How much can the input voltage be boosted at the output of boost converter?

[sakthivel.eee]

Dear All,
How much times of input voltage can be boosted at the output of boost converter. For example 10V can be boosted to 1000V? or 1V can be boosted to1000V? What are all the limitations? Losses will be more due to high current? Is there any limitations in the duty cycle and operation? Please provide the condition

Is there any application notes explains about this. IF please provide me the link.I know the equations and circuits.

Thanks in advance

Thanks & Regards,
Sakthivel.S

 

[betwixt]

Re: Reg:Boost Converter

Portable color TVs before LCD became popular used glass CRTs which ran on 20KV or more and they were powered from 12V.

With very careful design you can generate extremely high voltages, certainly in the 100KV regions from very low voltages. But please remember you don't get something for nothing, the total output POWER is always less than the power you consume to generate it. Power is calculated by multiplying the applied voltage by the current drawn (W=V*I). For example, assuming 100% efficiency, which you would never reach, 12V with 1A being drawn could produce 12KV but only at a current of 1mA. As the voltage is stepped up more and more the efficiency tends to drop so in practice you would get considerably less current out.

Brian.

 

[sakthivel.eee]

Re: Reg:Boost Converter

Thanks for your reply.I can really understand that. Is there any other constrain other than efficiency ?Any mathematical relations like upto some duty cycle only it can operate-able (Boost converter will be efficient) .Hence only X times of input voltage can be produced at the output

To what duty cycle i can operate so that my boost converter will be efficient?

How to protect my boost converter from short circuit at the output? ( Since output is directly connected to input through diode)

Is there any application notes explain about this issues?

Thanks in Advance

Thanks & Regards,
Sakthivel.S

 

[mess123]

Reg:Boost Converter

You can increase the duty cycle to about 0.8. Above 0.9 duty cycle, the output voltage will actually drop.
For boost converter, you can use the formula:

Vo / Vin = 1/(1-d)
where d is the duty cycle

 

[sakthivel.eee]

Re: Reg:Boost Converter

Dear Sir,
Why output voltage is dropping after 0.9 duty cycle?

Thanks & Regards,
Sakthivel.S

 

[gozimg]

Re: Reg:Boost Converter

the duty cycle is dowing when d>0.9 because they are the perturbation of ther parametres you can see the book of ericson.
good luck

 

[sakthivel.eee]

Re: Reg:Boost Converter

Dear Sir,
Thanks for your reply..Please give full book name and section..please...

Thanks & Regards,
Sakthivel.S

 

[sec]

Re: Reg:Boost Converter

I think one of the most important think to consider is how to choose a semiconductor,
mosfet with low rise/fall time and also a low charge on the input gate. You might want to go at higher frequency with these voltage because it require less capacitance, and ceramic capacitor are the best for high voltage and high frequency. Be sure to find a good diode or you could you synchronous rectifier ... Let your imagination do the job.