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RT9269
Tiny Package, High Efficiency, Constant Current LED Driver
General Description
The RT9269 is a compact, high efficient LED driver with high flexibility of application configurations in charge pump mode or in boost rectifier mode, delivering Tens of mA constant output current for driving 1~4 white LED's. The 0.25V low reference voltage minimized the power loss across the current-setting resistor. The wide applicable VDD range makes RT9269 suitable for 1 to 4 battery cell applications as well as being supplied with 2.5/3.3/5/6V system powers. The 500kHz high switching rate minimized the size of external components. Besides, the 17A low quiescent current together with high efficiency maintains long battery lifetime. The output current is set with 1 external resistor. And the chip enable (EN) pin can be used for tuning the LED brightness by controlling the ON/OFF duty with external clock. RT9269 is provided in SOT-23-6 package.
Features
0.25V Low Reference Voltage 17A Quiescent (Switch-off) Supply Current Zero Shutdown Mode Supply Current 85% Efficiency 500kHz Fixed Switching Rate Tuning LED brightness with EN Pin ON/OFF Duty Small SOT-23-6 Package RoHS Compliant and 100% Lead (Pb)-Free
Applications
LED Module Hand Held Panel Compact Back Light Module Small Battery Charger Constant Current Source
Pin Configurations
(TOP VIEW)
FB VDD 5 2 LX 4 3
Ordering Information
RT9269 Package Type E : SOT-23-6 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard)
6 1 EN
EXT GND
SOT-23-6 Note : There is no pin1 indicator on top mark for SOT-23-6 type, and pin 1 will be lower left pin when reading top mark from left to right.
Note : RichTek Pb-free and Green products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 100%matte tin (Sn) plating.
Marking Information
For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail.
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RT9269
Typical Application Circuit
D1 VIN C1 1uF VDD EXT RT9269 To VDD or Duty Control Brightness EN GND FB 0.25V C2 1uF
D2 C3 1uF
R1 15
R2 15
Figure 1. RT9269 drives single or parallel LED's in charge pump configuration
D1 VIN C1 1uF VDD EXT RT9269 To VDD or Duty Control Brightness EN GND FB 0.25V C2 1uF
D2 C3 1uF
R1 15
Figure 2. RT9269 drives 2 series connected LED's in charge pump configuration
VIN R1 1K
C2 10uF
L1 10uH to 100uH Q1
C1 1uF
VDD LX RT9269
C3 10uF
To VDD or Duty Control Brightness
EN GND
FB
0.25V R2 15
Figure 3. RT9269 drives 2~4 series connected LED's in boost rectifier configuration
Note: NICHIA NSCW100 is used for RT9269 LED parts.
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RT9269
Functional Pin Description
Pin No. Pin Name 1 2 3 4 5 6 EN EXT GND LX VDD FB Pin Function Chip Enable (Active High) Output Pin for Configuring Charge Pump or Driving External NMOS Ground Pin for Switching Input Positive Power Pin of RT9269 Feedback Input pin Internal Reference Voltage for the Error Amplifier is 0.25V.
Function Block Diagram
VDD RT9269 EXT LX FB 1.25V VDD R2 Shut Down EN Q2 N MOS
Over Temp. Detector
+
Loop Control Circuit
Q1 N MOS R1
GND
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RT9269
Absolute Maximum Ratings
Supply Voltage ----------------------------------------------------------------------------------------------------- -0.3V to 7V LX Pin Switch Voltage -------------------------------------------------------------------------------------------- -0.3V to (VDD +0.8V) Other I/O Pin Voltages ------------------------------------------------------------------------------------------- -0.3V to (VDD +0.3V) LX Pin Switch Current -------------------------------------------------------------------------------------------- 2.5A EXT Pin Driver Current -------------------------------------------------------------------------------------------- 200mA Power Dissipation, PD @ TA = 25C SOT-23-6 ------------------------------------------------------------------------------------------------------------ 0.25W Package Thermal Resistance SOT-23-6, JA ------------------------------------------------------------------------------------------------------- 250C/W Operating Junction Temperature ------------------------------------------------------------------------------- 125C Storage Temperature Range ------------------------------------------------------------------------------------ -65C to +150C
Electrical Characteristics
(VIN =3.3V, VDD set to 5V, Load Current = 0, TA = 25C, unless otherwise specified)
Parameter Start-UP Voltage Operating VDD Range No Load Current I (VIN) Switch-off Current I (VDD) Shutdown Current I (VIN) Feedback Reference Voltage Switching Rate Maximum Duty LX ON Resistance Current Limit Setting EXT ON Resistance to VDD EXT ON Resistance to GND EN Pin Trip Level Temperature Stability for VREF Thermal Shutdown Thermal Shutdown Hysterises
Symbol VST VDD INO LOAD ISWITCH IOFF VREF FS DMAX
Test Conditions IL = 1mA VDD pin voltage VIN = 3.3V, VOUT = 5V VIN = 6V EN Pin = 0V, VIN = 6V Close Loop, VDD = 5V VDD = 5V VDD = 5V VDD = 5V
Min -2 ----
Typ 0.98 -30 17 0.1 0.25
Max 1.05 6.5 --1
Units V V A A A V
------0.4 ----
500 75 0.4 500 5 5 0.8 50 165 10
------1.2 ----
kHz % mA V ppm/C C C
ILIMIT
VDD = 5V VDD = 5V VDD = 5V VDD = 5V
TS TSD TSD
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RT9269
Typical Operating Characteristics
Efficiency vs. Input Voltage
89
85
Efficiency vs. VIN
6LEDs, L = 33uH
4LEDs, L = 47uH
87
84
Efficiency (%)
85
Efficiency(%)
83
IOUT = 20mA
83
IOUT = 20mA
82 81 80 79
81
IOUT = 15mA
IOUT = 15mA
79 2.5 3 3.5 4 4.5 5 5.5 6
3
3.5
4
4.5
5
5.5
6
Input Voltage (V)
VIN(V)
Frequency vs. VDD
600 500
100
Efficiency vs. Input Voltage
IOUT = 20mA @VIN > 3.8V
90
Frequency(kHz) A
400 300 200 100
Efficiency (%)
80
IOUT = 15mA @VIN >
70
60
FB = GND, TA=25C
0 0 1 2 3 4 5 6
50 3
Refer tp Application Circuit Figure 2
3.5 4 4.5 5 5.5 6
VDD (V)
Input Voltage (V)
VFB vs. Ambient Temperature
256 254 252
Efficiency vs. Output Current
100 90 80
Efficiency (%)
VFB (mV)
70 60
VIN = 2.7V VIN = 4.2V VIN = 3.6V
250 248 246 244 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80
50 40 30 20 0.1 1 10 100
Ambient Temperature (C)
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Output Current (mA)
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RT9269
Power ON Waveform
VIN = 3.0V for 4LEDs
Power ON Waveform
VIN = 2.5V for 4LEDs
VIN
VIN
LX
200mA/Div
LX
200mA/Div
I IN IOUT
20mA/Div Refer tp Application Circuit Figure 3
I IN
20mA/Div
IOUT
Refer tp Application Circuit Figure 3
Time (2.5ms/Div)
Time (2.5ms/Div)
LX vs. Output Ripple
VIN = 3.0V for 4LEDs
LX vs. Output Ripple
VIN = 2.5V for 4LEDs
LX
LX
VOUT
20mA/Div
VOUT
20mA/Div
IOUT
IOUT
Refer tp Application Circuit Figure 3 Refer tp Application Circuit Figure 3
Time (500ns/Div) ((500ns/Div)
Time (1us/Div)
Power UP Waveform
Power UP Waveform
VIN
VIN
LX
VIN = 3.0V,IOUT = 20mA
LX
VIN = 2.5V,IOUT = 20mA
EN
IOUT
20mA/Div Refer tp Application Circuit Figure 3
EN
IOUT
20mA/Div Refer tp Application Circuit Figure 3
Time (250us/Div)
Time (100us/Div)
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RT9269
Power On Waveform
VEN = VIN = 3.8V IOUT = 20mA
Power Up Waveform
VEN = 1.25V VIN = 3.8V IOUT = 20mA
VEN
VEN
I IN
I IN
IOUT
Refer tp Application Circuit Figure 2
IOUT
Refer tp Application Circuit Figure 2
Time (10ms/Div)
Time (500us/Div)
EN Pin Shutdown Response
VEN = 1.25V VIN = 3.8V IOUT = 20mA
LX vs. Output Ripple
VEN = VIN = 3.8V, IOUT = 20mA
VLX I IN
VLX
IOUT VOUT IOUT
Refer tp Application Circuit Figure 2 Refer tp Application Circuit Figure 2
Time (500us/Div)
Time (1us/Div)
Power On Waveform
VEN = VIN = 3.2V IOUT = 40mA
Power Up Waveform
VIN I IN
VEN = 1.2V, VIN = 3.2V IOUT = 40mA
VIN I IN
IOUT IOUT VLX
Refer tp Application Circuit Figure 1
VLX
Refer tp Application Circuit Figure 1
Time (5ms/Div)
Time (250us/Div)
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RT9269
EN Pin Shutdown Response
VIN
VEN = 1.2V VIN = 3.2V IOUT = 40mA
LX vs. Output Ripple
VEN = VIN = 3.2V, IOUT = 40mA
I IN
VIN
IOUT VLX
Refer tp Application Circuit Figure 1
I IN VOUT
Refer tp Application Circuit Figure 1
Time (250us/Div)
Time (1us/Div)
Brightness Control
Brightness Control
VIN LX
80% Duty External Signal
VIN LX
80% Duty External Signal
EN
EN
IOUT
VIN = 3.0V IOUT = 20mA
IOUT
VIN = 2.5V IOUT = 20mA
Time (1ms/Div)
Time (1ms/Div)
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RT9269
Outline Dimension
H D L C B
b A A1 e
Symbol A A1 B b C D e H L
Dimensions In Millimeters Min 0.889 0.000 1.397 0.250 2.591 2.692 0.838 0.080 0.300 Max 1.295 0.152 1.803 0.560 2.997 3.099 1.041 0.254 0.610
Dimensions In Inches Min 0.031 0.000 0.055 0.010 0.102 0.106 0.033 0.003 0.012 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024
SOT-23-6 Surface Mount Package
Richtek Technology Corporation
Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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