XPost: alt.comp.hardware.pc-homebuilt, alt.comp.os.windows-10   
   From: nospam@needed.invalid   
      
   On Thu, 5/8/2025 7:21 AM, Larry Wolff wrote:   
      
   >   
   > Why is a step down DC to lower DC converter called a buck converter?   
   > Shouldn't it be called a variable duty cycle converter instead?   
   > I s'pose the name contrasts better with that of a boost converter.   
   >   
      
   There are three types, buck, boost, and buck-boost :-)   
      
   The buck-boost is the most complicated.   
      
   If you have a five volt input device, and the output is   
   variable and knob adjustable, then to make six volts   
   on output it runs in boost mode, and to make four   
   volts it runs in buck mode.   
      
   Someone at work commissioned someone outside the company   
   to build us a buck-boost on a PCB and the circuit was huge   
   in terms of component count.   
      
   In principle, you could do a boost first, followed by a buck,   
   and get a dial-adjustable voltage. But that's two conversions,   
   and the boost might only be 80% efficient, and the circuit   
   is going to get warm if you do it that way. A fully integrated   
   buck-boost changes modes, so there is only ever one conversion   
   going on at a time.   
      
   Buck is pretty efficient, or at least, it's easier to optimize.   
      
   *******   
      
   And thank goodness, there's a Wiki for this. As a bonus,   
   it even covers some of the methods used in LED lighting   
   (SEPIC and CUK, at least according to one article).   
      
      https://en.wikipedia.org/wiki/Buck%E2%80%93boost_converter   
      
     Paul   
      
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