Power supply for ECL board?

[choadnamath]

I have an ECL board that previously got its -5.2V and -2.0V from a custom power supply that ran off of 360-440 Hz, 3-phase aircraft power. I need to place this board in a ground-based VME chassis and use a 110VAC power supply to generate these voltages. I can't find a -5.2V or -2.0V power supply for the life of me. Do they exist? What does everyone else use to generate these voltages? I'm also wondering if it's possible to run a board that was designed specifically for -5.2 and -2.0V at PECL voltages? Hope someone can help

 

[pisoiu]

ECL and PECL are similar in function and characteristics. However, as their name says, ECL is powered from negative voltages and PECL from positive. The magnitudes are the same, 5V for power and Vcc-2V for the termination voltage. Without modifications, I do not think you will be able to supply it with positive voltages. You can use an inverter such as MAX755 to obtain negative voltage from positive, but you have to consider the power requirements, which are quite high for ECL family. From the -5V you can also obtain the -2V required for termination. Some of older PC power supplies also have -5V at output. Also, you will have to take care at the outputs, if they are ECL and you want to interface with another positive supply logic family, you will need converters.
https://www.onsemi.com/site/support/literature/list/0,4456,1161_273,00.html , you can find here a lot of appnotes for ECL family.

/pisoiu

 

[choadnamath]

Right on the power needs; the -5.2V needs 2.5A and the -2.0V needs 3.5A. It doesn't look like the MAX755 inverter can handle those amps.

 

[pisoiu]

Certainly not. Maybe the PC power supply will also fail to give such currents on -5V line. The -5V exists in the PC power supplies as a backward compatibility, some time ago, memories, especially old ones required -5V to operate, but in modern PC boards, this voltage is not used. This is why the manufacturers do not put a high price on the -5V line, it just have to be there, that's all. But it worth to check the label from the power supply, the current capabilities are usually indicated.

/pisoiu

 

[rfmw]

What's the real problem here? Why do you not use ordinary power supply box for negative voltages? If you have ECL, than your ground or chassis of the ECL circuit is at 0 Vdc level. Simply connect positive output (plus) of the power supply box to this potential, i.e. to your ECL circuit ground. Then your negative output (minus) of the power supply box to -5V or -2V ECL circuit input.

I'm too using ECL and use ordinary power supply boxes for supply voltages (-3.3V/-5.0V, -2.0V and -1.35V) and there is no problem if you know what you're doing. What you must be careful about is that your power supply boxes use transformer inside, so there is no galvanic connection to the 110V/220V side.