# Advantages of consequent buck converters

Lets assume we have a 12V source (i.e. an external PSU). We need to go down to 1V8 to supply some load. Leaving the costs behind and using only synchronous buck converters, what are the advantages and disadvantages of the options a) and b)?

a) Cascaded solution with intermediate 3V3 converter

b) Direct solution with no intermediate converter

Of course we assume that input voltage is within the spec for every converter etc. This is just an overall example, but I am trying to point out the differences. I would for instance say that solution a) is less effective, since each converter has a < 100% efficiency, so each additional converter in chain introduces more power losses. But for some reason I see this kind of solutions- this made me wonder whether there are some additional advantages here, or maybe disadvantages with option b)?

• You would need to check the actual specs for the devices you are intending to use to make a final choice but generally one conversion is going to be more efficient than two sequential conversions. Commented Oct 15, 2020 at 19:29
• Also conversion where the ratio Vout/Vin is large (12 V / 1.8 V) is generally more efficient than where that ratio is less (3.3 V / 1.8 V). If you see solution a) but the 3.3 V isn't used for anything else than feeding the 1.8 V regulator look closer because that doesn't make sense so maybe you missed something. Commented Oct 15, 2020 at 19:34
• @Bimpelrekkie for the applications I have seen, the scenario is the following:12V -> 3V3 -> here to many different parallel converters (i.e. 1V8, 1V5 etc.). Because of the architecture, the lower voltage converters had low VIN. But a similar application I have seen without the immediate 3V3 converter (then the converters for 1V8 and 1V5 have higher VIN to handle 12 V). Commented Oct 15, 2020 at 19:45
• Research how CPU’s use nearby onboard regulators from MOBO and you will find your answer. Commented Oct 15, 2020 at 21:34
• Could you make the answer more clear? Commented Oct 16, 2020 at 3:10