Abstrait

Minimized Standby Power Scheme For Forward Converter With Isolated Output- Feedback

J.Arul sheeba , B.Pushpavanam

A feedback network for forward converter that automatically reduces the current flowing through the opto-coupler under no-load condition is presented in this paper. Standby power is electricity used by appliances and equipment while they are switched off or not performing their primary function. On account of isolation requirements for safety concerns, feedback via optical coupling is very prevalent in the industry. The number of electronics products has continued to increase rapidly. As a result, the accumulated standby power loss caused by their power supply devices has gradually been a significant part of total electricity use. In order to reduce the standby power loss of the power converter the noload condition should be kept as low as possible. The conventional feedback system uses TL431 Commercial programmable shunt regulator, which results in increased power loss at no-load. A Feedback network for forward converter that automatically reduces the current flowing through the opto-coupler nearly zero under no load condition is achieved by replacing TL431 by reverse type shunt regulator. This feedback network for isolated switch-mode power supply uses a reverse type shunt regulator to generate error signal for optical coupling and a modified PWM controller to receive feedback signal. Thus the current through the feed-back circuit is minimized nearly zero under no-load condition. In this paper, simulation is done using MATLAB/SIMULINK and experimental results are presented.