アプリケーションノート 2040

50W Current-Mode Forward Converter Design with the MAX8540


要約: This application note details the design of a 50-watt, isolated, forward converter, using the MAX8540 synchronizable, high-frequency, current-mode PWM controller. Design procedures for both the power stage and controller are presented, along with actual performance measurements.

The converter delivers 20A of Load current at an output voltage of 2.5V. It employs synchronous rectifiers for secondary rectification. The input voltage range for the converter is 36-75VDC.

This design is available as an evaluation board. The evaluation board demonstrates how easy it is to implement the features network and telecom applications require. The design methods can easily be adapted to the design of high performance, full featured off-line power supplies.

Key features of the application are:
  • 300kHz switching frequency
  • Programmable input UV/OV Protection
  • Programmable hiccup current limit or latch mode overcurrent protection
  • Programmable maximum duty cycle clamp with feedforward
  • Programmable slope compensation with single resistor
  • Synchronization to external clock
  • Adjustable current limit threshold
  • Active low-enable feature for easy turn on/off of converter
  • Internal leading edge blanking on the current sense pin
  • Output overvoltage protection
  • Space-saving 16 pin QSOP