Buck Converter as constant current source

Thread Starter

imraneesa

Joined Dec 18, 2014
227
The equation you are using for inductor is not right. You should use ∆I = Vin*D*D’*T/2L. Based on your spec ripple current, you can find L value. Also, you need to know what output vlotage max ripple you want. Then you can find out capacitor value with equation ∆v = ∆I*T/8*C.
Try it and let me know your result.

Ben
Dear Sir,
What is D`, i know D is duty cycle. and T is 1/Fsw.
 

ian field

Joined Oct 27, 2012
6,536
The equation you are using for inductor is not right. You should use ∆I = Vin*D*D’*T/2L. Based on your spec ripple current, you can find L value. Also, you need to know what output vlotage max ripple you want. Then you can find out capacitor value with equation ∆v = ∆I*T/8*C.
Try it and let me know your result.

Ben
There's an online calculator for the MC34063.

You just enter the values you have and it calculates the rest.
 
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