There are two general methods of determining the proper coarse combinations for a DLP PGU.

The first method of determining coarse combinations is to input many coarse combinations spanning all LDC indexes and perform a PWM sweep. This will likely give a nearly complete brightness range, but there may be some gaps in output brightness that aren’t achievable, as well as heavily overlapping combinations that will ultimately be unnecessary. These can be fixed by going back to the coarse combination inputs and strategically adjusting the parameters, adding intermediate coarse combinations to close the gaps as in Figure 5-2, or removing coarse combinations that are not needed as in Figure 5-3. This gives a clear view of the achievable brightness range possible very quickly, and helps locate which areas need parameter adjustments. Because many coarse combinations are used, each successive sweep can take up to thirty minutes.

The second method of determining coarse combinations is to start at maximum brightness (LDC 0) and input only two or three coarse combinations (e.g. LDC 0 and LDC 1 with appropriate gain and current limit settings). This will not span the entire brightness output of the system, but each sweep will take a minimal amount of time. Once the two coarse combinations have been adjusted so they overlap slightly and give the largest brightness range for each combination, the combinations can be recorded and saved for entry later. Then, the next two coarse combinations (e.g. LDC 1 and LDC 2) can be entered and swept, again maintaining overlap and maximizing brightness range (Note: many LDC indexes will actually be omitted from the final coarse combination list). This can continue, two overlapping coarse combinations at a time, until the full brightness range has been achieved. Finally, one last sweep can be performed, with all recorded coarse combinations included, to show complete brightness range coverage while the coarse combination adjustment and determination is already solved.

Ultimately, these coarse combinations will differ slightly for each design of a DLP3030-Q1 based PGU. There will be some amount of trial and error involved in determining the optimal coarse combinations. Use Section 5.3 as a reference for adjusting coarse combination parameters as needed. Once desired coarse combinations have been found, the pre-work is finished and the PGU is ready to be calibrated. Section 6 goes through the step-by-step process of using the ACP to perform temperature compensation sweeps and production calibration.