World simplest SMPS Circuit

constant off-time smps

any how this is working very well for me. and i am using for all my battery charger and LED lighning purpose

ncp1010 india

Hey can you post a pic of assembled one ?

smps in parallel connection diagram

Hi everybody,
the circuit above is pretty .but i want a circuit diagram of smps which will be bi polarswitching without feedback or with. whole designing procedure (of ferrite t-x)with formula so that i can design as my want .now i need 100w 14.2v smps charger for lead acid battery i dont want to use mosfet want MJE13005 if not enough then paralell.pls help me as early as possible

Anichur

transformerless low current smps

Hii friends,


Even I need a smps circuit as above mentioned.

Is it possible to build this rating smps with the above mentioned topology or I need to go for something else?

Can anyone help me pls...

bjt smps circuit

can any one pl reply as how to change output current of the simplest circuit given above...

circuit diagram a smps

CHANGING OUTPUT CURRENT CAN DONE IN DIFFERENT WAY, yOU CAN CHANGE CURRENT LIMIT RESISTOR AT INPUT SIDE, BASE RESISTOR OR EVEN BY TURNS

is there any ic for making the smps ckt simpler..except for max5052(pwm controller)

hi
sir very good posting, iam new to forum just want smallest smps for mobile phone charger with daul supplys 3.0v and 6.0v out puts in very simple way

Hello everyone [ my first post! ]

James: your design is the closest I've found to **broken link removed** that is frequently bundled with USB-IDE-SATA adapters, which I've been trying to fully understand. I attached the schematic of the relevant part.

One difference is that the oscillator transistor is instead a pair in a "locking" configuration not unlike a GTO thyristor. I figure that's why a speedup capacitor (C3) is added to the base-driving resistor.

The second thing is the funny layout of the feedback secondary - diode - filter. It looks as if the capacitor stays charged all the time and the feedback signal swings around that level, but that R-C in series is greek to me. :|

What else can you tell me? (us?)

BTW, if anyone is interested I can attach the schematic in gschem format. It needs subckt's for the transformer and optocoupler.

-- arielCo

hi arielCo,

ok.seems like on your circuit there are primary side GND and also secondary side GND. if i would like to have a look on the switching waveform that going to the transformer, is it wrong for me to clip the black color clip of my probe to the PGND as a reference GND? am i right?

The black clip is connected to the chassis of your scope and thus to mains ground. But the secondary half of the circuit, and thus PGND, is mostly isolated from the primary save for the Y1 capacitor, which in principle says you should be ok as long as you don't touch anything in the primary half.

Now, if I were you I'd play SAFE on the last assumption and use a mains isolation transformer with the scope so that it's "floating". Also, be sure that the probe itself won't short anything in either side, and put a small fuse before the SMPS supply.

Have fun!

Now days Viper 12 and Viper 22 are available very cheap. Now I Started using those Ics instead of these circuits,
If some one looks for help please feel free to contact me @ grittinjames@yahoo.com

Re: smps design with mje13005 transistor

hello dear.....
i am khurram i see your posted cct thats good i nee more current like 1A what can i do change no of wire or some thing els i want to glow heigh power LED.
thankx

once i made SMPS using uc3843 IC it worked great
Output: 3 to 16v (Regulated)
Current: 2A
Switch Mode DC to DC Converter (2A) - YouTube