|
|
PDF RT9292 Data sheet ( Hoja de datos )
| Número de pieza | RT9292 | |
| Descripción | Asyn-Boost Converter | |
| Fabricantes | Richtek Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de RT9292 (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
|
No Preview Available !
RT9292
Small Package, High Performance, Asyn-Boost Converter
for 6 White LEDs
General Description
The RT9292 is a high frequency and high efficiency
asynchronous boost converter for WLED driving
application. It integrates a 28V MOSFET to support up to
6 White LEDs for panel backlighting and OLED power
applications. Besides, an internal soft start function is
integrated to reduce the inrush current. Moreover, the
device operates with 1MHz fixed switching frequency for
the use of small external components and better EMI
performance. For lower voltage application, the IC provides
a 26V over voltage protection function for using the low-
cost and small output capacitors. The LED current is
initially set by the external sense resistor (RSET), and the
feedback voltage for the RT9292 series will be 104mV
and 330mV respectively. The RT9292 is available in TSOT-
23-6 and WDFN-8L 2x2 tiny packages to achieve best
solution for PCB space and total BOM cost saving
considerations.
Ordering Information
RT9292
Package Type
J6 : TSOT-23-6
QW : WDFN-8L 2x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Note :
Feedback Reference Voltage
B : 104mV
D : 330mV
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.
Features
z VIN Operating Range : 2.5V to 5.5V
z 28V Internal Power N-MOSFET Switch
z Wide Range PWM Dimming (200Hz to 200kHz)
z Minimize the External Component Counts
z Internal Soft Start
z Internal Compensation
z Under Voltage Protection
z Over Voltage Protection
z Over Temperature Protection
z Internal Schottky Diode
z Small TSOT-23-6 and 8-Lead WDFN Packages
z RoHS Compliant and Halogen Free
Applications
z Cellular Phones
z Digital Cameras
z PDAs and Smart Phones and MP3 and OLED.
z Portable Instruments
Pin Configurations
(TOP VIEW)
VIN VOUT EN
654
23
LX GND FB
TSOT-23-6
GND
VIN
VOUT
EN
1
2
3
4
8 LX
7 NC
9
6 FB
5 GND
WDFN-8L 2x2
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
DS9292-02 April 2011
www.richtek.com
1
1 page  
Typical Operating Characteristics
90
85
80
75
70
65
60
55
50
00
Efficiency vs. Output Current
VIN = 4.2V
VIN = 3.7V
VIN = 3V
0.0505
VOUT = 20V, L = 22uH
0.1001 0.01155 02.002 0.20525
OOuutptpuuttCCuurrreenntt((mAA) )
03.03
90
85
80
75
70
65
60
55
50
0
Efficiency vs. Output Current
VIN = 4.2V
VIN = 3.7V
VIN = 3V
0.005
VOUT = 20V, L = 33uH
0.01 0.015 0.02
Output Current (A)
0.025
0.03
Output Voltage vs. Output Current
22
20
18
16
14
12
VIN = 3.7V
10
5 7.5 10 12.5 15 17.5 20 22.5 25 27.5 30
Output Current (mA)
DS9292-02 April 2011
RT9292
90
85
80
75
70
65
60
55
50
2.5
Efficiency vs. Input Voltage
Load = 30mA
Load = 10mA
Load = 20mA
VOUT = 20V, L = 22uH
3 3.5 4 4.5 5 5.5
Input Voltage (V)
Efficiency vs. Input Voltage
90
85
Load = 10mA
80
75
70
Load = 20mA
65
60
55
Load = 30mA
50
45
VOUT = 20V, L = 33uH
40
2.5 3 3.5 4 4.5 5 5.5
Input Voltage (V)
Quiescent Current vs. Input Voltage
700
650
600
550
500
450
400
350
300
250
200
2.6 3.1 3.6 4.1 4.6 5.1
Input Voltage (V)
www.richtek.com
5
5 Page 
RT9292
Current Limiting
The current flow through inductor as charging period is
detected by a current sensing circuit. As the value comes
across the current limiting threshold, the N-MOSFET will
be turned off so that the inductor will be forced to leave
charging stage and enter discharging stage. Therefore,
the inductor current will not increase over the current
limiting threshold.
OVP/UVLO/OTP
The Over Voltage Protection is detected by a junction
breakdown detecting circuit. Once VOUT goes over the
detecting voltage, LX pin stops switching and the power
N-MOSFET will be turned off. Then, the VOUT will be
clamped to be near VOVP. As the output voltage is higher
than a specified value or input voltage is lower than a
specified value, the chip will enter protection mode to
prevent abnormal function. As the die temperature >
160°C, the chip also will enter protection mode. The power
MOSFET will be turned off during protection mode to
prevent abnormal operation.
Inductor Selection
The recommended value of inductor for 6 WLEDs
applications is from 10uH to 33uH. Small size and better
efficiency are the major concerns for portable devices,
such as the RT9292 used for mobile phone. The inductor
should have low core loss at 1MHz and low DCR for better
efficiency. The inductor saturation current rating should
be considered to cover the inductor peak current.
Capacitor Selection
Input ceramic capacitor of 2.2uF and output ceramic
capacitor of 1uF are recommended for the RT9292
applications for driving 6 series WLEDs. For better voltage
filtering, ceramic capacitors with low ESR are
recommended. X5R and X7R types are suitable because
of their wider voltage and temperature ranges.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum operation junction temperature. The maximum
power dissipation depends on the thermal resistance of
IC package, PCB layout, the rate of surroundings airflow
and temperature difference between junction to ambient.
The maximum power dissipation can be calculated by
following formula :
PD(MAX) = ( TJ(MAX) − TA ) / θJA
Where TJ(MAX) is the maximum operation junction
temperature, TAis the ambient temperature and the θJAis
the junction to ambient thermal resistance.
For recommended operating conditions specification of
RT9292, the maximum junction temperature of the die is
125°C. The junction to ambient thermal resistance θJA is
layout dependent. The junction to ambient thermal
resistance for TSOT-23-6 package is 255°C/W and WDFN-
8L 2x2 package is 165°C/W on the standard JEDEC 51-3
single-layer thermal test board. The maximum power
dissipation at TA = 25°C can be calculated by following
formula :
PD(MAX) = (125°C − 25°C) / (165°C/W) = 0.606W for
WDFN-8L 2x2 packages
PD(MAX) = (125°C − 25°C) / (255°C/W) = 0.392W for
TSOT-23-6 packages
The maximum power dissipation depends on operating
ambient temperature for fixed TJ(MAX) and thermal
resistance θJA. For RT9292 packages, the Figure 6 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
0.8
0.7
WDFN-8L 2x2
0.6
Single Layer PCB
0.5
TSOT-23-6
0.4
0.3
0.2
0.1
0
0 25 50 75 100 125
Ambient Temperature (°C)
Figure 6. Derating Curves for RT9292 Packages
DS9292-02 April 2011
www.richtek.com
11
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet RT9292.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| RT9292 | Asyn-Boost Converter | Richtek Technology |
| RT9293 | Asynchronies Boost for 10 WLED Driver | Richtek Technology |
| RT9296 | Synchronous Boost Converter | Richtek Technology |
| RT9297 | 3A High Performance Step-Up DC/DC Converter | Richtek Technology |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |