EM65571AGH EMC [ELAN Microelectronics Corp], EM65571AGH Datasheet - Page 59

• Manufacturer Part Number: EM65571AGH
• Description: 130COM / 128SEG 65K Color STN LCD Driver
• Manufacturer: EMC [ELAN Microelectronics Corp]

Product Specification (V1.0) 08.04.2005
(This specification is subject to change without further notice)
7.25
7.26
7.27
When using 7x boosting ratio, the VEE operating voltage should not exceed 2.8V. For a
guaranteed result, the VOUT should be less than the recommended operating voltage of
20V.
The voltage conversion circuit has a built-in electronic volume, which allows the VBA to be
controlled with DV register setting. The DV registers are 7 bits, so it’s advisable to select
113 voltage values for the VBA voltage. The relationship between VBA and DV is shown in
the following equation:
where
The EM65571 has a built-in reference voltage regulator, which generates the voltage
amplified by the input voltage from the internal temperature compensation output voltage
VREF pin. The generated voltage is output at the V0 pin. Even if the boosted voltage level
fluctuates, V0 remains stable as long as VOUT is higher than V0. Stable power supply can
be obtained using this constant voltage, even if the load fluctuates. The EM65571 uses the
generated V0 level for the reference level of the electronic volume to generate an LCD
driver voltage.
The voltage converter contains the voltage generator circuit. The LCD driver voltages other
than V0, which is, V1, V2, V3 and V4 are obtained by dividing V0 through a resistor
network. The LCD driver voltage from EM65571 is biased at 1/5, 1/6, 1/7, 1/8, 1/9, 1/10,
1/11, 1/12 or 1/13. When using the internal power supply, connect a stabilizing capacitor
C2 to each of the pins V0 to V4. The capacitance of C2 should be determined while
observing the LCD panel to be used. When using an external power supply, apply external
LCD driver voltages to V0, V1, V2, V3, V4, and disconnect pins CAP1+, CAP1-, CAP2+,
CAP2-, CAP3+, CAP4+, CAP5+, CAP6+, VOUT, VEE. When using only the voltage
conversion circuit, turn off the internal booster circuit, disconnect pins CAP1+, CAP1-,
CAP2+, CAP2-, CAP3+, CAP4+, CAP5+, CAP6+ and VEE. Derive the voltage source to
be supplied to the voltage converter from the VOUT pin.
Electronic Volume
Voltage Regulator
Voltage Generator Circuit
Offset: CV1~CV4 setting
VREF: Internal temperature compensation output voltage
M: DV register value (8~20)
VBA
=
⎡
⎢ ⎣
1
+
M
130COM/128SEG 65K Color STN LCD Driver
+
381
Offset
⎤
⎥ ⎦
×
VREF
EM65571
• 53