How to increase the peak current of MC34063 to 2A?

[saurav_sdpl]

Max peak current of MC34063 is 1.5 A, wheres my application demands peak current of min 2A.

Plz suggest for this

Added after 2 hours 55 minutes:

I am using MC34063 as switching regulator for which i need 3-10V input DC to this IC
if i directly rectify 230V mains and use a zener to give input to regulator.Whether it will work or not.

And wat design considerations i have to take into account for this

plz help it urgent

 

[som_raparty]

Re: re smps

you cannot give directly the mains AC
first you need to rectify it using bridge rectifier
and to the rectified voltage the PFC should be done(i prefer for better efficiency)
then basing on your load you can convert the voltage to the desired level
have some forward/flyback and o/p is sensitive you can even use the isolation

bye
som

 

[ashad]

Re: re smps

hi
you directly rectify the 230v AC then regulate by SG3525 ......... i used it very good swich mode regulator ........ if any query then feel free to ask

 

[max0412]

Re: re smps

You can use an auxiliary winding for your vcc.

See page7 of this appnote (UC384X):

http://focus.ti.com/lit/ds/symlink/uc3844.pdf

Use an external switch (mosfet) if your peak current exceeds the max of the Mc34063:

see this appnote page 36:

http://www.onsemi.com/pub/Collateral/AN920-D.PDF

You should full wave rectify (smaller filter cap) and filter the mains ( use a bridge and capacitor) see appnote above .

To use a simple shunt to generate your Vcc would mean the use of a large and expensive power resistor (limit zener current).

I don't see how providing Active or Passive PFC would provide any efficiency improvement in fact quite the opposite. These are used to meet regulations for THD ,and I wouldn't go through the trouble unless it was required.

 

[saurav_sdpl]

Re: re smps

The max input voltage for 3525 is 35 V, if i directly rectify the mains and give it to 3525, how it will work.

Can u plz provide me tthe design for ^v output and 1A current from this IC from 100 to 240 V mains