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DEMO MANUAL DC2345A
QUICK START PROCEDURE
Figure 2. DC2345A Efficiency and LED Current Versus Input Voltage for 25V 2A LED Load.
Efficiency Peaks at 98% and Doesn't Stray Far from That Peak, Ranging from 95% to 97%
Throughout the Typical 9V-16V Automotive Input Range. Also Shown, the LT8391 Peak
Inductor Current Limit Can Maintain Stable Output with Reduced Output Power at Low V
I
L1
1A/DIV
I
LED
1A/DIV
INFINITE PERSIST
V
= 24V
IN
V
= 25V
LED
SPREAD SPECTRUM ON
1000:1 DIMMING: EXTERNAL PWM SOURCE, 120Hz
Figure 3. Infinite-Persist Scope Traces Show PWM Dimming and SSFM Working Together for
Flicker-Free Brightness Control with Both Externally and Internally Generated PWM Dimming.
4
100
BOOST
95
BUCK-BOOST
90
I
LED
85
80
75
70
0
10
5µs/DIV
3
EFFICIENCY
BUCK
2.5
2
1.5
1
V
= 25V
0.5
LED
I
= 2A
LED
f
= 400kHz
SW
0
20
30
40
50
60
V
(V)
IN
I
L1
1A/DIV
I
LED
1A/DIV
INFINITE PERSIST
V
= 24V
IN
V
LED
SPREAD SPECTRUM ON
128:1 DIMMING: INTERNAL PWM DIMMING, 200Hz
.
IN
10µs/DIV
= 25V
dc2345af
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