MSL3163BT

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 PART MSL3163BT MSL3164BT INTERFACE I2C interface SPI interface PACKAGE 40 pin, 6 x 6 x 0.75mm TQFN 40 pin, 6 x 6 x 0.75mm TQFN 2 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 • Fast Serial Interfaces Support up to 16 Devices per Bus: - MSL3164 20 MHz SPI - MSL3163 1 MHz I2C • 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 • Supports Adaptive, Real-time Area Dimming for Highest Dynamic Range LCD TVs and Monitors • Programmable String Phase Reduces Motion Blur • Global Intensity Control via Serial Interface • 100mA Peak, 60mA Average LED String Current • Single Resistor Sets Peak Current for all LED Strings • ±3% Current Accuracy and Current Balance • Video Frame (VSYNC) and Line (HSYNC) Sync Inputs • Sync Loss Detectors Optionally Disable LED Strings • Multiple MSL3163/4s Share String Power Supplies and Automatically Negotiate the Optimum Supply Voltage • E²PROM Allows Customized Power-On Defaults • Less Than 1µA LED String Off-Leakage Current • String Open Circuit and LED Short Circuit Fault Detection • Individual Fault Detection Enable for Each String • Over-temperature Shutoff Protection • Broadcast Write Simplifies Configuration • -40°C To +85°C Operating Temperature Range Application Circuit Ω Atmel LED Drivers-MSL3163/MSL3164 3 Package Pin-out 40 FBI2 FBO3 FBI3 PHI GSC PWM STR0 STR1 STR2 1 2 3 4 5 6 7 8 9 39 38 37 36 35 34 33 32 CGND 31 30 AD1 29 SDA 28 TEST 27 SCL 26 AD0 25 FLTB 24 STR15 23 STR14 22 STR13 21 STR12 11 STR4 12 STR5 13 STR6 14 STR7 15 CGND 16 GND 17 STR8 18 STR9 19 STR10 20 STR11 FBO2 FBO1 ILED GND FBI1 VDD VIN NC EN MSL3163 (TOP VIEW) Figure 1. Atmel LED DriverMSL3163 Pinout 40 Pin TQFN STR3 10 FBO2 FBO1 ILED GND 32 FBI1 VDD 40 FBI2 FBO3 FBI3 PHI GSC PWM STR0 STR1 STR2 1 2 3 4 5 6 7 8 9 39 38 37 36 35 34 33 CSB 31 30 AD1 29 MOSI 28 MISO 27 SCK 26 AD0 25 FLTB 24 STR15 23 STR14 22 STR13 21 STR12 VIN NC MSL3164 (TOP VIEW) EN Figure 2. Atmel LED DriverMSL3164 Pinout 40 Pin TQFN STR3 10 11 STR4 12 STR5 13 STR6 14 STR7 15 CGND 16 GND 17 STR8 18 STR9 19 STR10 20 STR11 4 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 1 2 3 4 5 PIN NAME MSL3163 MSL3164 FBI2 FBO3 FBI3 PHI GSC FBI2 FBO3 FBI3 PHI GSC PIN DESCRIPTION Efficiency Optimizer input 2 Connect FBI2 to FBO2 of the next device when chaining devices (Figure 7). If unused connect FBI2 to GND. 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. Efficiency Optimizer input 3 Connect FBI3 to FBO3 of the next device when chaining devices (Figure 7). If unused connect FBI3 to GND. 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. 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. LED string current sink outputs Connect the cathode of the n’th strings bottom LEDs to STRn. Connect unused STRn outputs to GND. Connect to ground Connect CGND to GND and to EP with short, wide traces. Signal ground Connect all GNDs to system ground and to EP with short, wide traces. 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. 6 7 - 14, 17 24 15 16, 32 25 26,30 27 PWM STR0 thru STR15 CGND GND FLTB PWM STR0 thru STR15 CGND GND FLTB selection inputs AD0, AD1 AD0, AD1 Slave ID AD1 and AD0 to GND through resistors to set the device address for the serial interface. Connect SCL SCK 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. 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. 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 28 TEST MISO 29 SDA MOSI 31 GND CSB 33 ILED ILED 34 35 6 EN VIN EN VIN Atmel LED Drivers-MSL3163 and MSL3164 16-string White & RGB LED Drivers with Adaptive Power Control, E²PROM, and SPI/I²C/SMBus Serial Interface PIN 36 37 38 39 40 PIN NAME MSL3163 MSL3164 VDD NC FBO1 FBI1 FBO2 VDD NC FBO1 FBI1 FBO2 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. No connect Leave NC unconnected. 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. Efficiency Optimizer input 1 Connect FBI1 to FBO1 of the next device when chaining devices (Figure 7). If unused connect FBI1 to GND. 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. 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. EP EP EP 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 DC ELECTRICAL CHARACTERISTICS VIN Operating Supply Voltage SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT VIN 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 PWMn = 0xFFF 4.75 5 18 5.5 28 V VIN Operating Supply Current IVIN mA 24 35 VIN Shutdown Supply Current VIN Sleep Current VDD Regulation Voltage Input High Voltage: SDA, SCL, PWM, PHI, GSC, MOSI, CSB Input Low Voltage: SDA, SCL, PWM, PHI, GSC, MOSI, CSB Input High Voltage: EN Input Low Voltage: EN Output High Voltage: PHI, GSC, MISO Output Low Voltage: PHI, GSC, SDA, MISO, FLTB ILED Regulation Voltage FBI Feedback Input Current FBO Feedback Output Current Range FBO Feedback Output Current Step Size FBI Input Disable Threshold STR0 thru STR15 Sink Current STR0 thru STR15 Sink Current Maximum STR0 thru STR15 Current Load Regulation STR0 thru STR15 Current Matching STR0 thru STR15 Minimum Headroom STR0 thru STR15 Short Circuit Fault Detection Threshold STR0 thru STR15 Current Slew Rate Thermal Shutdown Temperature ISHDN ISLEEP VDD VIH VIL EN = GND, SDA, SCL, AD0, AD1, PWM, PHI and GSC = GND EN = 1, SLEEP = 1, SDA, SCL, AD0, AD1, PWM, PHI and GSC = GND or VDD 2.4 0.7 x VDD 10 1.5 2.5 2.6 µA mA V V 0.3 x VDD V V 0.8 V V 0.4 V mV 365 365 μA μA μA 50 mV mA mA %/V 5 % V V mA/µs °C 67 1.22 VIN – 0.4 VOH VOL ISOURCE = 5mA ISINK = 5mA RILED = 12.7kΩ 350 0 0 1.1 VFBO ≤ VIN – 0.5V RILED = 12.7kΩ, ISTR = 0xFF, VSTRn = 1V RILED = 7.68kΩ, ISTR = 0xFF (Note 1) RILED = 12.7kΩ; ISTR = 0xFF, FLDBKEN = 0, VSTRn = 1V to 5V RILED = 12.7kΩ, ISTR = 0x7F, VSTRn = 1V VSTR SCREF Current rising (Note 2) Current falling (Note 2) (Note 2) RILED = 12.7kΩ; ISTR = 0xFF 55 60 100 0.033 -5 0.5 3.5 608 10868 135 8 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 AC ELECTRICAL CHARACTERISTICS OSC Frequency PHI Frequency PHI Lock GSC Frequency PWM Frequency PWM Duty Cycle fGSC fPWM 0 0 fOSC fPHI OSCCTRL = 0x04 18.15 0.04 4 10 50 100 20.00 21.88 10 MHz kHz PHI cycles MHz kHz % PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT I²C TIMING CHARACTERISTICS, MSL3163 SCL Clock Frequency Bus Timeout Period STOP to START Condition Bus Free Time Repeated START condition Hold Time Repeated START condition Setup Time STOP Condition Setup 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 1/tSCL ttimeout tBUF tHD:STA tSU:STA tSU:STOP tHD:DAT tVD:ACK tVD:DAT tSU:DAT tLOW tHIGH tf tr tSP (Note 8) 50 (Note 6) (Note 7) (Note 4) (Note 5) Bus timeout disabled (Note 3) OSCCTRL = 0x04 fOSC = 16MHz to 23MHz 0.5 0.26 0.26 0.26 50 0.05 0.05 100 0.5 0.26 120 120 0.45 0.45 0 30 600,000 / fOSC 1 MHz ms s µs µs µs µs ns µs µs ns µs µs ns ns ns PARAMETER SYMBOL CONDITIONS AND NOTES MIN TYP MAX UNIT SPI TIMING CHARACTERISTICS, MSL3164 SCK Frequency CSB Falling Edge to SCK Rising Edge Setup Time tCSB:SCK(SU) 100 20 MHz ns Atmel LED Drivers-MSL3163/MSL3164 9 PARAMETER SCK Falling Edge to CSB Rising Edge Setup Time MOSI to Falling Edge of SCK Setup Time SCK Falling Edge to MOSI Setup Time MOSI, CSB, SCK Signal Rise Time MOSI, CSB, SCK Signal Fall Time CSB Falling Edge to MISO Data Valid CSB Rising Edge to MISO High Impedance SCK Rising Edge to MISO Data Valid SYMBOL tSCK:CSB(SU) tMOSI(SU) tMOSI(HOLD) tR(SPI) tF(SPI) tCSB:MISO(DV) tCSB:MISO(HIZ) tVALID CONDITIONS AND NOTES MIN 50 16 20 TYP MAX UNIT ns ns ns 5.0 5.0 50 50 25 80 ns ns ns ns ns 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 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. Atmel LED Drivers-MSL3163/MSL3164 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: 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: 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: 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. 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 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 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19 0x1A CONTROL0 CONTROL1 POWERCTRL FLTSTATUS OCSTAT0 OCSTAT1 SCSTAT0 SCSTAT1 FLTMASK0 FLTMASK1 FBOCTRL0 FBOCTRL1 FBODAC1 FBODAC2 FBODAC3 ISTR OSCCTRL GSCCTRL GSCGEN GSCMUL GSCDIV GSCMAX PHICTRL PHIGEN FUNCTION LED string enables Fault configuration Fault status, global String open circuit fault status String short circuit fault status String fault masks Efficiency Optimizer control Efficiency Optimizer DAC readback 8-bit global string current Oscillator frequency REGISTER DATA D7 STR7EN D6 STR6EN D5 STR5EN STR13EN D4 STR4EN STR12EN D3 STR3EN STR11EN D2 STR2EN STR10EN D1 STR1EN STR9EN D0 STR0EN STR8EN FBOEN FLTDET OC0 OC8 SC0 SC8 FLTEN0 FLTEN8 ICHKDIS STR15EN STR14EN SLEEP OC7 OC15 SC7 SC15 FLTEN7 I2CTOEN PHIMINFEN GSCMAXFEN STRSCFEN STROCFEN FBOOCEN OC6 OC14 SC6 SC14 FLTEN6 PHIMINFLT GSCMAXFLT OC5 OC13 SC5 SC13 FLTEN5 FLTEN13 OC4 OC12 SC4 SC12 FLTEN4 FLTEN12 STRSCDET STROCDET OC3 OC11 SC3 SC11 FLTEN3 FLTEN11 INITPWM FBODAC1[7:0] FBODAC2[7:0] FBODAC3[7:0] ISTR[7:0] OC2 OC10 SC2 SC10 FLTEN2 FLTEN10 ACAL100 FBOOC OC1 OC9 SC1 SC9 FLTEN1 FLTEN9 ACALEN FLTEN15 FLTEN14 HDRMSTEP[1:0] SCCDLY[1:0] FBCLDLY[1:0] DECRSTEP[1:0] FBSDLY[1:0] FBCFDLY[1:0] - - - - GSCMAXEN GSCGEN[7:0] GSCGEN[15:8] GSCPOL OSCTRL[2:0] GSCPHISYNCEN GSCINTEN GSC processing GSCCHKcontrol SEL Internal GSC clock generator GSC multiplier GSC divider Max oscillator cycles between GSC pulses PHI processing control Internal PHI clock generator - - GSCMAX[7:0] GSCMAX[15:8] GSCMUL[4:0] GSCDIV[3:0] - - - PHIGEN[7:0] PHIGEN[15:8] PHIMINEN PHIPOL PHIINTEN Atmel LED Drivers-MSL3163/MSL3164 17 Table 2. Atmel LED Drivers-MSL3163/4 Register Map ADDRESS AND REGISTER NAME 0x1B 0x1C 0x1D 0x1E 0x1F 0x20 0x21 ↓ 0x3E 0x3F 0x40 0x41 ↓ 0x5E 0x5F 0x90 0x91 0x93 PHIMIN PWMCTRL GINT STR0SET ↓ STR15SET FUNCTION REGISTER DATA D7 D6 D5 D4 UNUSED D3 PHIMIN[7:0] FLDBKEN GINTEN PWMOFLOWEN PWMGLBLEN PHIMIN[11:8] PHADLYEN PWMDIRECT PWMEN D2 D1 D0 Min GSC pulses over PHI period PWM control Global PWM scaling Phase delay and EO assignment for string 0 ↓ Phase delay and EO assignment for string 15 12-bit PWM setting for string 0 ↓ 12-bit PWM setting for string 15 E²PROM read/ write access FBO status GINT[7:0] PHDLY0[7:0] COLSTR0[1:0] ↓ PHDLY15[7:0] COLSTR15[1:0] PWM0[7:0] ↓ PWM15[7:0] E2BUSY BLDACT FBOOPEN[3:1] E2ERR E2ADDR[6:0] FBOACTIVE[3:1] RWCTRL[2:0] FBOCAL FBOINITCAL PWM15[11:8] PWM0[11:8] PHDLY[11:8] PHDLY[11:8] PWM0 ↓ PWM15 - Do Not Access Address Range 0x60 Thru 0x8F E2ADDR E2CTRLSTA FBOSTATUS 18 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 0x00 0x01 CONTROL0 CONTROL1 POWER-UP CONDITION LED strings STR0 thru STR7 enabled LED strings STR8 thru STR15 enabled REGISTER DATA D7 1 1 D6 1 1 D5 1 1 D4 1 1 D3 1 1 D2 1 1 D1 1 1 D0 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 0x08 0x09 0x0A FLTMASK0 FLTMASK1 FBOCTRL0 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 Strings current set to 50% of RILED setting fOSC = 20MHz GSC synchronized to the falling edge of the external signal Although disabled, Internal GSC frequency = 20MHz / (19 + 1) = 1MHz GSC multiplied by 4 GSC not divided Although disabled, GSC max count is set to 19 clock cycles PHI synchronized to the falling edge of the external signal Although disabled, Internal PHI frequency = 20MHz / (8 * (10416 + 1)) = 240Hz No PHI minimum 0 1 0 0 1 1 1 1 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 1 1 0 0x0B FBOCTRL1 0 0 0 1 0 0 1 0 0x0F 0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19 0x1A 0x1C 0x1D ISTR OSCCTRL GSCCTRL GSCGEN GSCMUL GSCDIV GSCMAX PHICTRL PHIGEN PHIMIN 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1 0 0 1 0 0 1 0 0 0 1 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 0 1 0 0 0 0 0 0 1 0 0 1 0 1 0 1 0 0 0 0 0 0 Atmel LED Drivers-MSL3163/MSL3164 19 REGISTER NAME AND ADDRESS POWER-UP CONDITION 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 Although Disabled, Global Intensity is set to (127) / 256 = 49.6% 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 REGISTER DATA D7 D6 D5 D4 D3 D2 D1 D0 0x1E PWMCTRL 1 0 0 1 0 1 0 1 0x1F 0x20 0x21 ↓ 0x3E 0x3F 0x40 0x41 ↓ 0x5E 0x5F 0x90 0x91 0x93 GINT STR0SET ↓ STR15SET PWM0 ↓ PWM15 E2ADDR E2CTRLSTA FBOSTATUS 0 0 0* 0 1* 0 0 1 0 1* 0 1* 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 ↓ 0 0 0 0 ↓ 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 All Strings Have PWM Value = 512 GSC Cycles 0 0 E²PROM 7-bit address = 0x00 E²PROM read/write disabled Feed Back Output Status 0 0 0 * These bits set the FBOn string assignments. 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