ST7578
Selection of Application Voltage
Power Range Summary
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Positive Booster: (VDD2 x PCn x BE) ≥ V0 or (VDD2 x PCn x BE) ≥ Vop;
Negative Booster: [–VDD2 x (PCn - 1) x BE] ≤ XV0 or [VDD2 x (PCn - 1) x BE] ≥ (Vop - VG),
where VG = Vop x 2 / N;
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Vop requirement: [VDD2 x (PCn - 1) x BE] ≥ [Vop x (N - 2) / N] or [Vop ≤ VDD2 x (PCn – 1) x BE x N / (N - 2)].
PCn is the booster stage and BE is the booster efficiency. Referential values are listed below: (assume VDD2=2.4V)
Module Size ≤ 1.4”: BE=80% (min);
Module Size = 1.4”~1.8”: BE=76% (min).
Actual BE should be determined by module loading and ITO resistance value.
1.24 ≤ VG < VDD2. Recommend VG is: VDD2-VG around 0.5~0.8V.
VM=VG/2 and 0.62V ≤ VM < VDD2.
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The worse condition should be considered:
Low temperature effect and display on with snow pattern on panel (max: 1.8”).
Referential LCD Module Setting
VDD1=VDD2=2.8V, Panel Size=1.4”
Duty
Booster
Vop
Bias
1/9,
5X,
8.49V ~ 9V,
PRS=1
1/66
CP=H
BS[2:0]=0,1,1
Note: It is recommended to reserve some range for user adjustment and temperature effect.
Ver 1.2
49/52
2007/04/30
SITRONIX [ SITRONIX TECHNOLOGY CO., LTD. ]
