●Description
●LinkSwitch-HFintegrates a 700 V power MOSFET, oscillator, simple ON/OFF control scheme, a high voltage switched current source, frequency jittering, cycle-by-cycle current limit, and thermal shutdown circuitry onto a monolithic IC. The start-up and operating power are derived directly from the DRAIN pin, eliminating the need for a bias winding and associated circuitry.
●The 200 kHz maximum switching frequency allows very low flux transformer designs, practically eliminating audible noise with the simple ON/OFF control scheme using standard
●varnished transformer construction. Efficient operation at this high switching frequency is achieved due to the optimized switching characteristics and small capacitances of the integrated power MOSFET.
●Product Highlights
●Features Optimized for Lowest System Cost
●• Fully integrated auto-restart for short-circuit and open loop protection
●• Self-biased supply – saves transformer auxiliary winding and associated bias supply components
●• Tight tolerances and negligible temperature variation on key parameters eases design and lowers cost
●• High maximum switching frequency allows very low flux density transformer designs, practically eliminating audible noise
●• Frequency jittering greatly reduces EMI
●• Packages with large creepage to high voltage pin
●• Lowest component count switcher solution
●Much Better Performance over Linear/RCC
●• Lower system cost than RCC, discrete PWM and other integrated solutions
●• Universal input range allows worldwide operation
●• Simple ON/OFF control – no loop compensation needed
●• No bias winding – simpler, lower cost transformer
●• High frequency switching – smaller and lower cost transformer
●• Very low component count – higher reliability and single side printed circuit board
●• High bandwidth provides fast turn on with no overshoot and excellent transient load response
●• Current limit operation rejects line frequency ripple
●• Built-in current limit and hysteretic thermal shutdown protection
●Applications
●• Chargers for cell/cordless phones, PDAs, digital cameras, MP3/portable audio devices, shavers etc.
●• Standby and auxiliary supplies
