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參數(shù)資料
| 型號： | LP3950 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Color LED Driver with Audio Synchronizer |
| 中文描述： | 彩色LED驅(qū)動器與音頻同步 |
| 文件頁數(shù)： | 25/31頁 |
| 文件大?。?/td> | 1085K |
| 代理商： | LP3950 |
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Recommended External
Components
OUTPUT CAPACITOR, C
OUT
The output capacitor C
directly affects the magnitude of
the output ripple voltage. In general, the higher the value of
C
, the lower the output ripple magnitude. Multilayer ce-
ramic capacitors with low ESR (Equivalent Series Resis-
tance) are the best choice. At the lighter loads, the low ESR
ceramics offer a much lower V
ripple than the higher
ESR tantalums of the same value. At the higher loads, the
ceramics offer a slightly lower V
ripple magnitude than
the tantalums of the same value. However, the dv/dt of the
V
ripple with the ceramics is much lower that the tantal-
ums under all load conditions. Capacitor voltage rating must
be sufficient, 10V is recommended.
Some ceramic capacitors, especially those in small
packages, exhibit a strong capacitance reduction with
the increased applied voltage. The capacitance value
can fall to below half of the nominal capacitance. Too
low output capacitance can make the boost converter
unstable.
INPUT CAPACITOR, C
IN
The input capacitor C
directly affects the magnitude of the
input ripple voltage and to a lesser degree the V
ripple. A
higher value C
will give a lower V
ripple. Capacitor volt-
age rating must be sufficient, 10V is recommended.
OUTPUT DIODE, D
1
A Schottky diode should be used for the output diode. To
maintain high efficiency the average current rating of the
schottky diode should be larger than the peak inductor cur-
rent (
A
1.0A). Schottky diodes with a low forward drop and
fast switching speeds are ideal for increasing efficiency in
portable applications. Choose a reverse breakdown of the
schottky diode larger than the output voltage. Do not use
ordinary rectifier diodes, since slow switching speeds and
long recovery times cause the efficiency and the load regu-
lation to suffer.
INDUCTOR, L
1
LP3950’s high switching frequency enables the use of a
small surface mount inductor. A 4.7 μH shielded inductor is
suggested for 2.0 MHz switching frequency. Values below
2.2 μH should not be used at 2.0 MHz. At lower switching
frequencies 4.7 μH inductors should always be used. The
inductor should have a saturation current rating higher than
the peak current it will experience during circuit operation
(
A
1.0A). Less than 300 m
ESR is suggested for high
efficiency. Open core inductors cause flux linkage with circuit
components and, thus, may interfere with the normal opera-
tion of the circuit. This should be avoided. For high efficiency,
choose an inductor with a high frequency core material such
as ferrite to reduce the core losses. To minimize radiated
noise, use a toroid, pot core or shielded core inductor. The
inductor should be connected to the SW pin as close to the
IC as possible. Examples of suitable inductors are TDK type
VLF4012AT-
4R7M1R1
and
472MLD.
Coilcraft
type
MSS4020-
List of Recommended External Components
Symbol
C
VDD1
C
VDD2
C
OUT
C
IN
C
VDDIO
C
VDDA
C
1,2,3
R
T
R
SO
C
VREF
L
1
D
1
Symbol Explanation
Value
100
100
10
±
10%
10
±
10%
100
100
10
82
100
100
4.7
0.3
Unit
nF
nF
μF
μF
nF
nF
nF
k
k
nF
μH
V
Type
V
DD1
Bypass Capacitor
V
DD2
Bypass Capacitor
Output Capacitor from FB to GND
Input Capacitor from Battery Voltage to GND
V
DD_IO
Bypass Capacitor
V
DDA
Bypass Capacitor
Audio Input Capacitors
Oscillator Frequency Bias Resistor
SO Output Pull-up Resistor
Reference Voltage Capacitor, between V
REF
and GND
Boost Converter Inductor
Rectifying Diode, V
F
@
Maxload
RGB LED
Red, Green, Blue or White LEDs
Current Limit Resistors
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
Ceramic, X5R
1% (Note 19)
Ceramic, X5R
Shielded, Low ESR, I
SAT
A
1.0A
Schottky Diode
User Defined
R
RX
, R
GX
, R
BX
Note 19:
Resistor RT tolerance change will change the timing accuracy of RGB block. Also the boost converter switching frequency will be affected.
PCB Design Guidelines
Printed circuit board layout is critical to low noise operation
and good performance of the LP3950. Bypass capacitors
should be close to the V
pins of the integrated circuit.
Special attention must be given to the routing of the switch-
ing loops. Lengths of these loops should be minimized. It is
essential to place the input capacitor, the output capacitor,
the inductor and the schottky diode very close to the inte-
grated circuit and use wide routings for those components.
Sensitive components should be placed far from those com-
ponents with high pulsating current. A ground plane is rec-
ommended.
The power switch loop (the switch is on) has the greatest
affect on noise generation. The loop is formed by the input
L
www.national.com
25
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LP3950SL | Color LED Driver with Audio Synchronizer |
| LP3950SLX | Color LED Driver with Audio Synchronizer |
| LP3952 | 6-Channel Color LED Driver with Audio Synchronization |
| LP3952RLX | 6-Channel Color LED Driver with Audio Synchronization |
| LP3952RL | 6-Channel Color LED Driver with Audio Synchronization |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LP3950SL | 制造商:Texas Instruments 功能描述:LED DRIVER COLOUR POWERWISE LLP32 |
| LP3950SL/CSP1 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LP3950SL/NOPB | 功能描述:LED照明驅(qū)動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| LP3950SLX | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Color LED Driver with Audio Synchronizer |
| LP3950SLX/NOPB | 功能描述:IC LED DRVR WHITE BCKLGT 32-TSCP RoHS:是 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動器 系列:PowerWise® 標(biāo)準(zhǔn)包裝:1 系列:- 恒定電流:- 恒定電壓:- 拓撲:PWM，切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:642kHz 電源電壓:2.7 V ~ 5.5 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-VSON 包裝:剪切帶 (CT) 工作溫度:-30°C ~ 85°C 產(chǎn)品目錄頁面:1371 (CN2011-ZH PDF) 其它名稱:BD1603NUV-E2CT |
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