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Operation Whenever the mosfet Q1 is turned on energy is stored on the boost inductor. When the mosfet is turned off the voltage across the inductor reverses and adds to the input voltage to charge the output capacitor.
In case of boost chopper the output is higher than the input.
Tips on Boost chopper-
1. When the boost inductor is used in continuous mode it suffers from Right half plane zero. To avoid this issue the loop bandwidth is decreased.
2. Whenever, the mosfet Q1 is turned on the capacitor Co is discharged through diode D1. The time period depends on the reverse recovery charge of the diode. This may lead to failure of boost diode. To avoid this use a tandem diode, operate the boost diode in discontinuous mode, use a series inductor with higher saturation curve or use a SiC (silicon carbide) diode (CREE).
3. To gain higher efficiency use a series inductor with the diode D1 and active snubber.
Input inductor :- Select the inductor depending on the core saturation, number of turns, core and copper loss. Preferred Vendor :- Micrometal.
Boost diode (D1) :- Select the diode depending on reverse recovery time. Prefered vendor :- Fairchild, Onsemi, Infinion.
Output capacitor (Co) :- Depends on the ripple current and hold up time for the down converter Preferred Vendor :- Nichicon, Jamicon.
For more details please refer to the application note about buck chopper. (It would be posted soon as a pdf).
(If you are looking for any help, technical difficulties on your project please consider J Thomas for consultancy/Independent contractor.)
Ph :- 714 7263837
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