1
\$\begingroup\$

We are using a Isolated Fixed-Ratio DC-DC Converter from Vicor (http://www.vicorpower.com/documents/datasheets/ds_BCM4414xG0F4440yzz.pdf) that is powered through a 600VDC accumulator.

The DCDC powers the entire low voltage system of a electric vehicle. It's somewhere between 10-16 Amps depending on the state of charge and which systems are active. The DCDC has problems starting up and I believe it is because we are on the limit of the output capacitance for the DCDC and unplugging some systems at start-up seems to fix the problem. Usually we have to start it without cooling fans being connected, and then connect them once it has finished starting up.

I am waiting for parts to connect to the DCDC through the PMBus to monitor the current and other parameters at start-up.

I was wondering if there exist a nice solution for slewing the output current of the DCDC?

By the way, this is a student project if it seems like a strange issue.

\$\endgroup\$
  • 1
    \$\begingroup\$ Look at eFuse and hot-swap controllers. \$\endgroup\$ – John D Jul 17 '19 at 18:48
  • 1
    \$\begingroup\$ Is there anything in those 43 pages of datasheet that suggests you can control the output voltage? Maybe you could ramp it up. \$\endgroup\$ – TimWescott Jul 17 '19 at 19:33
1
\$\begingroup\$

If all else fails, and if you can reliably start the thing up with peripherals unplugged and then plug them in later, then you could intentionally stage the turn-on of the peripherals. Just have them on timed relays (or relays controlled from a microprocessor) that sequence them on in a way that doesn't challenge the power supply too much.

| improve this answer | |
\$\endgroup\$
1
\$\begingroup\$

You may be able to use a component specifically designed for this problem, the Inrush Current Limiting NTC Thermistor. In the following article, "How to Use NTC Thermistors for Inrush Current Limiting", it states:

An NTC thermistor limits an inrush current with its high initial resistance, and then its temperature rises because of energization and its resistance falls to a few percent of its level at room temperature, thus achieving a power loss that is lower than when a fixed resistor is used.

So, it's a temperature-dependent current-limiting resistor that heats up and then takes itself out of the equation. Just the thing to help a DC-to-DC converter start up into a challenging load. :-)

| improve this answer | |
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.