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PDF RT9278 Data sheet ( Hoja de datos )
| Número de pieza | RT9278 | |
| Descripción | High Efficiency Boost LDO Converter & High Power White LED Driver | |
| Fabricantes | Richtek | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de RT9278 (archivo pdf) en la parte inferior de esta página. Total 13 Páginas | ||
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®
RT9278
High Efficiency Boost LDO Converter & High Power White
LED Driver
General Description
Features
The RT9278 is a compact, high efficiency, synchronous
step-up converter, it provides a power supply solution for
products powered by either two-cell, three-cell Alkaline/
NiMH or one-cell Li-Ion/Li-polymer battery.
The RT9278 is boost converter with PWM control loop,
provide up to 95% efficiency by using a synchronous
rectifier. The maximum peak current in the internal switch
is limited to up to 2A.
It keeps the output voltage regulated when the input
voltage exceeds the setting output voltage. The output
voltage can be set by an external resister divider, or be
fixed to reduce external components. It integrates a linear
controller for linear regulator.
RT9278 is available in VDFN-10L 3x3 package.
Ordering Information
RT9278
Package Type
QV : VDFN-10L 3x3 (V-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Note :
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
95% Efficiency Synchronous Boost Converter
High Supply Capability
2A Current Limit
Input Voltage Range : 1.5V to 5.5V
600kHz Fixed Switching Rate
Adjustable Output Voltage Options Up to 5.5V
Output Voltage Keep Regulated when Input Voltage
Exceed Setting Output Voltage
1uA Supply Current in Shutdown Mode
External Compensation Network
Build in Linear Controller for Linear Regulator
Over Temperature Protection
Small 10-Lead VDFN Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Digital Still Camera
Camera White LED Flash Light
PDAs
Portable Device
Marking Information
RT9278PQV
AC- : Product Code
AC-YM
DNN
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
FB
COMP
GND
EN
LX
1
2
3
4
5
GND
11
10 LFB
9 LDRI
8 PGND
7 VDD
VOUT
RT9278QQV
AC=YM
DNN
AC= : Product Code
YMDNN : Date Code
VDFN-10L 3x3
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS9278-07 January 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
1 page  
RT9278
Functional Pin Description
Pin No.
Pin Name
Pin Function
1 FB
Feedback Input Pin.
2
COMP
Feedback Compensation Pin.
3 GND Ground.
4 EN
Enable Input Pin
5 LX
Switch Node.
6
VOUT
Output Pin
7 VDD Device Input Power Pin.
8
PGND
Power Ground.
9 LDRI Linear Controller Driver Output.
10 LFB
Linear Controller Feedback Input.
11 (Exposed Pad) GND
The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Function Block Diagram
COMP
FB
VDD
GND
EN
VREF = 0.8V
Error
AMPLIFIER
-
+
Error
Comparator
-
+
Oscillator
and
Shutdown
Control
Slope
Compen-
sation
LFB
VREF = 0.2V
-
+
Control
and
Driver
Logic
Current
Sense
VOUT
LX
PGND
LDRI
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS9278-07 January 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
5 Page 
Normal Operation
VOUT
VIN
(10mV/Div)
(1V/Div)
VLX
(5V/Div)
IIN
(500mA/Div)
VIN = 4.2V, VOUT = 5V, ILOAD = 300mA
Time (1μs/Div)
Load Transient Regulation
VIN = 4.2V, VOUT = 5V, ILOAD = 100mA to 400mA
400
200
0
100
0
-100
Time (1ms/Div)
Flash LED
VIN = 3.77V, Power LED = 200mA to 700mA
VIN
GPIO
ILED
IIN
(2V/Div)
(100mV/Div)
(500mA
/Div)
(500mA/Div)
Mode Transition
Time (10ms/Div)
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS9278-07 January 2012
RT9278
Load Transient Regulation
VIN = 1.5V, VOUT = 5V, ILOAD = 100mA to 300mA
400
200
0
50
0
-50
Time (1ms/Div)
Flash LED
VIN = 3.0V, Power LED = 200mA to 700mA
VIN
(100mV/Div)
(2V/Div)
GPIO
ILED
(500mA
/Div)
IIN (500mA/Div)
Time (10ms/Div)
Flash LED
VIN = 4.3V, Power LED = 200mA to 700mA
VIN
(100mV/Div)
GPIO
(2V/Div)
(500mA/Div)
ILED
IIN (500mA/Div)
Time (10ms/Div)
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet RT9278.PDF ] | |
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