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Steve Taranovich

Difference Amplifiers Enable Low-Loss, High-Performance Full-Wave Rectifier

Steve Taranovich
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etnapowers
etnapowers
3/11/2014 10:19:42 AM
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difference in polarization point
Looking at the circuit in figure 2, the full wave rectifier I see that the positive terminal of  A1 is polarized at GND DC , but the positive terminal of A2 is at a non zero voltage DC value. I wonder if this difference in the polarization of A1 and A2 influences the gain loop.

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etnapowers
etnapowers
3/11/2014 7:41:01 AM
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two inverters cascade full-wave rectifier
The diodes D1 and D2 of the circuit in Figure 2 are turned on/off alternatively , so I think that a diodes matching really accurate is very important to avoid a cross conduction due to a lack of matching between the turn-on and turn-off times of the diodes.

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etnapowers
etnapowers
3/11/2014 7:11:13 AM
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classic full wave rectifier
The figure 1 refers to an ideal no losses bridge, for diodes having a conduction threshold (˜1V) that is comparable to the input AC voltage amplitude, the output waveform is a littel bit different, so for this rectifier some low losses diodes are needed, expecially when the input AC voltage amplitude is low.

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chirshadblog
chirshadblog
3/11/2014 3:29:33 AM
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Re: phasing??
@samicksha: Actually both since quality has links to both the areas. So both parties do play a major role.  

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samicksha
samicksha
3/11/2014 12:03:51 AM
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Re: phasing??
@chirshadblog: What exactly you refer as quality here, is it performance related issue or quality of hardware.

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chirshadblog
chirshadblog
3/10/2014 4:21:08 AM
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Re: phasing??
@samicksha: Yes but is there a  big huge difference in quality ? 

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samicksha
samicksha
3/9/2014 11:58:01 PM
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Student
Re: phasing??
I guess most modern phasers are a part of a digital signal processor, often trying to emulate analog phasers.

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DaeJ
DaeJ
3/9/2014 10:56:56 PM
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Master
Re: An interesting addition to the canon of rectifier circuits...
A simple full-wave rectifier has D1 and D2 which is partially for rectifier circuit. Diode D1 and D2 acts like voltage clamping.  Output performance without D1 and D2 could be different while changing AC voltage wave.  My concern is that there would be a noise or output signal distortion when either class full rectifier circuit or a simple full rectifier circuit is integrated with other circuit, digital logic, or high frequency input signal.

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Netcrawl
Netcrawl
3/9/2014 3:10:57 AM
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Master
Re: phasing??
great article @Steve! thanks for that,  you clearly explained everything, rectification systems are primarily designed for conversting AC input signals into DC voltage signals, they're probably the most commonly used stuff in power electronics and transmission. 

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kendallcp
kendallcp
3/8/2014 10:56:30 AM
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Teacher
An interesting addition to the canon of rectifier circuits...
... but it's not really fair to compare it to a regular diode bridge and then ding the bridge for its disadvantages.  Add some opamps and the bridge becomes a much more workable solution.  Putting it in the feedback path of an op-amp eliminates the diode voltages (and their mismatches) and you can 'slap a cap' straight across it to give you the envelope.  That in turn can be directly sensed differentially or turned back into single ended form with a diff amp (manufacturers of diff amps take note!).  Did this in the 80s and it worked fine.  Helps to keep a lid on amplifier slewing as well.  That is always something to keep an eye on with rectifier circuits, which tend to underperform for low level high frequency signals since there's often an unmonitored opamp output thrashing about madly by a diode drop or two just to keep up.

There are better fits for single supply operation too.  It's pretty straightforward to produce an accurate full-wave rectifier circuit that needs no negative rail but still works on a bipolar signal.  The circuit shown here needs split supplies to cope with an AC signal.

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Page 1 / 2   >   >>
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