EM65568 ELAN Microelectronics Corp, EM65568 Datasheet - Page 49

• Manufacturer Part Number: EM65568
• Description: 130 Com/ 128 Seg 4096 Color Stn Lcd Driver
• Manufacturer: ELAN Microelectronics Corp

7.19 LCD Drive Circuit
This drive circuit generates four levels LCD drive voltage. The circuit has 384 segment outputs and 130 common outputs and
outputs combined display data and M signal. Two of common outputs, COMA and COMB, are special outputs. The COMA
and COMB outputs be not influenced by partial setting. Mainly use for display. The common drive circuit that has shift register
sequentially outputs common scan signals.
7.20 Oscillating Circuit
The EM65568 has the CR oscillator. The output from this oscillator is used as the timing signal source of the display and the
boosting clock to the booster.
This can use only in the master operation mode.
When in the master operation mode and external clock is used, feed the clock to CK pin.
The duty cycle of the external clock must be 50%.
The resistance ratio of CR oscillator is programmable. If change this ratio, also change frame frequency for display.
7.21 Power Supply Circuit
This circuit supplies voltages necessary to drive a 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. Instead, use an external power supply. When using the external
power supply, turn off the internal power supply (AMPON, DCON=”00”), disconnect pins CAP1+, CAP2+, CAP2-, CAP3+,
CAP3-, CAP4+, CAP4-, CAP5+, CAP5-,VOUT, VEE, VREF and VREG. Then, feed external LCD drive voltages to pins V0,
V1, V2, V3 and V4. The power circuit can be control by power circuit related register. So partial function of built-in power
circuit can use with external power supply.
á³1 Because the booster and voltage converter not operating, disconnect pins
á³2 Because the booster is not operating, disconnect pins
* This specification is subject to be changed without notice.
DCON AMPON Booster circuit Voltage conversion circuit
0
0
1
CAP1+, CAP1-, CAP2+, CAP2-, CAP3+, CAP3-, CAP4+, CAP4 -, CAP5+, CAP5-, VOUT, VREF, VREG and VEE.
CAP1+, CAP1-, CAP2+, CPA2-, CAP3+, CAP3-, CAP4+, CAP4-, CAP5+, CAP5- and VEE.
Apply external LCD drive voltages to corresponding pin.
Derive the voltage source to be supplied to the voltage converter from VOUT pin and then
Input the reference voltage at VREF pin.
0
1
1
DISABLE
DISABLE
ENABLE
DISABLE
ENABLE
ENABLE
130 COM/ 128 SEG 4096 Color STN LCD Driver
V0,V1,V2,V3 and V4 are supplied
49
Extemal voltage input
VOUT is supplied
-
Note
á 1
á 2
-
2005/3/8 (V1.2)
EM65568