I have two questions about boost converters, thanks.

[qwertyIC]

About boost converer, ask two quesiton,thanks

1. How much boost's max duty can reach generally? Can it exceed 90%? such as Vin=3V to Vout=30V.What it pay attention to?

2. Now I design a boost, typ duty is 32%(Vin=3.8,Vo=5.6), uttermost is 60%. Frequency is about 1.5M, or below(800K).
My quesion is: how much do I desgin boost's max_clk limit? 80%? 90%?or 95%? what are the advantage and disadvantage each?
thanks very much

 

[BradtheRad]

Re: About boost converer, ask two quesiton,thanks

95% duty cycle is possible. (At least it is in simulation.) There is sufficient time (5%) remaining for the output cycle to take place.

If your 3V supply can provide sufficient Amperes, then your output can be even greater than 30V. It depends on how light or heavy your load is.

Example, 3V at 800 mA (average) input, can convert to 55V at 46mA output. Duty cycle 95%.



It is not necessarily easy to manage behavior when you operate at very short or very long duty cycle. Or when you want to boost voltage several multiples.