MSL1064AW-R - Atmel - Datasheet.Wiki

Atmel LED Drivers

MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

Datasheet Brief

2 Atmel LED Drivers-MSL1061/MSL1064

General Description

The Atmel® LED Drivers-

MSL1061 and MSL1064 are

LED drivers with integrated

boost regulators capable of

driving six LED strings at

30mA up to 48V for lighting

applications to 8W, allowing

up to 72 LEDs per driver

backlighting applications.

The MSL1061/64 incorporates a current mode PWM boost regulator with

50V internal switch and a wide, 4.75V to 36V input voltage range. The

1.1MHz switching frequency uses a small-sized inductor and output capacitors

while maintaining high efficiency and low ripple voltage and noise. The boost

regulator uses digital control and requires no external compensation.

An I2C/SMB compatible serial interface operates up to 1MHz, giving access

to internal 8-bit PWM dimming and 4-bit analog current adjustment for 12-

bit current control. Individual string enable and fault reporting are available.

The MSL1061 operates with one of four I2C slave addresses selected from a

single input pin (AD0), whereas the lower cost MSL1064 has one fixed I2C

slave address.

The MSL1061/64 is also easy to employ without using an I2C interface,

dimming with an external PWM signal.

Analog dimming of LED string current is available for use with an ambient

light sensor (ALS) and/or temperature management with a thermistor or IC

temperature sensor.

The MSL1064 comes in a 5 x 5mm, 24-pin TQFN package, and the MSL1061

in a 5 x5mm, 28-pin TQFN. Both packages are lead-free, halogen-free and

RoHS-compliant, and operate over a -40°C to 85°C temperature range.

Applications

Long Life, Efficient LED Backlighting for:

• Notebook PCs and Desktop PC Monitors

• Medical and Industrial Instrumentation

• Portable Media Players (PMPs)

• Automotive Audio-visual Displays

Traffic Lights

Signage

Ordering Information

PART DESCRIPTION PACKAGE

MSL1061AV 6-ch LED driver 28-pin, 5x5x0.75mm TQFN

MSL1064AW 6-ch LED driver 24-pin, 5x5x0.75mm TQFN

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

3Atmel LED Drivers-MSL1061/MSL1064

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

Key Features

Application Circuit

• Drives 6 Strings of up to 12 LEDs per String

• Drives 72 White LEDs at 30mA for 8W Backlight

• Better than ±1.5% String-to-string Current Accuracy

• 4.75V to 36V Wide Input Supply Range

• Integrated Boost Regulator with 50V Internal Switch

• 1.1MHz Current Mode PWM Boost for Low Noise

• Up to 92% Boost Converter Efficiency

• Internal, Automatic Power Supply Management

• Adjustable LED Current up to 30mA per String

• String Outputs can be Paralleled for >30mA LEDs

• 256:1 Internal PWM Dimming Range Through I2C

• 16:1 Internal Analog Dimming Range Through I2C

• 12-Bit Total Internal PWM + Analog Dimming Range

• ALS Interface for Automatic Brightness Setting

• NTC Interface for Temperature Derating

• Individual Open-circuit and Short-circuit

Fault Detection

• Faults Automatically Disable the Faulty String

• Fault Reporting and Fault Reset Through I2C/SMB

• FLTB Logic Output Indicates Faults

• Enable Input Simplifies Operation Without I2C/SMB

• PWM Input Synchronizes PWM to System Clock

and Allows Logic PWM Control Without I2C

• Adjustable Over-voltage Protection

• Serial I2C/SMB Compatible Interface to 1MHz

• Four selectable I2C Slave Addresses (MSL1061)

• GUI Software for Ease of Evaluation

• -40°C - +85°C Operating Temperature Range

• Lead-free, Halogen-free, RoHS-compliant Package

STR0

STR5

…

SDA

SCL

AD0

VIN

PWM

FLTB

ILED

GND

MSL1061

MSL1064

OSC

I C or

SMBus

Fault

Alert

Set

String

current

1.5% maximum current

mismatch between

Strings

Up to 12

White

LEDs per

String

I C address selection

(MSL1061 only)

ALS or

NTC

= 4.75V to 36V

OUT

= 48V max

IADJ

OVP

4 Atmel LED Drivers-MSL1061/MSL1064

Quick Start Guide

This section summarizes for quick evaluation

the capabilities of, and differences between, the

MSL1061 and MSL1064.

The MSL1061 and MSL1064 are LED string drivers

with integrated boost regulators, which power, monitor,

and dim multiple LEDs at high efficiency for backlighting

and signage applications. Each MSL1061/64 contains six

outputs, each capable of sinking up to 30mA through a

string of series-connected LEDs.

How Many LEDs Can the Atmel LED

Drivers-MSL1061/64 Drive?

The MSL1061/64 includes 6 current sinks (STR0

through STR5) that each control the LED current of

multiple series-connected white LEDs. Any combination

of the 6-strings may be enabled, and not all the strings

need to be used.

Make sure that each enabled string contain the same

number of the same type of LED so that the total voltage

drop for each string is the same because the single boost

regulator supplies power to all six strings. Use a single

MSL1061/64 LEDs of a single color/chemistry, such

as white LED backlighting or single-color signage. For

multicolor applications (e.g. RG, RGB, RGGB, RGBA),

use separate MSL1061/64s per LED color/chemistry

type. Each MSL1061/64 manages its integrated boost

regulator to optimize efficiency for its strings of identical

LEDs with matched electrical characteristics.

The maximum number of LEDs allowed in a string is

determined by the maximum voltage rating of the boost

regulator’s internal power FET, which is 50V minus 2V

for switching noise transients, leaving 48V. The FET

is protected by the OVP trip, which has a 2% voltage

tolerance, plus another 1% for the external setting

resistors R8 and R9 (Figure 6 on page 15) reducing the

maximum voltage to 46.5V. The total voltage needed

to drive a string is the forward voltage drop across the

desired LED strings, plus the headroom needed across

a string output’s current sink (600mV) to maintain

regulation, plus the boost regulator’s rectifier forward

voltage (normally under 900mV) leaves 46.5V - 0.6V -

0.9V = 45V maximum for the LED string. The number of

LEDs that the MSL1061/4 can drive per string is 45V /

{maximum LED forward voltage per LED}, or 12 LEDs

per string using 3.75V maximum forward voltage LEDs.

Differences Between Atmel LED

Drivers-MSL1061/64

Use the MSL1061 for applications where multiple

drivers are connected to a single I2C bus such as RGB

and RGGB lighting. Use the lower cost MSL1064 for

single-driver applications, and multi-driver applications

that do not require all drivers on the same I2C

interface (Table 1).

5Atmel LED Drivers-MSL1061/MSL1064

FEATURE MSL1061 MSL1064 APPLICATION AND SUITABILITY

I2C interface 4 selectable slave addresses by

AD0 pin (0x60, 0x61, 0x62, 0x63) 1 xed slave address (0x62) Only one MSL1064 is uniquely

addressed on an I2C bus

Package 28-lead, 5mm x 5mm TQFN,

0.5mm pitch

24-lead, 5mm x 5mm TQFN,

0.65mm pitch

IPC-

2221A-2003

compliance

0.2mm min gap between SW pins

and adjacent conductors. Compliant

to 100V with board coating, 15V

without coating

0.6mm min total gap between SW

pins and adjacent conductors.

Compliant to 100V with or without

board coating

If compliance is necessary use

the MSL1064 or MSL1061 with

board coating.

Table 1. Atmel LED Drivers-MSL1061 and MSL1064 Comparison

Capabilities With and Without Using the Serial Interface

MSL1061/64 operates as stand alone LED drivers with full digital (PWM) and analog (DAC) LED brightness control

and fault reporting through I/O controls. Alternatively, LED dimming and fault reporting is managed over an I2C or SMB

serial interface, allowing software/firmare LED intensity control. More detailed fault management reporting and software

controlled shutdown (Table 2) via the serial interface.

FUNCTION CONTROLS AVAILABLE ON PINS ADDITIONAL CONTROLS AVAILABLE VIA I2C

Global on/off control EN pin (Table 3 on page 9) Run mode/sleep mode

Individual LED string on/off control Not available String enables register

Analog LED current adjustment ILED pin (Table 3 on page 8) Current setting register

PWM LED current adjustment PWM pin (Table 3 on page 8) PWM frequency register

PWM duty ratio register

Ambient light sensor (ALS) and/

or auto-matic temperature LED

current adjustment

IADJ pin (Table 3 on page 9) Current setting register

Fault monitoring FLTB pin indicates open-string, shorted-

string, and over-temperature faults

Status register identies open/short circuit and over-

temperature faults to individual strings

Table 2. Atmel LED Drivers-MSL1061/64 Stand Alone Capabilities and I2C Controlled Features

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

6 Atmel LED Drivers-MSL1061/MSL1064

VIN

N/C

24 23

21 20

VCC 1 18

OVP

VDD 2 17

STR0

TEST1 3 16

STR1

TEST2 4 15

STR2

SDA 5 14

STR3

SCL 6

MSL1064

(TOP VIEW)

STR4

7 8 9 10 11

PWM

FLTB

OSC

ILED

IADJ

STR5

Figure 2. 24-pin TQFN Package Dimensions

Packages and Pin Connections

Atmel LED Drivers-MSL1061/64 – 24-pin, 5mm x 5mm x 0.75mm TQFN package with 0.65mm lead pitch

Figure 1. 24-pin, 5mm x 5mm x 0.75mm TQFN

(0.65mm pin pitch) with Exposed Pad

7Atmel LED Drivers-MSL1061/MSL1064

Figure 3. 28-pin, 5mm x 5mm x 0.75mm

TQFN (0.5mm pin pitch) with Exposed Pad

VIN

N/C

28 27 26

25 24 23

VCC 1 21

OVP

VDD 2 20

TEST3

TEST1 3 19

STR0

TEST2 4 18

STR1

SDA 5 17

STR2

SCL 6 16

STR3

AD0 7

MSL1061

(TOP VIEW)

STR4

8 9 10

11 12 13

PWM

FLTB

OSC

N/C

ILED

IADJ

STR5

Figure 4. 28-pin TQFN Package Dimensions

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

8 Atmel LED Drivers-MSL1061/MSL1064

PIN NAME MSL1061 MSL1064 PIN DESCRIPTION

VCC 1 1

6V internal linear regulator output

VCC powers the internal power FET switch driver.

Bypass VCC to GND either with a 10µF or greater ceramic capacitor, or with a 10µF or

greater tantalum capacitor in parallel with a 1µF ceramic capacitor.

If the voltage at VIN is less than 6.5V, connect VCC directly to VIN to bypass the internal

linear regulator, and power the driver directly from VIN

VDD 2 2 2.9V internal linear regulator output

VDD powers internal logic. Bypass VDD to GND with at least a 4.7µF ceramic capacitor

TEST1 3 3 Factory test connection. Leave unconnected

TEST2 4 4 Factory test connection. Connect to GND

SDA 5 5 I²C serial data I/O

SDA is the data I/O for the I²C serial interface

SCL 6 6 I²C serial clock input

SCL is the clock input for the I²C serial interface

AD0 7 -

I²C slave ID selection input

For MSL1061, connect AD0 to GND, VDD, SCL, or SDA to set the I²C slave ID to 0x60,

0x61, 0x62, or 0x63. The MSL1064 I²C slave ID is xed at 0x62, and is not user-selectable

PWM 8 7 PWM control input

Drive PWM with a PWM signal up to 40kHz to pulse-width-modulate the LED current

FLTB 9 8

Fault indication output (active low)

FLTB sinks current to GND whenever the MSL1061/64 detects a fault.

Once a fault is detected, FLTB remains low until EN is toggled low/high, input power is

cycled off/on, or the fault status is reset through the I²C interface.

OSC 10 9

Oscillator control input

Connect a 115kΩ, 1% resistor from OSC to GND to set the internal oscillator frequency

to 11MHz and the boost regulator switching frequency to 1.1MHz

TEST3 11 -Factory test connection with internal 1.8kΩ pull-up to VDD. Leave unconnected

ILED 12 10

Maximum LED current control input

Connect a resistor from ILED to GND to set the full-scale LED string current.

For example, connect a 100kΩ resistor to GND to set a 20mA sink current through

each LED string

Pin Descriptions

Table 3. Pin Assignments

9Atmel LED Drivers-MSL1061/MSL1064

PIN NAME MSL1061 MSL1064 PIN DESCRIPTION

IADJ 13 11

Analog LED current dimming input

Apply a voltage between 0V to 1.22V to linearly control the LED current from 0 to 100%.

Connect IADJ to VDD if unused

STR5 14 12 LED string 5 current sink output

Connect the cathode of LED String 5 to STR5. Connect STR5 to GND if unused

STR4 15 13 LED string 4 current sink output

Connect the cathode of LED String 4 to STR4. Connect STR4 to GND if unused

STR3 16 14 LED string 3 current sink output

Connect the cathode of LED String 3 to STR3. Connect STR3 to GND if unused

STR2 17 15 LED string 2 current sink output

Connect the cathode of LED String 2 to STR2. Connect STR2 to GND if unused

STR1 18 16 LED string 1 current sink output

Connect the cathode of LED String 1 to STR1. Connect STR1 to GND if unused

STR0 19 17 LED string 0 current sink output

Connect the cathode of LED String 0 to STR0. Connect STR0 to GND if unused

OVP 21 18

Overvoltage detection input

Connect a resistive voltage divider from the boost output voltage to OVP to set the

overvoltage protection set point. OVP threshold is 1.28V

N/C 22 19 No internal connection. Leave unconnected

SW 23, 24, 25,

26 20, 21 Drain of the internal boost power MOSFET switch

Connect all SW pins together and to the boost regulator inductor and rectier

N/C - 22 No internal connection. Leave unconnected

EN 27 23

Enable input (active high)

Drive EN high to turn on the MSL1061/64, and drive it low to turn it off.

For automatic startup, connect EN to VIN through a 100kΩ resistor

VIN 28 24

Supply voltage input

Connect the input supply voltage to VIN.

VIN powers the internal linear regulator that powers VCC.

Bypass VIN to GND with a 1µF or greater ceramic capacitor

GND Exposed

pad

Exposed

pad Ground

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

10 Atmel LED Drivers-MSL1061/MSL1064

Absolute Maximum Ratings

Voltage (With Respect to GND Exposed Pad on Package Underside)

VIN ................................................................................................................................................................................................................. -0.3V to +40V

VCC, EN.........................................................................................................................................................................................................-0.3V to +8V

VDD, OVP, IADJ, FLTB, ILED, SDA, SCL, AD0, OSC, PWM ................................................................. -0.3V to +3.6V

SW ................................................................................................................................................................................................................ -0.3V to +50V

STR0, STR1, STR2, STR3, STR4, STR5 ................................................................................................................... -0.3V to +45V

Current (Into Pin)

STR0, STR1, STR2, STR3, STR4, STR5 .................................................................................................................................. .. ±35mA

All other pins .......................................................................................................................................................................................................... ±20mA

Continuous Power Dissipation at 70°C

24-Pin TQFN (see Note 8, Note 9) ........................................................................................................................................ 2286mW

28-Pin TQFN (see Note 8, Note 9) ........................................................................................................................................ 2286mW

Ambient Operating Temperature Range TA = TMIN to TMAX ..................................................... -40°C to +85°C

Junction Temperature ............................................................................................................................................................................ +125°C

Storage Temperature Range ................................................................................................................................... -65°C to +125°C

Lead Soldering Temperature, 10s ..............................................................................................................................................+300°C

11Atmel LED Drivers-MSL1061/MSL1064

Electrical Characteristics

(Circuit of Figure 6, VVIN = 12V, default register settings of Table 7, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C) (Note 1)

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

DC ELECTRICAL CHARACTERISTICS

VIN operating supply voltage VVIN = VVCC 4.75 6.5 V

VCC unconnected 6.5 36 V

VIN quiescent supply current VEN = 3V, VPWM = 0V VVIN = 12V 414 mA

VVIN = 6V, VVCC = 6V 414 mA

VIN shutdown supply current VEN = VPWM = 0V 1 4 10 µA

VCC output voltage 5.6 66.3 V

VCC line regulation 6.5V < VVIN < 36V 125mV

VCC dropout voltage VVIN = 6V, IVCC = 5mA, VPWM = 0V 100 300 550 mV

VCC short-circuit current VVCC = 0V 30 80 150 mA

VCC UVLO threshold VVCC rising, hysteresis = 150mV 4.1 4.3 4.5 V

VDD output voltage IVDD = 1mA 2.7 2.9 3.1 V

VDD short-circuit current VVDD = 0V 10 35 60 mA

VDD UVLO threshold VVDD rising, hysteresis = 80mV 2.4 2.5 2.6 V

Thermal shutdown threshold (rising) 135 °C

Thermal shutdown hysteresis 10 °C

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

DC ELECTRICAL CHARACTERISTICS - LED CURRENT CONTROL STR0 TO STR5

ILED regulation voltage R5 = 100kΩ 1.195 1.22 1.245 V

STR0 to STR5 full scale sink current VSTRn = 1V, R5 = 100kΩ, VIADJ = VPWM = 3V 19.7 20 20.3 mA

STR0 to STR5 maximum sink current VSTRn = 1V, R5 = 60kΩ, VIADJ = VPWM = 3V

(Note 10) 30 mA

STR0 to STR5 current matching VSTRn = 1V, R5 = 100kΩ, VPWM = 3V (Note 11) 1.5 %

STR0 to STR5 leakage current VEN = 0V, VSTRn = 40V 0.1 1 µA

VEN = 3V, VSTRn = 40V, VPWM = 3V 0.1 1 µA

STR0 to STR5 short circuit detection threshold 4 4.4 4.8 V

STR0 to STR5 open circuit detection threshold 0.1 V

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

DC ELECTRICAL CHARACTERISTICS - LOGIC I/OS

EN logic high input voltage 2.3 V

EN logic low input voltage 0.8 V

EN logic input current VEN = 3V 20 µA

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

12 Atmel LED Drivers-MSL1061/MSL1064

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

DC ELECTRICAL CHARACTERISTICS - BOOST REGULATOR

SW on resistance ISW = 100mA 0.4 0.6 Ω

SW current limit 2 A

OSC regulation voltage R4 = 115kΩ ±1% 1.195 1.22 1.245 V

STR0-STR5 boost regulation voltage R5 = 100kΩ, PWM=100% (Note 12) 600 mV

OVP threshold VOVP rising 1.25 1.28 1.31 V

OVP hysteresis 60 mV

OVP leakage current VOVP = 3.6V 1 µA

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

EN logic input series resistance Between EN input package pin and internal

Zener clamp 10.5 kΩ

EN logic input Zener clamp 5.8 V

SCL, SDA, AD0,

PWM logic high input voltage 2 V

SCL, SDA, AD0,

PWM logic low input voltage 0.9 V

SDA, SCL, AD0 input capacitance 10 pF

SDA output low voltage Sinking 6mA 0.4 V

FLTB output low voltage Sinking 1mA 0.1 0.2 V

IADJ, FLTB, PWM, SCL, SDA,

AD0 leakage current 10 µA

PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT

AC ELECTRICAL CHARACTERISTICS

PWM input frequency

INTPWM bit D3=0 in control register to select

external PWM input to be used for direct LED

string dimming control

0 50 kHz

PWM input duty ratio 0 100 %

PWM input minimum string on time 14 µs

PWM input minimum string off time 3.2 µs

PWM input frequency, external PWM clock mode INTPWM bit D3=1, EXTCLK bit D2=1 in

control register to select external PWM

input to be used as clock for internal PWM

dimming control

0 12 MHz

PWM input duty ratio, external PWM clock mode 30 70 %

PWM frequency (internal oscillator)

R4 = 115kΩ ±1%, INTPWM bit D3=1,

EXTCLK bit D2=0 in control register to select

internal oscillator to be used as clock for

internal PWM dimming control

911 12 MHz

Boost regulator switching frequency R4 = 115kΩ ±1% 0.99 1.1 1.21 MHz

Boost regulator maximum duty ratio R4 = 115kΩ ±1% 89 92 %

Boost regulator startup time 100 120 ms

13Atmel LED Drivers-MSL1061/MSL1064

Note 1. All parameters are tested at TA=25°C, unless otherwise noted. Specifications at temperature are guaranteed by design

Note 2. Minimum SCL clock frequency is limited by the bus timeout feature, which resets the serial bus interface if either SDA or SCL is held low for

ttimeout. Disable the bus timeout feature for DC operation

Note 3. tVD:ACK = SCL LOW to SDA (out) low acknowledge time

Note 4. tVD:DAT = minimum SDA output data-valid time following SCL low transition

Note 5. A master device must internally provide an SDA hold time of at least 300ns to ensure an SCL low state

Note 6. The maximum SDA and SCL rise times is 300ns. The maximum SDA fall time is 250ns. This allows series protection resistors to be

connected between SDA and SCL inputs and the SDA/SCL bus lines without exceeding the maximum allowable rise time

Note 7. MSL1061/64 includes input filters on SDA, SCL, and AD0 inputs that suppress noise less than 50ns

Note 8. Subject to thermal dissipation characteristics of the device

Note 9. When mounted according to JEDEC JEP149 and JESD51-12 for a two-layer PCB, θJA = 24.1°C/W, and θJC = 2.7°C/W

Note 10. Guaranteed by design and characterization. Not production tested

Note 11. STR0 to STR5 current matching is the difference of any one string current and the average of all string currents divided by the average of

all string currents

Note 12. The MSL1061/64 selects the string (STR0 through STR5) with the lowest voltage to control the boost regulator voltage

PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT

I²C SWITCHING CHARACTERISTICS

SCL clock frequency 1/tSCL

TOEN bit D1=0 in control

timeout

1000 kHz

TOEN bit D1=1 in control

timeout

0.066

Bus time-out period tTIMEOUT 15 25 ms

STOP to START condition bus

free time tBUF 0.5 µs

Repeated START condition

hold time tHD:STA 0.26 µs

Repeated START condition

set-up time tSU:STA 0.26 µs

STOP condition set-up time tSU:STOP 0.26 µs

SDA data hold time tHD:DAT 5 ns

SDA data valid acknowledge time tVD:ACK (Note 3) 0.05 0.55 µs

SDA data valid time tVD:DAT (Note 4) 0.05 0.55 µs

SDA data set-up time tSU:DAT 100 ns

SCL clock low period tLOW 0.5 µs

SCL clock high period tHIGH 0.26 µs

SDA, SCL fall time tF(Note 5, Note 6) 120 ns

SDA, SCL rise time tR120 ns

SDA, SCL input suppression

lter period tSP (Note 7, Note 10) 50 ns

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

14 Atmel LED Drivers-MSL1061/MSL1064

Block Diagram

The block diagram for the 28-pin MSL1061 is shown in Figure 5. The differences for the 24-pin MSL1064 are that the

MSL1064 provides only two pins for SW instead of four pins on the MSL1061, and the AD0 pin is not pinned out but

is instead bonded internally to SCL. The MSL1061 I2C slave address is selected using AD0 from one of the four address

pairs, 0xC0/0xC1 - 0xC6/0xC7, whereas the MSL1064 I2C slave address is fixed at 0xC4/0xC5.

Figure 5. Atmel LED Driver-MSL1061 Block Diagram

15Atmel LED Drivers-MSL1061/MSL1064

Typical Application Circuit

Figure 6. Backlight Example Driving 60 White LEDs

PARAMETER VALUE

Minimum input voltage 4.75V

Maximum input voltage (set by

minimum LEDs string voltage) 30V

Number of LEDs 60

Number of LED strings 6

Number of LED per string 10

LED forward current (set by R5) 20mA

White LED Osram LW-

Y3SG

Minimum LED forward voltage 2.9V

Typical LED forward voltage 3.3V

Maximum LED forward voltage 3.6V

Minimum LED string voltage 29V

Maximum LED string voltage 36V

Oscillator frequency (set by R4) 1.1MHz

Overvoltage protection (OVP) trip

point (set by R8 and R9) 45.9V

COMPONENT DESCRIPTION VENDOR PART

NUMBER

C4, C5, C6, C7* 1µF, 50V, X7R

C2 10µF, 10V, X7R or

tantalum (see note)

C3 33µF, 35V, X7R

C1 4.7µF, 6.3V, X7R

R8 1MΩ, 1%

R9 28.7kΩ, 1%

R4 115kΩ, 1%

R5 100kΩ, 1%

R7 100kΩ, 5%

R2 1MΩ, 5%

L1 10µH, 1.7A Sumida CDRH6D28-100

D1 60V, 2A Schottky Central Semi

CMSH2-60M

LEDs 60 x 30mA LED Osram LW-Y2SG

LED driver MSL1060 MSL1060

Table 4. Typ. Application Circuit Parameters Table 5. Typ. Application Circuit Bill of Materials

* Note: C7 is only required if tantalum capacitor is used for C2

4.7

16 Atmel LED Drivers-MSL1061/MSL1064

The MSL1061/64 is an LED driver with integrated boost

regulator for driving an array of LEDs with up to 8W of

power. The I²C/SMB serial interface, logic controls, and

fault management make the MSL1061/64 especially

suited to drive up to 72 white LEDs for portable device

backlighting. It is also ideal for industrial lighting and

signage applications, and can, for example, drive a 6

string x 18 series LED array totaling 108 red LEDs

(2.5V LED forward voltage drop).

The MSL1061/64 includes six current sinks (STR0

through STR5) that each control the LED current of

series-connected LEDs. A built-in step-up (boost)

regulator supplies power to the LEDs. The MSL1061/64

controls the output voltage of the boost regulator such

that all LED strings have sufficient voltage to maintain

regulated LED current. This control loop operates

automatically without any user interaction or set-up.

Application Information

VCC and VDD Regulators

The MSL1061/64 includes two linear voltage regulators

to generate the internal voltage rails, VDD and VCC. The

regulators allow the MSL1061/64 to operate directly

from the same higher voltage supply, VIN, which supplies

the LED boost regulator. Use the VDD and VCC regulators

only to power the MSL1061/64’s internal circuitry,

therefore do not draw any external current from them.

The VCC regulator generates a nominally 6V rail from VIN.

VCC powers the boost regulator’s power switch and the

VDD regulator. Bypass VCC to GND either with a 10µF

or greater ceramic capacitor or with a 10µF or greater

tantalum capacitor in parallel with a 1µF ceramic capacitor.

In applications where there is a local 4.75V to 6.5V

supply available, power VCC and VIN directly from this

supply. In this case use this supply or a separate higher

voltage supply to power the LED boost regulator. When

using a higher voltage supply connect it to the inductor,

L1 (Figure 6), and not to the MSL1061/64.

The VDD regulator generates a nominally 2.9V rail from

VCC. VDD operates the internal low-voltage circuits.

Bypass VDD to GND with a 4.7µF or greater capacitor.

Internal Oscillator - R4

The MSL1061/64 uses an internal oscillator with

frequency set by resistor R4 from OSC to GND (Figure

6). Use 115kΩ ±1% resistance value for R4. This sets

the internal LED dimming PWM frequency to 11MHz

and the boost regulator PWM frequency to 1.1MHz.

When using different values for R4 the MSL1061/64

performance is not guaranteed.

Setting the Full-scale LED String Current - R5

R5 sets the full-scale static LED current for all enabled

strings (Figure 6) from ILED to GND. The maximum full-

scale LED current is 30mA. The equation for calculating

external resistor R5 (Figure 6) to set the full-scale LED

string current IILED is:

2000

IILED =

where R5 is in kilohms and ILED is in milliamperes.

A value of 100kΩ for resistor R5 sets 20mA full-scale

LED current. The minimum allowed value for R5 is

66.7kΩ, which sets 30mA full-scale LED current.

Reduce the static LED current from full-scale using the

LED string current register. This register reduces LED

current proportional to the 4-bit IDAC register.

Detailed Description

17Atmel LED Drivers-MSL1061/MSL1064

Boost Regulator Components

The boost regulator is internally compensated, includes

an internal high voltage power switch, and requires only

an inductor, rectifier, and bypass capacitors. The current-

mode boost regulator operates in either continuous

conduction mode (CCM) or discontinuous conduction

mode (DCM). In CCM, the inductor current does not fall

to zero when operating at full power, keeping inductor

ripple current low and switching noise at a minimum.

The boost regulator switching frequency is 1.1MHz set

by the 115kΩ resistor R4 from OSC pin to GND (Figure

6). Select the inductor, rectifier diode, and output

capacitors per the following guidelines.

To minimize losses in the rectifier, choose one with fast

switching and low forward voltage drop. Ensure that the

rectifier can withstand a reverse voltage equal to the

regulator output voltage. The average forward current

is equal to the total LED string current (for example 6

strings x 30mA = 180mA), while the peak current is

equal to the inductor peak current (2A).

The boost output capacitor holds the voltage at the

output of the boost regulator while the internal power

switch is on and the rectifier is not conducting. Use

ceramic capacitors for small size and high ripple current

capacity, and derate them for operating voltage because

of the voltage coefficient of capacitance which decreases

the effective capacitance with increased operating

voltage. Use two parallel-connected 1µF 100V X7R

ceramic capacitors and a 10µH inductor with a 1.7A

peak current rating.

Boost Supply Over-voltage Protection

(OVP) - R8 and R9

The OVP input sets the boost regulator’s output voltage

upper limit, and protects the boost regulator from an

open-circuit LED fault. Set the OVP voltage VTRIP by

resistors R8 and R9 (Figure 6):

)98(

VV OVPTRIP

where VOVP=1.28V, nominal.

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

18 Atmel LED Drivers-MSL1061/MSL1064

Control the MSL1061/64 through an I2C interface using nine registers (Table 6). The power-up defaults (Table 7) are such

that an MSL1061/64 operates as a standalone LED driver if the I2C interface is not used.

The Internal register addressing auto-increments through the register map allowing sequential reads or writes without

needing to write separate addresses for each byte.

D7 D6 D5 D4 D3 D2 D1 D0

MSTRCNTRL Run/sleep

mode 0x00 - - - - - - - SLEEP

CNTRL

PWM

source, I2C/

SMB bus

timeout,

fault pin

enable

0x01 - - - - INTPWM EXTCLK TOEN FLTEN

- UNUSED 0X02 WRITES TO THIS REGISTER ADDRESS ARE IGNORED,

AND READS RETURN THE VALUE 0X00

STATUS Fault status

summary 0x03 - OTDET SCDET OCDET - - - FLTDET

OCSTATUS Open circuit

fault status 0x04 - - OC5 OC4 OC3 OC2 OC1 OC0

SCSTATUS Short circuit

fault status 0x05 - - SC5 SC4 SC3 SC2 SC1 SC0

PWMFREQ

PWM

frequency

prescaler

0x06 D7 D6 D5 D4 D3 D2 D1 D0

PWMDUTY PWM duty

ratio 0x07 D7 D6 D5 D4 D3 D2 D1 D0

- UNUSED 0X08 WRITES TO THIS REGISTER ADDRESS ARE IGNORED,

AND READS RETURN THE VALUE 0X00

STREN String

enables 0x09 - - STR5EN STR4EN STR3EN STR2EN STR1EN STR0EN

- unused 0x0A writes to this register address are ignored, and reads return the value 0x00

- unused 0x0B writes to this register address are ignored, and reads return the value 0x00

- unused 0x0C writes to this register address are ignored, and reads return the value 0x00

- unused 0x0D writes to this register address are ignored, and reads return the value 0x00

- unused 0x0E writes to this register address are ignored, and reads return the value 0x00

- unused 0x0F writes to this register address are ignored, and reads return the value 0x00

IDAC LED string

current 0x10 - - - - DAC3 DAC2 DAC1 DAC0

Table 6. Atmel LED Drivers-MSL1061/64 Register Map

19Atmel LED Drivers-MSL1061/MSL1064

Table 7. Atmel LED Drivers-MSL1061/64 Register Power-up Defaults

D7 D6 D5 D4 D3 D2 D1 D0

MSTRCNTRL Run mode 0x00 00000000

CNTRL

Fault detection is enabled

I²C bus timeout is disabled

PWM internal 11MHz clock is used,

prescaled by PWMFREQ

PWM control is by PWM pin.

PWMDUTY register is ignored

0x01 00000001

STATUS No faults (open, short, or temperature)

are detected 0x03 00000000

OCSTATUS None of the six LED outputs STR0 to

STR5 has an open circuit fault 0x04 00000000

SCSTATUS None of the six LED outputs STR0 to

STR5 has a short circuit fault 0x05 00000000

PWMFREQ Internal PWM frequency is the

maximum 43kHz 0x06 00000000

PWMDUTY Internal PWM duty ratio is 0.39% 0x07 00000000

STREN All of the six LED outputs STR0 to

STR5 are enabled 0x09 00111111

IDAC LED string current is 100% of the value

programmed by resistor R5 0x10 00001111

Atmel LED Drivers-MSL1061/MSL1064

6-string PWM LED Driver with Digitally Compensated, 1.1MHz,

48V Boost Regulator, ±1.5% Current Balance, I2C Interface

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