LC7574 datasheet(13/18 Pages) SANYO

13 / 18 page

Relationship between the Segment and Digit Outputs

• Figure 5 shows the case where the display data is set up so that the segment outputs S1 to S41 output the VSS level

with the same timing as the G1 and G2 digit outputs, and output the VFL level with the same timing as the G2 digit

output. Here, the segments corresponding to G2 will be turned on. The relationship between t3 and the oscillator

frequency fOSC in this case is t3 = 2048/fOSC.

• The G1 and G2 digit output waveforms in example 1 correspond to a dimmer data (DM0 to DM9) set to 3FEH. The

relationship between t1 and the oscillator frequency fOSC is t1 = 2/fOSC. Note that t1 and t2 in example 1 are identical

times.

• The G1 and G2 digit output waveforms in example 2 correspond to a dimmer data (DM0 to DM9) set to a smaller

value. Although t1 does not change, t2 becomes longer. Here, if the dimmer data (DM0 to DM9) is set to 1FFH and the

oscillator frequency fOSC is 1.6 MHz, then t2 can be calculated as follows.

• If the dimmer data (DM0 to DM9) is set to an even smaller value, t2 will become even longer as shown in example 3.

Note that t1 does not change in this case as well.

No. 6142-13/18

LC75742E, LC75742W

Example 1

S1 to S41

Example 2

Example 3

t2 = t3 – t1

× (1FF

H +1)

1024

fOSC

= 0.64 [ms]

Figure 5

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