dc-dc boost converter using supercap

[aspirecole]

im designing a boost converter, my input is 1 pack of supercap. the design should give 24V output.
the problem now is the voltage of the supercap is decreasing by time. how should i control the duty cycle of the pwm to make it constant 24 V for the output

 

[kam1787]

maybe you could share your design as it is now.................

 

[aspirecole]

this is my design

 

[ngochaigv888]

i think it doesn't work. when suppercap voltage is decreasing less than 24v, the output can't equal 24v.

 

[FvM]

I think it doesn't work. when suppercap voltage is decreasing less than 24v, the output can't equal 24v.

So you say, you didn't yet hear about boost converters? https://en.wikipedia.org/wiki/Boost_converter

how should i control the duty cycle of the pwm to make it constant 24 V for the output

The usual method is a voltage control loop generating variable pulse width. Any popular pwm controller can do, e.g. UC3842.

Instead of feedback control, you can theoretically use forward control, varying the pulse width with supercap voltage using an a priori characteristic. But the method won't be aware of load dependcy and non-ideal converter behaviour.

 

[kam1787]

So you say, you didn't yet hear about boost converters? https://en.wikipedia.org/wiki/Boost_converter

well, the "boost converter" you posted is so basic as to be pretty much useless in terms of giving advice. FvM was kind enough to suggest an IC.

 

[ngochaigv888]

So you say, you didn't yet hear about boost converters? https://en.wikipedia.org/wiki/Boost_converter

The usual method is a voltage control loop generating variable pulse width. Any popular pwm controller can do, e.g. UC3842.

Instead of feedback control, you can theoretically use forward control, varying the pulse width with supercap voltage using an a priori characteristic. But the method won't be aware of load dependcy and non-ideal converter behaviour.

are you using transformer.