Cirrus Logic AN368 - Manual (Page 69)

AN368
AN368REV2 69
Step 17) Designing the EMI Filter
Limitations are imposed on the values of the inductance, capacitance, and resistance assigned to the EMI
components in an effort suppress ringing that may be excited by the dimmer turn on and the boost stage
conduction. The value selected for inductors L1 and L2 was 3.3mH, and the value selected for resistors R1
and R8 was 2k
. The value for capacitor C4 was selected to be a 4700pF and C1 was selected to be a 0.1F.
a. I
Sense
DAC Dithering
Dithering on the I
Sense
reference is disabled by setting the DITHER bit in register Config17 at Address 49 to
‘0’. Since dithering is disabled for the example, the algorithm ignores settings for bit DITNODIM in the Config61
register at Address 93, bit DITCHAN in register Config61 at Address 93, bits DITLEVEL[1:0] in register
Config61 at Address 93, and bits DITATT[1:0] in register Config12 at Address 44.