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In the Powerline series, how does the continuous short circuit protection operate?

The Powerline series all use hiccup overload protection. If the output is overloaded or short circuited, the output is turned off to protect the converter. After a short delay, the output is restarted. If the short circuit condition still exists, the output is again disabled. This cycle continues until the fault condition is removed. The output thus “hiccups” every half second or so.

 

Why does the RP40 series run hot with no load?

The higher power converters are optimized to run with the highest efficiency at full load. This means, for example, that the switching transistors need to switch very rapidly to avoid wasting power in the region between fully on and fully off. With no load, the switching drivers still run at full power which makes the converters run warm.

 

Category: RP, powerline, no load, RP40, hot, power
Why do you specify a Derating Curve?

At a certain temperature the internal heat dissipation makes impossible for the converter to supply 100% of its power and it starts to gradually provide less power as the temperature goes higher. This temperature is specified as Ambient Temperature.

 

I have temperature problems. Can I use a heat sink to increase the temperature range?

The converters have a derating curve that starts usually between 70°C and 85°C. From that temperature point the power is reduced linearly. You can use a heat sink to move this temperature point up a few degrees. If your application doesn’t have a adequate ventilation system, even a large heat sink may not be effective. The solution would be to use a higher power converter instead.

 

Are all the triple outputs regulated from the Powerline series?

Only the main output is regulated. The problem with any multiple output converter is that there can only be one feedback loop, so triples have always only one regulated output, with two auxiliary unregulated low current outputs.

 

Can I use the Common Mode Choke used in my EMI filter to limit the Inrush current as well?

The inrush current is dependent on the converter, the load (especially the capacitive load) and the impedance of the primary power supply. Therefore, there is no recommended value for the inrush limiting inductor as this need to be individually worked out for each application. Having said that, usually 22µH~100µH works ok.

 

A CMC is a good inrush current limiter because the core does not go into saturation with high currents (the +ve inrush current is balanced out by the -ve inrush current), so it has a dual purpose: EMC filter and inrush limiting. However, for high power converters it is sometimes better to use a low inductance, high current, choke that is selected to reduce inrush rather than a high inductance choke selected for the best EMC filtering because otherwise too much power could be lost through the choke's resistance during normal operation.

 

Do RECOM products include EMI filtering?

EMI filtering is not included inside the converters. However, an external EMI filter is suggested in our Application Notes.

 

Is required any input or output capacitor?

For normal function, no external capacitor is needed. For EMI filtering, consult our recommendations in our Application Notes.