DC DC [MSXV]

In the Spring 2019 term, Taiping requested Vicor's new DCM 15V 240W Isolated DC-DC converters with the associated mounting hardware. Vicor supplied the team with the following: 

DCM Datasheet

DCM Design Guide

• Replace the large capacitors with capacitor multipliers?

  • https://www.youtube.com/watch?v=wopmEyZKnYo

ICL

The current inrush due to bulk capacitance at the input is limited by MOSFETM1. It has a capacitor C2 between gate and source, dramatically increasing the tun on time of the MOSFET. Thus it will operate for longer in its ohmic region, limiting the amount of current passing to the capacitors while they charge. Current is limited to <4A for an input voltage of 154V and bulk capacitance of 2000uF. The circuit takes up to 3 seconds to ‘reset’ as C2 discharges through R2 and turns the fet back off. Inrush current won’t be limited during this period.

Discharge

Since the input is at high voltage, a capacitor discharge circuit is required to make the board safer to handle after power is disconnected. When power is disconnected, M3 stops pulling the gate to M2 low, allowing current to flow through R3 and bringing the voltage of the caps down from 154V to 60V in about 2 seconds.