MSLB9082 datasheet(15/20 Pages) ATMEL

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Atmel LED Driver-MSLB9082

On/Off (EN) Control Input

The on/off control input, pin 9 of input connector J2,

turns on/off the LED driver. Drive it high (between 2.3

and 5V) to turn on the LED driver, and drive it low (0 to

0.8V) to turn it off. The on/off control input is internally

pulled up by a 100k

Ω resistor. For automatic start-up,

leave EN unconnected.

External PWM Control Input

The MSL3162 operates in one of three modes: internal

PWM mode, external PWM mode, or gated PWM mode.

Internal PWM mode dims the LEDs with a frequency

and phase set by the MSL3162, and the state of

the PWM input is ignored and has no effect on LED

brightness. In this case, each string can have a different

PWM set by the MSL3162’s PWMn register setting. To

control the brightness of all LEDs simultaneously, set the

GINT register between 0 and 3F.

External PWM and gated PWM modes use the duty

cycle of the signal applied to the PWM input; connector

J2, pin 10. The PWM input is pulled high through a

100k

Ω resistor. If not used, leave PWM unconnected

or drive it high. The MSL3162 digitizes the PWM input

signal and determines the duty cycle of that signal. This

value replaces the GINT register value to control the

global brightness (of all LEDs simultaneously). In this

case, individual string brightness is controlled through

the PWMn register.

Gated PWM mode turns on all LEDs when PWM is

driven high, and turns them off when PWM is driven

low. By programming the PWMn registers and GINT for

100% duty cycle, the LEDs are directly PWM dimmed

by the signal applied to the PWM input.

Fault Indicator Output

The MSL3162 includes fault detection circuitry that

detects and open-circuited LED string, and an LED string

with one or more short-circuited LEDs. If any fault is

detected, the output is driven low. Use this output as an

alert signal to a system controller. Once the controller

gets the alert signal, it determines which LED is faulty

by reading the STATUS, OCSTATUS, and SCSTATUS

registers through the I2C serial interface.

Connecting the LEDs to the Atmel LED Driver-

MSL9082 LED Driver

The MSLB9082 driver board drives LED arrays with

up to eight parallel strings of up to 12 series LEDs each

through the output connector, J3. Eight connections for

LED cathode connections allow the use of separate LED

strings or common-anode-connected LED strings.

Driving LEDs with Greater than 80mA

LED Current

The MSL3162 is capable of driving up to 80mA per

LED string. The MSLB9082 board has two string

drivers connected to each driver connection (STRA-

STRH), with one disabled. This allows driving up to

180mA per LED string by enabling the two drivers and

setting the same PWM duty ratios and phasing for both

MSL3162 driver inputs (dual-string mode). See the

MSL3162 datasheet for more details on programming

the MSL3162.

Table 8 shows the switch settings and the full-scale,

per-string LED current for each setting when operating

in parallel mode.

Atmel LED Driver-MSLB9082

LED Backlight Driver Module

Compact, 8-channel, 20W LED Driver Board with I2C Interface

MSLB9082 Datasheet(PDF) 15 Page - ATMEL Corporation

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