BL9581 Datasheet, PDF (1/16 Pages) SHANGHAI BELLING CO., LTD. – High Brightness LED Driver with Internal Switch

BL9581
36V, 1.2A Step-down
High Brightness LED Driver with Internal Switch
FEATURES
DESCRIPTION
z Simple low parts count
z Internal 36V NDMOS switch
z Up to 1.2A output current
z Single pin on/off and brightness control
using DC voltage or PWM
z Soft Start
z High efficiency (up to 97%)
z Wide input voltage range: 6V to 36V
z Output shutdown
z Up to 1MHz switching frequency
z Inherent open-circuit LED protection
z Typical 3% output current accuracy
z High-side current sense
z Hysteretic control: no compensation
z Adjustable constant LED current
z Over temperature protection
z Pb-free SOT23-5 packages
APPLICATIONS
z Low voltage halogen replacement LEDs
z Automotive lighting
z Low voltage industrial lighting
z LED back-up lighting
z Illuminated signs
z LCD TV backlighting
The BL9581 is a continuous mode inductive
step-down converter, designed for driving
single or multiple series connected LEDs
efficiently from a voltage source higher than
the LED voltage. The device operates from
an input supply between 6V and 36V and
provides an externally output current up to
1.2A. Depending upon supply voltage and
external components, this can provides up to
24 watts of output power.
The BL9581 includes the output switch and a
high-side output current sensing circuit, which
uses an external resistor to set the nominal
average output current.
Output current can be adjusted by applying
an external control signal to the 'ADJ' pin.
The ADJ pin will accept either a DC voltage
or a PWM waveform. During DC dimming,
this will provide a continuous output current
that is proportional to the external applied DC
voltage. During the PWM dimming, this will
provide a gated output current and the
average current is proportional to the duty
cycle. Applying a voltage of 0.2V or lower to
the ADJ pin turns the output off and switches
the device into a low current standby state.
ORDERING INFORMATION
BL9581 X XXX
Package:
RN: SOT23--5
Features:
P: Standard (default, lead free)
C: Customized
TYPICAL APPLICATION
VIN(6V-36V)
Rs
0.1ohm
C1 4.7uF
D1
L1 47uH
VIN
ISENSE
LX
N/C ADJ
BL9581
GND
GND
PPMIC BU
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BL9581 Rev 1.3
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2/2010
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