Hi Vonelab,
Firtly....what level electronics experience have you got, that might help in us targeting the right sort of help. Here goes an explanation assuming a little knowledge of soldering, basic components, caps, inductors etc.
Pretty cool cct though Wildrice....and nice layout. I've been doing LED 'picture frames' for a while, but never thought to layout the cct on the actual frame!
I'll attempt to explain it for vonelab, and hopefully you can add the bits I'm missing out.....I'm keen for a full explanation too....explaining it to you helps me understand it myself.
Firstly the pwr supply looks like its works by simply using the transformer(wound on a toroid) to jack up the AA voltage. The transistor and 390ohm resistor form an oscillator. With an oscillating signal on one side of the toroid, you'll get the same signal on the other, but at a higher voltage....the increase in voltage depends on the ratio of turns from input to output. Because there are more turns on the output, the voltage is higher. The capacitor and diode on the output (labelled V+) smoothes the oscillating voltage to DC. Here's my take on the operation.
When the cct is first switched on, current will flow thru the 5T part of the transformer but will take a short amount of time to go thru all the whirly bits of the coil...it acts as an inductor, which delays current flow. Think of it like a coil of hose, and the water takes a bit of time to get to the end. As it is flowing though it generates a magnetic field, that is coupled via the toroid to the 20T part. This induces a higher voltage on the 20T coil...the dotted part of the 20T part of the coil goes higher than the battery voltage. This voltage is saved in the capacitor and the charge in the cap can be used by the rest of the cct. After a short time the current builds up enough and turns on the transistor, which then drags that point low. The diode prevents this low voltage being noticed at the capacitor....if it doesn't block fast enough, current flows back into the cct and is disappated as heat.
Please correct me if I'm wrong, but it's now the 20T part of the coil that is now drawing current from the battery (because the transistor is turned on). This induces a voltage on the 5T part like the first part of the cycle . The induced voltage on the 5T part means the base of the transistor is now too low to keep the transistor going....and it switches off......then the process repeats..giving an oscillator, where one part (V+) is higher than the battery voltage.
Incidentally Wildrice.....do you have any references to more of these cool little voltage step up ccts?
The reference to schottkey, is for special diodes that react quicker than your average diode....meaning better efficiency.
As for the PWM cct.....now that's pretty neat. I've used the old two inverter cct to make clock signals before....but this configuration is interesting....and cheap as well. Wildrice, what sort of pattern do you get....random or some sort of sequence....how sensitive is it to component tolerences? Can you give a quicky description of this part of the cct as well...I know you'll have to get deep and dirty with descriptions of hysteresis....?
hope this helps...any corrections welcome
phil