1
dc1573af
DEMO MANUAL DC1573A
Description
LT3760
8-Channel 100mA
High Voltage LED Driver
DC1573A is an 8-Channel 100mA High Voltage LED Driver
featuring the LT
®
3760. The LT3760 drives up to 100mA
per string and has a maximum LED string voltage of 45V.
DC1573A is set at 1MHz switching frequency for smallest
inductor and capacitor size as well as maximum PWM
dimming performance. Overvoltage protection is set at
55V in case the LEDs are removed from the circuit. If the
LEDs are opened, the
FAULT
terminal output flag goes
low and reports the fault condition. The V
IN
terminal is
powered from 10V to 14V input separated from the 24V
PV
IN
supply for best thermal performance. If one or more
of the 8 LED channels is not used, its LED pin or terminal
should be tied to LED+ to disable it. Multiple channels can
be used in parallel for higher LED current by tying their
LED1-8 pins together.
perForMAnce sUMMArY
The LT3760 data sheet gives a complete description of
the part, operation and applications information. The data
sheet must be read in conjunction with this demo manual
for demonstration circuit 1573A. The LT3760 is assembled
in a small 28-lead FE (4.4mm TSSOP) package with a
thermally enhanced ground pad. Proper board layout is
essential for maximum thermal performance. See the
Layout Considerations section in the data sheet.
Design files for this circuit board are available at
http://www.linear.com/demo
L
, LT, LTC, LTM, µModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(T
A
= 25°C)
PARAMETER
CONDITION
VALUE (TYPICAL)
PV
IN
Power Input Voltage Range
Operating
20V to 28V
V
IN
Pin Input Voltage Range
Operating
8V to 14V
Switching Frequency
R
T
= 39.2k
1MHz
LED String Current I
LED(1-8)
R14 = 5.76k
100mA
OVP Open LED Voltage
R8 = 11k, R7 = 20k
55V
Efficiency
PV
IN
= 24V, V
IN
= 10V, V
LED
= 45V, I
LED1-8
= 100mA
92%
Undervoltage Lockout
R1 = 499k, R4 = 40.2k
20.1V
Low Voltage Turn-On (UVLO + V
HYST
)
R1 = 499k, R4 = 40.2k
21.4V
Peak Switch Current Limit
R
S1
= 0.015Ω
3.3A