MSL1064AW

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 Atmel LED Drivers-MSL1061/MSL1064 6-string PWM LED Driver with Digitally Compensated, 1.1MHz, 48V Boost Regulator, ±1.5% Current Balance, I2C Interface General Description The Atmel® LED DriversMSL1061 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 12bit 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 MSL1061AV MSL1064AW DESCRIPTION 6-ch LED driver 6-ch LED driver PACKAGE 28-pin, 5x5x0.75mm TQFN 24-pin, 5x5x0.75mm TQFN 2 Atmel 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 • 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 Application Circuit VIN = 4.75V to 36V VOUT = 48V max VIN EN SW OVP Fault Alert FLTB OSC ILED Set String current Up to 12 White LEDs per String …. ALS or NTC IADJ MSL1061 MSL1064 STR0 . STR5 SDA . . . 1.5% maximum current mismatch between Strings PWM GND SCL AD0 I C or SMBus I C address selection (MSL1061 only) Atmel LED Drivers-MSL1061/MSL1064 3 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). 4 Atmel 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 Table 1. Atmel LED Drivers-MSL1061 and MSL1064 Comparison FEATURE I2C interface MSL1061 4 selectable slave addresses by AD0 pin (0x60, 0x61, 0x62, 0x63) 28-lead, 5mm x 5mm TQFN, 0.5mm pitch 0.2mm min gap between SW pins and adjacent conductors. Compliant to 100V with board coating, 15V without coating MSL1064 1 fixed slave address (0x62) 24-lead, 5mm x 5mm TQFN, 0.65mm pitch 0.6mm min total gap between SW pins and adjacent conductors. Compliant to 100V with or without board coating APPLICATION AND SUITABILITY Only one MSL1064 is uniquely addressed on an I2C bus Package IPC2221A-2003 compliance If compliance is necessary use the MSL1064 or MSL1061 with board coating. 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. Table 2. Atmel LED Drivers-MSL1061/64 Stand Alone Capabilities and I2C Controlled Features FUNCTION Global on/off control Individual LED string on/off control Analog LED current adjustment PWM LED current adjustment Ambient light sensor (ALS) and/ or auto-matic temperature LED current adjustment Fault monitoring CONTROLS AVAILABLE ON PINS EN pin (Table 3 on page 9) Not available ILED pin (Table 3 on page 8) PWM pin (Table 3 on page 8) ADDITIONAL CONTROLS AVAILABLE VIA I2C Run mode/sleep mode String enables register Current setting register PWM frequency register PWM duty ratio register IADJ pin (Table 3 on page 9) Current setting register FLTB pin indicates open-string, shortedstring, and over-temperature faults Status register identifies open/short circuit and overtemperature faults to individual strings Atmel LED Drivers-MSL1061/MSL1064 5 Packages and Pin Connections Atmel LED Drivers-MSL1061/64 – 24-pin, 5mm x 5mm x 0.75mm TQFN package with 0.65mm lead pitch N/C 24 VCC VDD TEST1 TEST2 SDA SCL 1 2 3 4 5 6 7 PWM 23 22 21 20 N/C 19 18 OVP 17 STR0 16 STR1 Figure 1. 24-pin, 5mm x 5mm x 0.75mm TQFN (0.65mm pin pitch) with Exposed Pad VIN SW MSL1064 (TOP VIEW) SW EN 15 STR2 14 STR3 13 STR4 8 FLTB 9 OSC 10 ILED 11 IADJ 12 STR5 Figure 2. 24-pin TQFN Package Dimensions 6 Atmel 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 28 VCC VDD TEST1 TEST2 SDA SCL AD0 1 2 3 4 5 6 7 8 PWM 27 26 25 24 23 N/C 22 21 OVP 20 TEST3 19 STR0 VIN SW SW SW SW EN MSL1061 (TOP VIEW) 18 STR1 17 STR2 16 STR3 15 STR4 Figure 3. 28-pin, 5mm x 5mm x 0.75mm TQFN (0.5mm pin pitch) with Exposed Pad 9 FLTB 10 OSC 11 N/C 12 ILED 13 IADJ 14 STR5 Figure 4. 28-pin TQFN Package Dimensions Atmel LED Drivers-MSL1061/MSL1064 7 Pin Descriptions Table 3. Pin Assignments PIN NAME MSL1061 MSL1064 PIN DESCRIPTION 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 2.9V internal linear regulator output VDD powers internal logic. Bypass VDD to GND with at least a 4.7µF ceramic capacitor Factory test connection. Leave unconnected Factory test connection. Connect to GND I²C serial data I/O SDA is the data I/O for the I²C serial interface I²C serial clock input SCL is the clock input for the I²C serial interface 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 fixed at 0x62, and is not user-selectable PWM control input Drive PWM with a PWM signal up to 40kHz to pulse-width-modulate the LED current 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. 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 Factory test connection with internal 1.8kΩ pull-up to VDD. Leave unconnected 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 VCC 1 1 VDD TEST1 TEST2 SDA 2 3 4 5 2 3 4 5 SCL 6 6 AD0 7 - PWM 8 7 FLTB 9 8 OSC 10 9 TEST3 11 - ILED 12 10 8 Atmel 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 PIN NAME IADJ MSL1061 13 MSL1064 11 PIN DESCRIPTION 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 LED string 5 current sink output Connect the cathode of LED String 5 to STR5. Connect STR5 to GND if unused LED string 4 current sink output Connect the cathode of LED String 4 to STR4. Connect STR4 to GND if unused LED string 3 current sink output Connect the cathode of LED String 3 to STR3. Connect STR3 to GND if unused LED string 2 current sink output Connect the cathode of LED String 2 to STR2. Connect STR2 to GND if unused LED string 1 current sink output Connect the cathode of LED String 1 to STR1. Connect STR1 to GND if unused LED string 0 current sink output Connect the cathode of LED String 0 to STR0. Connect STR0 to GND if unused 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 No internal connection. Leave unconnected Drain of the internal boost power MOSFET switch Connect all SW pins together and to the boost regulator inductor and rectifier No internal connection. Leave unconnected 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 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 Ground STR5 14 12 STR4 15 13 STR3 16 14 STR2 17 15 STR1 18 16 STR0 19 17 OVP 21 18 N/C SW N/C 22 23, 24, 25, 26 - 19 20, 21 22 EN 27 23 VIN 28 24 GND Exposed pad Exposed pad Atmel LED Drivers-MSL1061/MSL1064 9 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) SW ............................................................................................................................................................................................................................................±3A 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 10 Atmel 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 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 DC ELECTRICAL CHARACTERISTICS VIN operating supply voltage VIN quiescent supply current VIN shutdown supply current VCC output voltage VCC line regulation VCC dropout voltage VCC short-circuit current VCC UVLO threshold VDD output voltage VDD short-circuit current VDD UVLO threshold Thermal shutdown threshold (rising) Thermal shutdown hysteresis PARAMETER CONDITIONS AND NOTES MIN TYP MAX UNIT V VIN = V VCC VCC unconnected VEN = 3V, VPWM = 0V VEN = VPWM = 0V 6.5V < VVIN < 36V VVIN = 6V, IVCC = 5mA, VPWM = 0V VVCC = 0V VVCC rising, hysteresis = 150mV IVDD = 1mA VVDD = 0V VVDD rising, hysteresis = 80mV VVIN = 12V VVIN = 6V, VVCC = 6V 4.75 6.5 4 4 1 5.6 1 100 30 4.1 2.7 10 2.4 4 6 2 300 80 4.3 2.9 35 2.5 135 10 6.5 36 14 14 10 6.3 5 550 150 4.5 3.1 60 2.6 V V mA mA µA V mV mV mA V V mA V °C °C CONDITIONS AND NOTES MIN TYP MAX UNIT DC ELECTRICAL CHARACTERISTICS - LED CURRENT CONTROL STR0 TO STR5 ILED regulation voltage STR0 to STR5 full scale sink current STR0 to STR5 maximum sink current STR0 to STR5 current matching STR0 to STR5 leakage current STR0 to STR5 short circuit detection threshold STR0 to STR5 open circuit detection threshold PARAMETER DC ELECTRICAL CHARACTERISTICS - LOGIC I/OS EN logic high input voltage EN logic low input voltage EN logic input current VEN = 3V 2.3 0.8 20 V V µA CONDITIONS AND NOTES MIN R5 = 100kΩ VSTRn = 1V, R5 = 100kΩ, VIADJ = VPWM = 3V VSTRn = 1V, R5 = 60kΩ, VIADJ = VPWM = 3V (Note 10) VSTRn = 1V, R5 = 100kΩ, VPWM = 3V (Note 11) VEN = 0V, VSTRn = 40V VEN = 3V, VSTRn = 40V, VPWM = 3V 4 0.1 0.1 4.4 0.1 TYP MAX 1.195 19.7 30 1.5 1 1 4.8 1.22 20 1.245 20.3 V mA mA % µA µA V V UNIT Atmel LED Drivers-MSL1061/MSL1064 11 PARAMETER EN logic input series resistance EN logic input Zener clamp SCL, SDA, AD0, PWM logic high input voltage SCL, SDA, AD0, PWM logic low input voltage SDA, SCL, AD0 input capacitance SDA output low voltage FLTB output low voltage IADJ, FLTB, PWM, SCL, SDA, AD0 leakage current PARAMETER CONDITIONS AND NOTES Between EN input package pin and internal Zener clamp MIN TYP 10.5 5.8 MAX UNIT kΩ V V 2 0.9 10 Sinking 6mA Sinking 1mA 0.1 0.4 0.2 10 V pF V V µA CONDITIONS AND NOTES MIN TYP MAX UNIT DC ELECTRICAL CHARACTERISTICS - BOOST REGULATOR SW on resistance SW current limit OSC regulation voltage STR0-STR5 boost regulation voltage OVP threshold OVP hysteresis OVP leakage current PARAMETER AC ELECTRICAL CHARACTERISTICS PWM input frequency PWM input duty ratio PWM input minimum string on time PWM input minimum string off time PWM input frequency, external PWM clock mode PWM input duty ratio, 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 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 R4 = 115kΩ ±1% R4 = 115kΩ ±1% 0 30 INTPWM bit D3=0 in control register to select external PWM input to be used for direct LED string dimming control 0 0 14 3.2 12 70 50 100 kHz % µs µs MHz % VOVP = 3.6V CONDITIONS AND NOTES MIN TYP R4 = 115kΩ ±1% R5 = 100kΩ, PWM=100% (Note 12) VOVP rising 1.25 1.195 ISW = 100mA 0.4 2 1.22 600 1.28 60 1 MAX 1.31 1.245 0.6 Ω A V mV V mV µA UNIT PWM frequency (internal oscillator) Boost regulator switching frequency Boost regulator maximum duty ratio Boost regulator startup time 9 0.99 89 11 1.1 92 100 12 1.21 120 MHz MHz % ms 12 Atmel 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 PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT I²C SWITCHING CHARACTERISTICS TOEN bit D1=0 in control register to disable bus timeout TOEN bit D1=1 in control register to enable bus timeout 0 1000 0.066 15 0.5 0.26 0.26 0.26 5 (Note 3) (Note 4) 0.05 0.05 100 0.5 0.26 (Note 5, Note 6) 120 120 (Note 7, Note 10) 50 0.55 0.55 25 ms µs µs µs µs ns µs µs ns µs µs ns ns ns kHz SCL clock frequency 1/tSCL Bus time-out period STOP to START condition bus free time Repeated START condition hold time Repeated START condition set-up time STOP condition set-up time SDA data hold time SDA data valid acknowledge time SDA data valid time SDA data set-up time SCL clock low period SCL clock high period SDA, SCL fall time SDA, SCL rise time SDA, SCL input suppression filter period tTIMEOUT tBUF tHD:STA tSU:STA tSU:STOP tHD:DAT tVD:ACK tVD:DAT tSU:DAT tLOW tHIGH tF tR tSP 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 Atmel LED Drivers-MSL1061/MSL1064 13 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 14 Atmel LED Drivers-MSL1061/MSL1064 Typical Application Circuit Figure 6. Backlight Example Driving 60 White LEDs 4.7 Table 4. Typ. Application Circuit Parameters Table 5. Typ. Application Circuit Bill of Materials PARAMETER Minimum input voltage Maximum input voltage (set by minimum LEDs string voltage) Number of LEDs Number of LED strings Number of LED per string LED forward current (set by R5) White LED Minimum LED forward voltage Typical LED forward voltage Maximum LED forward voltage Minimum LED string voltage Maximum LED string voltage Oscillator frequency (set by R4) Overvoltage protection (OVP) trip point (set by R8 and R9) Atmel LED Drivers-MSL1061/MSL1064 VALUE 4.75V 30V 60 6 10 20mA Osram LWY3SG 2.9V 3.3V 3.6V 29V 36V 1.1MHz 45.9V COMPONENT C4, C5, C6, C7* C2 C3 C1 R8 R9 R4 R5 R7 R2 L1 D1 LEDs LED driver DESCRIPTION 1µF, 50V, X7R 10µF, 10V, X7R or tantalum (see note) 33µF, 35V, X7R 4.7µF, 6.3V, X7R 1MΩ, 1% 28.7kΩ, 1% 115kΩ, 1% 100kΩ, 1% 100kΩ, 5% 1MΩ, 5% 10µH, 1.7A 60V, 2A Schottky 60 x 30mA LED MSL1060 VENDOR PART NUMBER Sumida CDRH6D28-100 Central Semi CMSH2-60M Osram LW-Y2SG MSL1060 15 * Note: C7 is only required if tantalum capacitor is used for C2 Detailed Description 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. 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 fullscale LED current is 30mA. The equation for calculating external resistor R5 (Figure 6) to set the full-scale LED string current IILED is: 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. I ILED = 2000 R5 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. 16 Atmel 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 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 currentmode 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): VTRIP = VOVP ( R8 + R 9 ) R9 where VOVP=1.28V, nominal. Atmel LED Drivers-MSL1061/MSL1064 17 Register Map Summary 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. Table 6. Atmel LED Drivers-MSL1061/64 Register Map REGISTER FUNCTION Run/sleep mode PWM source, I2C/ SMB bus timeout, fault pin enable UNUSED Fault status summary Open circuit fault status Short circuit fault status PWM frequency prescaler PWM duty ratio UNUSED String enables unused unused unused unused unused unused LED string current ADDRESS REGISTER DATA D7 D6 D5 D4 D3 D2 D1 D0 SLEEP MSTRCNTRL 0x00 CNTRL 0x01 - - - - INTPWM EXTCLK TOEN FLTEN STATUS OCSTATUS SCSTATUS PWMFREQ PWMDUTY STREN IDAC 0X02 0x03 0x04 0x05 0x06 0x07 0X08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 0x10 D7 D7 WRITES TO THIS REGISTER ADDRESS ARE IGNORED, AND READS RETURN THE VALUE 0X00 OTDET D6 D6 SCDET OC5 SC5 D5 D5 OCDET OC4 SC4 D4 D4 OC3 SC3 D3 D3 OC2 SC2 D2 D2 OC1 SC1 D1 D1 FLTDET OC0 SC0 D0 D0 WRITES TO THIS REGISTER ADDRESS ARE IGNORED, AND READS RETURN THE VALUE 0X00 STR5EN STR4EN STR3EN STR2EN STR1EN STR0EN writes to this register address are ignored, and reads return the value 0x00 writes to this register address are ignored, and reads return the value 0x00 writes to this register address are ignored, and reads return the value 0x00 writes to this register address are ignored, and reads return the value 0x00 writes to this register address are ignored, and reads return the value 0x00 writes to this register address are ignored, and reads return the value 0x00 DAC3 DAC2 DAC1 DAC0 18 Atmel 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 Register Map Power-up Defaults Table 7. Atmel LED Drivers-MSL1061/64 Register Power-up Defaults REGISTER MSTRCNTRL POWER-UP CONDITION Run mode 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 No faults (open, short, or temperature) are detected None of the six LED outputs STR0 to STR5 has an open circuit fault None of the six LED outputs STR0 to STR5 has a short circuit fault Internal PWM frequency is the maximum 43kHz Internal PWM duty ratio is 0.39% All of the six LED outputs STR0 to STR5 are enabled LED string current is 100% of the value programmed by resistor R5 ADDRESS 0x00 REGISTER DATA D7 0 D6 0 D5 0 D4 0 D3 0 D2 0 D1 0 D0 0 CNTRL 0x01 0 0 0 0 0 0 0 1 STATUS OCSTATUS SCSTATUS PWMFREQ PWMDUTY STREN IDAC 0x03 0x04 0x05 0x06 0x07 0x09 0x10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1 0 0 0 0 0 1 1 0 0 0 0 0 1 1 0 0 0 0 0 1 1 Atmel LED Drivers-MSL1061/MSL1064 19 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: (+1)(408) 441-0311 Fax: (+1)(408) 487-2600 www.atmel.com Atmel Asia Limited Unit 01-5 & 16, 19F BEA Tower, Millennium City 5 418 Kwun Tong Road Kwun Tong, Kowloon HONG KONG Tel: (+852) 2245-6100 Fax: (+852) 2722-1369 Atmel Munich GmbH Business Campus Parkring 4 D-85748 Garching b. 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