally set an accurate current limit. In either case, this pin can also be used for remote ON/OFF or to synchronize the oscillator to an external, lower frequency signal.
Fully integrated soft-start for minimum stress/overshoot
Externally settable accurate current limit
Wider duty cycle for more power, smaller input capacitor
No turn off glitches line under-voltage (UV) detection
Line over voltage (OV) shutdown extends line surge limit
Regulates to zero load without dummy loading
132kHz Frequency reduces transformer/power supply size
Half frequency option for video applications
Hysteretic thermal shutdown for automatic recovery
Large thermal hysteresis prevents PC board over heating