30W micro switch regulated power supply composed of TOP224Y

Published:2011/12/5 1:25:00 Author:May | Keyword: 30W, micro switch, regulated power supply | From:SeekIC

Here we introduce a kind of 30W micro switch regulated power supply composed of TOP224Y, its circuit is shown in the diagram. Its feature is using TL431 to replace regulation tube VDz2 in the sampling circuit. That is, it can reach the technical target of micro switch power supply by using high stability band gap reference voltage Uref to replace normal zener diode. The excellent characteristic is concentrated reflecting on, when AC input voltage u changes from 85V to 265V, Sv=±0.2%; when load current changes from 10% (0.2A) to 100% (2A), S1=±0.2%. It can compare with linearity integrated power supply. Electric isolation outside error amplifier consists of TIA31(IC3) and optical coupler NEC2501(IC2). When it is conncted with internal error amplifier, it can greatly improve regulation performance by precision adjusting the control end of TOP224Y(IC1). It can get sampling voltage after +15V regulation output dividing by R4 and R5. Compared with TL431's internal 2.5V reference voltage, it can adjust control end current Ic by changing potential of K end to control LED's current. R4 and C8 also can determine the frequency property of outside error amplifier.



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