Description

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.