The EVLSRK1001-TO 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 100 pF 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 (TO220FP package) and can be easily implemented into an existing converter to substitute rectifier diodes.
• Synchronous rectifier for flyback converter, with fixed turn-on and adaptive turnoff
• Vcc range: 3.5 V to 32 V
• DVS sensing voltage: 185V AMR
• Max frequency: 500 kHz
• Internal gate drive for N-channel MOSFET
• SR MOSFET type: FDPF190N15A (150 V – 19 mΩ) TO220FP
Fig 2 Schematics