參數(shù)資料
型號(hào)： AD5228BUJZ50-R2
廠商： Analog Devices Inc
文件頁(yè)數(shù)： 7/20頁(yè)
文件大?。?/td> 0K
描述： IC DGTL POT 50K UP/DN TSOT23-8
產(chǎn)品變化通告： Product Discontinuance 27/Oct/2011
標(biāo)準(zhǔn)包裝： 1
接片： 32
電阻（歐姆）： 50k
電路數(shù)： 1
溫度系數(shù)： 標(biāo)準(zhǔn)值 35 ppm/°C
存儲(chǔ)器類型： 易失
接口： 2 線按鈕
電源電壓： 2.7 V ~ 5.5 V
工作溫度： -40°C ~ 105°C
安裝類型： 表面貼裝
封裝/外殼： SOT-23-8 薄型，TSOT-23-8
供應(yīng)商設(shè)備封裝： TSOT-23-8
包裝： 標(biāo)準(zhǔn)包裝
其它名稱： AD5228BUJZ50-R2DKR
AD5228
Rev. A | Page 15 of 20
APPLICATIONS
MANUAL ADJUSTABLE LED DRIVER
The AD5228 can be used in many electronics-level adjustments
such as LED drivers for LCD panel backlight controls. Figure 41
shows a manually adjustable LED driver. The AD5228 sets the
voltage across the white LED D1 for the brightness control.
Since U2 handles up to 250 mA, a typical white LED with VF of
3.5 V requires a resistor, R1, to limit U2 current. This circuit is
simple but not power efficient. The U2 shutdown pin can be
toggled with a PWM signal to conserve power.
04422-
0-
042
PUSH-UP
BUTTON
PUSH-DOWN
BUTTON
A
W
B
10k
Ω
VDD
GND
PRE
PU
PD
U1
AD5228
C1
1
μF
C2
0.1
μF
5V
U2
AD8591
+
–
V+
V–
SD
5V
C3
0.1
μF
R1
6
Ω
WHITE
LED
D1
PWM
Figure 41. Low Cost Adjustable LED Driver
ADJUSTABLE CURRENT SOURCE FOR LED DRIVER
Because LED brightness is a function of current rather than of
forward voltage, an adjustable current source is preferred as
shown in Figure 42. The load current can be found as the VWB
of the AD5228 divided by RSET.
SET
WB
D1
R
V
I
=
(7)
The U1 ADP3333ARM-1.5 is a 1.5 V LDO that is lifted above
or lowered below 0 V. When VWB of the AD5228 is at its
minimum, there is no current through D1, so the GND pin of U1
is at –1.5 V if U3 is biased with the dual supplies. As a result,
some of the U2 low resistance steps have no effect on the output
until the U1 GND pin is lifted above 0 V. When VWB of the
AD5228 is at its maximum, VOUT becomes VL + VAB, so the U1
supply voltage must be biased with adequate headroom. Similarly,
PWM signal can be applied at the U1 shutdown pin for power
efficiency.
04422-
0-
043
PUSH-UP
BUTTON
PUSH-DOWN
BUTTON
A
W
B
10k
Ω
R1
418k
Ω
VDD
GND
PRE
PU
PD
U2
AD5228
5V
U3
AD8591
+
–
V+
V–
5V
PWM
VIN
VOUT
GND
U1
ADP3333
ARM-1.5
SD
RSET
0.1
Ω
VL
ID
D1
Figure 42. Adjustable Current Source for LED Driver
ADJUSTABLE HIGH POWER LED DRIVER
The previous circuit works well for a single LED. Figure 43
shows a circuit that can drive three to four high power LEDs.
The ADP1610 is an adjustable boost regulator that provides the
voltage headroom and current for the LEDs. The AD5228 and
the op amp form an average gain of 12 feedback network that
servos the RSET voltage and the ADP1610 FB pin 1.2 V band gap
reference voltage. As the loop is set, the voltage across RSET is
regulated around 0.1 V and adjusted by the digital
potentiometer.
SET
R
LED
R
V
I
SET
=
(8)
RSET should be small enough to conserve power but large enough
to limit maximum LED current. R3 should also be used in par-
allel with AD5228 to limit the LED current within an achievable
range. A wider current adjustment range is possible by lowering
the R2 to R1 ratio as well as changing R3 accordingly.
04422-0-044
SS
RT GND
IN
U2
ADP1610
SW
FB
PWM
1.2V
SD
COMP
CSS
10nF
CC
390pF
RC
100k
Ω
L1
10
μF
D1
C3
10
μF
R4
13.5k
Ω
D2
D3
D4
VOUT
C2
10
μF
5V
+
–
AD8541
U1
L1–SLF6025-100M1R0
D1–MBR0520LT1
U3
V+
V–
5V
C8
0.1
μF
U1
AD5228
BA
10k
Ω
R3
200
Ω
W
R1
100
Ω
R2
1.1k
Ω
RSET
0.25
Ω
Figure 43. Adjustable Current Source for LEDs in Series
相關(guān)PDF資料
PDF描述
AD5231BRU50-REEL7 IC DGTL POT 1024POS 16-TSSOP TR
AD5232BRU50-REEL7 IC DGTL POT DUAL 256POS 16-TSSOP
AD5233BRUZ10 IC DGTL POT 64POS 10K QD 24TSSOP
AD5235BRU25-RL7 IC DGTL POT DUAL 1024POS 16TSSOP
AD5242BRU1M-REEL7 IC DGTL POT 256POS 16-TSSOP T/R
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD5228BUJZ50-R2 制造商:Analog Devices 功能描述:DIGIPOT 5BIT UP/DOWN 50K, SMD, 5228
AD5228BUJZ50-RL7 功能描述:IC DGTL POT 50K UP/DN TSOT23-8 RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 數(shù)字電位器 系列:- 標(biāo)準(zhǔn)包裝:3,000 系列:DPP 接片:32 電阻（歐姆）:10k 電路數(shù):1 溫度系數(shù):標(biāo)準(zhǔn)值 300 ppm/°C 存儲(chǔ)器類型:非易失 接口:3 線串行（芯片選擇，遞增，增/減） 電源電壓:2.5 V ~ 6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:8-TDFN（2x3） 包裝:帶卷 (TR)
AD5228EVAL 制造商:AD 制造商全稱:Analog Devices 功能描述:32-Position Manual Up/Down Control Potentiometer
AD522AD 制造商:Rochester Electronics LLC 功能描述:INSTRUMENTATION AMPLIFIER - Bulk
AD522B 制造商:AD 制造商全稱:Analog Devices 功能描述:High Accuracy Data Acquisition Instrumentation Amplifier
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*