RT9271 Просмотр технического описания (PDF) - Richtek Technology
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RT9271 Datasheet PDF : 15 Pages
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RT9271
Typical AppIication Circuit
C1
VIN
1uF
2.4 to 3.2V
LX
10uH
D1
SS0520
Dimming
Control
VCC
EN
LX
OVP
GND FB
C3
D2
1uF
R2
12
Figure 1. RT9271 Drivers 1 WLED Application Circuit
C1
VIN
1uF
2.4 to 5V
Dimming
Control
LX
10uH
D1
SS0520
VCC
EN
LX
OVP
GND FB
D2
C3
1uF
D3
R2
12
Figure 2. RT9271 Drivers 2 Series WLEDs Application Circuit
C1
VIN
1uF
2.4 to 6V
Dimming
Control
LX
10uH
D1
SS0520
VCC
EN
LX
OVP
D2
C3
D3
1uF
D4
GND FB
R2
12
Figure 3. RT9271 Drivers 3 Series WLEDs Application Circuit
Note : 1. D1 is Schottky diode (SS0520).
2. D2 ~ D4 are the WLED (HT-S91CW-DT) of HARVATEK.
3. LX is the SH4018 series of ABC TAIWAN ELECTRONICS CORP.
Recommended Circuits for Driving LEDs
Figure 1 to Figure 3 illustrates the recommended application circuits for driving white LEDs. The series connected LEDs
are driven with identical current to emit uniform luminescence, and the 250mV low reference voltage can minimize the
efficiency loss across the current-sensing resistor. The recommended current setting for driving white LEDs is 10mA to
20mA, and the dimming control can be implemented by toggling EN pin with 60Hz to 1kHz PWM clock. Please refer to
application notes for guidance of component selection and board layout.
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DS9271-13 March 2007
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