LT3796-1_14 Datasheet, PDF (1/36 Pages) –

Features
n _{3000:1 True Color PWM™ Dimming}
n _{Wide Input Voltage Range: 6V to 100V}
n _{Current Monitoring Up to 100V}
n _{High Side PMOS Disconnect and PWM Switch Driver}
n _{Constant-Current and Constant-Voltage Regulation}
n _{Dual Current Sense Amplifiers with Reporting}
n _{C/10 Detection for Battery and SuperCap Charging}
n _{Linear Current Sense Threshold Programming}
n _{Short-Circuit Protection}
n _{Adjustable Frequency: 100kHz to 1MHz}
n _{Frequency Synchronization (LT3796)}
n _{Independent Top Gate Enable Pin (LT3796-1)}
n _{Programmable Open LED Protection with VMODE Flag}
n _{Programmable Undervoltage Lockout with Hysteresis}
n _{Soft-Start with Programmable Fault Restart Timer}
n _{Available in 28-Lead TSSOP Package}
Applications
n _{High Power LED, High Voltage LED, Dual String}
n _{Battery and SuperCap Chargers}
n _{Accurate Current Limited Voltage Regulators}
LT3796/LT3796-1
100V Constant-Current and
Constant-Voltage Controller
with Dual Current Sense
Description
The LT^®3796/LT3796-1 are DC/DC controllers designed to
regulate a constant-current or constant-voltage and are
ideal for driving LEDs. The fixed frequency and current
mode architecture result in stable operation over a wide
range of supply and output voltages. Two ground referred
voltage FB pins serve as the input for several LED protec-
tion features, and also allow the converter to operate as a
constant-voltage source. The LT3796/LT3796-1 feature a
programmable threshold output current sense amplifier
with rail-to-rail common mode range. A separate high
side amplifier is gain configurable with two resistors and
can be used to regulate a second current or a voltage
in combination with one of the FB pins. The PWM input
provides LED dimming ratios of up to 3000:1.
The LT3796-1 is optimized for a second output current
regulation loop that can be enabled/disabled with a PMOS
switch, either to drive a second LED string or to extend
analog dimming range.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and 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, 7321203,
7746300.
Typical Application
V_IN
9V TO 60V
100V (TRANSIENT)
CSOUT
INTV_CC
FAULT
VMODE
Boost LED Driver with Input Current Monitor
50mΩ
22µH
2.2µF
×3
1M
118k
10nF 40.2k
100k 100k
2k
499k
97.6k
PWM
0.1µF
V_IN
EN/UVLO
V_REF
CTRL
CSOUT
PWM
ISMON
SYNC
V_S CSP
LT3796
CSN
GATE
SENSE
GND
FB1
ISP
ISN
FAULT
VMODE
V_C RT
FB2
10nF
10k
31.6k
250kHz
TG
INTV_CC
SS
0.1µF
15mΩ
INTV_CC
4.7µF
1M
13.7k
2.2µF
×4
620mΩ
85V LED
400mA
37961 TA01a
For more information www.linear.com/3796
Efficiency vs V_IN
100
95
90
85
80
75
70
0 10 20 30 40 50 60
V_IN (V)
37961 TA01b
3796fb
1