1、附 录 附录 A 英文原文 TOPSwitch FamilyThree-terminal Off-line PWM Switch TOPSwitch device belongs to three-line PWM switch. It is a new type of IC which merges PWM and MOSFET. It has many advantages: small volume,light weight,high density and lowcost. High frequency switching power supplymade from it can no
2、 t only simplify the circuit, but also can imp rovethe EMC characteristics and reduce the cost. The TOPSwitch family implements, with only three pins, allfunctions necessary for an off-lineswitched mode controlsystem: high voltage N-channel power MOSFET with controlledturn-on gate driver, voltage mo
3、de PWM controller withintegrated 100 kHz oscillator, high voltage start-up bias circuit,bandgap derived reference, bias shunt regulator/error amplifierfor loop compensation and fault protection circuitry. Comparedto discrete MOSFET and controller or self oscillating (RCC)switching converter solution
4、s, a TOPSwitch integrated circuitcan reduce total cost, component count, size,weight and at thesame time increase efficiency and system reliability. Thesedevices are intended for 100/110/230 VAC off-line PowerSupply applications in the 0 to 100 W (0 to 50 W universal)range and 230/277 VAC off-line p
5、ower factor correction (PFC)applications in the 0 to 150 W range. Pin Functional Description DRAIN Pin: Output MOSFET drain connection. Provides internal biascurrent during start-up operation via an internal switched highvoltagecurrent source. Internal current sense point. CONTROL Pin: Error amplifi
6、er and feedback current input pin for duty cyclecontrol. Internal shunt regulator connection to provide internalbias current during normal operation. Trigger input for latchingshutdown. It is also used as the supply bypass andauto-restart/compensation capacitor connection point. SOURCE Pin: Output M
7、OSFET source connection. Primary-side circuitcommon, power return, and reference point. TOPSwitch Family Functional Description TOPSwitch is a self biased and protectedlinear control current-to-duty cycleconverter with an open drain output.High efficiency is achieved through theuse of CMOS and integration of themaximum number of functions possible.CMOS significantly reduces biascurrents as compared to bipolar ordiscrete solutions.
