regulated switched LED regulator designs (experimental)

the thing ::

how to set it up in practice . . . involves a number of tests ::

1. Detach the mosfet and the feedback Mod line -- from simulation and from build
   Regulate the frequency and duty to match those of the simulation
2. Re-attach the mosfet , ( /!\ /!\ /!\ ) set some 20Ω or greater in series with the 6LF22 to limit the current through LED-s --and-- set electrical fuse or limitting resistor in series with the LED-s --or-- double the number of LED-s ( /!\ /!\ /!\ ) - - - - - - - - - we are going to verify the transformer ::
   do the same mods on the simulation and test for the differences . . .
   -- if the real build performs worse you need to recalculate and rebuild the transformer accounting for resistance not present in ↑this↑ circuit
   -- if the build performs better then the primary side is "over-driven" the timing of the switching wave-forms has to be re-evaluated and adjusted
3. Attach the Mod line --and-- ( /!\ /!\ /!\ ) set the regulation to be greater than in simulation (!! dont remove electrical fuse or extra LED-s !!) ( /!\ /!\ /!\ ) ,
   -- regulate it bit below the desired LED current (in case the regulation failure -- the regulator has to be re-designed --or-- replaced with better known one)
4. if everything worked out so far the additional tests are required such as ::
• test for bit higher than simulated input voltage (the Cl batteries may have up to 1.8V per cell e.g. 10.8V for fresh 6LF22)
• test for battery contact strobe !!!
  -- here everything can fail -- use fuses and perhaps build a protective controller that can fast switch off the circuit under test
• test for the lower than in simulation input voltage !!!
  -- may result in oscillations failure and the MOS-FET being "constantly ON" (attempting to remain in conduction mode) . . .
• etc. ...

---

Basic simple ::

add VCO , Mod2 divider , the 2 to 4 decoder and a current sense / +integrator -- and it's basically done . ..

---

[Eop]

Predicate research for using the LED as a photodiode

in prior of doing the following i measured the target Blue LED that did output some millivolts but no nanoamps , then a high efficiency Blue LED that i used for below experiments (← the series array of theses gave pretty much alike data than the single one) . . . then the iR LED parallel array from the (used for . . . ?? pre-clearing the image in) laser printer , it output over 1V and i guess several microamps . . .

. . . all that illuminated from the narrow beam 1W Power LED

the conflicting data (with web) is that when illuminating the LED it outputs fw.-polarity voltage -- e.g. [+] from anode and [-] from cathode * . . . all 3-types of the above without the exception ???

Note* ::  no conflict (http://www.ques10.com/p/9330/explain-with-neat-diagram-construction-and-worki-1/) , conflict ( . . . there was a site that actually textually claimed that ? intentionally or not . . . can't re-find it at this time . . . and it was not the only one such . . .)

---

first couple of web found setups (slightly modified)

and my own guesses of j-Fet setups

---

[Eop]

theoretical experiment of 3 to 12 V boost converter

Simple , minimal ::

. . . with error as switch gets near constant 18mA to it's base due xa should be xi

however using cascade drive for switch poses problems -- also a good definition method for vc2 (LMx39/x93 OUTP)

some fixes -- no change . . . need to opt. the drive power usage


[Eop]

the Actual/Built LED verifier

as i was not about to build a PCB for this the sot-jFets were not used . . .

Spice design ::

Real build ::

---

[Eop]

Comparing Constant Current Circuits (to sort/verify the LED-s with)

▼Fast/Simple/Robust/Trivial Op-Amp + BJT Setup▼
→ apx. 16mA ±30µA(0.2%)

[fig.1]

▼Complex/Trivial Op-Amp + BJT Setup▼
 → apx. 18mA ±24µA(0.1%)

[fig.2]

▼Simple/Experimental BJT Setup ( !? the Best ?! )▼
→ apx. 18mA ±60nA(0.0003%) 

[fig.3]

▼Full/Trivial BJT + N-jFet Setup ( also better than any op-amp variant ??? )▼
→ apx. 18mA ±300nA(0.002%) 

[fig.4]

▼Complex/Experimental Op-Amp + MOS-Fet Setup▼
(likely worse than it's BJT alternate -- the 2-nd ↑↑ fig. )
→ apx. 18mA ±120µA(0.7%) 

[fig.5]

▼Trying to get it right here▼
-- it seems that the op-amps should be fed from the separate supplies or otherwise the PSRR won't recover the precision reached at reference voltages
→ apx. 18mA ±48µA(0.3%) 

[fig.6]

((the work is in progress ...))

▼If you are stupid then knowing the right Op-Amp-s could save your day▼
(the node "SE" had the greatest error although the node "a0" has the least ??? -- about LT1012A)
→ apx. 18mA ±10µA(0.06%)

[fig.7]

-------- Update 2017.12.24 ::

▼a conditional opposite to "If you are stupid then knowing the right Op-Amp-s could save your day"▼

→ apx. 18mA ±7µA(0.04%)

 [fig.8.1]

a "Russian LM308" **

 [fig.8.2]

** it's nearest LT's substitute (so far)

---

[Eop]

"constant efficiency" flasher concept (test)

yet another led flasher

inspired/adopted from →

i couldn't simulate ↑such↑ although it showed up some oscillations on startup ?? a hint the real thing may do something

---

[Eop]

SCS Counter + SW-d Capacitor Single 1.5V-cell LED Driver

(none of the following is not yet tested in practise - - you have to match the average currents @ critical chains , in case of a failure the grid should be redesigned to lower or higher currents or conceptually redesigned - - there might be some combinations / features - that never work in practice or won't ever work as good as required - that are hard to foresee)

Re-ranging SCS on a different component base ::

"Simple" circuit that suppose to run from single Ag-cell up to AA

[EoF]