Ballast design

AN3040

12/27

Doc ID 16181 Rev 2

3.2

PFC power section design

3.2.1

Input capacitor

The input high-frequency filter capacitor has to attenuate the switching noise due to the high

frequency inductor current ripple. The worst conditions will occur on the peak of the

●

The coefficient of the maximum high-frequency voltage ripple r = 0.05.

●

Total system efficiency is possible. Taking into account a minimum half-bridge switching

Equation 14

3.2.2

Output capacitor

admitted overvoltage, the output power and the desired voltage ripple. With the following

values:

●

●

the bulk capacitor can be calculated as:

Equation 15

33 µF, 450 V has been used.

3.2.3

Boost inductor

is greater than the maximum frequency of the internal starter to ensure correct TM

Equation 16

nF

904

r

V

f

2

V

P

C

min

in

min

sw

min

in

outTOT

4

=

⋅

⋅

⋅

π

⋅

⋅

η

=

F

13

r

V

f

2

2

V

P

C

1

busPFC

main

busPFC

outTOT

1

μ

=

⋅

⋅

⋅

π

=

(

)

busPFC

out

pfc

min

inrms

busPFC

2

inrms

pfc

V

P

f

2

V

2

V

V

L

⋅

η

⋅

⋅

⋅

−

⋅

=