EM65571 ELAN Microelectronics Corp, EM65571 Datasheet - Page 57

• Manufacturer Part Number: EM65571
• Description: 130com / 128seg 65k Color Stn Lcd Driver
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 08.04.2005
(This specification is subject to change without further notice)
7.22
7.23
The EM65571 has a CR oscillator. The output from this oscillator is used as the timing
signal source of the display and the boosting clock for the booster.
When external clock is used, feed the clock to CK pin.
The duty cycle of the external clock must be 50%.
The resistance ratio of the CR oscillator is programmable. If you change this ratio, also
change the frame frequency for display.
This circuit supplies voltages necessary to drive an LCD. The circuit consists of a booster
and a 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,
the display quality will degrade considerably. Instead, use an external power supply.
When using an external power supply, turn off the internal power supply (AMPON,
DCON=”00”), disconnect pins CAP1-, CAP1+, CAP2+, CAP2-, CAP3+, CAP4+, CAP5+,
CAP6+, VOUT and VEE. Then, feed the external LCD drive voltages to pins V0, V1, V2, V3
and V4. The power circuit can be controlled by a power circuit related register. So, partial
function of the built-in power circuit can be used with external power supply.
Note:
Power Supply Circuit
Oscillator Circuit
DCON AMPON Booster Circuit Voltage Conversion Circuit
0
0
1
1
2
When the booster and voltage converter are not operating, disconnect pins CAP+,
CAP-, CAP2+, CAP2-, CAP3+, CAP4+, CAP5+, CAP6+, VOUT and VEE.
Apply external LCD driver voltages to the corresponding pins.
Since the booster is not operating, 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.
0
1
1
Disable
Disable
Enable
Disable
Enable
Enable
130COM/128SEG 65K Color STN LCD Driver
V0, V1, V2, V3 and V4 are supplied
External Voltage Input
VOUT is supplied
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EM65571
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1