This is hopefully a simple question for all of you. I'm trying to select an off the shelf SMPS to give me +/- 15V rails for audio, and also a 5V high current rail for logic. I've never seen an off the shelf SMPS where the current source and sink capabilities of the +/- rails are equal in their specifications. Does it matter, and do they exist? I understand on an elemental level how SMPS work, but have never designed one from scratch. I always try to shoot for equal impedance on the PS when designing a linear power supply so this is slightly out of my wheelhouse.
My circuit requirements will need about 200mA in total from the 15v rails.
I've been looking at the MeanWell RT-50C as a possible option. In the datasheet of most SMPS power supplies, I've noticed that the negative rail current sinking capability is typically much lower than the positive rail. In this particular supply, it can supply 1.5A for the positive rail, and seemingly can only sink .5A from the negative rail. I know that SMPS can sometimes be a little wonky or noisy if there isn't enough load on them, or if there is too much load on them. My common sense tells me that this is perhaps fine for my application, but maybe it's overkill? I'd like to get away with a smaller one if possible.
My question is that when sizing an SMPS, will I need to make that lower current on the negative rail my target, or are they somehow additive between rails (i.e. 2A total between rails in this case)? I'm asking because it seems that the positive rail in this case would be working at a different regulation than the negative rail. I'd like to keep the noise as low as possible. Thanks in advance!
My circuit requirements will need about 200mA in total from the 15v rails.
I've been looking at the MeanWell RT-50C as a possible option. In the datasheet of most SMPS power supplies, I've noticed that the negative rail current sinking capability is typically much lower than the positive rail. In this particular supply, it can supply 1.5A for the positive rail, and seemingly can only sink .5A from the negative rail. I know that SMPS can sometimes be a little wonky or noisy if there isn't enough load on them, or if there is too much load on them. My common sense tells me that this is perhaps fine for my application, but maybe it's overkill? I'd like to get away with a smaller one if possible.
My question is that when sizing an SMPS, will I need to make that lower current on the negative rail my target, or are they somehow additive between rails (i.e. 2A total between rails in this case)? I'm asking because it seems that the positive rail in this case would be working at a different regulation than the negative rail. I'd like to keep the noise as low as possible. Thanks in advance!
