LT3791_15 Datasheet, PDF (1/28 Pages) Linear Technology – 60V 4-Switch Synchronous Buck-Boost LED Driver Controller

Features
n _{4-Switch Single Inductor Architecture Allows VIN}
Above, Below or Equal to V_OUT
n _{Synchronous Switching: Up to 98.5% Efficiency}
n _{Wide VIN Range: 4.7V to 60V}
n _{Wide VOUT Range: 0V to 60V (52V LED)}
n _{±6% LED Current Accuracy: 0V ≤ VLED < 52V}
n _{True Color PWM™ and Analog Dimming}
n _{LED and Input Current Regulation with Current}
Monitor Outputs
n _{No Top MOSFET Refresh in Buck or Boost}
n _{VOUT Disconnected From VIN During Shutdown}
n _{Open or Shorted LED Fault Protection}
n _{Capable of 100W or Greater per IC}
n _{38-Lead TSSOP with Exposed Pad}
Applications
n _{Automotive Head Lamps/Running Lamps}
n _{General Purpose Lighting}
LT3791
60V 4-Switch Synchronous
Buck-Boost LED Driver
Controller
Description
The LT^®3791 is a synchronous 4-switch buck-boost LED
driver controller. The controller can regulate LED current
up to 52V of LED string with input voltages above, below,
or equal to the output voltage. The constant-frequency,
forced-continuous current mode architecture allows its
frequency to be adjusted or synchronized from 200kHz to
700kHz. No top MOSFET refresh switching cycle is needed
in buck or boost operation. With 60V input, 60V output
capability and seamless transitions between operating
regions, the LT3791 is ideal for LED driver applications in
automotive, industrial, and even battery-powered systems.
The LT3791 provides input current monitor, LED current
monitor, and open or shorted LED fault condition, during
which the LT3791 either restarts or latches off.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered and True Color PWM
is a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
Typical Application
98.5% Efficient 100W (33.3V 3A) Buck-Boost LED Driver
V_IN
15V TO 58V
499k
15.8k
28k
0.003Ω
V_IN
1µF
INTV_CC
50Ω
470nF
IVINN
IVINP
INTV_CC
EN/UVLO
OVLO
200k 200k
LT3791
BST2
BST1
TG1
SWI
BG1
SNSP
SHORTLED
OPENLED
SNSN
PGND
PWM
BG2
IVINMON
SW2
ISMON
CLKOUT
TG2
FB
V_REF
CTRL
ISP
0.1µF
ISN
PWMOUT
SS SYNC V_C
RT SGND
10nF
22nF _86.6k
300kHz
0.1µF
0.1µF
10µH
0.004Ω
2.2µF
100V
×5
4.7µF
1M
34.2k
4.7µF
50V
×5
0.033Ω
3A, 100W
LED POWER
3791 TA01a
For more information www.linear.com/LT3791
Efficiency vs V_IN
100
98 _BOOST
96
BUCK-BOOST
BUCK
94
92
90
10
20
30
40
50
60
INPUT VOLTAGE (V)
3791 TA01b
3791fb
1