DLP4710LCFQL datasheet(29/45 Pages) TI2

29 / 45 page

7.8 Micromirror Landed-On/Landed-Off Duty Cycle

7.8.1 Definition of Micromirror Landed-On and Landed-Off Duty Cycle

The micromirror landed-on/landed-off duty cycle (landed duty cycle) denotes the amount of time (as a

percentage) that an individual micromirror is landed in the ON state versus the amount of time the same

micromirror is landed in the OFF state.

As an example, a landed duty cycle of 75/25 indicates that the referenced pixel is in the ON state 75% of the

time (and in the OFF state 25% of the time), whereas 25/75 indicates that the pixel is in the OFF state 75% of

the time. Likewise, 50/50 indicates that the pixel is ON 50% of the time and OFF 50% of the time.

When assessing landed duty cycle, the time spent switching from the current state to the opposite state is

considered negligible and is thus ignored.

Because a micromirror can only be landed in one state or the other (ON or OFF), the two numbers (percentages)

nominally add to 100.In practice, image processing algorithms in the DLP chipset can result a total of less that

100.

7.8.2 Landed Duty Cycle and Useful Life of the DMD

Knowing the long-term average landed duty cycle (of the end product or application) is important because

subjecting all (or a portion) of the DMD’s micromirror array (also called the active array) to an asymmetric landed

duty cycle for a prolonged period of time can reduce the DMD’s usable life.

It is the symmetry or asymmetry of the landed duty cycle that is relevant. The symmetry of the landed duty cycle

is determined by how close the two numbers (percentages) are to being equal. For example, a landed duty cycle

of 50/50 is perfectly symmetrical whereas a landed duty cycle of 100/0 or 0/100 is perfectly asymmetrical.

7.8.3 Landed Duty Cycle and Operational DMD Temperature

Operational DMD temperature and landed duty cycle interact to affect the usable life of the DMD. This interaction

can be used to reduce the impact that an asymmetrical landed duty cycle has on the useable life of the DMD.

Figure 6-1 describes this relationship. The importance of this curve is that:

• All points along this curve represent the same usable life.

• All points above this curve represent lower usable life (and the further away from the curve, the lower the

usable life).

• All points below this curve represent higher usable life (and the further away from the curve, the higher the

usable life).

In practice, this curve specifies the maximum operating DMD temperature that the DMD should be operated at

for a give long-term average landed duty cycle.

7.8.4 Estimating the Long-Term Average Landed Duty Cycle of a Product or Application

During a given period of time, the landed duty cycle of a given pixel depends on the image content being

displayed by that pixel.

In the simplest case for example, when the system displays pure-white on a given pixel for a given time period,

that pixel operates very close to a 100/0 landed duty cycle during that time period. Likewise, when the system

displays pure-black, the pixel operates very close to a 0/100 landed duty cycle.

Between the two extremes (ignoring for the moment color and any image processing that may be applied to an

incoming image), the landed duty cycle tracks one-to-one with the gray scale value, as shown in Table 7-1.

Table 7-1. Grayscale

Value and Landed Duty

Cycle

Grayscale

Value

Nominal

Landed Duty

Cycle

0/100

www.ti.com

DLP4710LC

DLPS178C – MAY 2020 – REVISED JULY 2023

Submit Document Feedback

Product Folder Links: DLP4710LC

DLP4710LCFQL Fiches technique(PDF) 29 Page - Texas Instruments

DLP4710LCFQL Fiches technique(HTML) 29 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Fiches technique Télécharger

Lien URL