AN1657 is a Philips application note on power supply design for 17-inch CRT monitors. It introduces the design principle, technical features and application cases of the power supply.
This document discusses the design of 90W wide-range-mains SMPS for CRT monitors based on the L6565 QR controller. It details two specific designs: a low-cost version meeting EnergyStar requirements (Pin < 2W) and an evolved version compliant with the IEA's "1W initiative".
The note explains the advantages of the Quasi-resonant (QR) flyback topology for noise-sensitive applications like monitors. It provides a detailed electrical schematic and component specifications for the EnergyStar-compliant design, including transformer winding details and feedback circuitry using a TL431 and optocoupler.
| Input Voltage Range | 88 to 264 Vac |
|---|---|
| Mains Frequency | 50/60 Hz |
| Maximum Output Power | 92 W |
| Target Efficiency | > 85% |
| OFF-Mode Input Power (EnergyStar) | < 2W |
| OFF-Mode Input Power (IEA) | < 1W |
| Core Material | 3C85 |
| Air Gap | 1mm |
The designs are based on the L6565, a control IC specifically designed to handle Quasi-resonant (QR) flyback converters.
Regulation is performed using a TL431 and optocoupler arrangement on the secondary side, which feeds information back to the current sense pin of the L6565.