Demonstration board for evaluating the SRK1001 Adaptive Synchronous Rectification Controller, Flyback Converter with SR MOSFET

The EVLSRK1001-PF is a demonstration board, designed for evaluation of the SRK1001 synchronous rectification controller. The SRK1001 implements a control scheme specific for secondary-side synchronous rectification in flyback converters and provides high-current gate-drive outputs for driving N-channel Power MOSFET. The device can operate both in quasi-resonant (QR) applications and in fixed frequency (FF) mixed DCM-CCM applications. The board is provided with a setting suitable for QR application. To use in FF applications, a 100pF capacitor needs to be added in C3. A 120 kΩ resistor (R3) is provided on the TON pin that fixes the blanking after the turn-on to about 1.44 µs. The blanking time after turn-off is set to 3 μs through a 100 kΩ resistor (R4) on TOFF pin. In order to use the DIS/SYNC pin functionality, the user has to remove the zero ohm resistor R9: the PCB already provides a NPN transistor connected to this pin for remote ON/OFF. The board includes the SR MOSFET (PowFLAT 5 x 6 package) and can be easily implemented into an existing converter to substitute rectifier diodes.

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