I have tried to find replacement DC-DC converters, that would behave so that +5V and -5V can be unequally loaded, but I need it to have the same pinout, because I don't want to spend more money and time to order new boards. The pin out seems to be somewhat common, but the datasheets are not very clear about the COM / Common pin and what happens when loading the rails unequally against the Common.
Traco TEN5 looks like a suitable and relatively easily available replacement:
http://www.tracopower.com/products/ten5.pdfHas anyone used dual polarity models from the TEN5 series?
If the output isn't regulated or is only poorly regulated on the +5V and not regulated on the -5V then this is what you should expect to happen.
They promise +/- 0.5% regulation with 2% voltage accuracy so it doesn't count as "poorly regulated", right?
I did more measurements with DCW05B-05 and DCW05A-05.
Voltage between +Vout and -Vout is stable 10V (measured variation only 20mV). It does not change with asymmetric loading of +Vout and -Vout.
I put an adjustable load between COM and +Vout and another adjustable load (well, manually adjusted by swapping 5W resistors) between COM and -Vout.
When there is equal load on both rails then +Vout = +5.0V and -Vout = -5.0V.
Uneven loading causes the COM level to shift towards the more loaded rail. The effect is strongest one one rail is completely without load and the other is heavily loaded. When both rails have significant load (90mA on negative and 400mA on positive) I measured voltages -5.2V and 4.8V.
I tried connecting COM to -Vin, but that did not influence the behaviour at all.
I'm curious.. Can some power supply expert tell based on this how they implemented the module? I don't get how they produce the COM voltage.
Pin names (+Vin, -Vin, +Vout, -Vout, COM) as in the datasheet, that I provided a link to in the original post.