MAX16826_15 Datasheet, PDF (8/26 Pages) Maxim Integrated Products – Programmable, Four-String HB LED Driver with Output-Voltage Optimization and Fault Detection

MAX16826
Programmable, Four-String HB
LED Driver with Output-Voltage
Optimization and Fault Detection
Pin Description
PIN NAME
FUNCTION
1
PGND Power Ground
2, 3
GND Analog Ground
Timing Resistor and Capacitor Connection. A resistor, R19 (in the Typical Application Circuit), from V_CC to
4
RTCT RTCT and a capacitor C33, from RTCT to GND set the oscillator frequency. See the Oscillator section to
calculate RT and CT component values.
Synchronization and Enable Input. There are three operating modes:
SYNC/EN = LOW: Low current shutdown mode with all circuits shut down except shunt regulator.
5
SYNC/EN
SYNC/EN = HIGH: All circuits active with oscillator frequency set by RTCT network.
SYNC/EN = CLOCKED: All circuits active with oscillator frequency set by SYNC clock input. Conversion
cycles initiate on the rising edge of external clock input. The frequency programmed by R19/C33 must be
10% lower than the input SYNC/EN signal frequency.
Soft-Start Timing Capacitor Connection. Connect a capacitor from CSS to GND to program the required soft-
6
CSS start time for the switching regulator output voltage to reach regulation. See the Soft-Start (CSS) section to
calculate C_CSS.
7
COMP ^{Switching Regulator Compensation Component Connection. Connect the compensation network between}
COMP and FB.
Switching Regulator Feedback Input. Connect FB to the center of a resistor-divider connected between the
8
FB switching regulator output and GND to set the output voltage. FB is regulated to a voltage set by an internal
register. See the Setting Output Voltage section for calculating resistor values.
Switching Regulator Overvoltage Input. Connect OVP to the center of a resistor-divider connected between the
9
OVP
switching regulator output and GND. For normal operation, configure the resistor-divider so that the voltage at
this pin does not exceed 1.25V. If operation under load dump conditions is also required, configure the resistor-
divider so that the voltage at OVP is less than 1.25V.
Slope Compensation Resistor and PWM Comparator Input Connection. Connect a resistor, R17, from RSC to
10
RSC the switching current-sense resistor to set the amount of the compensation ramp. See the Slope Compensation
(RSC) section for calculating the value.
11
SDA I²C Serial Data Input/Output
12
SCL I²C Serial Clock Input
LED String 1 Logic-Level PWM Dimming Input. A high logic level on DIM1 enables the current sink to operate at
13
DIM1 the maximum current as determined by its sense resistor and internal register value. A low logic level disables
the current source.
LED String 2 Logic-Level PWM Dimming Input. A high logic level on DIM2 enables the current sink to operate at
14
DIM2 the maximum current as determined by its sense resistor and internal register value. A low logic level disables
the current source.
LED String 3 Logic-Level PWM Dimming Input. A high logic level on DIM3 enables the current sink to operate at
15
DIM3 the maximum current as determined by its sense resistor and internal register value. A low logic level disables
the current source.
LED String 4 Logic-Level PWM Dimming Input. A high logic level on DIM4 enables the current sink to operate at
16
DIM4 the maximum current as determined by its sense resistor and internal register value. A low logic level disables
the current source.
17
CS1 ^{LED String 1 Current-Sense Input. CS1 is regulated to a value set by an internal register. The regulation voltage}
can be set between 97mV and 316mV.
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