Atmel LED Drivers MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Datasheet Brief Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface General Description The Atmel LED DriversMSL3163 and MSL3164 compact, high-power LED string drivers use internal current control MOSFETs to sink up to 100mA per string, with current accuracy and matching better than 3%. The MSL3163/4 drive 16 parallel strings of ten white LEDs each, for a total of 160 white LEDs per device. Sixteen interconnected devices control up to 2560 white LEDs. The MSL3163/4 adaptively controls the DC-DC converters that power the LED strings, using Atmel's Adaptive SourcePower technology. These Efficiency Optimizers minimize power use while maintaining LED current accuracy. The MSL3164 features a 20 MHz SPI serial interface, and the MSL3163 offers a 1 MHz I2C serial interface. Both interfaces support video frame-by-frame LED string intensity control for up to 16 interconnected devices to allow active area dimming. The devices include an advanced PWM engine that easily synchronizes to a video signal, and per-string phase adjustment to reduce unwanted LCD artifacts such as motion blur. Additionally, an on-chip E²PROM allows the power-up defaults to be customized through the serial interface. A unique combination of peak current control and pulse width management offer simple full screen brightness control, versatile area dimming and a consistent white point. One external resistor provides the global peak reference current for all LED strings, and global peak current fine-tuning is available through an 8-bit register. Global string drive pulse width is adjusted with an 8-bit global intensity register, and individual string pulse width is modulated with 12-bit registers. The MSL3163/4 feature fault monitoring of open circuit, short circuit, loss of video sync and over temperature conditions, and provides a fault output to notify the system controller. Detailed fault status and control are available through the serial interface. The MSL3163/4 are offered in a 6 x 6 x 0.75mm, 40-pin TQFN package and operate over the -40°C to 85°C temperature range. 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 16-CHANNEL LED STRING DRIVERS 2 PART INTERFACE PACKAGE MSL3163BT I2C interface 40 pin, 6 x 6 x 0.75mm TQFN MSL3164BT SPI interface 40 pin, 6 x 6 x 0.75mm TQFN Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Key Features • 12-bit PWM String Dimming Operates at 240Hz • ±3% Current Accuracy and Current Balance • Fast Serial Interfaces Support up to 16 Devices per Bus: • Video Frame (VSYNC) and Line (HSYNC) Sync Inputs - MSL3164 20 MHz SPI • Sync Loss Detectors Optionally Disable LED Strings - MSL3163 1 MHz I2C • Multiple MSL3163/4s Share String Power Supplies and Automatically Negotiate the Optimum Supply Voltage • 8-bit Adaptive Power Correction Maximizes Efficiency of up to Three String Power Supplies • Drives 16 Parallel LED Strings of 10 White LEDs Each for up to 2560 White LEDs per Serial Bus • E²PROM Allows Customized Power-On Defaults • Less Than 1µA LED String Off-Leakage Current • Supports Adaptive, Real-time Area Dimming for Highest Dynamic Range LCD TVs and Monitors • String Open Circuit and LED Short Circuit Fault Detection • Programmable String Phase Reduces Motion Blur • Individual Fault Detection Enable for Each String • Global Intensity Control via Serial Interface • Over-temperature Shutoff Protection • 100mA Peak, 60mA Average LED String Current • Broadcast Write Simplifies Configuration • Single Resistor Sets Peak Current for all LED Strings • -40°C To +85°C Operating Temperature Range Application Circuit Ω Atmel LED Drivers-MSL3163/MSL3164 3 FBO2 FBI1 FBO1 NC VDD VIN EN ILED GND CGND Package Pin-out 40 39 38 37 36 35 34 33 32 31 FBI2 1 30 FBO3 2 29 SDA FBI3 3 28 TEST PHI 4 27 SCL GSC 5 26 AD0 PWM 6 MSL3163 STR0 7 (TOP VIEW) STR1 8 23 STR14 STR2 9 22 STR13 STR3 10 21 STR12 4 Figure 1. Atmel LED DriverMSL3163 Pinout 40 Pin TQFN CGND GND STR8 STR9 STR10 STR11 VIN EN ILED GND CSB 20 VDD 19 STR7 18 NC 17 STR6 16 FBO1 15 STR5 14 FBI1 13 24 STR15 STR4 12 25 FLTB FBO2 11 AD1 40 39 38 37 36 35 34 33 32 31 FBI2 1 30 AD1 FBO3 2 29 MOSI FBI3 3 28 MISO PHI 4 27 SCK GSC 5 26 AD0 PWM 6 MSL3164 STR0 7 (TOP VIEW) STR1 8 23 STR14 STR2 9 22 STR13 STR3 10 21 STR12 25 FLTB 11 12 13 14 15 16 17 18 19 20 STR4 STR5 STR6 STR7 CGND GND STR8 STR9 STR10 STR11 24 STR15 Figure 2. Atmel LED DriverMSL3164 Pinout 40 Pin TQFN Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Figure 3. Package Dimensions: 40 Pin 6mm x 6mm x 0.75mm TQFN (0.5mm pin pitch) with exposed pad Atmel LED Drivers-MSL3163/MSL3164 5 Package Pin Description Table 1. Pin Assignments PIN PIN NAME MSL3163 MSL3164 PIN DESCRIPTION 1 FBI2 FBI2 Efficiency Optimizer input 2 Connect FBI2 to FBO2 of the next device when chaining devices (Figure 7). If unused connect FBI2 to GND. 2 FBO3 FBO3 Efficiency Optimizer output 3 Connect FBO3 to the third power supply’s feedback node or to FBI3 of the previous device when chaining devices (Figure 7). If unused connect FBO3 to GND. 3 FBI3 FBI3 Efficiency Optimizer input 3 Connect FBI3 to FBO3 of the next device when chaining devices (Figure 7). If unused connect FBI3 to GND. 4 PHI PHI Phase synchronization input Drive PHI with an external signal from 40Hz to 10kHz to synchronize the MSL3163/4 clock. PHI is typically the VSYNC signal input. 5 GSC GSC Gate shift clock input Drive GSC with the gate shift clock of the video signal, from 0 to 10MHz. GSC is typically the HSYNC signal input. PWM input PWM allows direct external control of the brightness of all LED strings. The PWM input may also be used as a gate signal for the output of the PWM. Drive PWM with a pulse-width modulated signal with duty ratio ranging from 0% to 100% and frequency up to 5kHz.When not configured for use as an input PWM is high-impedance. 6 PWM PWM 7 - 14, 17 24 STR0 thru STR15 STR0 thru STR15 LED string current sink outputs Connect the cathode of the n’th strings bottom LEDs to STRn. Connect unused STRn outputs to GND. 15 CGND CGND Connect to ground Connect CGND to GND and to EP with short, wide traces. 16, 32 GND GND Signal ground Connect all GNDs to system ground and to EP with short, wide traces. 25 FLTB FLTB Fault indication output (active low) Open drain output FLTB sinks current to GND whenever a fault condition is verified. Toggle EN low or read the fault registers to clear FLTB. Once cleared, FLTB reasserts if the fault conditions persist. 26,30 6 ID selection inputs AD0, AD1 AD0, AD1 Slave Connect AD1 and AD0 to GND through resistors to set the device address for the serial interface. 27 SCL SCK 28 TEST MISO 29 SDA MOSI 31 GND CSB MSL3163: I²C serial clock input SCL is the clock input for the I²C serial interface. MSL3164: SPI serial shift clock SCK is the clock input for the SPI interface. MSL3163: factory test I/O Factory test. Make no electrical connection to TEST. MSL3164: Master input slave output MISO is the SPI serial data output. MSL3163: I²C serial data I/O SDA is the data I/O for the I²C serial interface. MSL3164: Master input slave output MOSI is the SPI serial data input. MSL3163: ground. Connect GND to system ground and to EP with short, wide traces. MSL3164: chip select (active low) CSB is the chip select input for SPI transactions. CSB is active low. Maximum LED string current setting input Connect a resistor from ILED to GND to set the full-scale LED string current for all strings using ISTRING = 762 / RILED. For example, connect a 12.7kΩ resistor to GND to set a 60mA maximum sink current through each LED string. 33 ILED ILED 34 EN EN Enable input (Active high) Drive EN high to turn on the MSL3163/4, drive EN low to turn off the MSL3163/4. For automatic startup connect EN to VIN. When EN is low the entire device, including the serial interface, is turned off. Driving EN high initiates a boot load of the E2PROM data into the control registers, simulating a cold start-up. 35 VIN VIN Supply voltage input Connect a 5V supply to VIN. Bypass VIN to GND with a 10µF ceramic capacitor placed close to VIN. Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface PIN PIN NAME MSL3163 MSL3164 PIN DESCRIPTION 2.5V internal LDO regulator output VDD powers internal logic. Bypass VDD to GND with a 4.7µF ceramic capacitor placed close to VDD. 36 VDD VDD 37 NC NC 38 FBO1 FBO1 Efficiency Optimizer output 1 Connect FBO1 to the first power supply’s feedback node or to FBI1 of the previous device when chaining devices (Figure 7). If unused connect FBO1 to GND. 39 FBI1 FBI1 Efficiency Optimizer input 1 Connect FBI1 to FBO1 of the next device when chaining devices (Figure 7). If unused connect FBI1 to GND. 40 FBO2 FBO2 Efficiency Optimizer output 2 Connect FBO2 to the second power supply’s feedback node or to FBI2 of the previous device when chaining devices (Figure 7). If unused connect FBO2 to GND. EP EP EP No connect Leave NC unconnected. Exposed pad, power ground EP is the path that the string currents take to ground. EP also provides thermal relief for the die. Provide large traces from EP back to the string power supplies. Also connect EP to system ground, and to GND using short, wide traces. Absolute Maximum Ratings Voltage (With Respect to GND, CGND = EP = GND) VIN, EN......................................................................................................................................................................... -0.3V to +6V VDD.......................................................................................................................................................................... -0.3V to +2.75V MSL3163: SDA, SCL............................................................................................................................................. -0.3V to +6V MSL3164: MISO, MOSI, CSB, SCK............................................................................................ -0.3V to (VIN + 0.3V) FLTB............................................................................................................................................................................... -0.3V to +6V ILED, AD0, AD1..................................................................................................................................-0.3V to (VDD + 0.3V) PHI, GSC, PWM, FBO1, FBO2, FBO3, FBI1, FBI2, FBI3................................................. -0.3V to (VIN + 0.3V) STR0 thru STR15................................................................................................................................................ -0.3V to +40V CGND........................................................................................................................................................................ -0.3V to +0.3V Current (Into Pin) VIN................................................................................................................................................................................................ 50mA EP............................................................................................................................................................................................-1700mA STR0 thru STR15.............................................................................................................................................................. 105mA All other pins.............................................................................................................................................................................20mA Continuous Power Dissipation 40-Pin 6mm x 6mm QFN (derate 37mW/°C above TA = +70°C)......................................................2963mW 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 Atmel LED Drivers-MSL3163/MSL3164 7 Electrical Characteristics (Typical Application Circuit, VIN = 5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VIN = 5V, TA = +25°C). PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT 4.75 5 5.5 V 18 28 DC ELECTRICAL CHARACTERISTICS VIN Operating Supply Voltage VIN Operating Supply Current VIN IVIN EN = VIN, SLEEP = 0, RILED = 12.7kΩ, PHI = 240Hz, GSC = 983.04kHz, POWERCTRL = 0x4F, ISTR = 0xFF, OSCCTRL = 0x04, GSCINTEN = 0, PHIINTEN = 0, STRnEN = 1 PWMn = 0x7FF mA PWMn = 0xFFF 24 VIN Shutdown Supply Current ISHDN EN = GND, SDA, SCL, AD0, AD1, PWM, PHI and GSC = GND 10 µA VIN Sleep Current ISLEEP EN = 1, SLEEP = 1, SDA, SCL, AD0, AD1, PWM, PHI and GSC = GND or VDD 1.5 mA VDD Regulation Voltage VDD 2.4 Input High Voltage: SDA, SCL, PWM, PHI, GSC, MOSI, CSB VIH 0.7 x VDD Input Low Voltage: SDA, SCL, PWM, PHI, GSC, MOSI, CSB VIL 2.5 1.22 VOH ISOURCE = 5mA Output Low Voltage: PHI, GSC, SDA, MISO, FLTB VOL ISINK = 5mA ILED Regulation Voltage VIN – 0.4 350 0 FBO Feedback Output Current Range VFBO ≤ VIN – 0.5V 0 FBO Feedback Output Current Step Size FBI Input Disable Threshold RILED = 12.7kΩ, ISTR = 0xFF, VSTRn = 1V STR0 thru STR15 Sink Current Maximum RILED = 7.68kΩ, ISTR = 0xFF (Note 1) STR0 thru STR15 Current Load Regulation RILED = 12.7kΩ; ISTR = 0xFF, FLDBKEN = 0, VSTRn = 1V to 5V STR0 thru STR15 Current Matching STR0 thru STR15 Short Circuit Fault Detection Threshold STR0 thru STR15 Current Slew Rate Thermal Shutdown Temperature RILED = 12.7kΩ, ISTR = 0x7F, VSTRn = 1V VSTR RILED = 12.7kΩ; ISTR = 0xFF SCREF 55 60 mV μA 365 μA μA 50 mV 67 mA 100 mA 0.033 %/V -5 5 % 0.5 V 3.5 V Current rising (Note 2) 608 Current falling (Note 2) 10868 (Note 2) V 365 1.1 STR0 thru STR15 Sink Current V V 0.4 RILED = 12.7kΩ FBI Feedback Input Current V V 0.8 Output High Voltage: PHI, GSC, MISO V V Input Low Voltage: EN STR0 thru STR15 Minimum Headroom 2.6 0.3 x VDD Input High Voltage: EN 8 35 135 mA/µs °C Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT 18.15 20.00 21.88 MHz 10 kHz AC ELECTRICAL CHARACTERISTICS OSC Frequency fOSC PHI Frequency fPHI OSCCTRL = 0x04 0.04 PHI Lock PHI cycles 4 GSC Frequency fGSC PWM Frequency fPWM 0 PWM Duty Cycle PARAMETER 10 MHz 50 kHz 100 % MAX UNIT 1 MHz 0 SYMBOL CONDITIONS AND NOTES MIN TYP I²C TIMING CHARACTERISTICS, MSL3163 SCL Clock Frequency Bus Timeout Period STOP to START Condition Bus Free Time 1/tSCL ttimeout Bus timeout disabled (Note 3) 0 OSCCTRL = 0x04 30 fOSC = 16MHz to 23MHz ms 600,000 / fOSC s tBUF 0.5 µs Repeated START condition Hold Time tHD:STA 0.26 µs Repeated START condition Setup Time tSU:STA 0.26 µs STOP Condition Setup Time tSU:STOP 0.26 µs SDA Data Hold Time tHD:DAT 50 ns SDA Data Valid Acknowledge Time tVD:ACK (Note 4) 0.05 0.45 µs SDA Data Valid Time tVD:DAT (Note 5) 0.05 0.45 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 SDA, SCL Rise Time tr SDA, SCL Input Suppression Filter Period tSP PARAMETER SYMBOL (Note 6) (Note 7) (Note 8) CONDITIONS AND NOTES 120 ns 120 ns 50 MIN TYP ns MAX UNIT 20 MHz SPI TIMING CHARACTERISTICS, MSL3164 SCK Frequency CSB Falling Edge to SCK Rising Edge Setup Time Atmel LED Drivers-MSL3163/MSL3164 tCSB:SCK(SU) 100 ns 9 PARAMETER SYMBOL SCK Falling Edge to CSB Rising Edge Setup Time tSCK:CSB(SU) 50 ns tMOSI(SU) 16 ns tMOSI(HOLD) 20 ns MOSI to Falling Edge of SCK Setup Time SCK Falling Edge to MOSI Setup Time CONDITIONS AND NOTES MIN TYP MAX UNIT MOSI, CSB, SCK Signal Rise Time tR(SPI) 5.0 ns MOSI, CSB, SCK Signal Fall Time tF(SPI) 5.0 ns CSB Falling Edge to MISO Data Valid tCSB:MISO(DV) 50 ns CSB Rising Edge to MISO High Impedance tCSB:MISO(HIZ) 50 ns 80 ns SCK Rising Edge to MISO Data Valid tVALID 25 Note 1. Subject to thermal dissipation characteristics of the device Note 2. Guaranteed by design, not production tested. Note 3. 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 bus timeout via the Power Control register 0x02[6]. Note 4. tVD:ACK = SCL LOW to SDA (out) LOW acknowledge time. Note 5. tVD:DAT = minimum SDA output data-valid time following SCL LOW transition. Note 6. A master device must internally provide an SDA hold time of at least 300ns to ensure an SCL low state. Note 7. 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 8. MSL3163/4 includes input filters on SDA, SCL, AD0 and AD1 inputs that suppress noise less than 50ns. 10 Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Block Diagram The block diagram for the Atmel LED Drivers-MSL3163/4 is shown in Figure 4. Figure 4. Atmel LED Drivers-MSL3163/4 Block Diagram Atmel LED Drivers-MSL3163/MSL3164 11 Typical Application Circuit Ω Ω Ω Figure 5. Atmel LED Driver-MSL3164 Driving 160 White LEDs in 16 Strings at 60mA Per String. 12 Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Detailed Description The MSL3163 and MSL3164 are highly integrated, flexible multi-string LED drivers with power supply control to maximize system efficiency. The drivers easily connect to a video subsystem. Although optional, this offers a simple architecture for use in LCD TV backlight applications. Up to 16 drivers easily connect together to drive large numbers of LED strings in a system. The drivers provide multiple methods of controlling LED brightness, through both peak current control and through pulse width control of the string drive signals. Peak current control offers excellent color consistency, while pulse width control allows brightness management. An on-chip E2PROM holds all the default control register values. At power-up the data in the E2PROM automatically copy directly to the control registers, setting up the device for operation. The devices interface to a µC via I2C (MSL3163) or SPI (MSL3164). The robust 1MHz I2C interface supports up to 16 devices on the bus. The 20MHz bus addressable SPI interface supports up to 16 devices per Chip Select line. While typically the LED drive PWM signal is internally generated, both drivers also accept an external direct-drive PWM signal and offer optional string drive phase spreading. With direct-drive PWM, a Pulse Width Modulated signal applied to the PWM input sets the PWM duty and the frequency of the LEDs drive signal. With phase spreading enabled, a progressive 1/16 PWM-frame time delay per string helps reduce both the transient load on the LED power supplies, and the power supply input capacitor size requirements. The PWM frequency of the drivers is either synchronized to an external signal applied to PHI, or generated from the internal oscillator for stand-alone applications. Typically the VSYNC signal from the video system is used for the PHI input. The on-time of each string is individually programmed via the device registers, providing a peak resolution of 12-bits when using the on-chip PWM generator. The actual resolution of the PWM frequency depends upon on the ratio of the GSC frequency (typically provided by a systems HSYNC signal, but can Atmel LED Drivers-MSL3163/MSL3164 be internally generated) to the PHI frequency, because the on-time of a string is programmed as a 12-bit count of the number of GSC clock cycles. This count can be further scaled by an 8-bit Global intensity value, when enabled. The GSC clock is also used to precisely set each string’s phase delay so that it is synchronized relative to the video frame. The Efficiency Optimizers control a wide range of different architectures of external DC/DC and AC/DC converters. Multiple drivers in a system communicate with each other in real time to select an optimized operating voltage for the LEDs. This allows design of the power supply for the worst case Forward Voltage (Vf) of the LEDs without worrying about excessive power dissipation issues. During the start-up sequence the MSL3163/4 automatically reduce the power supply voltage to the minimum voltage required to keep the LEDs in current regulation. The devices can be configured to periodically perform this optimization to compensate for changes of the LED’s forward voltage, and to assure continued optimum power savings. Internal Regulators and Enable Input The MSL3163/4 includes an internal linear regulator that operates from the 5V nominal input supply, VIN, and provides an internal 2.5V supply, VDD, to power the low-voltage internal circuitry. Bypass VDD (pin 36) to GND with a 4.7μF capacitor. Bypass VIN (pin 35) to GND with a 10µF capacitor. The MSL3163/4 enable input, EN, enables the device. Drive EN low to enter low power operation, which lowers quiescent current draw to less than 20µA. With EN low the serial interface is ignored. Drive EN high to turn on the device. When EN is driven high the contents of the E2PROM are boot-loaded into the control registers, simulating a cold start-up. 13 Setting the LED String Current with RILED and ISTR The MSL3163/4 features 16 current sink outputs, rated at 40V, each designed to sink up to 100mA peak. Limit average current to 60mA if the PCB copper around the MSL3163/4 is the only heat sink employed. The maximum string current, IILED, for all 16 LED string inputs is set by a single external resistor, RILED, placed from ILED to GND, whose value is determined using: RILED = 762 I ILED . For example, a full-scale LED current of 60mA returns RILED = 12.7kΩ. The current for all LED strings is reduced from its fullscale value with 8-bit resolution using ISTR, the String Current Control register 0x0F. Figure 6. FBOn Connects to the Power Supply Voltage Divider Through a Diode 14 Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Connecting the Efficiency Optimizer to an LED String Power Supply and Selecting Resistors The MSL3163/4 are designed to control LED string power supplies that use a voltage divider (RTOP and RBOTTOM in Figure 6) to set output voltage, and whose regulation feedback voltage is not more than 3.5V. The Efficiency Optimizer improves power efficiency by injecting a current of between 0µA and 255µA into the voltage divider of the external power supply, dynamically adjusting the power supply’s output to the minimum voltage required by the LED strings. To select the resistors first determine VOUT(MIN) and VOUT(MAX), the minimum and maximum string supply voltage limits, using: VOUT(MIN) = (Vf (MIN) *[#ofLEDs])+ 0.5 , and VOUT(MAX) = (Vf (MAX) *[#ofLEDs])+ 0.5 , where Vf(MIN) and Vf(MAX) are the LED’s minimum and maximum forward voltage drops at the peak current set by RILED (page 10). For example, if the LED data are Vf(MIN) = 3.5V and Vf(MAX) = 3.8V, and ten LEDs are used in a string, then the total minimum and maximum voltage drops across the LEDs are 35V and 38V. Adding an allowance of 0.5V of for the string drive MOSFET headroom brings VOUT(MIN) to 35.5V and VOUT(MAX) to 38.5V. Do not to exceed the 40V maximum specification of the string drivers STR1 thru STR15. Then determine RTOP using: RTOP = VOUT ( MAX ) − VOUT ( MIN ) I FBOn ( MAX ) , where IFBOn(MAX) is the 255µA maximum output current of the Efficiency Optimizer outputs FBOn (if cascading multiple MSL3163/4s determine IFBOn(MAX) as shown in the next section). Finally, determine RBOTTOM using: Atmel LED Drivers-MSL3163/MSL3164 RBOTTOM = RTOP * VFB VOUT(MAX) _ VFB , , where VFB is the regulation feedback voltage of the power supply. Place a diode (1N4148 or similar) between FBOn and the supply’s feedback node to protect the MSL3163/4 against current flow into FBOn. Using Multiple Atmel LED DriversMSL3163/4s to Control a Common Power Supply Cascade multiple MSL3163/4 devices into a chain configuration, with the FBIn of one device connected to the FBOn of the next (Figure 7). Connect the first FBOn to the power supply feedback resistor node through a diode, and the unused FBIn inputs (and any unused FBOn outputs) to GND as close to the MSL3163/4 as possible. Assign all strings powered by a common supply to the proper FBOn output using String Set registers (STRnSET) 0x20 thru 0x3F. The chained devices work together to ensure that the system operates at optimum efficiency. Note that the accuracy of the feedback chain may degrade through each link of the FBIn/FBOn chain by as much as 2%. Determine the potential worst case maximum FBOn current IFBOn(MAX/MIN) using: IFBOn(MAX / MIN) = 255µA* (0.98)N-1 , where N is the number of MSL3163/4s connected in series. Use this result in the above RTOP resistor equation for the term IFBOn(MAX) instead of using 255µA. Take care in laying out the traces for the Efficiency Optimizer connections. Minimize the FBIn/FBOn trace lengths as much as possible. Do not route the signals close to traces with large variations in voltage or current, because noise may couple into FBIn. If these traces must be routed near noisy signals, shield them from noise by using ground planes or guard traces. 15 Figure 7. Example of Cascading Multiple Devices to Optimize Common Power Supplies Direct PWM Control of the LED Strings An external PWM signal applied to the PWM input allows direct PWM control over the strings when bits PWMEN and PWMDIRECT are set in PWM Control register 0x1E. This configuration bypasses PHI and GSC, but allows automatic LED string phase delay using bit D2 of register 0x1E. The PWM input can also be configured as a gate for the output of the PWM engine using the PWM Global Enable bit D3 of the PWM Control register 0x1E. 16 Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Register Map and the E2PROM Register Map Summary Control the MSL3163/4 using the 96 registers in the range 0x00 thru 0x5F (Table 2). It may be convenient, and it is allowed, to read and write to unused bits in this range when accessing registers, but always write zeros. Reads from unused bits always return zeros. Three additional registers, 0x90, 0x91 and 0x93 allow access to the E2PROM and provide Efficiency Optimizer status. The power-up default values for all control registers are stored within the on-chip E²PROM, and any of these E²PROM values may be changed through the serial interface. Table 2. Atmel LED Drivers-MSL3163/4 Register Map ADDRESS AND REGISTER NAME FUNCTION REGISTER DATA D7 D6 D5 D4 D3 STR7EN STR6EN STR5EN STR4EN STR15EN STR14EN STR13EN STR12EN D2 D1 D0 STR3EN STR2EN STR1EN STR0EN STR11EN STR10EN STR9EN STR8EN 0x00 CONTROL0 0x01 CONTROL1 0x02 POWERCTRL Fault configuration SLEEP 0x03 FLTSTATUS Fault status, global - - 0x04 OCSTAT0 OC7 OC6 OC5 OC4 OC3 0x05 OCSTAT1 OC15 OC14 OC13 OC12 0x06 SCSTAT0 SC7 SC6 SC5 0x07 SCSTAT1 SC15 SC14 0x08 FLTMASK0 FLTEN7 0x09 FLTMASK1 0x0A FBOCTRL0 0x0B FBOCTRL1 0x0C FBODAC1 0x0D FBODAC2 0x0E FBODAC3 LED string enables String open circuit fault status String short circuit fault status String fault masks Efficiency Optimizer control I2CTOEN PHIMINFEN GSCMAXFEN STRSCFEN STROCFEN FBOOCEN PHIMINFLT GSCMAXFLT FBOOC FLTDET OC2 OC1 OC0 OC11 OC10 OC9 OC8 SC4 SC3 SC2 SC1 SC0 SC13 SC12 SC11 SC10 SC9 SC8 FLTEN6 FLTEN5 FLTEN4 FLTEN3 FLTEN2 FLTEN1 FLTEN0 FLTEN15 FLTEN14 FLTEN13 FLTEN12 FLTEN11 FLTEN10 FLTEN9 FLTEN8 HDRMSTEP[1:0] FBCLDLY[1:0] SCCDLY[1:0] DECRSTEP[1:0] Efficiency Optimizer DAC readback 0x10 OSCCTRL Oscillator frequency 0x11 GSCCTRL GSC processing GSCCHKcontrol SEL GSCGEN Internal GSC clock generator 0x14 GSCMUL GSC multiplier - - - 0x15 GSCDIV GSC divider - - - GSCMAX Max oscillator cycles between GSC pulses PHICTRL PHI processing control PHIGEN Internal PHI clock generator 0x17 0x18 0x19 0x1A Atmel LED Drivers-MSL3163/MSL3164 ACAL100 ACALEN ICHKDIS FBODAC3[7:0] ISTR 0x16 INITPWM FBCFDLY[1:0] FBODAC2[7:0] 0x0F 0x13 FBSDLY[1:0] FBODAC1[7:0] 8-bit global string current 0x12 STRSCDET STROCDET FBOEN ISTR[7:0] - - - - - OSCTRL[2:0] - - - GSCMAXEN GSCPOL GSCPHISYNCEN GSCINTEN GSCGEN[7:0] GSCGEN[15:8] GSCMUL[4:0] - GSCDIV[3:0] GSCMAX[7:0] GSCMAX[15:8] - - - - - PHIMINEN PHIPOL PHIINTEN PHIGEN[7:0] PHIGEN[15:8] 17 Table 2. Atmel LED Drivers-MSL3163/4 Register Map ADDRESS AND REGISTER NAME FUNCTION REGISTER DATA D7 D6 D5 D4 0x1B 0x1C D3 Min GSC pulses over PHI period - - - - 0x1E PWMCTRL PWM control FLDBKEN - GINTEN PWMOFLOWEN 0x1F GINT Global PWM scaling STR0SET Phase delay and EO assignment for string 0 0x20 0x21 ↓ 0x3E 0x3F 0x40 0x41 ↓ 0x5E 0x5F D1 D0 PHIMIN[7:0] PHIMIN 0x1D D2 UNUSED PHIMIN[11:8] PWMGLBLEN PHADLYEN PWMDIRECT PWMEN GINT[7:0] PHDLY0[7:0] COLSTR0[1:0] - - PHDLY[11:8] ↓ ↓ ↓ STR15SET Phase delay and EO assignment for string 15 PHDLY15[7:0] PWM0 12-bit PWM setting for string 0 ↓ ↓ ↓ PWM15 12-bit PWM setting for string 15 PWM15[7:0] COLSTR15[1:0] - - PHDLY[11:8] PWM0[7:0] - - - - - - - PWM0[11:8] - PWM15[11:8] - Do Not Access Address Range 0x60 Thru 0x8F 0x90 E2ADDR 0x91 E2CTRLSTA E²PROM read/ write access 0x93 FBOSTATUS FBO status 18 E2BUSY E2ADDR[6:0] BLDACT FBOOPEN[3:1] E2ERR - FBOACTIVE[3:1] RWCTRL[2:0] FBOCAL FBOINITCAL Atmel LED Drivers-MSL3163/MSL3164 Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface Register Power-Up Defaults Register power-up default values are shown in Table 3 Table 3. Atmel LED Drivers-MSL3163/4 Register Power-Up Defaults REGISTER NAME AND ADDRESS POWER-UP CONDITION REGISTER DATA D7 D6 D5 D4 D3 D2 D1 D0 0x00 CONTROL0 LED strings STR0 thru STR7 enabled 1 1 1 1 1 1 1 1 0x01 CONTROL1 LED strings STR8 thru STR15 enabled 1 1 1 1 1 1 1 1 Efficiency Optimizer outputs enabled FBO open circuit detection enabled String open circuit detection enabled LED short circuit detection enabled 0x02 POWERCTRL GSC maximum fault detection disabled PHI minimum fault detection disabled I2C bus timeout detection enabled Device awake 0 1 0 0 1 1 1 1 0x08 FLTMASK0 1 1 1 1 1 1 1 1 0x09 FLTMASK1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 Strings current set to 50% of RILED setting 0 1 1 1 1 1 1 1 Fault detection enabled on all strings Current sink error confirmation delay = 4µS FBO power supply correction delay = 2ms Efficiency Optimizer recalibration delay = 1s Efficiency Optimizer correction steps = 6 Current sink error detection not disabled Auto recalibration enabled PWM settings used during auto recalibration PWM duty cycle = 100% during initial calibration Efficiency Optimizer operates using 1µA steps LED short circuit confirmation delay = 4µs 0x0A FBOCTRL0 0x0B FBOCTRL1 0x0F ISTR 0x10 OSCCTRL fOSC = 20MHz 0 0 0 0 0 1 0 0 0x11 GSCCTRL GSC synchronized to the falling edge of the external signal 0 0 0 0 0 0 0 0 GSCGEN Although disabled, Internal GSC frequency = 20MHz / (19 + 1) = 1MHz 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0x14 GSCMUL GSC multiplied by 4 0 0 0 0 0 0 1 1 0x15 GSCDIV GSC not divided 0 0 0 0 0 0 0 0 GSCMAX Although disabled, GSC max count is set to 19 clock cycles 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 PHICTRL PHI synchronized to the falling edge of the external signal 0 0 0 0 0 0 0 0 PHIGEN Although disabled, Internal PHI frequency = 20MHz / (8 * (10416 + 1)) = 240Hz 1 0 1 1 0 0 0 0 0 0 1 0 1 0 0 0 PHIMIN No PHI minimum 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0x12 0x13 0x16 0x17 0x18 0x19 0x1A 0x1C 0x1D Atmel LED Drivers-MSL3163/MSL3164 19 REGISTER NAME AND ADDRESS 0x1E PWMCTRL 0x1F GINT 0x20 0x21 ↓ 0x3E 0x3F 0x40 0x41 ↓ 0x5E 0x5F STR0SET ↓ STR15SET REGISTER DATA POWER-UP CONDITION D7 D6 D5 D4 D3 D2 D1 D0 PWM Operation enabled Internal PWM engine determines tON and tOFF Phase delay enabled PWM input not esed as gate for PWM engine output String on-times allowed to extend beyond PWM frame GINT ignored String current fold-back enabled 1 0 0 1 0 1 0 1 Although Disabled, Global Intensity is set to (127) / 256 = 49.6% 0 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0* 1* 0 0 0 0 0 0 All Strings set to 0 Phase Delay Strings Efficiency Optimizer assignments are: FBO1: Strings 0,4,8,12 FBO2: Strings 1,2,5,6,9,10,13,14 FBO3: Strings 3, 7, 11, 15 ↓ PWM0 ↓ 0 0 0 0 0 0 0 0 1* 1* 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 ↓ All Strings Have PWM Value = 512 GSC Cycles PWM15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0x90 E2ADDR E²PROM 7-bit address = 0x00 0 0 0 0 0 0 0 0 0x91 E2CTRLSTA E²PROM read/write disabled 0 0 0 0 0 0 0 0 0x93 FBOSTATUS Feed Back Output Status 0 0 0 0 0 0 0 0 * These bits set the FBOn string assignments. 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