em65570sagh ELAN Microelectronics Corp, em65570sagh Datasheet - Page 35

• Manufacturer Part Number: em65570sagh
• Description: 68com/98seg 65k Color Stn Lcd Drivers
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 04.18.2006
(This specification is subject to change without further notice)
7.14 Power Supply Circuit
7.15 Booster Circuit
7.16 Electronic Volume
VEE=3V
VSS=0V
This circuit supplies voltages necessary to drive an LCD. The circuit consists of
booster and voltage converter.
Boosted voltage from the booster is fed to the voltage converter that converts this input
voltage into V0, V1, V2, V3 and V4 that are used to drive the LCD. This internal power
supply should not be used to drive a large LCD panel containing many pixels.
Otherwise, display quality will degrade considerably. The power circuit can be control
by power circuit related register.
Placing capacitor C1 across CAP1+ and CAP1-, across CAP2+ and CAP2-, across
CAP3+ and CAP3-, across CAP4+ and CAP2- and across VOUT and VSS boosts the
voltage coming from VEE and VSS n-times and outputs the boosted voltage to VOUT
pin. The twice, third, fourth or fifth boosted voltages are output to the VOUT pin by the
boost step register set. The boost step registers set by the command.
When use built-in booster circuit, output voltage (VOUT) must less than recommended
operating voltage (19 Volt). If output voltage (VOUT) is beyond the recommended
operating voltage, proper function of the IC cannot be guaranteed.
The voltage conversion circuit has built-in an electronic volume, which allows VEV to
be controlled with DV register setting. The DV registers are 7-bits, so can select 128
voltage values for the VEV voltage. The relationship between VEV and DV is given by
follows equation:
VEV=K * (373 + (DV+CV)) ----------------------------------------------------- (1)
DV: Electronic volume setting value
CV: Vop offset setting value of OTP
K: Coefficient 4.005 * 10
Boosted 3 times
VOUT=9V
DCON AMPON
0
1
-3
0
1
Booster Circuit
disable
enable
68COM/98SEG 65K Color STN LCD Drivers
VEE=3V
VSS=0V
Voltage Conversion Circuit
disable
enable
Boosted 5 times
VOUT=15V
EM65570S
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