Power Integrations (TOP242PN) AC/DC Off-Line Switcher IC, TOPSwitch-GX

AC/DC Off-Line Switcher IC, TOPSwitch-GX, Flyback, 85 VAC - 265 VAC, 132 kHz,720 mA out, 15W, DIP-8Product OverviewThe TOP242PN is a TOPSwitch-GX Integrated Off-line Switcher IC flyback supplyprovides 4 outputs, delivering 7W from a 230VAC ±15% input. Resistor R7 programsthe internal TOP242PN current limit to 78% of nominal, just above the levelneeded for full load at low line. This feature allows a more continuoustransformer design for better efficiency and cross-regulation, without requiringa larger core size. Resistor R12, C10 and L2 filter conducted EMI; R12 is aflameproof fusible type, also functioning as a fuse. For lower cost, if thesupply does not have to meet conducted EMI with the output connected to earthground, the common mode choke can be replaced with a ? filter. A Zener clamp(D11 and VR1) was selected over an RCD clamp to minimize zero load consumption.