dc/dc converter 12 to 24
Hi srikanthvajjala
Did you not take the time to read through the links I gave you. There is no set in stone ripple it depends on your design requirements.
Here is a cut and paste from the daycounter link.
"The main question when designing a converter is what sort of inductor should be used. In most designs the input voltage, output voltage and load current are all dictated by the requirements of the design, whereas, the Inductance and ripple current are the only free parameters. It can be seen form Equation 1, that the inductance is inversely proportional to the ripple current. In other words, if you want to reduce the ripple, then use a larger inductor.
Thus, in practice a ripple current is decided upon which will give a reasonable inductance."
"There are tradeoffs with low and high ripple current. Large ripple current means that the peak current is ipk greater, and the greater likelihood of saturation of the inductor, and more stress on the transistor."
"So when choosing an inductor make sure that the saturation current of the inductor is greater than ipk. Likewise, the transistor should be able to handle peak current greater than ipk. The inductor should also be chosen such that the it can handle the appropriate rms current."
This is why you typically increase your calculated inductance to insure you stay in CCM
"It should be noted that when there is a light load the circuit can slip into discontinuous mode, where the inductor becomes fully discharged of it's current each cycle. When a load is reapplied the inductor needs to recharge, and so the transistor's duty cycle increases pulling the inductor towards ground, and because of the increased duty cycle Vout decreases when we really want it to increase.
This causes an instability, which is well known for boost converters, and not a problem with buck converters."
You can use this to select your ripple as a guideline,it really depends on your load and the other factors already mentioned.Trying to find an ferrite inductor for your converter may be a bit of a challenge and probably wont be cheap and will likely be the determining factor in your ripple.
"One way to combat this instability is to choose a large enough inductor so that the ripple current is greater than twice the minimum load current. When this condition is met then the inductor is always in continuous mode. "
The rest is here including equations.
https://www.daycounter.com/LabBook/BoostConverter/Boost-Converter-Equations.phtml