UC2825 smps controller

[sss]

does anybody used this chip before?
i'm using it right now for my car smps and its great

 

[2pist]

I'm using a NE556 dual timer. Cheap and works great. I use 1/2 as an oscillator and the other 1/2 as pwm with a 30v zener tied from the negative rail to pin 11 on the 556 for regulation.

 

[himanshuraval]

does anybody used this chip before?
i'm using it right now for my car smps and its great

hi sss
put your full working schematic here with thanks

 

[himanshuraval]

I'm using a NE556 dual timer. Cheap and works great. I use 1/2 as an oscillator and the other 1/2 as pwm with a 30v zener tied from the negative rail to pin 11 on the 556 for regulation.

hi 2pist

you also put here your NE556 based schematic please

 

[sss]

hi himanshuraval
i'll put a schematic when i'll finish it
gotta design more things like remote and stuff like that

 

[N-Channel]

UC 2825 PWM IC

Hi SSS,

Unitrode's (now TI's) numbering of chips goes something like this:

UC1XXX - Mil-Spec (-55C to +125C)
UC2XXX - Industrial (-40C to + 105C)
UC3XXX - Consumer (0C to +70C)

Hence, the UC 2825 is the industrial version of the UC3825. The Mil-Spec version would be the UC1825.

Basically, this series of PWM chips is pin-for-pin compatible with Motorola's (Now ON's) MC34025 (0C to +70C) and MC33025 (-40C to +105C) dual-ended PWM IC with 1MHZ oscillator. Good for off-line and DC-DC push-pull, half- and full-bridge topologies. Good bandwidth on the error amp, too. Can be used as either voltage-mode or current-mode.

Great chip! I have used them in 42-14V DC-DC Convcerters. A BIG improvement over the SG1525/2525/3525 (400kHz max) voltage mode-only PWM ICs.

Hope this insight helps!


'73,

Steve, N8XO

 

[agent.5]

I found this SMPS schematic using UC3825 (the military version of 2825). It looks very clean and quite low in part counts.

What does he mean when he say

"Transformer: 4.5 + 4.5 turns : 120 turns (that's core-specific of course)"

?

 

[sss]

4.5+4.5 turns mean 4.5 turns centre tap and another 4.5 turns
(2 primary coils with 4.5 turns each-push pull design)
i gues 120 is the number of turns for the secondary

 

[N-Channel]

UC3825

agent.5,

I think you have it backward: the UC3825 is the consumer (commercial) version of the UC2825. And, the UC1825 is the Mil-Spec version. As for the schematic, I would be interested in seeing it.

Steve

 

[agent.5]

Schematic

http://www.klausmobile.narod.ru/projects/pr_05_carpower_e.htm

And I think you are right , the UC1825 is the military version.

 

[Tolik]

Hi SSS,

Can I see your UC2825 schematic ?