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參數(shù)資料
| 型號： | LM3551SDX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 顯示驅(qū)動器 |
| 英文描述： | 1A White LED Driver with Flash Timeout Protection |
| 中文描述： | LED DISPLAY DRIVER, QCC14 |
| 封裝： | 4 X 4 MM, LLP-24 |
| 文件頁數(shù)： | 9/15頁 |
| 文件大小： | 756K |
| 代理商： | LM3551SDX |
Block Diagram
20151203
Circuit Description
OVERVIEW
The LM3551/2 are high power white LED flash drivers ca-
pable of delivering up to 1A of output current. The devices
utilize a highly efficient inductive DC/DC boost converter to
achieve the required output voltage. A current-mode PWM
control scheme regulates the output current over a wide
input voltage range. Both the LM3551 and the LM3552 have
two low-side load disconnect FET’s allowing for a continuous
low-power Torch-mode and a high-power, short duration
Flash-mode.
Several application specific safety features are integrated
into the LM3551/2 design. A flash timeout circuit is present
on-chip to prevent a failure in the flash LED caused by a
timing violation. Over-Voltage Protection protects the output
capacitor, inductor and main power switch in the event of an
open circuit condition. Other safety features include inductor
current limit, thermal shutdown, and an undervoltage lock-
out.
CIRCUIT COMPONENTS
Inductive DC/DC Boost Converter
In order to achieve the output voltages required to power
high power white LEDs, the LM3551 and LM3552 utilize a
highly efficient inductive DC/DC converter. The boost con-
verter utilizes a current-mode controlled, constant frequency
(1.25MHz.), PWM architecture. This architecture creates a
predictable noise spectrum that allows for easy filtering and
low noise. A very low on-resistance power NFET(R
=
0.165
) and high value current limit (2.2A typ.) help effi-
ciently provide a high power output (700mA
@
5V) over the
entire lithium-ion voltage range. The feedback voltage for
both the LM3551 and LM3552 is tightly regulated to 1.265V.
SD/EN Pin
The LM3551 and LM3552 provide two different options in
regards to turn-on control logic. The LM3551 utilizes a shut-
down pin (SD) that turns on the part when a voltage less than
0.3V is applied. An internal 1.2M
pull-up to V
is provided
to place the LM3551 into shutdown when no control signal is
provided. The LM3552 utilizes a enable pin (EN) that turns
on the part when a voltage greater than 1.2V is applied. An
internal 1.2M
pull-down to GND is provided to place the
LM3552 into shutdown when no control signal is provided.
Low-side Load Disconnect FETs
The LM3551 and LM3552 have two low-side load disconnect
NFETs (FET-T and FET-F) that provide the physical mecha-
nism of Torch Mode and Flash Mode. In Torch Mode, FET-T
is enabled allowing current to flow through it. FET-T has an
on-resistance of 0.98
and is capable of handling currents
up to 200mA. In Flash Mode, both FET-T and FET-F are
enabled. FET-F has an on-resistance of 0.36
and is ca-
pable of handling currents up to 500mA. The total Flash
current is equal to the sum total of the current flowing
through FET-T and FET-F. See the
CURRENT SET EQUA-
TIONS
in the Application Informations section for more infor-
mation regarding setting LED current .
In shutdown mode, the LM3551/2 provide a true load dis-
connect helping to keep the total shutdown current to a
minimum.
Over-Voltage Protection (OVP)
The over voltage protection (OVP) is engaged when a failure
mode occurs (FB pin grounded, Flash LED becomes open or
disconnected, etc.). In the event of a failure, OVP prevents
the output voltage from exceeding 12.4V (typ). When the
OVP level is reached, the switch FET shuts off preventing
the output voltage from climbing higher. Once the FET has
shut off, the output will droop at a rate determined by the
value of the output capacitor and current leakage through
the OVP pin and any other leakage path. When the output
L
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相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM3552SD | 1A White LED Driver with Flash Timeout Protection |
| LM3552SDX | 1A White LED Driver with Flash Timeout Protection |
| LM3552 | 1A White LED Driver with Flash Timeout Protection |
| LM3551 | 1A White LED Driver with Flash Timeout Protection |
| LM3595 | The LM3595 is a parallel white-LED driver that is capable of driving four white LEDs. |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3551SDX/NOPB | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3552 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:1A White LED Driver with Flash Timeout Protection |
| LM3552SD | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3552SD/NOPB | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3552SDEV | 功能描述:電源管理IC開發(fā)工具 LM3552SD EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
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