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ST7038
Ver 1.1
45/61
2007/01/25
Built-in Follower circuit:
There are 3 kinds of built-in Follower circuits. By instruction, the follower can be configured to be:
OPF[2:1]
Description
(0,0)
Select built-in Follower
(0,1)
Select built-in bias resistor (9.9K)
(1,0)
Select built-in bias resistor (3.3K)
(1,1)
Select external bias circuit (built-in Follower is OFF)
Note:
l
When using built-in bias resistors (9.9K or 3.3K), the current consumption maybe larger than using built-in Follower.
Furthermore, the loading of built-in Booster is increasing too. That will cause the Booster efficiency drop and V0 maybe
affected.
Referential Power Connection:
When using internal Booster, Regulator and Follower, the referential connection is shown below.
2X Booster, Regulator & Follower
S
T
70
38
V
SS
V
OUT
CAP3P
OPEN
C1
CAP1P
CAP1N
C1
OPEN CAP2N
CAP2P
CAP4P
OPEN
V0
V1
V2
V3
V4
V
SS
V
OP
1.8V~3.3V
V
DD
/V
DD2
Note:
l
If LCD panel size is larger than 2
”
, a V0 capacitor is recommended.
If LCD panel size is larger than 3
”
, 4 Follower capacitors (V1~V4) are recommended.
l
When V
DD2
<2.4V, the Booster efficiency maybe lower and the ITO resistance should be lower to solve this problem.