The synchronous rectifiers are widely accepted for high efficiency in power conversion applications. Because they utilize power MOSFETs versus Schottky diodes, low RDS(ON) is a very significant parameter for synchronous rectification switches. An integrated switch has been introduced as optimized solution for this application. This guide describes benefits of an integrated solution and provides necessary information to evaluate it.

The Power SPM demo board has designed to demonstrate FPP06R001 functionality and how it can be implemented. A single-ended forward topology with RCD clamp is used as primary DC-DC converter. A switch-mode power supply controller, KA7553A controls the forward converter. The FPP06R001 serves as secondary-side synchronous rectifier. NOR gates are used for creating the driving signals for the FPP06R001, and two pulse transformers pass the signals to secondary-side. By adjusting resistance of R15, dead time between freewheeling switch turn-off and forwarding switch turn-on can be varied. Initial value of R15 is set to 1.8kOhm. Also R23 determines dead time between forwarding switch turn-off and freewheeling switch turn-on. Initial value of R23 is 100kOhm.

• Power SPM, integrated power MOSFETs and high current gate driver in a single transfer molded package
• 75V, 3.6mOhm(typical) power switches and 2.5A capability gate driver IC
• Forward topology with synchronous rectifier operates at 100kHz
• 380V input
• 12V output at 20A
• 91.7% efficiency at full load