EVLSRK1004B

The EVLSRK1004x are demonstration boards, designed for evaluation of the SRK1004x synchronous rectification controller.

The SRK1004 is a family of controllers intended for secondary-side synchronous rectification (SR) in both Non- Complementary Actively Clamped Flyback converters and Quasi Resonant Flyback converters. The six different variants of this IC provide a gate-drive output voltage suitable for N-channel logic-level or standard level power MOSFETs.

The control scheme of this IC is such that the SR MOSFET is switched on as soon as current starts flowing through its body diode and it is then switched off as current approaches zero. The SRK1004 can be used with the SR MOSFET placed either between the secondary-side GND and transformer (low-side configuration) or between the transformer and output voltage (high-side configuration).

The boards are provided with a setting suitable for ACF or QR application in low-side mode. In this case, the devices are supplied directly from the converter’s output voltage.

When operated in high-side configuration, a special function enables a quick detection of short-circuit conditions to inhibit its operation as if the IC were powered directly from the output voltage. In the case that it is used in high-side configuration, it is recommended to power the board from a dedicated auxiliary winding and to use R5 > 47 K to configure Vout,sc (for short-circuit detection with Vout > 0 V). For example R5 = 150 K to configure Vout,sc = 2 V.

The boards include the SR MOSFET (PowerFLAT 5 x 6 package) and can be easily implemented into an existing converter to substitute rectifier diodes.