DC boost converter max power ?

[budm]

Re: DC boost converter max power ?

No, I am trying to find out how much your circuit is drawing the current from the 12V supply Voltage when you have load at the output of your boost converter.
Basically trying to figuring what you put in and what you get out.

[budm]

Re: DC boost converter max power ?

http://powerelectronics.com/power-ma...e-calculations
Lots of reading.

[bianchi77]

Re: DC boost converter max power ?

Do you want to know efficiency ? it's less than 1A since my 1A fuse still survives

[budm]

Re: DC boost converter max power ?

So it takes close to 12W of input power and you are getting about 5W of output.
Use the calculator as a guide and play with freq, inductance, etc. to improve it.

[bianchi77]

Re: DC boost converter max power ?

last test was 8W bulb, so roughly with about 10W input.. my inductor 380uH...I tried 700uH it's saturated and fall down to 24V output..

input voltage I measured 11.4V , I haven't measured current, probably about 500mA-800mA

[budm]

Re: DC boost converter max power ?

Read this about inductor, the saturation is not dues to higher inductance. Look at the spec of the inductor you are using.
https://cdn.badcaps-static.com/pdfs/...46da0651f2.pdf
BTW, 8W incandescent?

[bianchi77]

Re: DC boost converter max power ?

Ok, thanks again for the information, it's neon 8W bulb, please have a look on the video above...I chuck in DC voltage to another SMPS input...but that's ok I love learning and experimenting, have a good sunday..

[bianchi77]

Re: DC boost converter max power ?

Anyway, do you use any chips from maxim or others for boost step up application ? Do you have any suggestions ?
https://www.maximintegrated.com/en/p...-up-boost.html
https://www.maximintegrated.com/en/p.../MAX17597.html

Good spec, but QFN package is a trouble to be tested on breadboard...
https://cdn.badcaps-static.com/pdfs/...2220f97844.pdf page 9

[Khron]

Re: DC boost converter max power ?

Is the UC384x range, or the MC34063 not good enough for you anymore?

http://translate.google.com/translat...istory_state0=

https://translate.google.fi/translat...%2F&edit-text=

https://translate.googleusercontent....Be2jFQ#2580874

I found all these on Google image search, btw...

[budm]

Re: DC boost converter max power ?

I saw the video, it does not look like it is lighting up at full 8W.

[bianchi77]

Re: DC boost converter max power ?

I'm happy with UC384X even with transistor, only a comparison with maxim product..
yes it's not stable on 8W I reckon...but it has a power to light up 8W already, that's a progress for me...
now under test RL = 5K, the output is 185V on 380uH...I increase the inductor from the previous experiment but there's no increase on Vo ...I got no idea why now ?
It's not ideal inductor condition, since I made a series some small inductors...
@Khron thanks for the shematic,
I love this design,
http://translate.google.com/translat...istory_state0=

Is it really more than 13A on the output ? Interested..I reckon that transistor has something to do with this current boost..
Can I replace the PWM with 555 ? I don't have the PWM chip on the schematic now..

[bianchi77]

Re: DC boost converter max power ?

that's the circuit I've been playing now...185V at RL = 5K ...
Any suggestions for modification ?
Cheers

[Khron]

Re: DC boost converter max power ?

http://www.ebay.com.au/sch/i.html?_f...c&LH_PrefLoc=1

I specifically searched on the Australian eBay, ordered them by cheapest price + shipping, and only from (within) Australia. It's not rocket science.

I'm really sorry, but you have no excuse

How did you come up with the 13A output figure, i wonder?
Let me guess - because you just saw the recommended transistor current rating, but have no real idea how a boost converter works...

PS: Do you even have an oscilloscope?

[bianchi77]

Re: DC boost converter max power ?

Thanks for the chip link, but that would be another month to wait, I'll buy it later on, but I'm interested to find a way to increase amperage for 555, this is what I have on my hand..
Yes I have osciloscope...
I got 220V RL=7K Duty cycle 99.44% L = 420uH....I think I can't go higher..
I've tried with 700uH and it dropped to Vo = 24V any other clues ?

I'm pretty sure there's a way to get better current with this 555 than replacing the chip with MC34063.
I'm learning one chip to other, easier for me..

[joshnz]

Re: DC boost converter max power ?

what is you oscillator frequency?
what is your target output voltage?
what is your target output power?

[bianchi77]

Re: DC boost converter max power ?

my frequency is 921 Hz
target output voltage is 220V
target output power = 10W

Any ideas ?

[budm]

Re: DC boost converter max power ?

I thought you are running the existing one at 3KHz, how did you come up with 921 Hz. That is very low, your inductor is going to be big.

[bianchi77]

Re: DC boost converter max power ?

Yes I have a big inductor, combine with small ones...I don't have a single 400uH 3A inductor now..
if I stay with 3KHz I will not get the Vo higher with lower RL

[budm]

Re: DC boost converter max power ?

The inductor and the frequency you choose are related, so you have to choose the correct parameter.

[bianchi77]

Re: DC boost converter max power ?

ok thanks, I need a good inductor in one piece, since I have some inductors with some values in series, it will reduce efficiency a lot since it's connected with small pin to the other not in one complete inductor...probably between 330uH 3A and 470uH 3A will be the right value to obtain 10W 220V...not far away from now...it's RL = 7K for 215V constant...