TOP232-234

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 of TOPSwitch-FX 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. The second added terminal is the FREQUENCY (F) pin and is available only in the Y package. This pin provides the half frequency option when connected to CONTROL (C) instead of SOURCE (S). The features on the new pins of TOPSwitch-FX can be disabled by shorting them to the SOURCE, which allows the device to operate in a three terminal