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參數(shù)資料
| 型號(hào)： | ADM8845ACPZ |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 顯示驅(qū)動(dòng)器 |
| 英文描述： | Charge Pump Driver for LCD White LED Backlights |
| 中文描述： | LED DISPLAY DRIVER, QCC16 |
| 封裝： | 3 X 3 MM, 0.90 MM HEIGHT, LEAD FREE, LFCSP-16 |
| 文件頁數(shù)： | 12/18頁 |
| 文件大?。?/td> | 341K |
| 代理商： | ADM8845ACPZ |
ADM8845
Preliminary Technical Data
ADM8845 BRIGHTNESS CONTROL WITH A DIGITAL PWM SIGNAL
PWM brightness control provides the widest brightness control
method by pulsing the white LEDs on and off using the digital
input control pins, CTRL1 and/or CTRL2. PWM brightness
control also removes any chromaticity shifts associated with
changing the white LED current, as the LEDs operate at either
zero current or full current (set by the R
SET
resistor).
Rev. PrJ 06/04 | Page 12 of 18
The digital PWM signal applied with a frequency of 100Hz to
200kHz turns the current control sinks on and off using CTRL1
and/or CTRL2. The average current through the LEDs changes
with the PWM signal duty cycle. If the PWM frequency is much
less than 100Hz, flicker may be seen in the LEDs. For the
ADM8845, zero duty cycle will turn off the LEDs and a 50%
duty cycle will result in an average LED current I
LED
being half
the programmed LED current. For example, if R
SET
is set to
program 20mA/LED, a 50% duty cycle will result in an average
I
LED
of 10mA/LED. I
LED
being half the programmed LED current.
ADM8845
CTRL1
CTRL2
Vout
FB2
FB3
FB4
FB5
FB6
FB1
C3
Iset
Rset
C1
C2
PWM Input
or
High/Low
PWM Input
or
High/Low
Figure 24. ADM8845 Digital PWM Brightness Control Application
Diagram
By applying a digital PWM signal to the digital input control
pins, CTRL1 and/or CTRL2 you can adjust the brightness of the
sub and/or main displays. The ADM8845 six white LEDs are
organized into 2 groups, Main Display (FB1-FB4) and Sub
Display (FB4 - FB6), refer to Page 10.
The ADM8845 main and sub display brightness can be
controlled together or separately. By applying a digital PWM
signal to both CTRL1 and CTRL2 pins. The duty cycle of the
applied digital PWM signal determines the brightness of the
main and sub displays together. By varying the duty cycle of the
applied PWM signal you vary the brightness of the main and
sub displays from 0% to 100%.
By holding CTRL1 low and applying a digital PWM signal to
CTRL2, the sub display is turned off and the main display is on,
the brightness of the main display is determined by the duty
cycle off the applied digital PWM signal.
Also applying a digital PWM signal to CTRL1 and holding
CTRL2 low, the sub display is turned on and the main display is
off, the brightness of the sub display is determined by the duty
cycle off the applied digital PWM signal.
Also applying a digital PWM signal to CTRL1 and holding
CTRL2 high, the sub display is turned on and the main display
is turned on, the brightness of the sub display is determined by
the duty cycle off the applied digital PWM signal. The
brightness of the main display is set to the maximum
(maximum is set by the R
SET
resistor).
By holding CTRL1 high and applying a digital PWM signal to
CTRL2, the sub display is turned on and the main display is on,
the brightness of the main display is determined by the duty
cycle off the applied digital PWM signal. The brightness of the
sub display is set to the maximum (maximum is set by the R
SET
resistor)
When CTRL1 and CTRL2 go low the LED Current Control
Sinks shutdown. Shutdown of the Charge Pump is delayed by
15mS. This timeout period (t
CP
) allows the ADM8845 to
determine if a digital PWM signal is present on CTRL1 and
CTRL2 or if the user has selected a full chip shutdown, see
Figure 25 ADM8845 Application Timing.
If digital PWM brightness control of the LEDs is not required
then a constant logic level 1 (V
CC
) or 0 (GND) must be applied.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADM8845ACPZ-REEL | 功能描述:IC LED DRVR WHITE BCKLGT 16LFCSP RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 標(biāo)準(zhǔn)包裝:6,000 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?開路漏極，PWM 輸出數(shù):4 內(nèi)部驅(qū)動(dòng)器:是 類型 - 主要:LED 閃爍器 類型 - 次要:- 頻率:400kHz 電源電壓:2.3 V ~ 5.5 V 輸出電壓:- 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-HVSON 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C 其它名稱:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| ADM8845ACPZ-REEL1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Charge Pump Driver for LCD White LED Backlights |
| ADM8845ACPZ-REEL7 | 功能描述:IC LED DRVR WHITE BCKLGT 16LFCSP RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 標(biāo)準(zhǔn)包裝:6,000 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?開路漏極，PWM 輸出數(shù):4 內(nèi)部驅(qū)動(dòng)器:是 類型 - 主要:LED 閃爍器 類型 - 次要:- 頻率:400kHz 電源電壓:2.3 V ~ 5.5 V 輸出電壓:- 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-HVSON 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C 其它名稱:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| ADM8845ACPZ-REEL71 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Charge Pump Driver for LCD White LED Backlights |
| ADM8845ACPZ-WP1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Charge Pump Driver for LCD White LED Backlights |
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