MAX16826 Datasheet, PDF (22/26 Pages) Maxim Integrated Products – Programmable, Four-String HB LED Driver with Output-Voltage Optimization and Fault Detection

Programmable, Four-String HB LED Driver with
Output-Voltage Optimization and Fault Detection
SEPIC Topology
The SEPIC power topology is very useful when the
input voltage is expected to be higher or lower than the
output voltage of the switching regulator stage as
required by the number of LEDs used in a single string.
The SEPIC topology is more complex than the simple
boost topology and it requires the use of two additional
energy storage components, L2 and C25, in Figure 9.
L1
C25
D1
V_IN
Q1
R11
C26
R13
R15
C28
L2
R32
R33
R34
R17
R12
R14
R16
V_OUT
R35
SYSTEM
µC
DIM
SDA
SCL
ENABLE
GND
C27
GND
GND GND
GND
GND
GND
GND
C29 _R18
IN
DL RSC CS
DIM1
DIM2
DIM3 ^{DIMMING INPUTS}
DIM4
MAX16826
SDA _{I2C INTERFACE}
SCL
SYNC/EN
COMP _FB
OVP
DR4
DR3
DR2
DR1
DL1
CS1
DL2
CS2
DL3
CS3
DL4
CS4
CSS
RTCT
VCC GND PGND
R19
C30
C33
C32
R27 R25 R23 R21
R20
Q5
R31
C44
R22
Q4
R30
C43
R26
R24
Q3
Q2
R29
R28
C42
C41
GND GND
GND
GND
GND GND GND
GND
Figure 9. SEPIC-Based LED Driver
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