Spacecraft bus voltages vary from the well-established 28-V to more than the 100-V typically used in highpower commercial communications satellites, this reference design shows an example for a space-grade 50-W isolated intermediary bus converter, while implementing over-current protection (OCP) limit function. This design features INA901-SP radiation hardened current monitor, LM139AQML-SP quadcomparator, and UC1901-SP to create an isolated feedback flyback with current sensing and overcurrent flags – the UC1843A-SP current mode PWM controller is used to switch the low side MOSFET of the flyback converter and provide voltage and current to the output, the UC1901-SP senses the output voltage and completes the loop for the isolated feedback. The INA901-SP senses the input current which is provided to the LM139AQML-SP to create an overcurrent flag.
Features
- Isolated magnetic feedback using UC1901-SP
- Current sensing using INA901-SP
- Overcurrent comparison using LM139AQML-SP
- Pulse-by-pulse current limiting
- Double pulse suppression
- Multiple feedback paths supported