Hi all, I'm in a situation where I have to provide power from a well-regulated clean source to something noisy, and I don't want the noise to get back to the clean power source. The well-regulated clean source will be 50 VDC, and the noisy things are compact brushless DC switching fans, four of them. Case constraints make it difficult to use any other cooling technique.
I know I can put the noisy things behind a CLC filter, but it'd be nice to do even better. I wish I could add a voltage regulator, but designed to sortof back-regulate and minimize disturbance on the clean power at the expense of the fans, which shouldn't much care how stable their voltage is. I plan to run the fans in series, with capacitors parallel to each, for a total voltage requirement of 48 VDC.
My suspicion from looking at the operating principle of a typical linear regulator is that they actually present a rather noisy and variable load on the supplying circuit. One alternative I could think of would be to use a current source directing current into the load in parallel with a zener reference. This would seem to minimize noise to the supplying circuit since the load draws constant current at constant voltage. I can find what seem like halfway decent current sources ( NSI45030T1G from on semi ) but they're all designed for keeping LED's evenly bright and the datasheets don't include things I care about like bandwidth or rejection ratio v frequency. This leads me to suspect I'm not on the right track.
Does anyone have any recommendations in this regard? I'd prefer options that keep my BOM smaller, so IC's are preferable to filter cascades. Cost is not a very significant factor, nor is energy efficiency.
I know I can put the noisy things behind a CLC filter, but it'd be nice to do even better. I wish I could add a voltage regulator, but designed to sortof back-regulate and minimize disturbance on the clean power at the expense of the fans, which shouldn't much care how stable their voltage is. I plan to run the fans in series, with capacitors parallel to each, for a total voltage requirement of 48 VDC.
My suspicion from looking at the operating principle of a typical linear regulator is that they actually present a rather noisy and variable load on the supplying circuit. One alternative I could think of would be to use a current source directing current into the load in parallel with a zener reference. This would seem to minimize noise to the supplying circuit since the load draws constant current at constant voltage. I can find what seem like halfway decent current sources ( NSI45030T1G from on semi ) but they're all designed for keeping LED's evenly bright and the datasheets don't include things I care about like bandwidth or rejection ratio v frequency. This leads me to suspect I'm not on the right track.
Does anyone have any recommendations in this regard? I'd prefer options that keep my BOM smaller, so IC's are preferable to filter cascades. Cost is not a very significant factor, nor is energy efficiency.
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