60W WIDE-RANGE POWER SUPPLY FOR LCD MONITOR OR TV, USING THE L5991
This document describes a reference design for a 60W Switch Mode Power Supply dedicated to LCD TV sets or monitors. The board accepts full range input voltage (90 to 265Vrms) and delivers 5V and 12V. It has good efficiency and very good standby performance, able to meet the most stringent standby rules.
The proposed reference design can supply an LCD monitor or an LCD-TV as well, up to 22″ panels, together with multimedia functions like audio. The SMPS accepts a full range input voltage and delivers 2 output voltages, a 5V dedicated to the scaler and µP, and a 12V dedicated to the backlight and audio. The required standby power consumption is 0.8W at 230Vac.
The circuit is also fully protected against faults like output short circuit or over voltage. The market cost pressure has requested a design approach with particular attention to the solution cost. The board technology used is the standard thru-hole, but it can be changed very easily in SMT because most of components are available also in this technology. The circuit has been tested deeply in all the most salient aspects with positive results and it has been integrated with a 22″ LCD-TV application without showing any problem.