MAX16826 Datasheet, PDF (10/26 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
Simplified Block Diagram
OVT
IN 29
26V
SHUNT
OVT
VCC
REF
GND
VCC 31 ^5V
VCC
OVP 9
DL 32
PGND 1
CS 30
FB 8
RSC 10
CSS 6
COMP 7
RTCT 4
SYNC/EN 5
GND 2
GND ₃
SDA 11
SCL 12
OVT
CURRENT-
MODE
PWM
BLOCK
I²C
STATE
MACHINE
OVT
DOUBLE-
BUFFERED
REGISTER
AND DACS
MAX16826
7-BIT ADC
AND
SHORTED
STRING
FAULT
DECTECTION
LINEAR
CURRENT-
SINK
DRIVERS
28 DR4
25 DR3
22 DR2
19 DR1
26 CS4
23 CS3
20 CS2
17 CS1
27 DL4
24 DL3
21 DL2
18 DL1
16 DIM4
15 DIM3
14 DIM2
13 DIM1
Detailed Description
The MAX16826 HB LED driver integrates a switching
regulator controller, a 4-channel linear current sink dri-
ver, a 7-bit ADC, and an I²C interface. The IC is
designed to operate from a 4.75V to 24V input voltage
range and can withstand automotive load dump tran-
sients up to 40V.
The current-mode switching regulator controller is con-
figurable as a boost or SEPIC converter to regulate the
voltage to drive the four strings of HB LEDs. Its program-
mable switching frequency (100kHz to 1MHz) allows the
use of a small inductor and filter capacitors. The four
current sink regulators use independent external current-
sense resistors to provide constant currents for each
string of LEDs. Four DIM inputs allow a very wide range
of independent pulsed dimming to each LED string. An
internal 7-bit ADC measures the drain voltage of the
external driver transistors to enable output voltage opti-
mization and fault monitoring of the LEDs. The
MAX16826 is capable of driving four strings of LEDs.
The number of LEDs in each string is only limited by the
topology of choice, the rating of the external compo-
nents, and the resolution of the ADC and internal DAC.
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