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Old 3rd July 2012, 06:36 PM   #91
DF96 is offline DF96  England
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No contradiction at all. Linearity does not necessarily imply large output, and it does not necessarily require simple proportionality as a constant bias can be involved too. All linearity, in the context of a PSU, means is that if raising the input from 20V to 25V raises the output by 0.5mV (from 12V to 12.0005V) then raising the input to 30V means that the output goes up 1mV to 12.001V.

I think it was your mistaken introduction of 'proportional' which led you astray.
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Old 3rd July 2012, 06:42 PM   #92
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Linear voltage regulator is opposed to the one that uses PWM. But who is well known vendor of chips for PWM regulators? A company with "Linear" in their name.
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Old 3rd July 2012, 06:44 PM   #93
wahab is offline wahab  Algeria
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"Bootstrap" is one of the worse technical terms since it s barely analytical.
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Old 3rd July 2012, 06:49 PM   #94
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What is confusing in bootstrap?
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Old 3rd July 2012, 06:50 PM   #95
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No, you are confusing linear with affine. When there is a constant bias involved, the system does not comply with the superposition theorem anymore and it is therefore not linear. At least that's what I've been thought at the Delft University of Technology.

Current feedback has at least three different meanings nowadays:
-In the oldest literature that I've read, it meant series feedback at the output, no matter what happens at the input.

-In the book/PhD thesis of Ernst Nordholt it means series feedback at the output and shunt feedback at the input, resulting in an accurate current to current transfer.

-In the context of current feedback op-amps it applies to the exact same feedback configuration as normal voltage feedback (shunt at the output, series at the input), but with an op-amp having a low open-loop input impedance at its negative input.
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Old 3rd July 2012, 06:51 PM   #96
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Quote:
Originally Posted by Wavebourn View Post
Linear voltage regulator is opposed to the one that uses PWM. But who is well known vendor of chips for PWM regulators? A company with "Linear" in their name.
And what if I use a quadratic device like a FET or tube? It has some proportionality, but not necessarily linear (equal output measure per equal input measure)
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Old 3rd July 2012, 06:59 PM   #97
wahab is offline wahab  Algeria
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Quote:
Originally Posted by Wavebourn View Post
What is confusing in bootstrap?
It is not analytical ethymologicaly speaking.

"Positive feedback loop" is the right term and it s quite remotely
linked to "bootstrap".
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Old 3rd July 2012, 07:34 PM   #98
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Right, bootstrap is actually a jargon term for specific positive feedback from output of the voltage follower to it's input.
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Old 3rd July 2012, 09:42 PM   #99
DF96 is offline DF96  England
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Quote:
Originally Posted by MarceldvG
No, you are confusing linear with affine.
Possibly. I think UK EEs generally extend 'linear' to include 'affine', as 'affine' is not a word which crops up often on EE courses here. 'Linear' is taken to mean 'no new frequency components in the output'.

Interestingly, the strict definition of linear excludes all sources (e.g. DC PSU, AC oscillators) so may be mathematically correct but perhaps unhelpful?
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Old 4th July 2012, 10:23 AM   #100
wahab is offline wahab  Algeria
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Quote:
Originally Posted by DF96 View Post
No contradiction at all. Linearity does not necessarily imply large output, and it does not necessarily require simple proportionality as a constant bias can be involved too. All linearity, in the context of a PSU, means is that if raising the input from 20V to 25V raises the output by 0.5mV (from 12V to 12.0005V) then raising the input to 30V means that the output goes up 1mV to 12.001V.
Linearity of such PSU is not tied to its regulation factor seen from
input to output but to the relation between its voltage reference
and its output.
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