LED Driver. RT8561A Datasheet

RT8561A Driver. Datasheet pdf. Equivalent

RT8561A Datasheet
Recommendation RT8561A Datasheet
Part RT8561A
Description High Voltage 8-CH LED Driver
Feature RT8561A; ® RT8561A High Voltage 8-CH LED Driver General Description The RT8561Ais a 40V 8-CH LEDdriver capa.
Manufacture Richtek
Datasheet
Download RT8561A Datasheet




Richtek RT8561A
®
RT8561A
High Voltage 8-CH LED Driver
General Description
The RT8561Ais a 40V 8-CH LEDdriver capable of delivering
30mA to each channel with 10 LEDs (3.6V per diode),
total of 80 LEDs with one driver. The RT8561A is a current
mode boost converter operated at 1MHz, wide VIN range
covers from 6V to 24V and the on-chip current switch is
rated at 2.5A.
The PWM output voltage loop regulates the LED pins to
0.6V with an auto-adjustment circuit allowing voltage
mismatches between LED strings. The RT8561A automati-
cally detects and disconnects any unconnected and/or
broken strings during operation from PWM loop to prevent
VOUT from over voltage.
The 1.5% matched LED currents on all channels are simply
programmed with a resistor or a current sink. Both analog
dimming and digitally controlled PWM dimming are
supported by the RT8561A. Analog dimming is linearly
controlled by an external voltage. With an on-chip output
clamping amplifier and a 300kΩ resistor, PWM dimming
signal is easily low-pass filtered to an analog dimming
signal with one external capacitor for noise-free PWM
dimming. A very high contrast ratio true digital PWM
dimming can be achieved by driving ACTL pin with a PWM
signal.
Other protecting features include programmable output
over voltage protection, LED current limit, PWM switch
current limit and thermal shutdown.
The RT8561A is packaged with a tiny footprint package of
WQFN-24L 4x4 packages.
Ordering Information
RT8561A
Package Type
QW : WQFN-24L 4x4 (W-Type)
Note :
Lead Plating System
G : Green (Halogen Free and Pb Free)
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 High Voltage : VIN up to 24V, VOUT up to 40V, Driving
up to 80 x 3.6V LEDs (10 each channel)
z Channel Current Programmable 10mA to 30mA and
Matched to 1.5%
z Current Mode PWM 1MHz Boost Converter
z Easy Analog and Digital Dimming Control
z Programmable Soft Start
z Automatic Detecting Unconnected and/or Broken
Channel
z Programmable Over Voltage Protection
z Disconnects LED in Shutdown
z Providing High Accuracy Digital Dimming by PWM
at ACTL Pin
z VIN Under Voltage Lockout
z Over Temperature Protection
z Current Limiting Protection
z Small 24-Lead WQFN Package
z RoHS Compliant and Halogen Free
Applications
z UMPC and Notebook Computer Backlight
z GPS, Portable DVD Backlight
z Desk Lights and Room Lighting
Pin Configurations
(TOP VIEW)
24 23 22 21 20 19
LED1 1
18 VCC
LED2 2
17 CREG
LED3 3
LED4 4
GND
16 LED8
15 LED7
LED5 5
OVP 6
14 LED6
25 13 EN
7 8 9 10 11 12
WQFN-24L 4x4
Marking Information
CZ= : Product Code
CZ=YM
DNN
YMDNN : Date Code
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8561A-02 April 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



Richtek RT8561A
RT8561A
Typical Application Circuit
VIN
6V to 24V
L
10µH
D
VOUT
40V MAX
R10VIN1
CVIN1
10µF
COUT
10µF
RT8561A
...: :
::
::
::
:
:
:
:
10
LED
String
:: ::
19, 20 SW
18 VCC
CVIN1
2.2µF
5V
1k
13 EN
VOUT
R1
R2
6 OVP
4.7µF
0.1µF
1R.V8Ck
C3.V9CnF
17 CREG
9 SS
7 VC
12 DCTL
LED1 1
LED2 2
LED7 15
LED8 16
RISET 10
.
.
.
RISET
4.75k
ILED (mA) =
20 x 4.75
RISET (k)
GND 21, 22, 23, 24, 25 (Exposed Pad)
ACTL 11 1k
PWM Signal
Figure 1. 1MHz, 20mA Full Scale Current PWM Dimming Control
VIN
6V to 24V
10LµH
D
VOUT
40V MAX
R10VIN1
CVIN1
10µF
COUT
10µF
RT8561A
...:: ::
::
:
:
:
::
:
10
LED
String
:: ::
19, 20 SW
18 VCC
CVIN1
2.2uF
5V
1k
13 EN
VOUT
R1
R2
6 OVP
4.7µF
0.1µF
RVC
1.8k
17 CREG
9 SS
7
12
VC
DCTL
LED1 1
LED2 2
LED7 15
LED8 16
RISET 10
.
.
.
RISET
4.75k
ILED (mA) =
20 x 4.75
RISET (k)
GND 21, 22, 23, 24, 25 (Exposed Pad)
ACTL 11 1k
Analog
Dimming
CVC
3.9nF
DCTL can be floating or
connected to ACTL
Figure 2. 1MHz, 20mA Full Scale Current Analog Dimming Control
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8561A-02 April 2012



Richtek RT8561A
RT8561A
VIN
6V to 24V
L
10µH
D
VOUT
40V MAX
R10VIN1
CVIN1
10µF
COUT
10µF
RT8561A
...: :
::
::
::
::
:
:
:
:
:
10
LED
String
:
CVIN1
2.2µF
VOUT
19, 20 SW
18 VCC
5V 1k 13 EN
R1 6 OVP
R2
4.7µF
0.1µF
1R.V8Ck
3C.V9CnF
17 CREG
9 SS
7 VC
1k 12 DCTL
LED1 1
LED2 2
LED7 15
LED8 16
RISET 10
.
.
.
RISET
4.75k
ILED (mA) =
20 x 4.75
RISET (k)
GND 21, 22, 23, 24, 25 (Exposed Pad)
ACTL 11
0.1µF
PWM Signal
Figure 3. 1MHz, 20mA Full Scale Current PWM to Analog Dimming Control
VIN
4V to 36V
L
10µH
D
VOUT
40V MAX
Note :
VAVDD
6V to 24V
R10VIN1
CVIN1
2.2µF
CVIN1
10µF
COUT
10µF
RT8561A
19, 20 SW
:
:
:
:
:
:
...
:
:
:
:: :
18 VCC
5V 1k 13 EN
LED1 1
LED2 2
.
.
:
::10 LED String
:
VOUT
R1
R2
4.7µF
6 OVP
17 CREG
9 SS
LED7 15
LED8 16
RISET 10
.
RISET
4.75k
ILED (mA) =
20 x 4.75
RISET (k)
0.1µF
1R.V8Ck
C3.V9CnF
7 VC
12 DCTL
GND 21, 22, 23, 24, 25 (Exposed Pad)
ACTL 11
PWM Signal
1. Due to the limitation of maximum duty 5V input can support typically to VOUT = 33V.
2. Due to the limitation of maximum duty 4V input can support typically to VOUT = 26V.
Figure 4. Wide Range VIN Application by Connecting VCC Pin to LCD Driver Power AVDD
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8561A-02 April 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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