In today's high-performance power system designs, ensuring reliability is critical so efficient features must be able to handle potential problems. Synchronous rectification current reversal is such a problem. This occurs when the capacitor current (parasitics) causes the MOSFET to be prematurely activated at light loads and then the reverse current flows back from the output capacitor back to the synchronous rectifier. This not only causes the system energy efficiency to be seriously affected, but also may lead to operational failures.
To prevent this from happening, steps must be taken to increase the delay when the system is under light-load conditions. Adaptive dead-time control mechanism can make up for the existence of parasitic inductance, thereby reducing the adverse effects of body diode conduction. In this way, the synchronous rectifier shutdown point can be adjusted to maintain a constant dead time regardless of the output load at that time. Thus sustaining energy efficiency and requiring fewer thermal management regulations (due to reduced heat dissipation).
Thanks to its proprietary adaptive dead-time control algorithm, ON Semiconductor's FAN6248 dual MOSFET driver controller IC addresses these challenges. At the same time, it helps engineers maximize power efficiency and make the system as compact, simple and cost-effective as possible.
The device is optimized for use in modern LLC resonant converter topologies, minimizing body diode conduction in synchronous rectification MOSFETs. By eliminating the risk of reverse current by using a unique control method, it also avoids synchronous rectification false triggering. With two sense inputs, the drain-to-source voltage across the MOSFET can be accurately determined, allowing for any asymmetric or poor coupling of the secondary winding. If it is confirmed that the dead time is too long, then the bias voltage will be reduced accordingly. This increases the MOSFET's voltage threshold, which in turn extends the on-time of the synchronous rectifier (thus shortening the associated deadtime). Conversely, if the dead time is too short, the voltage threshold of the MOSFET is reduced, thereby inhibiting the conduction period of the synchronous rectifier. Designating a FAN6248 controller increases the power efficiency of the system and enables stable operation over the entire load range without the risk of reversing the current.
Watch the FAN6248 Evaluation Board demo video and visit the website for more information.
Sock Shoes,Soft Sock Shoes,Green Sock Shoes,Athletic Sock Shoes
Shangqiu JIAYING SHOES CO.,LTD. , https://www.jysportshoes.com