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參數資料
| 型號： | HD66420 |
| 廠商： | Hitachi,Ltd. |
| 英文描述： | (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| 中文描述： | （內存提供160通道4級灰度的點陣圖形液晶顯示驅動程序） |
| 文件頁數： | 38/52頁 |
| 文件大?。?/td> | 167K |
| 代理商： | HD66420 |
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HD66420
38
Power Supply Circuits
HD66420 has following circuits for power supply circuit: operational amplifiers, resistive dividers, bias
control circuit and contrast control circuit. LCD driving voltage, VLCD, must be generated externally.
LCD Drive Voltage Power Supply Levels:
To drive the LCD, a 6-level power supply is necessary. These
levels are generated internally or supplied from outside. When an internal voltage levels generator is
chosen, external capacitors are needed to stabilize these levels. AS the HD66420 incorporates operational
amplifiers to these levels, this circuit gives better quality of display with less power consumption. This
divided ratio is programmable.
Bias current of internal operational amplifier is determined with a resister which is inserted between
IREFM and GND. This resister value is between 1M
and 5M
. Larger resister value make less power
consumption at internal operational amplifier. However, too large value loose operational margin of
amplifiers.
Keep following relationship among voltage levels;
V
CC
≥
IREFMP > IREFM
≥
GND
VLCD > V
CC
> GREF
≥
GND
VLCD
≥
V1O
≥
V2O
≥
V3O
≥
V4O
≥
V5O
≥
GREF
VLCD–V
CC
≥
1.0V
IREFP–IREFM
≥
1.0V
V
CC
–GREF
≥
1.0V
Contrast Control:
Internal contrast control circuit can change the output voltage level of VLCD by setting
data to contrast control register, R16. VLCD adjustable range are showed below;
1/6 bias
0.75 * (VLCD-GND)
≤
VLCD
≤
0.99 * (VLCD-GND)
1/9 bias
0.82 * (VLCD-GND)
≤
VLCD
≤
0.993 * (VLCD-GND)
相關PDF資料 |
PDF描述 |
|---|---|
| HD66420TA0 | LCD Display Driver |
| HD66421 | (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| HD66421TB0 | (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| HD66503 | 240-Channel Common Driver with Internal LCD Timing Circuit(帶內部LCD定時電路的240通道驅動器) |
| HD66520T | 160-Channel 4-Level Grayscale Display Column Driver with Internal Bit-Map RAM(點陣圖形LCD160通道驅動器) |
相關代理商/技術參數 |
參數描述 |
|---|---|
| HD66420TA0 | 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:LCD Display Driver |
| HD66421 | 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:(RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| HD66421TB0 | 制造商:Renesas Electronics Corporation 功能描述: |
| HD66503 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
| HD66520 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
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