AOZ1960 Datasheet, PDF (1/20 Pages) Alpha & Omega Semiconductors – Multi-String Boost White LED Driver

AOZ1960
Multi-String Boost White LED Driver
General Description
The AOZ1960 is a high-efficiency boost regulator with
integrated 55V boost switch and 30V input protection
switch. It is designed to drive 6 parallel strings of multiple
series-connected white LEDs for LCD backlight
applications. The current of each string is individually
regulated by an internal current regulator. The AOZ1960
has a wide input voltage range from 7V to 24V. The
maximum LED current can be adjusted from 15mA to
30mA using an external resistor connected to ISET pin.
The AOZ1960 support two dimming control modes to
enable a wide variety of applications. In analog dimming
mode, the LED current can be directly adjusted through
ABRT pin to achieve 10% to 100% brightness range.
In digital dimming mode, a PWM signal on DBRT controls
the brightness by turning the current regulators on and
off. The brightness is proportional to the duty cycle of the
PWM signal.
The AOZ1960 has multiple features to protect the
regulator under fault conditions. An internal 30V input
protection switch protects against catastrophic failure
conditions such as output short-circuits. A separate
over-voltage protection (OVP) loop limits the output
voltage if LED strings fail open. Cycle-by-cycle
over-current protection (OCP) limits the peak inductor
current. Built-in soft-start minimizes the inrush current
during startup. Thermal shutdown provides another level
of protection.
The integrated 55V power MOSFET reduces the cost
and external component count, while allowing output
voltages as high as 55V. Low dropout voltage of LED
current regulator (500mV) minimizes power loss. In
addition, automatic pulse skipping operation improves
efficiency at light loads. The AOZ1960 features
programmable switching frequency allows for trade-offs
between solution size and electrical efficiency.
The AOZ1960 is available in a thermally enhanced
24-pin 7mm x 4mm DFN package and operates over the
temperature range of -40°C to +85°C.
Features
z 7V to 24V input voltage range
z Integrated 30V input switch
z 55V/2A internal N-channel MOSFET
z Six parallel strings
z Programmable switching frequency
z 500mV low dropout current regulator
z Resistor programmable maximum LED current
z Analog dimming via ABRT pin
z Digital PWM dimming via DBRT pin
z Dimming range with 8-bit resolution
z Cycle-by-cycle current limit
z Open and short LED protection
z Output over-voltage and short protection
z Thermal overload protection
z Internal Soft-start
z 7mm x 4mm DFN package
Applications
z Notebook PC display
z Tablet PC display
z Desktop monitors
z Portable DVD players
z Digital photo frames
z Car navigation display
Rev. 1.0 August 2010
www.aosmd.com
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