Simple Current Limits Compared (Updated!)

Type.1

Type.2

Update !!!

► emerged by the predecessor of the second from the right - a "constant current shunt" - that was the best performing such in one of the experimental linear regulators (now revisited)see also :: yet another constant current source

Regulator Redesign (/Lab -- as always . . .)

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2015-04-15 ::
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 . . . trying to "de(/un)-bug" the last design from prev. post -- normalize power range , minimize the error . . .

+ a modified v.'s foldback diagram

Customizing/"improving" the 78Lxx for 1.2V

i only guess it's 3.0V
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2015-04-16 ::
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"Minimizing Compile" , exploring the switcher mode v. , experimenting with foldback . . .

thought to use the LT's µ-P 2.5V LDO -- but the 3uA is likely causing it's instability in high loads env.

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2015-04-17 ::
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Optimizing "Design"

Update! :: the foldback re-visited . . .

Update+ :: ±10µV version ::

Update+ :: ±12µV version with foldback updated to support high load capacities (no frequency test - what so ever- carried out + i donno how to thermal compensate - /!\ so i never do /!\) e.g. you have to recalculate the design before any attempt to assemble it

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[EoP]
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a low control current capable voltage regulator

Here's the grid - simulated fine (actually excellent -- that's why the design's revisited . . .) in prev. (a non TEST) v. but it didn't regulate "at all" in a real build -- here "we" possibly identified why -- if the R1 is too high (too little load) the VZ may go high thus also VT climbs out of the range and - bam! - we have a multiples of higher voltage on output than it's expected (the RED outlines the voltage regulation logic) ::

Next - omitting the CC module + startup chain - simplifies the design but we loss a magnitude of precision ::

Here follows a very poor example of a step-dn swithing regulator - asctually i didn't preserve the original v. of it (this is a fast feature restoration) coz i could not clear/filter the unwanted ringing and simulates extreamly slow . . . however the feature is a "built in" PPM (a pulse position modulation) capability (extra to low control current capability) -- needs a lot more testing to get it near right . . . (notice the varying supply internal resistance -- is why the efficiency graph wont link up exactly) ::

Omitting the VT reference point results in additional precision loss . . . but it revealed some specific behaviours of this type of regulation scheme (some of which're mentioned on o figure) ::

Here we've a near max low control current scheme - it starts auto-limit it's output current (depending on input supply) @ 150...200mA (output current max 235mA -- SC current 238mA) . . . and it seems to use some 110µA for regulation . . .

. . . a big deal considering the Solar battery test design with avg. 10.5µA TOT.supply draw - 8.8µA load current = 1.7µA (16%) regulation current . . . ::

. . . while the "near max low" v. ↑↑ has 108uA / 18mA avg. = 0.59% ( 120µA / 83mA peak = 0.15%) regulation currents

Adjusting the adjustable voltage regulator

The goal as in trivia is to gain more stability and precision while keeping the design robust . . .

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9V ± 1.8µV , 300/646mA (max.load/SC.supply current)
-- the stability (ringing(OpAmp-s e.c.)) + SC condition are a question marks here

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((Simple with SC don't care /!\)) 9V + 0.6 ± 2.6mV , 300/687mA

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((Simple SIPMOS with SC handling)) 9V + 4 ± 475 µV , 300/687mA

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((BJT alternate of the above)) 9V - 48 ± 255.6µV , 300/56.7(398)mA (max.load/SC.supply current.average(.peak))

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((feature test for FET switching)) 9V - 7 ± 13mV , 346/706(CuLm+)mA , 23.7kHz (here for err. compare)
-- the main targets were the inductor&frequency versus load&error (the current limit is a quick fit -- feature test)

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[EoP] (XT kogu aeg on mingi vitustus selle küljendamisega -- ma korjan mittevajalikud reavahed maha - aga voila! - peale save´imist on nad kuskilt tagasi tekkinud (teksti ja pildi vahele topitakse <BR> tag´id - et kui on huvi lõpmatuseni oma tekstiga jantida ÕööÖ×ØÛÜÚÝ♒☣☠☦☯ ))

Rebuilt two transformers

There seems to be a dependency for 50Hz Sine transformers - such that the less ampere turns on secondary the less actual output power . . . no matter the copper diameter !

The TF.2 has 2-le - and the TF.1 has 3-ple in parallel secondary winding from 01..0.08mm wire - e.g. - a lot of amp.-turns.
so here what we got

	Transformer-Rating-A.xls						Transformer-Rating-B1.xls
TF.2	5W2DRW	After					W2V33	Before
	2x	Z.in	10283.84	(Ω)				Z	9833.044786
32xEI+2E		XL.in	10260.87	(Ω)				XL	9809.347823
17.5	dpth	L.in	32.66136	(H)				L(H)	31.22412389
41	wdth	R.in	687	(Ω)				R1(Ω)	682.25
33	hght
6:8:13:8:6		Z.out	74.103	(Ω)
21		XL.out	70.26131	(Ω)
		L.out	223.6487	(mH)				L(mH)	26.7864545
		R.out	23.55	(Ω)				R2(Ω)	0.9
		TFRT	11.78039	(1)				N(1)	34.086046
	~AC
		Norm.IN	240	(V)					240
		Norm.OUT	20.37283	(V)					7.041004405
	~DC
		Norm.IN	240	(V)
		Norm.OUT	28.33159	(V)
	about*						Simulated
	*REAL	RL(Ω)	u. RL(V)	p. RL(W)	i.RL(mA)
	SCir.Max	0	0	0	310.6169		3xVtg.Mpl	1.34W 25.7V 51.5mA @ 497sz
	RL.P.Max	74.103	14.17819	2.712727	191.3309		normal	1.27W 8.48V 150mA @ 56sz
		80%	170%	210%	130%
TF.1	NiMH-YR	After					YR	Before
	3x	Z.in	14195.2	(Ω)				Z	9320.274036
30xEI+2E		XL.in	14153.2	(Ω)				XL	9215.587833
16	dpth	L.in	45.05103	(H)				L(H)	29.33412714
35	wdth	R.in	1091.25	(Ω)				R1(Ω)	1393
29.5	hght
5:7.75:9.5:7.75:5		Z.out	482.172	(Ω)
19.5		XL.out	477.6543	(Ω)
		L.out	1520.421	(mH)				L(mH)	27.65934601
		R.out	65.85	(Ω)				R2(Ω)	2.55
		TFRT	5.425875	(1)				N(1)	32.08109189
	~AC
		Norm.IN	240	(V)					240
		Norm.OUT	44.23476	(V)					7.481042129
	~DC
		Norm.IN	240	(V)
		Norm.OUT	63.58902	(V)
	about*						Simulated
	*REAL	RL(Ω)	u. RL(V)	p. RL(W)	i.RL(mA)
	SCir.Max	0	0	0	115.654		3xVtg.Mpl	2W 9.6V 208mA @ 46.5sz
	RL.P.Max	482.172	36.98703	2.837246	76.70921		normal	2.45W 2.88V 847mA @ 3.4sz
		0%	1280%	120%	10%

and a figure

  

note :: for the TF.1 is shown L.1.Before some 29(H) and .After 45(H) -- there's another experiment listing the values for the original NiMH charger's TF as R.i = 1251(Ω) and L.i = 47.5(H) , R.ii.YR (yellow,red wire , center tapped , total) = 2.4(Ω) , 9.11(V) - & - R.ii.BB (blue,blue , total) = 54.3(Ω) , 28.8(V) - but there's no much other data - i guess the ~AC.peak! voltages were required at the time --- so the table has data for TF.1 from the more complete experiment . . .if we multiply the 29.3(H) with Pi/2 we get 46.1(H) -- so i guess there's a current measurement peculiarity involved -- as Z = U/I = U.AVG / I.AVG , I.AVG = I.MAX·(2/π) -- or -- the prev. more precise Z.correct = Z·(π/2) → L.i = 46.4(H) , L.ii.YR = [P.i=P.ii=U².x/Z.x] = 44.546(mH) -- !!! however it does not much affect the DC(direct current) test values that are compared here