HT0313A Tomato LSI, Inc., HT0313A Datasheet - Page 30

• Manufacturer Part Number: HT0313A
• Description: 65COM/132SEG DRIVER & CONTROLLER FOR STN LCD
• Manufacturer: Tomato LSI, Inc.

HT0313A
VLCD voltage (V0) is resistively divided into four voltage levels (V1, V2, V3 and V4) and those output
impedance are converted by the voltage follower for increasing drive capability. The following table shows
the relationship between V1 to V4 level and each duty ratio.
The power supply circuit equipped in the HT0313A for LCD drive has very low power consumption (in normal
mode : HPM = “L”). If use for LCD panels with large loads, this low-power supply may cause display quality
to degrade. When this occurs, setting the HPM pin to “H”(high power mode) can improve the quality of the
display. Moreover, if the quality of display is inadequate even after High Power mode has been set, then it is
necessary to add a liquid crystal drive power supply externally (VOUT or V0 or V1, V2, V3, V4).
TOMATO LSI Inc.
c. Voltage follower circuits
d. High power mode
Table 6-10. The relationship between V1 to V4 level and duty ratio
Duty Ratio
1/33
1/49
1/65
65COM / 132SEG DRIVER & CONTROLLER FOR STN LCD
DSEL1
H
L
L
30
DSEL0
H / L
H
L
LCD Bias
1/5
1/6
1/6
1/8
1/7
1/9
(4/5) x V0
(5/6) x V0
(5/6) x V0
(7/8) x V0
(6/7) x V0
(8/9) x V0
V1
(3/5) x V0
(4/6) x V0
(4/6) x V0
(6/8) x V0
(5/7) x V0
(7/9) x V0
V2
(2/5) x V0
(2/6) x V0
(2/6) x V0
(2/8) x V0
(2/7) x V0
(2/9) x V0
V3
Ver 0.0
(1/5) x V0
(1/6) x V0
(1/6) x V0
(1/8) x V0
(1/7) x V0
(1/9) x V0
V4