Moteur de recherche de fiches techniques de composants électroniques
  French  ▼
ALLDATASHEET.FR

X  

LM2621 Fiches technique(PDF) 6 Page - Texas Instruments

No de pièce LM2621
Description  LM2621 Low Input Voltage, Step-Up DC-DC Converter
Download  18 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  TI [Texas Instruments]
Site Internet  http://www.ti.com
Logo TI - Texas Instruments

LM2621 Fiches technique(HTML) 6 Page - Texas Instruments

Back Button LM2621_15 Datasheet HTML 2Page - Texas Instruments LM2621_15 Datasheet HTML 3Page - Texas Instruments LM2621_15 Datasheet HTML 4Page - Texas Instruments LM2621_15 Datasheet HTML 5Page - Texas Instruments LM2621_15 Datasheet HTML 6Page - Texas Instruments LM2621_15 Datasheet HTML 7Page - Texas Instruments LM2621_15 Datasheet HTML 8Page - Texas Instruments LM2621_15 Datasheet HTML 9Page - Texas Instruments LM2621_15 Datasheet HTML 10Page - Texas Instruments Next Button
Zoom Inzoom in Zoom Outzoom out
 6 / 18 page
background image
LM2621
SNVS033C – MAY 2004 – REVISED MARCH 2005
www.ti.com
DETAILED DESCRIPTION
OPERATING PRINCIPLE
The LM2621 is designed to provide step-up DC-DC voltage regulation in battery-powered and low-input voltage
systems. It combines a step-up switching regulator, N-channel power MOSFET, built-in current limit, thermal
limit, and voltage reference in a single 8-pin VSSOP package Figure 13. The switching DC-DC regulator boosts
an input voltage between 1.2V and 14V to a regulated output voltage between 1.24V and 14V. The LM2621
starts from a low 1.1V input and remains operational down to 0.65V.
This device is optimized for use in cellular phones and other applications requiring a small size, low profile, as
well as low quiescent current for maximum battery life during stand-by and shutdown. A high-efficiency gated-
oscillator topology offers an output of up to 1A.
Additional features include a built-in peak switch current limit, and thermal protection circuitry.
Figure 13. Functional Diagram
GATED OSCILLATOR CONTROL SCHEME
A unique gated oscillator control scheme enables the LM2621 to have an ultra-low quiescent current and
provides a high efficiency over a wide load range. The switching frequency of the internal oscillator is
programmable using an external resistor and can be set between 300 kHz and 2 MHz.
This control scheme uses a hysteresis window to regulate the output voltage. When the output voltage is below
the upper threshold of the window, the LM2621 switches continuously with a fixed duty cycle of 70% at the
switching frequency selected by the user. During the first part of each switching cycle, the internal N-channel
MOSFET switch is turned on. This causes the current to ramp up in the inductor and store energy. During the
second part of each switching cycle, the MOSFET is turned off. The voltage across the inductor reverses and
forces current through the diode to the output filter capacitor and the load. Thus when the LM2621 switches
continuously, the output voltage starts to ramp up. When the output voltage hits the upper threshold of the
window, the LM2621 stops switching completely. This causes the output voltage to droop because the energy
stored in the output capacitor is depleted by the load. When the output voltage hits the lower threshold of the
hysteresis window, the LM2621 starts switching continuously again causing the output voltage to ramp up
towards the upper threshold. Figure 14 shows the switch voltage and output voltage waveforms.
6
Submit Documentation Feedback
Copyright © 2004–2005, Texas Instruments Incorporated
Product Folder Links: LM2621


Numéro de pièce similaire - LM2621_15

FabricantNo de pièceFiches techniqueDescription
logo
Texas Instruments
LM2621 TI1-LM2621_15 Datasheet
507Kb / 17P
[Old version datasheet]   Low Input Voltage, Step-Up DC-DC Converter
More results

Description similaire - LM2621_15

FabricantNo de pièceFiches techniqueDescription
logo
Texas Instruments
LM2621MM TI-LM2621MM Datasheet
1Mb / 17P
[Old version datasheet]   LM2621 Low Input Voltage, Step-Up DC-DC Converter
logo
National Semiconductor ...
LM2621 NSC-LM2621_05 Datasheet
655Kb / 11P
   Low Input Voltage, Step-Up DC-DC Converter
LM2621 NSC-LM2621 Datasheet
254Kb / 10P
   Low Input Voltage, Step-Up DC-DC Converter
logo
Texas Instruments
LM2621 TI1-LM2621_14 Datasheet
1Mb / 16P
[Old version datasheet]   Low Input Voltage, Step-Up DC-DC Converter
LM2621 TI1-LM2621_15 Datasheet
507Kb / 17P
[Old version datasheet]   Low Input Voltage, Step-Up DC-DC Converter
logo
Semtech Corporation
SC1633 SEMTECH-SC1633 Datasheet
181Kb / 7P
   LOW VOLTAGE STEP-UP DC-DC CONVERTER
logo
List of Unclassifed Man...
AIC1641 ETC-AIC1641 Datasheet
160Kb / 12P
   LOW VOLTAGE STEP-UP DC/DC CONVERTER
logo
Silicon Standard Corp.
SS6640 SSC-SS6640 Datasheet
336Kb / 12P
   Low Voltage Step-Up DC/DC Converter
logo
Analog Intergrations Co...
AIC1640 AIC-AIC1640 Datasheet
37Kb / 2P
   LOW VOLTAGE STEP-UP DC/DC CONVERTER
logo
Semtech Corporation
SC1631 SEMTECH-SC1631 Datasheet
168Kb / 7P
   LOW VOLTAGE STEP-UP DC-DC CONVERTER
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18


Fiches technique Télécharger

Go To PDF Page


Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com