Enhanced, Energy Efficient, Low Power Off-line Switcher

Description

TinySwitch-IIintegrates a 700 V power MOSFET, oscillator, high voltage switched current source, current limit and thermal shutdown circuitry onto a monolithic device. The start-up and operating power are derived directly from the voltage on the DRAIN pin, eliminating the need for a bias winding and associated circuitry. In addition, the TinySwitch-II devices incorporate auto-restart, line under voltage sense, and frequency jittering. An innovative design

minimizes audio frequency components in the simple ON/OFF control scheme to practically eliminate audible noise with standard taped/varnished transformer construction. The fully

integrated auto-restart circuit safely limits output power during fault conditions such as output short circuit or open loop, reducing component count and secondary feedback circuitry cost.

Product Highlights

TinySwitch-IIFeatures Reduce System Cost

• Fully integrated auto-restart for short circuit and open loop fault protection – saves external component costs

• Built-in circuitry practically eliminates audible noise with ordinary dip-varnished transformer

• Programmable line under-voltage detect feature prevents power on/off glitches – saves external components

• Frequency jittering dramatically reduces EMI (~10 dB)

– minimizes EMI filter component costs

• 132 kHz operation reduces transformer size – allows use of EF12.6 or EE13 cores for low cost and small size

• Very tight tolerances and negligible temperature variation on key parameters eases design and lowers cost

• Lowest component count switcher solution

• Expanded scalable device family for low system cost