Cirrus Logic AN374 - Manual (Page 31)

AN374
AN374REV2 31
Once the data has been entered, the curve fitter can be understood by performing the following steps:
Step 1) White Gain setting
The entry procedure that is required to preform a curve fit for the White Gain polynomial is detailed in
Figure 27.
1. Enter white LED currents (in Amperes) and dim. Right click to see options to load data from a CSV file.
2. Enter the Weight Factor. Values > 1 favor high dim levels in the fit and values < 1 favor low dim levels.
3. Click the Calculate Coefficients button.
4. Adjust results. Polynomial coefficients can be modified over and above the fit results.
5. Click the UPDATE REGISTERS button to update the Color System tab under REGISTERS with Q3, Q2,
Q1, and Q0. Values are not written to the chip; only the tab is populate.
Step 1:
Enter the white
LED currents
and dim.
Step 2:
Enter the
Weight Factor.
Step 4:
Adjust results.
Step 5:
Click the UPDATE
REGISTERS button.
Step 3:
Click the Calculate
Coefficients button.
Error graph -
give ratio of
fit to the data.
Figure 27. SYSTEM DESIGN - White Gain Tab