Analog Devices EVAL-LT8356-1-AZ Demo Manual page 4

DEMO MANUAL EVAL-LT8356-1-AZ
BOOST LED DRIVER SETUP
EVAL-LT8356-1-AZ is assembled as a buck-boost mode
LED Driver, but with minor adjustments can be reconfig-
ured as a boost LED driver. In buck-boost mode, the LED
connection is at VIN, and a level shifter is used for the FB
network. In a boost LED Driver, the LED- connection is
at GND and a resistor divider is used for the FB network.
To configure EVAL-LT8356-1-AZ as a boost LED driver,
remove R20, R22, Q3, FB2, C12 and C11. Install 0Ω for
4
R14 and 1M for R9. Consult the data sheet for OVP cal-
culations and details about the FB pin. Connect the LED
string from LED+ to LED– (GND boost) as seen in Figure 2.
Note that when EVAL-LT8356-1-AZ is reconfigured
as a boost LED Driver, other components may need
to be adjusted depending on their voltage rating and
power capabilities.
Figure 2. EVAL-LT8356-1-AZ as a Boost LED Driver
Rev. A