Progressive current limiting

Figures ::

Legend :: opamp.Q1 mirrors the current at R5 , opamp.Q2 limits the current progressively ... and incase of the SC it cuts the output the more off the lower is the output voltage -- so there's double level progressive limiting (the fig.2 shows the 1-st and the fig.-s 3 to 5 show the 2-nd - a short circuit - limiting levels) . . . the resistor values for R24 to R26 and R21 , R22 , also for the R14 may need to be adjusted to get the real build of the circuit stable (maybe it takes more adjustments -- but these are known to be more likely critical at this stage of dev.)

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revised the yy78Lxx 5V variants

tests so far ::
PS! -- although the following setups perform well the real tings may not coz the Spice models use highly accurate fixed current sources - - - while there's no indication the real 78Lxx-s had any implemented //// the last time i tested my real 78Lxx-s showed an ulta poor performance where the voltage started to drop already at !!!above 30-/40 mA drain and significantly differed from the nominal at 50mA (while i didn't notice them getting hot -- so that a possible thermal prot. feature could have had engaged ???)

partial apx. match to d/s ::

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testing out the custom xx78L05xxx variant

amazingly -- worked from scratch -- no matter the blind guessed j-Fet and Zener values and much randomly chosen 2N2222 and 2N2907 for "tech."

but the OUTP voltage little drifts with INP voltage and the fold-back (from140mA) starts to work from 14V external supply ( ? wrong zeners . . . )

the model is currently adjusted to 5.0V at Abs.Max 35.0V input

as usual the component level model (78L05) is more stable than the .cir net-list model ( LT1761-5 )

NB! Not all the plotted parameters are relevant/consistent with the ↑↑ shown test
(they are relics from another grid that was used as a draft for these ones)

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"Level 2" ::

. . . with custom LM324 CLM ( Component Level Model ) (( which i also needed to test ))

This is why the net-list models are not good at complex circuits ↓↓ (i actually didn't expect to get it "stable" . . .)

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LM317 component level versus LT317 macro model

about the real things LM317x LT317x

simulation models (Custom against Linear)

a curious thing ↑here↑ is that the CLM(component level model) seems to be more stable than the ↓next↓ macro (more simplified) model

Models about ::

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TL431 Spice model variants´ TEST

presented as we go
► 1-st

► 2-nd

► 2-nd - in detail

wider range

component level models (sub circuits compared)

the best - upper two are the attempts to achieve better precision×frequency-rejection //// the reverse Vref´s emitter (EB) diode in Rank#(7) is a contemporary relic from an attempt to force the "Hot Start" for U4,U5 . . .

pulse e.g. stepped load response

overall ranking so far ...

? best CLM-s !!! for static operation . . .
. . . for undefined input the U5 e.g. X4 is likely better choice /// might be quite expensive regulator as the RF transistors cost $ 0.2÷1.0 per pcs.  /// (i can't comment nor recommend nor reject the macro models - but usually they are too optimistic !!!)

hi, hi - UPS! seems i used Amps insted of milli-Amps

that re-ranks the rank back to "Static" -- the red box is "for super cool experiments only!!" . . .
. . . so U2 // X1 the best CLM !!!

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Linear v. Switcing regulator - a specific occasion

Amazingly the case when there's no much difference
(that was revealed in revising an old design . . . )
-- the input supply is some avg. rectified output of a wall transformer

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5V regulator variants for 6F22

LDO utilizing a low R.DS of a MOSFET

a switchng variant of the prev. LDO !! no current limiting nor other specific situation handling !!

( !note : of course the OUTP loading is inverse proportional to R.int.BATT )
Component count optimized v. of EF regulator

Max. precision v. of prev.

-- the fold-back v.

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3-transistor "precision" LDO

Left-Below is the ® , Below-Right is over current-(/SC-) proof advance of it (as usual -- not tested as a real thing !)

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testing textbook voltage regulators

the src. A (fig. ⓐ) - won't start up with higher ß , silica "western" transistors

if we add a "startup**" it won't be overload proof -- it is possible to set there a time constant based startup "boost" that charges the output capacitor to near nominal output at no or moderate load connected . . . why all this fuzz - i just studied the circuit for it's simplicity . . .
. . . the next is what i came out as a near reasonable practical solution for the type of regulator (or what's left of that type)

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update: an alternate "startup**" v. that is still overload proof only it requires extra "Discharge" button to get off the "output disabled mode" -- to make it also "user proof" requires a special discharge or power button so that the discharge engages only when external supply can't charge the caps. -- all cool the simlpe things are not simple . . .

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the src. B (the leftmost fig.) -- works good as shown as long the input voltage is higher the output plus NPN-s BE vtg. drop + Op Amp-s incapability to reach positive rail some 1 to 2 V

if we power the regulator control circuitry from separate supplies - we get the foldback v. of the above src.

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rev. +1.2V Linear Voltage Regulator with Current Limit

not built in real yet /!\ e.g. possibly no reverse pol. prot. + unknown amount of spec. not handled states ...

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a fuzzy science on old transformers 2

finding the optimum simple design for 9V linear adapter

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using std. parts 7805 , TL431

the load peak/-step response is somewhat unexpected here

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using low ß , high power switch (such as *MJE13003)

the load regulation stays below acceptable

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using bridged LM78L05 and LM324

fine tuning the bridge may induce better results this 1 however won´t pass because it´s load response

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same as above with an attempt to add a reference to be used in better line rejection ...

... can´t gain steady reference - won´t test all possible situations for such a noisy one = reference failure , halt, halt

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using low ß , high power switch* and random intuitive design

looks pass - tough i don´t know about higher frequency load responce

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supply test defaults update

±1µV precision @ 1Hz ::


PS! this simulation uses 2N3906 for switch transistor
for 300mA continuous drainthere should be
6x 2N3906 in parallel or higher I.continuos switch
Switching v. ::

PS! this circuit is too complex to succeed @ 1-st build
- "we" feature here a quick poor setup example
for testing the grid at higher varying rate loads . . .

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Adjusting the fixed (3 terminal) voltage regulators

extends:: Adjusting the adjustable voltage regulator , Apr 5, 2015

(Std./)Simple v. :

with LT1086 (1.24V - adjustable) it gives seemingly errorless output ?

Op. Amp. v. :

it looks it is impossible to gain the ±2µV error level with just the one op-amp ►►
(the reference must be flawless as it shows on the graph. ???)
The Red LED-s are so cool for voltage adjustment -- their non-linear range begins below 275µA , they have sharper "turn on" than conventional detergents -- which puts them to (Diode,Stabistor,Red-LED,Zener Diode) this position - i assume . . .

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Update :: 2016-03-11 ► Insane :

 

seemingly "absolute" voltage reference at 1 Hz

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