PDF預(yù)覽

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8

LM27952 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver

May 2005

LM27952

White LED Adaptive 1.5X/1X Switched Capacitor Current

Driver

General Description

The LM27952 is a switched capacitor white-LED driver ca-

pable of driving up to 4 LEDs with 30mA through each LED.

Its 4 tightly regulated current sinks ensure excellent LED

current and brightness matching. LED drive current is pro-

grammed by an external sense resistor. The LM27952 oper-

ates over an input voltage range from 3.0V to 5.5V and

requires only four low-cost ceramic capacitors.

The LM27952 provides excellent efficiency without the use

of an inductor by operating the charge pump in a gain of 3/2,

or in a gain of 1. Maximum efficiency is achieved over the

input voltage range by actively selecting the proper gain

based on the LED forward voltage requirements.

The LM27952 uses constant frequency pre-regulation to

minimize conducted noise on the input. It has a fixed 750kHz

switching frequency optimized for portable applications. The

LM27952 consumes less than 1碌A(chǔ) of supply current when

shut down.

The LM27952 is available in a 14-pin No-Pullback Leadless

Leadframe Package: LLP-14.

Features

n

n

n

n

n

n

n

n

n

n

Drives up to 4 LEDs with up to 30mA each

Regulated current sources with 0.2%(typ.) matching

3/2x, 1x Gain transition based on LED V

F

Peak Efficiency Over 85%

Input Voltage Range: 3.0V to 5.5V

PWM Brightness Control

Very Small Solution Size - NO INDUCTOR

Fixed 750kHz Switching Frequency

<

1碌A(chǔ) Shutdown Current

14-pin LLP Package: 4.0mm X 3.0mm X 0.8mm

Applications

n

White LED Display Backlights

n

White LED Keypad Backlights

n

General Purpose LED Lighting

Typical Application Circuit

20148001

漏 2005 National Semiconductor Corporation

DS201480

www.national.com

next

LM27952SD相關(guān)型號(hào)PDF文件下載

• 型號(hào)
  版本
  描述
  廠商
  下載
• LM27
  英文版
  SOT-23, 3 Degree Celcious Accurate, 120-150 Degree Celcious ...
  NSC
  LM27
• LM27
  英文版
  SOT-23 ±3°C Accurate 120°C-150°C Factory ...
  NATIONAL
  LM27
• LM271
  英文版
  Seoul Semiconductor [CYAN LAMP LED]
  SEOUL
  LM271
• LM272
  英文版
  STMicroelectronics [DUAL POWER OPERATIONAL AMPLIFIER]
  
  LM272
• LM27A
  英文版
  【3∑C Accurate, 120∑C-150∑C Factory Preset Thermostat (LM...
  NSC
  LM27A
• LM2700
  英文版
  600kHz/1.25MHz, 2.5A, Step-up PWM DC/DC Converter
  NSC
  LM2700
• LM2700
  英文版
  600kHz/1.25MHz, 2.5A, Step-up PWM DC/DC Converter
  NSC [Natio...
  LM2700
• LM2702
  英文版
  TFT Panel Module
  NSC
  LM2702
• LM2702
  英文版
  TFT Panel Module
  NATIONAL
  LM2702
• LM2703
  英文版
  Micropower Step-up DC/DC Converter with 350mA Peak Current L...
  NSC
  LM2703
• LM2703
  英文版
  Micropower Step-up DC/DC Converter with 350mA Peak Current L...
  LM2703
• LM2704
  英文版
  Micropower Step-up DC/DC Converter with 550mA Peak Current L...
  NSC
  LM2704
• LM2704
  英文版
  Micropower Step-up DC/DC Converter with 550mA Peak Current L...
  LM2704
• LM2705
  英文版
  Micropower Step-up DC/DC Converter with 150mA Peak Current L...
  NSC
  LM2705
• LM2705
  英文版
  Micropower Step-up DC/DC Converter with 150mA Peak Current L...
  NATIONAL
  LM2705
• LM2706
  英文版
  National Semiconductor [Miniature, Variable, Step-Down DC-D...
  NSC
  LM2706
• LM2707
  英文版
  Inductive-Boost Series LED Driver with Programmable Oscillat...
  NSC
  LM2707
• LM2707
  英文版
  Inductive-Boost Series LED Driver with Programmable Oscillat...
  NATIONAL
  LM2707
• LM2710
  英文版
  Step-up PWM DC/DC Converter Integrated with 5 Buffers
  NSC
  LM2710
• LM2710
  英文版
  Step-up PWM DC/DC Converter Integrated with 5 Buffers
  NATIONAL
  LM2710

您可能感興趣的PDF文件資料

• LM2776DBVR
• LM2776DBVT
• LM2787
• LM2733
• LM27761DSGR
• LM2767
• LM2734
• LM2734YQMK
• LM2703
• LM2731XMF
• LM27341
• LM2738XMY

熱門(mén)IC型號(hào)推薦

• LT1227CS8
• LTC1346ACSW
• LT1764AEQ
• LM26CIM5X-XPA
• LM4041DYM3-ADJ
• L4949EP013TR
• LGDT3303
• LM3940IMP-3.3
• LT1013CN8
• LMV321M5X
• LP2985A-50DBVR
• LTC1642CGN