# Talk:Voltage doubler

This article says "The negative peaks of the AC waveform are "clamped" to 0 V (actually −VF, the small forward bias voltage of the diode) by the diode."
Why state it that way instead of just saying clamping is at -VF?
ICE77 (talk) 00:20, 20 August 2015 (UTC)

Because nominally the circuit is clamping to 0V.  With an ideal switching element it would actually clamp to 0V.  The forward volt drop of the diode can be looked on as an error that needs to be taken into account. SpinningSpark 10:58, 22 August 2015 (UTC)
Ideal components are nothing but fiction. Let's stick to the real world. I think it's a more practical approach.
ICE77 (talk) 06:03, 27 August 2015 (UTC)

Just about every competent textbook ever written about electronics starts by analyzing ideal circuits.  They do this because that is the more general case, and gives the greatest insight.  Deviations from the ideal can be discussed, but particular component types must then be specified. SpinningSpark 14:55, 27 August 2015 (UTC)

"The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input." - Is it just me? I don't really like that description. I would sooner describe the diodes in a simple passive circuit as "steering" devices rather than "switching" devices. Anyone else? 31.125.76.2 (talk) 10:59, 29 July 2020 (UTC)

I've moved the above comment from the GA review which is a closed discussion. SpinningSpark 11:43, 29 July 2020 (UTC)

"As with a bridge circuit, it is impossible to simultaneously ground the input and output of this circuit.[6]"
The reference [6] is to p107 of Ryder's 1970 text Electronic Fundamentals and Applications. It's an excellent text, but it says nothing at all about grounding either bridge or multiplier circuits. It doesn't even mention Greinacher, and its only Greinacher-like circuit isn't a doubler but a quadrupler which (rightly) is usually credited to Cockroft and Walton. The reference should be removed.

"The Delon circuit uses a bridge topology for voltage doubling"
It's a full-wave circuit but not in a bridge topology. It can only resemble a bridge if the diodes are viewed as one leg and the capacitors as the other. That's a tortuous misinterpretation, which requires that the input appears between the junctions in the two legs and the output between the top and bottom - the opposite of accepted bridge topology.
It seems likely that The Delon circuit uses a bridge topology is a wrong assumption based on where it's widely seen: in computer power supplies, many of which include an encapsulated bridge rectifier. To accommodate low-voltage mains, for reasons of economy they use half the component in a Delon doubler - but not the whole bridge, because the Delon circuit doesn't use a bridge topology.

It looks like a bridge topology to me. Constant314 (talk) 08:54, 29 May 2024 (UTC)

I tried to copy the "Cross-coupled switched capacitors" example (Figure 9) using 5V supply, but the output voltage only seems to go to a maximum of 5.7V, so I am wondering if there is a mistake in this wikipedia article. Here is my circuitjs code (can be imported with File->"Import From Text...") if anyone wants to try to replicate...I hope I didn't make an error: 

$ 1 1e-7 2.803162489452614 50 5 50 1e-10
v 736 704 736 656 0 2 100000 2.5 2.5 0 0.25
v 848 704 848 656 0 2 100000 2.5 2.5 3.141592653589793 0.25
g 848 704 848 720 0 0
g 736 704 736 720 0 0
R 688 304 656 304 0 0 40 5 0 0 0.5
w 688 304 752 304 0
207 736 656 736 624 4 φ₁
207 848 656 848 624 4 φ₂
207 992 480 992 448 4 φ₂
f 784 352 752 352 32 1.5 0.02
w 752 336 752 304 0
w 752 304 896 304 0
f 864 352 896 352 32 1.5 0.02
w 896 304 896 336 0
w 784 352 800 352 0
w 800 352 848 400 0
w 864 352 848 352 0
w 848 352 800 400 0
w 800 400 752 400 0
w 752 400 752 368 0
w 896 368 896 400 0
w 896 400 848 400 0
w 896 400 896 496 0
c 896 544 896 496 6 1e-8 -3.1365118538833987 0.001 0
w 752 400 752 416 0
w 752 416 752 496 0
c 752 496 752 544 6 1e-8 0.44813214075182994 0.001 0
w 752 416 960 416 0
159 960 416 1024 416 10 20 10000000000 2.5
159 960 496 1024 496 10 20 10000000000 2.5
w 896 496 960 496 0
207 992 400 992 368 4 φ₁
w 1024 416 1056 416 0
w 1056 416 1056 448 0
w 1056 448 1056 496 0
w 1056 496 1024 496 0
O 1056 448 1120 432 1 0
207 752 544 752 528 4 φ₁
207 896 544 896 528 4 φ₂
o 36 1 0 4098 10 0.1 0 1Em3rgent0rdr (talk) 06:59, 18 September 2025 (UTC)
What did you connect the 
  
    
      
        
          ϕ
          
            1
          
        
      
    
    {\displaystyle \phi _{1}}
  
 and 
  
    
      
        
          ϕ
          
            2
          
        
      
    
    {\displaystyle \phi _{2}}
  
 terminals of the capacitors to? There's a lot of handwaiving in that area of the circuit. ~Kvng (talk) 20:24, 22 September 2025 (UTC)

I attached 
  
    
      
        
          ϕ
          
            1
          
        
      
    
    {\displaystyle \phi _{1}}
  
 to a 25% duty square wave (min 0V max 5V) and 
  
    
      
        
          ϕ
          
            2
          
        
      
    
    {\displaystyle \phi _{2}}
  
 to another 25% duty square wave that is 180 degrees out-of-phase, so that the positive portion of their cycles are non-overlapping, which is usually what I interpret is the intended  the useage of "
  
    
      
        
          ϕ
          
            1
          
        
      
    
    {\displaystyle \phi _{1}}
  
" and "
  
    
      
        
          ϕ
          
            2
          
        
      
    
    {\displaystyle \phi _{2}}
  
".  The output voltage just seems to be a 5V square wave. And if I use 50% duty square waves 
  
    
      
        
          ϕ
          
            1
          
        
      
    
    {\displaystyle \phi _{1}}
  
 and 
  
    
      
        
          ϕ
          
            2
          
        
      
    
    {\displaystyle \phi _{2}}
  
, then the output is basically just 5V with some ripple. Em3rgent0rdr (talk) 18:40, 24 September 2025 (UTC)
Google searching for the cited book (Liu, Mingliang 2006, Demystifying Switched Capacitor Circuits), I do find a pdf to the book (I won't share the link cause I'm not sure it is a legitimate copy) and on page 233 there is "Figure 6.4 Cross-coupled charge-pump configured as a voltage doubler", but it is significantly more complicated that this wikipedia page's Figure 9.  So maybe a bunch of important details got dropped by whoever made Figure 9. Em3rgent0rdr (talk) 18:45, 24 September 2025 (UTC)

Ok, so I've copied that Figure 6.4 from the Mingliang Liu book, and this complete circuit does seem to function and generates output voltage of 9.6V from a 5V input source with phi1 and phi2 as two 45% duty-cycle square waves out-of-phase. Here is the circuitjs txt:
$ 1 1e-7 1.4391916095149893 50 5 50 1e-10
v 688 704 736 704 0 2 100000 2.5 2.5 0 0.45
v 688 784 736 784 0 2 100000 2.5 2.5 3.141592653589793 0.45
g 688 784 672 784 0 0
g 688 704 672 704 0 0
R 832 224 816 224 0 0 40 5 0 0 0.5
w 704 240 752 240 0
207 736 704 768 704 4 φ₁
207 736 784 768 784 4 φ₂
f 784 288 752 288 96 1.5 0.02
w 752 272 752 240 0
w 832 240 912 240 0
f 880 288 912 288 96 1.5 0.02
w 912 240 912 272 0
w 784 288 800 288 0
w 800 288 848 336 0
w 880 288 864 288 0
w 864 288 816 336 0
w 816 336 752 336 0
w 752 336 752 304 0
w 912 304 912 336 0
w 912 336 848 336 0
w 912 544 912 592 0
w 752 336 752 384 0
w 752 544 752 592 0
207 800 608 800 640 4 φ₁
207 864 608 864 640 4 φ₂
403 784 672 1088 736 0 6_1_0_4098_5_0.1_-1_2_6_3
207 832 384 832 352 4 out
403 784 752 1088 816 0 7_1_0_4098_5_0.4_-1_2_7_3
f 800 352 800 384 97 1.5 0.02
w 800 288 800 352 0
f 864 352 864 384 105 1.5 0.02
w 864 288 864 352 0
w 848 384 832 384 0
w 832 384 816 384 0
w 752 384 784 384 0
w 912 384 880 384 0
w 912 384 912 336 0
w 832 224 832 240 0
w 832 240 752 240 0
r 800 464 800 512 0 100000
w 800 464 832 464 0
w 832 464 864 464 0
c 864 464 864 512 4 0.00001 9.642390046756153 0.001 0
w 864 512 832 512 0
w 832 512 800 512 0
w 832 464 832 384 0
f 784 608 752 608 105 1.5 0.02
w 752 624 752 640 0
c 752 544 752 384 4 0.00001 -4.650082848980891 0.001 0
c 912 544 912 384 4 0.00001 -4.639822409654963 0.001 0
f 880 608 912 608 105 1.5 0.02
w 912 640 912 624 0
w 800 608 784 608 0
w 864 608 880 608 0
w 912 640 960 640 0
w 960 640 960 240 0
w 960 240 912 240 0
w 752 640 704 640 0
w 704 640 704 240 0
w 832 544 832 512 0
w 832 544 848 544 0
f 800 576 800 544 104 1.5 0.02
w 800 608 800 576 0
w 784 544 752 544 0
w 816 544 832 544 0
f 864 576 864 544 96 1.5 0.02
w 880 544 912 544 0
w 864 608 864 576 0
g 832 544 832 592 0 0
g 752 288 736 288 0 0
g 912 288 928 288 0 0
g 800 544 800 528 0 0
g 864 544 864 528 0 0
207 864 384 864 416 4 out
207 800 384 800 416 4 out
207 912 608 944 608 4 out
207 752 608 720 608 4 out Em3rgent0rdr (talk) 19:39, 24 September 2025 (UTC)