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FAB1248 – DC/DC Converter +48Volts Short Circuit Testing

I decided to test how my FAB1248 DC/DC Converter will behave in a short circuit condition. It is unavaoidable to experience short circuit when you’re playing around with electronics. Sooner or later, you’ll experience it. The question is will the FAB Modules survive if there was ever an accidental short-circuit?

Will our FAB1248 Module release the magic smoke?  Will you need to buy another FAB Module from me to replace your short-circuited DC/DC Converter?

Here are the results of my testing:


We connected our FAB1215 Power Supply Module, with a FAB1248 plugin to a 12Volts DC Adapter (wall wart). We then attached a multimeter to monitor the voltage lines across GND and +48V output.

Voltage level (without load, open circuit) = 47.88Volts

Next, we connected the 48Volt line directly to Ground, thus creating a short-circuit condition. A big spark occurred. We let the 48Volt line connect to Ground for several seconds. Measured output voltage during this short circuit condition is 34.8mV according to the multimeter.

Next, we removed the short-circuit condition.  Measured output voltage went up to 1.25Volts, but not our original 47.8Volts…. Hmmmm….. at this point, I’m wondering if the FAB1248 survived… It doesn’t seem to be looking good. It’s only hovering around 1.25Volts.

Removed the 12Volts input voltage  from the FAB Module. Now, the measured output voltage is now 0 volts, naturally… since there is no voltage  input source.

Hooked up the 12Volts input again to the FAB Module…. Voila!  We measure 47.88Volts again, and our FAB1248 module is still working properly. I repeated this test procedure several times and each time, the FAB1248 comes back to life after doing a “reset” …. just unplug the 12Volt source, and plug it again.

So I’m happy to report, that yes, the FAB1248 will survive a short-circuit condition and not break down.  You may need to “reset” the converter by powering off, then powering back on…. of course, after you’ve removed the short-circuit condition.

Extra Pads for FAB2010 and FAB3010 Modules

I added extra pads on the PCB so you can have easy access to the V+,GND,OUT+,OUT- signal lines on the board.  This is useful if you’ll be using our FAB2010 XLR Input Module, and FAB3010 XLR Output Module in your own project and you just want to solder your voltage and control wires directly to the board (without using the Ribbon connector or a breakout board).

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FAB1248 Testing – 12Volts to 48Volts DC/DC converter

I made some tests using the final component values for our FAB1248 DC/DC converter.

Using a 12Volts DC input, phantom power voltage output remained constant at 47.90Volts, up to 47.84Volts at various loads and current draw.

For example, at 57mA current load, voltage output measured is 47.87Volts, with 152mV ripple according to our oscilloscope. This translates to about 0.31% ripple!  Ripple frequency has a period of 6.07us, or 164.7khz.

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FAB3000 Series Wiki Documentation Update

FAB3000 Output Modules All modules related to the Output Section. These will include XLR Male jacks, TRS jacks, Output Transformers, Balanced Line Drivers, Sends, Auxilliary Outputs, etc

  • FAB3010 – XLR Output Module
  • FAB3110 – Output Transformer Module
  • FAB3130 – Edcor Output Transformer, PC Series Module

FAB9002 – “Bridge” Extension Module

Our different FAB Modules come in different standard sizes (2.0 x 2.5, 2.0 x 3.0″, etc…), and sometimes you may want to keep all your Modules equal in length when laid side by side in (2) columns.  Some cases where I see this is if you want your XLR Input and Output Modules aligned at the same offset, so you can mount them on your chosen case.

This utility module is a simple “extender” module, whose sole function is to add some extra length space to your modules. It’s just a direct pass-through, as you can see from the PCB traces in the diagram below. That is all, nothing special, nothing extraordinary…. but could be useful in certain cases.


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