180 ohm is the suggested value for 12V input and 1A Ipk. Read https://www.onsemi.com/pub/Collateral/AN920-D.PDFhow did you calculated 62ohms.I will connect 180 ohm to pin8 to try it.
I'd prefer 2.7k and 8.2k; or 3.3k and 10k...
I used 6.8k and 2.2k as formula says Vout=((6.8k/2.2k)+1)*1.25)...
What would most likely cause this is current sense just like FvM has mentioned. For your application, the current sense resistor that you are using is too high and so the controller switches too early.vout=5v when there is no load.When i connect the dc load vout decreases so much.
I am using breadboard to change components easily
That's a badly designed circuit. 34063 needs a current limiting resistor at pin 8, refer to data sheets. Suggested dimensioning rule is Ic/Ib=20, about 62 ohms for 3.6V input and 1A peak current.
Ipk(switch)=2Iout((ton/toff)+1)=2*0.3*(1.31+1)=1.386
Lmin= ((Vin(min)-Vsat)/Ipk(switch))*ton (3.2-1/1.386)*11.35*10^-6=18uH
I was calculating Iout 500ma but Ipk current was equal to 2.31a and its too much for it.It can only handle 1.5A so i seleceted output 300ma and ipk(switch) is smaller than 1.5A refer to datasheet.
Frequency is 50kHz
Rsc=0.33/Ipk(switch)=0.33/1.386=0.23ohm.
I use 100uH for inductor maybe its too high?
I'm talking about the pin 8 current limiting resistor, you have confirmed its necessity in post #4. Ic/Ib ratio is a matter of appropriate dimensioning of this resistor. If you had read AN920, you would know about.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?