LT3599_15 Datasheet, PDF (1/26 Pages) Linear Technology – 4-Channel 120mA LED Driver

LT3599
4-Channel 120mA LED Driver
with ±1.5% Current Matching
FEATURES
n _{True Color PWM}^TM _{Dimming Ratio Up to 3000:1}
n _{Drives Four Strings of LEDs at Up to 120mA}
n _{±1.5% Accurate LED Current Matching}
n _{Wide Input Voltage Range: 3.1V to 30V}
n _{Output Voltage Up to 44V}
n _{Regulates LED Current Even When VIN > VOUT}
n _{Disconnects LEDs in Shutdown}
n _{Programmable Maximum VOUT (Regulated)}
n _{Open/Short LED Protection and Fault Flags}
n _{Programmable LED Current Derating}
n _{Adjustable Frequency: 200kHz to 2.1MHz}
n _{Synchronizable to an External Clock}
n _{Analog Dimming Up to 20:1}
n _{Programmable Input UVLO with Hysteresis}
n _{Thermally Enhanced 32-Pin (5mm × 5mm) QFN and}
28-Pin TSSOP Packages
APPLICATIONS
n _{Automotive Navigation TFT LCD Displays}
n _{Desktop and Notebook TFT LCD Displays}
DESCRIPTION
The LT^®3599 is a fixed frequency 2A step-up DC/DC
converter designed to drive four strings of 120mA LEDs
up to a 44V output voltage. The switching frequency
is programmable from 200kHz to 2.1MHz through an
external resistor.
LED dimming can be achieved with analog dimming on
the CTRL pin, and with pulse width modulation dimming
on the PWM pin. The LT3599 accurately regulates LED
current even when the input voltage is higher than the
LED output voltage.
Additional features include programmable LED current
derating, switching frequency synchronization to an ex-
ternal clock, LED string disable control, OPENLED alert
pin, SHORTLED alert pins and programmable maximum
output voltage when all LED strings are disconnected.
The LT3599 is available in the thermally enhanced 32-pin
(5mm × 5mm) QFN and 28-pin TSSOP packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. True Color PWM is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 7199560.
TYPICAL APPLICATION
PV_IN
8V TO 24V
200k
3.3μF
V_IN
3.1V TO 5.5V
V_IN
V_IN
1μF
100k
100k
31.6k
PWM
33.2k
53.6k
53.6k
90% Efficient 12W LED Driver
10μH
V_IN
SW
SHORTLED
OPENLED
SHDN/UVLO
PWM
SYNC
CTRL
LT3599
RT
V_REF
V_OUT
V_{O_SW}
FB
1M
31.6k
T_SET
80.6k
DISABLE4
I_SET SS
LED1
LED2
LED3
LED4
GND VC
80mA PER STRING
16.5k
47nF
100pF
10k
2.2nF
4.7μF
s2
3599 TA01a
LED Current Matching
1.5
ALL FOUR LED STRINGS
1.0
0.5
0
–0.5
–1.0
–1.5
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3599 TA01b
3599fe
1