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參數(shù)資料
| 型號(hào)： | LM8342SD |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 消費(fèi)家電 |
| 英文描述： | Programmable TFT VCOM Calibrator with Non-Volatile |
| 中文描述： | SPECIALTY CONSUMER CIRCUIT, DSO10 |
| 封裝： | LLP-10 |
| 文件頁(yè)數(shù)： | 9/16頁(yè) |
| 文件大?。?/td> | 951K |
| 代理商： | LM8342SD |
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Application Section
INTRODUCTION
The LM8342 is an integrated combination of a digitally con-
trolled current sink and a non-volatile register (7 bits EE-
PROM). Programming the register can be done using the
I
2
C compatible interface. The LM8342 replaces the potenti-
ometer adjustment, and thereby simplifies the V
calibra-
tion procedure. With the LM8342, the factory operator can
physically view the screen head-on when performing this
step, easing manufacturing especially for large TFT panel
sizes.
The following sections discuss the principle of operation of a
TFT-LCD and, subsequently give a description of how to use
the LM8342, including the I
2
C compatible interface and con-
trol inputs. After this, two typical LM8342 configurations are
presented. Subsequently an evaluation system is intro-
duced, including a μC-board programming using the I
2
C
compatible interface. At the end of this application section
board layout recommendations are given.
PRINCIPLE OF OPERATION OF A TFT-LCD
This section offers a brief overview of the principle of opera-
tion of TFT-LCD’s. It gives a detailed description of how
information is presented on the display. Further an explana-
tion of how data is written to the screen pixels and how the
pixels are selected is included.
Figure 1
shows a simplified illustration of an individual LCD
pixel. The top and bottom plates of a pixel consist of Indium-
Tin Oxide (ITO), which is a transparent, electrically conduc-
tive material. ITO is at the inner surfaces of two glass sub-
strates that are the front and back glass panels of a TFT
display. Sandwiched between two ITO plates is an insulating
material (liquid crystal). Liquid crystals alter the polarization
of light, depending on how much voltage (V
) is applied
across the two plates. Polarizers are placed on the outer
surfaces of the two glass substrates. In combination with the
liquid crystal, the polarizers create an electrically variable
light filter that modulates light transmitted from the back to
the front of a display.Apixel’s bottom plate is at the backside
of a display where a light source is applied, and the top plate
is at the front, facing the viewer. For most TFT displays, a
pixel transmits the greatest amount of light when V
≤
±
0.5V, and it becomes less transparent as the voltage in-
creases with either positive or negative polarity.
Figure 2
shows a simplified diagram of a TFT display, show-
ing how individual pixels are connected to the row, column
and V
driver. Each pixel is represented by a capacitor
with an NMOS transistor connected to its top plate. Pixels in
a TFT panel are arranged in rows and columns. Row lines
are connected to the NMOS gates, and column lines to the
NMOS sources. The back plate of every pixel is connected
to a common voltage called V
. The voltage applied to the
top plates (i.e. Gamma Voltage) controls the pixel bright-
ness. The column drivers supply this gamma voltage via the
column lines, and ‘write’ this voltage to the pixels one row at
a time. This is accomplished by having the row drivers
selecting an individual row of pixels when the column drivers
write the gamma voltage levels. The row drivers sequentially
apply a large positive pulse (typically 25V to 35V) to each
row line. This turns on the NMOS transistors connected to an
individual row, allowing voltage from the column lines to be
written to the pixels.
20139223
FIGURE 1. Individual LCD Pixel
20139224
FIGURE 2. TFT Display
L
www.national.com
9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM8342SDX | Programmable TFT VCOM Calibrator with Non-Volatile |
| LM883E | 3-Terminal Adjustable Regulator |
| LM883K | 3-Terminal Adjustable Regulator |
| LM883HVKSTL | 3-Terminal Adjustable Regulator |
| LM883 | Voltage Regulators |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM8342SD/NOPB | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| LM8342SDX | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| LM8342SDX/NOPB | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| LM8360 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
| LM8361 | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:P-MOS LSI LM8361 |
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