DataSheetWiki


LM27952 fiches techniques PDF

National Semiconductor - White LED Adaptive 1.5X/1X Switched Capacitor Current Driver

Numéro de référence LM27952
Description White LED Adaptive 1.5X/1X Switched Capacitor Current Driver
Fabricant National Semiconductor 
Logo National Semiconductor 





1 Page

No Preview Available !





LM27952 fiche technique
May 2005
www.DataSheet4U.com
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 1µA of supply current when
shut down.
The LM27952 is available in a 14-pin No-Pullback Leadless
Leadframe Package: LLP-14.
Features
n Drives up to 4 LEDs with up to 30mA each
n Regulated current sources with 0.2%(typ.) matching
n 3/2x, 1x Gain transition based on LED VF
n Peak Efficiency Over 85%
n Input Voltage Range: 3.0V to 5.5V
n PWM Brightness Control
n Very Small Solution Size - NO INDUCTOR
n Fixed 750kHz Switching Frequency
n <1µA Shutdown Current
n 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
© 2005 National Semiconductor Corporation DS201480
20148001
www.national.com

PagesPages 8
Télécharger [ LM27952 ]


Fiche technique recommandé

No Description détaillée Fabricant
LM2795 LM2794/LM2795 Current Reg Switched Cap LED Sup w/Analog PWM Brightness Control (Rev. L) Texas Instruments
Texas Instruments
LM27951 Switched-Capacitor Current Driver (Rev. C) Texas Instruments
Texas Instruments
LM27951 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver National Semiconductor
National Semiconductor
LM27952 LM27952 White LED Adaptive 1.5X/1X Switched Capacitor Current Driver (Rev. B) Texas Instruments
Texas Instruments

US18650VTC5A

Lithium-Ion Battery

Sony
Sony
TSPC106

PCI Bus Bridge Memory Controller

ATMEL
ATMEL
TP9380

NPN SILICON RF POWER TRANSISTOR

Advanced Semiconductor
Advanced Semiconductor


www.DataSheetWiki.com    |   2020   |   Contactez-nous  |   Recherche