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Atmel MSL3080 Datasheet

8 String 60mA LED Driver with Integrated Boost Controller

Atmel MSL3080

8 String 60mA LED Drivers

with Integrated Boost Controller

FULL DATASHEET

Features:

• Drives 8 parallel 60mA LED strings at up to

40V LED string voltage

• Integrated boost controller

• Offers true 12-bit LED dimming at 120Hz

• String open circuit and LED short circuit fault detection

and automatic shut down

• ±3% current accuracy and current balance

• Single resistor sets current for all LED strings

• External PWM dimming

• Internal PWM dimming control engine

•

Single PWM input sets dimming duty cycle and frequency

• Internal PWM dimming (use optional)

•

Synchronizes PWM dimming to LCD panel refresh rate

•

Frequency multiplier allows PWM dimming at multiples

of LCD panel refresh frequency (see Programming Guide)

• 1MHz I²C/SMBus interface; use optional

• Resistor programmable LED short circuit threshold

• Die over-temperature cut-off protection

• -40°C to +85°C operating temperature range

• Lead free, halogen free, RoHS compliant package

Description:

The MSL3080 8-channel LED drivers with integrated boost regulator controller offers a complete solution

to drive parallel LED strings at up to 40V. The LED current sinks control up to 60mA each for up to 19W

of LED power. The MSL3080 has eight current sinks. Parallel connect the current sinks for increased

string current. A single resistor sets LED current, with string matching and accuracy within ±3%.

The advanced integrated PWM circuitry allows up to 4095:1 dimming, and offers simple PWM dimming

control. External PWM dimming is controlled by a signal at the PWM input, which sets both the PWM

duty cycle and frequency of the dimming signals. The internal PWM dimming is controlled by registers

accessible through the I

C serial interface.

The MSL3080 feature integrated fault detection circuitry that detects and acts upon string open-circuit

and LED short circuit faults, boost regulator over-voltage faults, and die over-temperature faults. A

proprietary Efciency Optimizer maintains sufcient boost regulator output voltage to maintain LED

current regulation while minimizing power use. A 1MHz I

C/SMBus serial interface allows optional

dimming control, fault inspection and control of driver conguration; for serial interface information see

the “MSL3040/50/60/80/86/87/88 Programming Guide”.

The MSL3080 IS offered in the 24-pin VQFN lead-free, halogen-free, RoHS compliant package and

operate over -40°C to +85°C.

DBIE-20120814

MSL3050/MSL3060/MSL3080 Datasheet

Preliminary

I²C and SMBus are trademarks of their respective owners.

MSL3050/60/80 preliminary datasheet revision 0.1 Page 1 of 24

5, 6 and 8 String 60mA LED Drivers with Integrated Boost

Controller

______________ General Description

The MSL3050/MSL3060/MSL3080 multi-channel LED drivers with

integrated boost regulator controller offer a complete solution to

drive parallel LED strings at up to 40V. The LED current sinks

control up to 60mA each for up to 19W of LED power. The

MSL3050 has five current sinks, the MSL3060 has six and the

MSL3080 has eight. Parallel connect the current sinks for

increased string current. A single resistor sets LED current, with

string matching and accuracy within ±3%.

The advanced integrated PWM circuitry allows up to 4095:1

dimming, and offers simple PWM dimming control. External PWM

dimming is controlled by a signal at the PWM input, which sets

both the PWM duty cycle and frequency of the dimming signals.

The internal PWM dimming is controlled by registers accessible

through the I2C serial interface.

The MSL3050/60/80 feature integrated fault detection circuitry

that detects and acts upon string open-circuit and LED short

circuit faults, boost regulator over-voltage faults, and die over-

temperature faults. A proprietary Efficiency Optimizer maintains

sufficient boost regulator output voltage to maintain LED current

regulation while minimizing power use. A 1MHz I

C/SMBus serial

interface allows optional dimming control, fault inspection and

control of driver configuration; for serial interface information see

the MSL3050/60/80/50/60/80/86/87/88 Programming Guide.

The MSL3050/60/80 are offered in the 24-pin VQFN lead-free,

halogen-free, RoHS compliant package and operate over -40°C

to +85°C.

_____________________ Applications

Long Life, Efficient LED Backlighting for:

Televisions and Desktop Monitors

Medical and Industrial Instrumentation

Automotive Audio-Visual Displays

Channel Signs

Architectural Lighting

_____________ Ordering Information

PART DESCRIPTION PKG

MSL3050

5-CH LED driver with integrated boost

controller and resistor based LED Short

Circuit threshold setting, with single

PWM input.

24 pin

4 x 4 x 0.75mm

VQFN

MSL3060

6-CH LED driver with integrated boost

controller and resistor based LED Short

Circuit threshold setting, with single

PWM input.

24 pin

4 x 4 x 0.75mm

VQFN

MSL3080

8-CH LED driver with integrated boost

controller and resistor based LED Short

Circuit threshold setting, with single

PWM input.

24 pin

4 x 4 x 0.75mm

VQFN

____________________ Key Features

 Drives 5/6/8 parallel 60mA LED strings at up to 40V LED

string voltage

 Integrated boost controller

 Offers true 12-bit LED dimming at 200Hz

 String open circuit and LED short circuit fault detection and

automatic shut down

 ±3% current accuracy and current balance

 Single resistor sets current for all LED strings

 External PWM dimming

 Internal PWM dimming control engine

 Single PWM input sets dimming duty cycle and frequency

 Internal PWM dimming (use optional)

 Synchronizes PWM dimming to LCD panel refresh rate

 Frequency multiplier allows PWM dimming at multiples of

LCD panel refresh frequency (see Programming Guide)

 1MHz I²C/SMBus interface; use optional

 Resistor programmable LED short circuit threshold

 Die over-temperature cut-off protection

 -40°C to +85°C operating temperature range

 Lead free, halogen free, RoHS compliant package

_______________ Application Circuit

ENABLE

= 5V

SDA

SCL

FLTB

PWM

ILED

PGND GND EP

STR3

STR2

STR1

STR0

GATE

VIN PVIN

INTERFACE

FBI

FAULT

OUTPUT

PWM

INPUT

COMP

MSL3080

STR4

STR5

STR6

STR7

LED

PWR

= 12V

10 H

25m

2nF

22k

20 F

3.12k

47.5k

91.3k

60V 3A

FDC

5612

10 F

APPLICATION CIRCUIT

Summary of content (23 pages)

PAGE 1
5, 6 and 8 String 60mA LED Drivers with Integrated Boost Controller ______________ General Description The MSL3050/MSL3060/MSL3080 multi-channel LED drivers with integrated boost regulator controller offer a complete solution to drive parallel LED strings at up to 40V. The LED current sinks control up to 60mA each for up to 19W of LED power. The MSL3050 has five current sinks, the MSL3060 has six and the MSL3080 has eight. Parallel connect the current sinks for increased string current.
PAGE 2
Table of Contents 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Packages and Pin Connections.................................................................. 3 Pin Descriptions........................................................................................... 4 Absolute Maximum Ratings........................................................................ 5 Electrical Characteristics............................................................................ 6 Typical Operating Characteristics.................
PAGE 3
PHASE SHIFTED LED DIMMING SIGNALS /MSL3060/MSL3080 1.0 Packages andDatasheet Pin Connections Preliminary By default, string PWM dimming is staggered in time to reduce t MSL3040/41 automatically determine the stagger times based o frequency. FB 1 VIN 2 COMP CS EN FLTB PVIN ● GND PHASE SHIFTED LED DIMMING SIGNALS 1.1 24 pin 4 x 4 x 0.
PAGE 4
2.0 Pin Descriptions Table 2.1 Pin Assignments Name MSL3080 Pin Description VLED Voltage Regulator Feedback Input: Connect a resistive voltage divider from the boost regulator output, VLED, to FB to set the unoptimized boost regulator output voltage. The feedback regulation voltage is 2.5V. FB 1 VIN 2 Power Supply Input: Power supply input. Apply 4.5V to 5.5V to VIN. Decouple VIN to GND a 1µF or greater capacitor placed close to VIN.
PAGE 5
3.0 Absolute Maximum Ratings Voltage (with respect to GND) VIN, PVIN, EN, SDA, SCL, PWM, FLTB, SCTH, ILED, CS, COMP, FB, GATE................................................................ -0.3V to +5.5V STR0 to STR7.................................................................................................................................................................... -0.3V to +40V PVIN to VIN.........................................................................................................
PAGE 6
4.0 Electrical Characteristics VVIN = 5V, VEN = 5V, Default Register Settings of Table 1, TA = -40°C to 85°C, unless otherwise noted.
PAGE 7
MSL3050/MSL3060/MSL3080 Datasheet Preliminary 5.0 Typical Operating Characteristics Typical Operating Characteristics (Typical Operating Circuit, unless otherwise stated) (Typical Operating Circuit, unless otherwise stated, TA = +25°C, unless otherwise noted) BOOST REGULATOR EFFICIENCY vs. OUTPUT CURRENT 100 10000 1000000 90 10000 85 IIN(µA) (µA) IIN 80 75 70 10100 VPWR = 12V 60 0.
PAGE 8
CH1 = V CH3 = VSTRx, CH4 = IPWR(continued) 5.0 Typical Operating EN, CH2 = VLED,Characteristics CH1 = VLED, CH2 = VGATE, CH3 = IINDUCTOR (Typical Operating Circuit, unless otherwise stated, TA = +25°C, unless otherwise noted) BOOST WAVEFORMS 100% LED DUTY CYCLE AUTO CALIBRATION CH2 = VLED, CH3 = VSTRx MSL3050/MSL3060/MSL3080 Datasheet CH1 = VLED, CH2 = VGATE, CH3 = IINDUCTOR BOOST REGULATOR WAVEFORMS 10% TO 99.5% LED DUTY CYCLE MSL3050/60/80 preliminary datasheet revision 0.1 © Atmel Inc., 2011.
PAGE 9
MSL3050/MSL3060/MSL3080 Datasheet Preliminary 6.0 Block BlockDiagram Diagram Figure 6.1. Block Diagram MSL3080 Figure 1. MSL3050/MSL3060/MSL3080 Block Diagram MSL3050/60/80 preliminary datasheet revision 0.1 © Atmel Inc., 2011. All rights reserved.
PAGE 10
MSL3050/MSL3060/MSL3080 Datasheet Preliminary 7.0 Typical Application Circuits Figure 7.1. Typical Operating Circuit for Eight 60mA Strings of 10 White LEDs each. Typical Application Circuits VPWR = 12V 10 F VIN = 5V 1 F 2 VIN ENABLE 21 3 I2C INTERFACE 4 PWM INPUT 14 FAULT OUTPUT 20 5 18 GATE 22 CS VLED 47.5k SDA MSL3080 FB 1 22k PWM 3.12k 2nF FLTB COMP 23 SCTH STR0 STR1 ILED STR2 STR3 93.
PAGE 11
MSL3050/MSL3060/MSL3080 Datasheet Figure 7.2. Typical Operating Circuit for Four 120mA Strings of 10 White LEDs each. VPWR = 12V Preliminary 10 F VIN = 5V 1 F 2 VIN ENABLE 21 3 I2C INTERFACE 4 PWM INPUT 14 FAULT OUTPUT 20 5 18 GATE 22 CS VLED 47.5k SDA MSL3080 FB 1 22k PWM 3.12k 2nF FLTB COMP 23 SCTH STR0 STR1 ILED STR2 STR3 93.1k STR4 STR5 15 FDC5612 25m EN SCL 2x 10 F B380 19 PVIN 82k 16 10 H 2x 1 F STR6 CGND PGND 17 EP STR7 GND 24 6 7 8 9 10 11 12 13 Figure 3.
PAGE 12
MSL3050/MSL3060/MSL3080 Datasheet Figure 7.3. Typical Operating Circuit for One 480mA String of 10 White LEDs. VPWR = 12V Preliminary 10 F VIN = 5V 1 F 2 VIN ENABLE 21 3 I2C INTERFACE 4 PWM INPUT 14 FAULT OUTPUT 20 5 18 GATE 22 CS VLED 47.5k SDA MSL3080 FB 1 22k PWM 3.12k 2nF FLTB COMP 23 SCTH STR0 STR1 ILED STR2 STR3 93.1k STR4 STR5 15 FDC5612 25m EN SCL 2x 10 F B380 19 PVIN 82k 16 10 H 2x 1 F STR6 CGND PGND 17 EP STR7 GND 24 6 7 8 9 10 11 12 13 Figure 4.
PAGE 13
8.0 Detailed Description The MSL3080 is an LED driver with eight internal current regulators, each capable of driving up to 60mA LED current. They feature an integrated boost regulator controller with a proprietary Efficiency Optimizer voltage control algorithm that lowers power use to the minimum required to assure LED current regulation. The driver outputs allow parallel connection to increase string current, at the expense of the number of strings, and a single resistor sets the current for all strings.
PAGE 14
8.2 Boost Regulator Overview The MSL3080 boost regulator boosts the input voltage up to the regulated output voltage (for design details see the section “Boost Regulator” beginning on page 17, the following text presents an overview of the boost regulator controller). The boost regulator uses an external switching MOSFET, current sense resistor, inductor, rectifier, and input and output capacitors (Figure 8.1).
PAGE 15
8.4 Gate Driver The gate driver drives the gate of the external boost regulator switching MOSFET. The drain of the switching MOSFET in turn drives the boost inductor and rectifier to boost the input voltage to the regulated output voltage. The gate driver sources and sinks up to 1A allowing fast switching speed and allows the use of MOSFETs with high gate capacitance.
PAGE 16
8.10 Internal Supervisory and LDO The MSL3080 has a Power-On-Reset circuit that monitors VIN and allows operation when VIN exceeds 4.25V. The MSL3080 has built-in LDOs that generate 2.5V to power the logic and oscillator sections. An integrated supervisor ensures that the LDO and internal oscillator are stable before enabling the boost controller. The boost controller goes through a soft-start before the LED drivers are enabled. 8.
PAGE 17
9.0 Application Information 9.1 Bypassing VIN and PVIN Bypass VIN with a capacitor of at least 1µF. Bypass PVIN to PGND with at least 2µF. Place all bypass capacitors close to the MSL3080. 9.2 Setting the LED Current Set the on-current for all LED strings with a resistor from ILED to GND. Choose the resistor using: where ILED is the LED full-scale current in Amps. The maximum LED current per-string is 60mA.
PAGE 18
Figure 9.1 Open-Circuit and Short-Circuit Detection Block Diagram 9.5 Boost Regulator The boost regulator boosts the input voltage to the regulated output voltage that drives the LED anodes. The MSL3080 boost regulator uses an external MOSFET switch and current sense resistor, allowing a wide variety of input/output voltage combinations and load currents. The boost regulator switching frequency is 625kHz.
PAGE 19
9.6 The Efficiency Optimizer (EO) MSL3050/MSL3060/MSL3080 Datashee Prelimi A voltage the boost regulator output voltage to FB sets the regulation voltage (RTOP 8.1 oninto page 14). BOTTOM in Figure power divider supplyfrom noise rejection, while minimizing power dissipation. It does thisand byRinjecting a current the FB The EO improves power efficiency by dynamically adjusting the power supply output voltage to the minimum required to power the LEDs. 256 steps (8-bit resolution).
PAGE 20
OUT ( in MAX MAX total ) LEDs a) string,f (the minimum and maximum voltage drop across a string is 35V and 38V. Adding allowance of 0. for the current regulator headroom brings VOUT(MIN) to 35.5V and VOUT(MAX) to 38.5. Next determine RTOP using: where Vf(MIN) and Vf(MAX) are the LED’s minimum and maximum forward voltage drops at the full-scale current set by RI (page 14). For( MAX example, if the LED minimum forward voltage is Vf(MIN) = 3.5V and maximum is Vf(MAX) = 3.8V, using 10 VOUT )  VOUT ( MIN ) .
PAGE 21
Inductors have two types of maximum current ratings, RMS current and saturation current. Make sure that the peak inductor current is less than the saturation current rating. Note that during load current transients, which occur whenever the LEDs are turned on or off (due to PWM dimming), the inductor current may overshoot its steady state value. How much it overshoots depends on the boost regulator loop dynamics.
PAGE 22
crossover is: zero frequency. or the switching frequency fSW. The of the ESR Assure that the loop crossover frequency is at frequency least 1/5thth equation of the lower of the ESR zero fESRZ, theof right-half-plane zero fRH Next determine the desired crossover frequency as 1/5 Series Resistance the output capacitor. where COUT is the value of the output capacitor, and ESR is the Equivalent th .
PAGE 23
10.0 LED Dimming Control 10.1 External and I2C Control of LED Brightness Control LED brightness using Pulse Width Modulation (PWM) with a PWM signal applied to the external PWM input. The LED PWM dimming occurs at the same frequency and duty cycle as the input signal. For all drivers, use PWM input frequency between 20Hz and 50kHz and duty cycle between 0% and 100%.