AOZ1934 Datasheet, PDF (1/14 Pages) Alpha & Omega Semiconductors – High Efficiency Boost 20-, 30- LED Driver

AOZ1934/1935
High Efficiency Boost 20-, 30- LED Driver
General Description
The AOZ1934/5 is an ideal power solution for white LED
backlighting for medium to small size LCD panels. It is a
highly integrated step up DC-DC converter with input
voltage range from 2.7V to 25V, accommodating
1-, 2-, 3-, or 4-cell lithium ion batteries or 3.3V, 5V, 12V
or 20V regulated supplies. The AOZ1934/5 integrates a
40V power MOSFET as well as compensation and soft
start circuitry, which results in a simpler and smaller
solution with much fewer external components. A high
switching frequency (800kHz) allows the use of a smaller
inductor and capacitor to further reduce the solution size.
Each of the regulated current sinks in the AOZ1934/5
provides 20mA factory programmed current. With a
maximum of 40V at the output of the step-up converter,
each string can connect up to ten LEDs in series, for a
total of 20 LEDs for AOZ1934 and 30 LEDs for AOZ1935.
The AOZ1934/5 is equipped with fast PWM dimming
control for wide dimming range and has an enable pin for
IC ON/OFF control. Various protection features are built
into the AOZ1934/5, including cycle-by-cycle input
current limit protection, output over-voltage protection,
LED fault (open or short) protection and thermal
shutdown protection. The leakage current in shutdown
mode is 0.1µA.
The AOZ1934/5 is available in a 16-lead 3 x 3 x 0.75mm
thin QFN package.
Features
z Wide input range: 2.7V to 25V
z Drive up to 30 LEDs
– AOZ1934 up to 20 LEDs (10s2p)
– AOZ1935 up to 30 LEDs (10s3p)
z Up to 92% efficiency
z High frequency step-up converter (800kHz)
z Highly integrated solution
– Integrated 40V Power MOSFET
– Internal compensation and soft start
z Integrated current sinks:
AOZ1934 – 2 channels, AOZ1935 – 3 channels
– ±2% Typ. current accuracy
– 1.5% Typ. current matching
z PWM dimming with <1µs delay time
z Low operating quiescent current (500µA)
z LED open/short protection
z Both internal fixed and external adjustable
Over-voltage protection
z Cycle-by-cycle inductor current limit (2.5A)
z 0.1µA shutdown current
z Green Package: 3 x 3 QFN-16
z -40°C to +85°C temperature range
Applications
z Netbook
z Tablet PCs
z GPS
z Portable media players
z 1-, 2-, 3-, 4-cell Li Ion LED applications
Rev. 1.0 August 2010
www.aosmd.com
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