[April 03, 2006] Synchronous gains for notebooks Tweet (Electronics Weekly Via Thomson Dialog NewsEdge) By Steve Bush [email protected] Philips is claiming a three to five per cent efficiency gain in notebook computer adapter designs using its GreenChip SR family of secondary-side synchronous rectifier controllers. The TEA1761 and TEA1762 are the only secondary control ICs available to integrate both synchronous rectification and primary feedback/control functionality, all in one, said the firm. Operating range is 8.5V to 38V, no auxiliary winding is required, and the external Mosfet gate driver can deliver 10V. The TEA1761 is the simpler model and comes in an SO8 package, while the more expensive SO14 TEA1762 has extra features including a 2.5V reference output and an additional optocoupler drive. Both are fabricated on silicon-on-insulator wafers and the 1761 is available now. The firm also announced a three-chip set for PC power supplies. Dubbed GreenChip PC, the chipset allows operation at greater than 80 per cent efficiency. Most current desktop PC power supplies are only 60 to 70 per cent efficient when operating, claimed the firm. Responsible are features including feed-forward regulation, an integrated reset switch for the primary-side active clamp, and the use of active rectifiers instead of Schottky diodes for secondary side rectification. The associated topology is claimed to have several advantages including: components with lower breakdown voltages; no post-regulation or separate standby controller; no reset winding and fewer secondary windings. [ Back To TMCnet.com's Homepage ]