IR2153 SMPS Low Current

[bud17]

Hi, I have built my first SMPS. I use IR2153 oscilator 50 kHz and 2x EE4215 ferrite core. Primary turn 40 turn (0.5mm 3 strand) and secondary turn 4 turn (0.5mm 8 strand).
My first target is only 15V 20A, but when I attach load (DC Vacum Cleaner 12V 100Watt), output current only 3.5A.
What's wrong with my SMPS? Please help.

Thank You.

 

[wally7856]

When you said "2x EE4215 ferrite core" does this mean 1 pair or 2 pair of EE4215 core. Please show picture.

Also, you have a half bridge topology and you are using an output for a forward converter.

Did you get any specs with your cores like the Ae value.

 

[Voitano]

N1/N2 transformer winding ratio 10 is too big, try 8, and add an output coil - 4uH, ETD29 with 5 turns, 0,5mm gap. There is no feedback control there?

 

[Voitano]

And as described wally7856, output rectifier is wrong type

 

[bud17]

Thank you for replay.

To wally7856:
Yes 2 pair core EE4215 for 1 transformer (see attch) and this core is no gap.
Ae EE4215 in 181 mm2, so if 2x EE4215 then Ae 362 mm2.
Yes I use half bridge topology, and output I use forward converter just for while (not final).

To Voitano:
Yes, there is no feedback.
Because this is first my smps, if this SMPS OK (output current >= 10A), I will try use feedback (TL491 or SG3525) to control the output.

 

[wally7856]

With 40 turns and an Ae of 3.62 you are running a Gauss level of 1118G.

According to Aberham Pressman's book you should try to be around 1600G. So you only need 28 turns.

Your Primary is good for 350 to 400 watts. Your secondary is 16vdc with wire that is good for about 6.5A continuous = 104W.

A forward output is only half wave so you can only expect half power, and as Voitano said you have no output inductor so you have worse output.

 

[Voitano]

Q4-Q7,D4-D5 are not necessary. As output rectifier build Graetz bridge with fast diodes

 

[mone]

C3 change to lower that 1uF.

 

[Voitano]

C3 should be 10 to 100uF

 

[mone]

C3 should be 10 to 100uF

http://www.diysmps.com/forums/showthread.php?733-Another-IR2153-smps&p=12651&viewfull=1#post12651

 

[bud17]

Thank you,

I have changed this circuit.
The secondary side I changed from forward converter become full bridge (four diode->bridge).
And the output still 3.5A (15Vdc drop to 10Vdc).

So I chnage primary turn I change from 40 turns become 14 turns 0.5mm 3 strands (Bmax=1600G, f=43kHz, Ae=3.62cm2, Vp=138Vdc).
Secondary turn I change from 3 turns become 2 turns 0.5mm 16 strands.
Output SMPS become 18.8V, is to high voltage for me.
If I want to decrease become +- 15Vdc what should I do?

I'm sorry, I am newbie.

Thank you.

 

[wally7856]

Is the Vp 138vdc a measured value.

I cannot read the Rt, Ct values you used.

Did you use high frequency diodes in the output bridge.

 

[bud17]

From dioda bridge (primary side) is 276 Vdc then half of that is 138 Vdc.
Rt=33k and Ct=470pf.
Output diode I use MUR1560.

 

[wally7856]

138vdc x 10 to the 8th power / 4 x 21500 hz x 1600 G x 3.62 cm^2 = 27.7 turns

4 = constant
21500 hz = ir2153 switching freq / 2
1600 G recommended Gauss level
3.62 cm^2 = your transformer core area Ae

You calculated 14 turns because you did not divide frequency by 2. Use 28 turns.

138vdc/28 turns = 4.92 volts per turn.

15vdc secondary / 4.92 volts per turn = 3.043 secondary turns.

For your drooping voltage i think you should have a total of 4 pieces of 470uF not just 2.

Also it may be the way you physically wound your transformer. How exactly did you put the winding's on.

Primary use 28 turns.
Secondary use 3 turns.

transformer should be wound as.

1/2 primary 14 turns.
Secondary 3 turns.
1/2 primary 14 turns.

Then connect the two primary's in series making sure the phasing is correct.

 

[bud17]

OK, I will try it.

Thank you.

 

[bud17]

Hello, I will report.
I'm sorry is to long because I busy.

I change mys smps:
1. Core ferrite from 2 pair EE42 to 1 pair ETD39
2. Frequency from 65kHz to 95kHz.
3. Output 2x15V
4. 4pcs 470uf (secondary side)

When I give load (dummy load 0.5 Ohm resistor 100W) for 2 sec:
1. Voltage drop from 30V (no load) to 9V
2. Ampere increase from 0 (no load) to 35A
3. MUR1560 bridge very-very hot.

Please advice.

Thankyou.

 

[Voitano]

Hi, make photos of your set, and describe, what is your problem.

Voltage drop from 30 to 9V? 30V at 0,5 ohms, it is 60Amps = 1800W, this core transfer aprox. 450W at 100kHz.

 

[bud17]

Ok I will take the picture.
When connect 0.5 Ohm, voltage is 9V and current is 35A then 9x35=315W.
But when disconnect from 0.5 Ohm (with no load) then voltage is 30V.

 

[Voitano]

Voltage drop is normal, try 10-15 ohm load
Look here for some inspiration http://danyk.cz/iz_2_35_en.html