|
|
PDF RT8474 Data sheet ( Hoja de datos )
| Número de pieza | RT8474 | |
| Descripción | High Voltage Multiple-Topology LED Driver | |
| Fabricantes | Richtek | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de RT8474 (archivo pdf) en la parte inferior de esta página. Total 12 Páginas | ||
|
No Preview Available !
®
RT8474
High Voltage Multiple-Topology LED Driver with Dimming Control
General Description
The RT8474 is a current-mode LED driver supporting wide
input voltage range from 4.5V to 50V and output voltage
up to 50V. With internal 500kHz operating frequency, the
size of the external PWM inductor and input/output
capacitors can be minimized. High efficiency is achieved
by a 100mV current sensing control. LED dimming control
can be done from either analog or PWM signal. The RT8474
provides an internal soft-start function to avoid inrush
current and thermal shutdown to prevent the device from
overheat.
The RT8474 is available in the SOP-8 (Exposed pad)
package.
Ordering Information
RT8474
Package Type
SP : SOP-8 (Exposed-Option 2)
Lead Plating System
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.
Features
High Voltage : VIN Up to 50V, VOUT Up to 50V
Support Multiple-Topologies (Buck / Boost / Buck-
Boost)
Built-In 2A Power Switch
Current-Mode PWM Control
500kHz Fixed Switching Frequency
Analog or PWM Control Signal for LED Dimming
Internal Soft-Start to Avoid Inrush Current
Under-Voltage Lockout
Thermal Shutdown
RoHS Compliant and Halogen Free
Applications
Desk Lights and Room Lighting
Industrial Display Backlight
Marking Information
RT8474
GSPYMDNN
RT8474GSP : Product Number
YMDNN : Date Code
Pin Configurations
(TOP VIEW)
VCC
ISP
ISN
NC
8
27
GND
36
9
45
CREG
SW
CTL
VC
SOP-8 (Exposed Pad)
Simplified Application Circuit
VIN
R3 C1
Analog Dimming
or PWM Dimming
C5
RT8474
VCC
ISP
ISN
CTL
R1
R2
C2
VC
SW
CREG
C3
GND
D1
RSENSE
L1
C4
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8474-04 April 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1
1 page  
Typical Application Circuit
Buck Configuration
VIN
4.5V to 50V
Analog Dimming
or PWM Dimming
R2
5.1M
R3
10
C5
1µF
R1
10k
C2
3.3nF
D1
C1
RT8474
R4
1 VCC
(Short
ISP 2 Option)
RSENSE
100mV
6 CTL
ISN 3 R5 (Short Option)
5 VC
8 CREG
C3
1µF GND
SW 7
9 (Exposed Pad)
L1
Note : VIN, VSW, VISP, VISN < 50V
Boost Configuration
RT8474
C4
VIN
R2
10
C1
10µF
L1
22µH
RT8474
R1
D1 0.1
C4
1µF
VLED
50V (MAX)
1 VCC
SW 7
Analog Dimming
or PWM Dimming
C3
1µF
6 CTL
ISP 2
20R
51R
R3
10k
C5
3.3nF
5 VC
ISN 3
8 CREG
C2
1µF GND
9 (Exposed Pad)
VZ
VF > VLED
Note :
1. VIN, VSW, VISP, VISN < 50V
2. VLED : the voltage across the LED string
3. Vz : Zener diode breakdown voltage
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8474-04 April 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
5
5 Page 
RT8474
Layout Considerations
PCB layout is very important when designing power
switching converter circuits. Some recommended layout
guide lines are as follows :
The power components L1, D1 and C4 must be placed
as close to each other as possible to reduce the ac
current loop area. The PCB trace between power
components must be as short and wide as possible
due to large current flow through these traces during
operation.
Place L1 and D1 as close to each other as possible.
The trace should be as short and wide as possible.
The input capacitor C5 must be placed as close to the
VCC pin as possible.
Place the compensation components to the VC pin as
close as possible to avoid noise pickup.
VIN power trace to ISP
must be wide and short.
VIN
Keep the ISP and ISN with
the Kelvin sense connection.
ISP
RSENSE
Locate input capacitor as
close to VCC as possible.
R3
GND
VCC
C5 ISP
ISN
GND NC
8
27
GND
36
9
45
Locate the compensation
components to VC pin as
close as possible.
C1 ISN
D1
C4
C3
CREG
SW
L1
CTL Place these components
VC as close as possible.
R1 Normal trace.
R2
C2
Power trace must be wide
and short when compared
to the normal trace.
GND
Figure 2. PCB Layout Guide
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8474-04 April 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
11
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet RT8474.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| RT8470 | High Brightness LED Driver | Richtek |
| RT8471 | High Brightness LED Driver | Richtek |
| RT8472 | High Brightness LED Driver | Richtek |
| RT8473 | High Brightness LED Driver | Richtek |
| 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 |