Power Integrations has detailed the design of a 27W power supply for LCD monitors which is based on its TNY380PN.

Specified to be more than 80% efficient in full load conditions the 15V main output, 5V auxiliary output, power supply draws less than 80mW input power when delivering 30mW to the system in standby mode, said the supplier.

The transformer used in supply, designated the DER-229, was designed to reduce parasitic losses between windings. High switching frequency at full load suppresses acoustic noise from the power supply and enables the use of very small magnetic components.

DER-229 is available for download.