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Switchmode Power Supplies-General discussion

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1. Anyone know any good book or links which shows how to derive the formula to choose the inductor and the output capacitor for the buck regulator, boost regulator & inverter?

2.

BUCK:

The ripple current < = 2 times the minimum output current

The peak inductor current =max output current + ripple current

whats the ripple current & peak inductor current in the boost regulator & inverter?
 
Thanks Mneary but I actually did come across that pdf & it does not show how to derive L & Cout.

Im not using any mosfets. Im just using the basic configuration with a switch, inductor, capacitor, snubber circuit (R snub + Csnub) , flyback diode and load resistor.
 
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Are you looking for an academic derivation or a design calculator? National, LTC and TI all have calculators (mostly spice based).
 
Hi,


Often an approximation is used that is really pretty good...

The output voltage is considered constant with the input switching from positive to ground, and this allows us to compute the ripple current.
The ripple current is then applied to the output capacitor and that allows us to compute the ripple voltage.

The ripple current calculation also allows us to be able to specify the capacitor rating, and the value to get some decent ripple voltage spec.
The ripple voltage calculation is often needed to be able to tell if the power supply output is smooth enough for a given application, however a secondary filter improves this much when possible.

The ripple current calculation is based on V=L*di/dt and the ripple voltage is based on dv=i*dt/C, both of which are approximated by their delta equivalent forms.
 
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Have you looked at **broken link removed**.
 
**broken link removed**

chapters 12,13, and 14. Chapter 12 on basic magnetics is one of best I've seen.

Training is in MKS system names but it also explains CGS system. Many tech papers mix the two making learning very confusing.
 
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Hi,


Often an approximation is used that is really pretty good...

The output voltage is considered constant with the input switching from positive to ground, and this allows us to compute the ripple current.
The ripple current is then applied to the output capacitor and that allows us to computer the ripple voltage.

The ripple current calculation also allows us to be able to specify the capacitor rating, and the value to get some decent ripple voltage spec.
The ripple voltage calculation is often needed to be able to tell if the power supply output is smooth enough for a given application, however a secondary filter improves this much when possible.

The ripple current calculation is based on V=L*di/dt and the ripple voltage is based on dv=i*dt/C, both of which are approximated by their delta equivalent forms.

Im looking for a book or information that uses this approach to derive L & C equations for the 3 main types of switching regulators
 
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