|
|
PDF LT3599 Data sheet ( Hoja de datos )
| Número de pieza | LT3599 | |
| Descripción | 4-Channel 120mA LED Driver | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT3599 (archivo pdf) en la parte inferior de esta página. Total 24 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
LT3599
4-Channel 120mA LED Driver
with ±1.5% Current Matching
FEATURES
DESCRIPTION
n True Color PWMTM 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
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.
LT, LTC and LTM 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
90% Efficient 12W LED Driver
PVIN
8V TO 24V
10μH
200k
3.3μF
VIN
VIN
3.1V TO 5.5V
VIN
1μF
100k
100k
31.6k
PWM
33.2k
53.6k
52.3k
VIN SW
SHORTLED
OPENLED
SHDN/UVLO
PWM
SYNC
CTRL
LT3599
RT
VREF
220pF
VOUT
VO_SW
1M
FB
31.6k
TSET
80.6k
DISABLE4
ISET SS
LED1
LED2
LED3
LED4
GND VC
80mA PER STRING
16.5k
47nF
2k
10nF
100pF
3599 TA01a
4.7μF
s2
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
TEMPERATURE (°C)
100 125
3599 TA01b
3599f
1
1 page  
www.DataSheet4U.com
LT3599
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise specified
SHDN/UVLO Pin Turn-On
Threshold (VSD_UVLO)
1.45
1.40
1.35
1.30
1.25
–50
–25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G01
SHDN/UVLO Pin
(Hysteresis) Current
6
5
JUST BEFORE PART TURN-ON
4
3
2
1
AFTER PART TURN-OFF
0
–50 –25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G02
VIN Current (Shutdown)
500
450
400
350
300
250
200
VIN = 30V
150
100
50 VIN = 3V
0
–50 –25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G03
VREF
1250
1240
1230
1220
VIN = 30V
VIN = 3V
1210
–50
–25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G04
Switching Frequency
3.0
Switching Frequency vs RT
10000
2.5
2.1MHz
2.0
1.5
1MHz
1.0
1000
0.5
0.2MHz
0
–50 –25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G05
100
10
100
RT (k)
1000
3599 G06
LED Current vs CTRL Pin
120
ISET = 13.3k
100
80
60
40
20
0
0 0.2 0.4 0.6 0.8 1.0 1.2
CTRL PIN VOLTAGE (V)
3599 G07
Soft-Start Pin Current
13
12
11
10
9
8
7
–50 –25 0 25 50 75 100 125
JUNCTION TEMPERATURE (°C)
3599 G08
3599f
5
5 Page 
www.DataSheet4U.com
LT3599
APPLICATIONS INFORMATION
The companies below offer Schottky diodes with high
voltage and current ratings. Standard silicon diodes (PN
junction diodes) should not be used.
Table 3. Suggested Diodes
PART
MAX
CURRENT
(A)
MAX REVERSE
VOLTAGE
(V)
MANUFACTURER
B250A
DFLS240
B240A
B350A
B340A
2
2
2
3
3
50 Diodes, Inc.
40 www.diodes.com
40
50
40
HSM150G
HSM150J
HSM350G
1
1
3
50 Microsemi
50 www.microsemi.com
50
Overvoltage Protection
The LT3599 uses the FB pin to provide overvoltage protec-
tion. A resistor divider is connected between the VO_SW
pin and ground (Figure 2). There is an internal PMOS
switch between VOUT and VO_SW, which is controlled by
the PWM signal. The PMOS switch addition prevents the
feedback resistor divider from draining the output capaci-
tor during PWM off-period, allowing for a higher dimming
range without falsely tripping the OPENLED flag. It also
reduces the system current in shutdown. This PMOS has
about 1k resistance, so select FB resistor values taking
this resistance into account.
To set the maximum output voltage, select the values
of R1 and R2 (see Figure 2) according to the following
equation:
VOUT(MAX)
=
1.223V
⎛
⎝⎜
1+
R2 ⎞
R1⎠⎟
LT3599
FB
VOUT
VO_SW
R2
R1
3599 F02
Figure 2. Overvoltage Protection Voltage Feedback Connections
The output voltage should be set 10% higher than the
normal LED string operating voltage. Under normal
operation, LED1 to LED4 pin voltages are monitored and
provide feedback information to the converter for output
voltage regulation given the programmed LED current.
The output voltage regulation loop is activated only when
all LEDs are open.
Programming Maximum LED Current
Maximum LED current can be programmed by placing a
resistor between the ISET pin and ground (RISET). The ISET
pin resistor can be selected from 11k to 44.2k.
The LED current can be programmed according to the
following equation:
ILED
≈ 1330
RISET
(Amps)
(CTRL > 1V)
See Table 4 and Figure 3 for resistor values and corre-
sponding programmed LED current.
LED current can also be adjusted by programming the
CTRL pin voltage.
Table 4. RISET Value Selection for LED Current
LED CURRENT (mA)
RESISTOR ON ISET PIN (k)
30mA
44.2
50mA
26.7
99mA
13.3
120mA
11
120
100
80
60
40
20
0
0 20 40 60 80 100 120 140 160
RISET (k)
3599 F03
Figure 3. RISET Value Selection for LED Current
3599f
11
11 Page | ||
| Páginas | Total 24 Páginas | |
| PDF Descargar | [ Datasheet LT3599.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT3590 | 48V Buck Mode LED Driver | Linear Technology |
| LT3591 | White LED Driver | Linear Technology |
| LT3592 | 500mA Wide Input Voltage Range Step-Down LED Driver | Linear Technology |
| LT3593 | 1MHz White LED Driver | Linear Technology |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |