LT3796 Datasheet, PDF (1/32 Pages) Linear Technology – 100V LED Controller with Current Monitor

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}
n _{Programmable Open LED Protection with VMODE Flag}
n _{Programmable Undervoltage Lockout with Hysteresis}
n _{Soft-Start with Programmable Fault Restart Timer}
n _{Low Shutdown Current: <1μA}
n _{Available in 28-Lead TSSOP Package}
APPLICATIONS
n _{High Power LED, High Voltage LED}
n _{Battery and SuperCap Chargers}
n _{Accurate Current Limited Voltage Regulators}
LT3796
100V Constant-Current and
Constant-Voltage Controller
with Dual Current Sense
DESCRIPTION
The LT^®3796 is a DC/DC controller designed to regulate a
constant-current or constant-voltage and is ideal for driv-
ing LEDs. It drives a low side external N-channel power
MOSFET from an internal regulated 7.7V supply. The fixed
frequency and current mode architecture result in stable
operation over a wide range of supply and output volt-
ages. Two ground referred voltage FB pins serve as the
input for several LED protection features, and also allow
the converter to operate as a constant-voltage source.
The LT3796 features a programmable threshold output
sense amplifier with rail-to-rail common mode range. The
LT3796 also includes a separate high side current sensing
amplifier that is gain configurable with two resistors. The
TG pin inverts and level shifts the PWM signal to drive
the gate of the external PMOS. The PWM input provides
LED dimming ratios of up to 3000:1, and the CTRL input
provides additional analog dimming capability.
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)
C_SOUT
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
3796 TA01a
Efficiency vs V_IN
100
95
90
85
80
75
70
0 10 20 30 40 50 60
V_IN (V)
3796 TA01b
3796f
1