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5

17 different switchers might sound like a lot, but it is "just" 24 dB more emissions than having only one. Well designed switcher is easily 30 dB from the EMC limits, so there shouldn't really be a problem. Of course you need to design them well, but it's still not as difficult task as you might think. Without doing more math, to me the EMC trouble seems ...


4

In the context of linear voltage regulators, the pass element (transistor) is controlled by negative feedback to achieve regulation. Here's a (very simplified) linear regulator: simulate this circuit – Schematic created using CircuitLab Q1 passes output current in the direction of the arrow (and that is the reason it is called the pass transistor). ...


4

The catch diode insures a proper return path for the inductors current. Without the diode there is risk of damage to the MOSFET switch and a greatly reduced output. There is also a possibility of incorrect polarity at the output, possibly causing damage or drawing excessive current from the source. The diode solves many problems on both the ON and OFF cycle ...


3

Using DCDC buck converters is definitely the way to go. You can find inexpensive types in SOT-23-6. This one might be just the ticket: https://www.diodes.com/assets/Datasheets/AP63200-AP63201-AP63203-AP63205.pdf - it uses spread-spectrum to reduce peak EMI and controls drive to reduce ringing at the inductor. EMI Tips: Use shielded inductors for the DCDCs....


1

Yes, that would work. But why not connect the switch directly to the resistors in the first place?


1

As you say the inductor cannot allow current flowing through it, to change instantaneously. When you turn off your switch it is equivalent to raising the series resistance for the switch and hence the inductor in series. If the current is not to change instantaneously when you change the resistance then the voltage will rise across the inductor to achieve ...


1

The loop compensation of the buck converter depends on many factors as you can imagine. Below are a few simple statements to help you narrow down your search and find the answers you are looking for: control mode: it corresponds to the way you control the converter. There are many control schemes but the most popular are fixed-frequency voltage- or current-...


1

You have 24V DC coming in, but you can efficiently convert that to other voltages using stepdown switchers. For instance you have a number of strands at 5.8V and 8.4V - for these you could step down to about 9.5V or so and them use simple linear constant current drivers per strand - or even have two step down regs at say 9.5 and 6.8V or so. This approach ...


1

The 17 switchers design should be fine. This is purely for driving LEDs, so you don't have any ultra sensitive components to worry overly about. Besides just following good design and layout practices there are two simple things that come to mind for me: Firstly you can run them on a couple of different clocks. That would spread the noise out instead of ...


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