LX27901ID-TR

LX27901 ® TM Multipurpose High Performance LED Controller P RELIMINARY D ATASHEET DESCRIPTION The controller allows the user to utilize three different converter drive schemes, LLC (resonant), conventional PWM control, and Microsemi’s proprietary synchronous scheme, all selectable by the multi-function ENABLE pin. The LX27901 is designed to operate with Microsemi’s proprietary lossless (magnetic) current balancing schemes. The controller also provides a proprietary synchronous regulation function to allow the user to control the LED current and dimming from an unregulated switching power supply source, to minimize the number of power conversion stages and the associated losses and component costs.  LLC, PWM and proprietary synchronous modes to drive the LED strings  LED strings can be dimmed by PWM or analog methods  Proprietary algorithm to provide accurate brightness control at high efficiency over wide dimming duty cycle range  Accurate parallel LED strings current matching using Microsemi’s patented non-dissipative current-balancing technology  Robust protection from open or shorted LED conditions  Dedicated fault indication  0.8A Source & Sink Drive Capability In non-resonant mode, the controller provides two 180° phaseshifted pulse-width modulated drive signals for implementing various two-switch DC-DC converter topologies, such a half-bridge and asymmetrical forward converter. It can also be used for one-switch topologies.  On Chip 5.25V Regulator  Direct connection to input voltage rail up to 27V  LLC max operating frequency to 1 MHz, PWM to 150 kHz  Synchronous regulation function to minimize power conversion stage  RoHS compliant & halogen Free APPLICATIONS  LCD LED Backlight TV  LCD LED Backlight Monitors  Other LED Backlight Systems LX27901 A versatile set of system monitoring and protection functions are incorporated in the LX27901 design to provide reliable protection of the device and the system. These can account for shorted and open LED strings for example. Three input pins, ISNS, VSNS and UVS/SYN are assigned to support regulation and protection. A Direct PWM input dimming dedicated fault indication pin allows operation can be realized by the user to generate a direct fault inputting a suitable dimming pulse report to the system and configure train to the DIM pin. The LX27901 supports analog LED current control addition protection features with utilizing the BRTA pin for setting the simple external circuits. analog LED current. The device is available in 16 lead SOIC surface mount package in the industrial temperature range. In addition, a proprietary dimming algorithm ACU_BRITE® is incorporated. The controller Refer to the Application Note titled integrates the pulsed LED current “Some Proprietary LED Current and compares it with a reference for Balancing Techniques”. very accurate brightness control irrespective of duty cycle. Page 1 Copyright  2012 Rev. 0.3_03-27-2013 W W W. Microsemi .CO M The LX27901 is an extremely versatile high-performance controller for driving LEDs from the HVDC (output) rail of a standard PFC front-end. KEY FEATURES Microsemi Analog Mixed Signal Group One Enterprise Aliso Viejo, CA 92656 USA LX27901 ® TM Multipurpose High Performance LED Controller P RELIMINARY D ATASHEET IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com D TA (C) THERMAL DATA JA = 82.2 C/W Plastic SOIC 16 Pin RoHS Compliant / Pb-free LX27901ID -40 to +85 Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX27901ID-TR) THERMAL RESISTANCE-JUNCTION TO AMBIENT Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. JA number above is with 4-layer pcb board. AABSOLUTE MAXIMUM RATINGS VIN VDD ENABLE Notes: Exceeding these ratings could cause damage to the device. All voltages are with respect to GND. Currents are positive into, negative out of specified terminal. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” are not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability. AOUT C_R GND MSC LX27901ID xxxx Supply Input Voltage, VIN ............................................................................... 0.3V to 36V Signal Outputs, VDD, AOUT, BOUT, C_OUT..............................................-0.3V to 6.5V Signal Inputs, C_R, BRTA .................................................................. -0.3V to VDD+0.3V Signal Inputs, ENABLE, DIM, ISNS, VSNS, UVS/SYN ................... -0.3V to VDD+0.3V Signal Outputs COMP, SST/BCOM, FAULT ............................................... -0.3V to VDD Maximum Junction Temperature ............................................................................... 150°C Storage Temperature Range ......................................................................... -65C to 150C Peak Package Solder Reflow Temperature (40 seconds maximum exposure) ........... 260°C Lead Temperature. (Soldering 10 seconds)................................................................ 300°C PACKAGE PIN OUT W W W. Microsemi .CO M PACKAGE ORDER INFO BRTA DIM SST/ BCOM BOUT C_OUT COMP ISNS FAULT UVS/ SYN VSNS LX27901ID D PACKAGE (Top View) RoHS / Pb-free Matte Tin Pin Finish ELECTRICAL CHARACTERISTICS Unless otherwise listed, the following specifications apply over the operating ambient temperature of -40°C < Temp < 85°C, and VIN = 7.5V to 27V, except where otherwise noted and the following test conditions: VIN = 12V, C C_R = 330pF, RC_R= 15K Parameters Symbol Test Conditions/Comments MIN TYP MAX Units 27 V 5.25 5.5 V 7 10 mA VIN = 24V, VENABLE < 0.8V 200 400 µA ENABLE < 0.8V 0.1 Power VIN Controller Operating Voltage VDD Power Supply Input Current IIN Sleep Mode Current IDDSLEEP VDD Off Voltage 7.5 1µF bypass cap on VDD pin, IVDD = 0 to 5mA 5.0 AOUT, BOUT = no load, VDD = no load V Enable ENABLE On ENH 1.7 V Page 2 Copyright  2012 Rev. 0.3_03-27-2013 Microsemi Analog Mixed Signal Group One Enterprise Aliso Viejo, CA 92656 USA LX27901 Controller Input Voltage LX27901 ® TM Multipurpose High Performance LED Controller P RELIMINARY D ATASHEET ELECTRICAL CHARACTERISTICS Unless otherwise listed, the following specifications apply over the operating ambient temperature of -40°C < Temp < 85°C, and VIN = 7.5V to 27V, except where otherwise noted and the following test conditions: VIN = 12V, C C_R = 330pF, RC_R= 15K Shut Down LLC Resonant Mode Threshold PWM Switching Mode Threshold Synchronous LED Drive Mode Threshold Symbol Test Conditions/Comments MIN TYP ENL MAX Units 0.8 V VLLCTH LLC resonant drive mode, VDD = 5.25V 2 3 V VPWMTH PWM switching drive mode, VDD = 5.25V 3 4 V VSYN Synchronous LED drive mode, VDD = 5.25V 4 VDD V Input High Current ENIIH ENABLE = 2V 10 µA Input Low Current ENIIL 0V < VENABLE < 0.8V 5 µA W W W. Microsemi .CO M Parameters Under Voltage Lockout VDD Startup Threshold VDDUVLOR Rising Threshold. 4.35 4.6 4.8 V VDD UVLO Threshold VDDUVLOF Falling Threshold. 4.0 4.2 4.45 V VDD UVLO Hysteresis VDDUVLOH 0.4 V Output ISINK, AOUT and BOUT, TA = 25°C 5 6 Ω RSOURCE ISOURCE, AOUT and BOUT, TA = 25°C 5 6 Ω Dead Time OUTDT TA = 25°C, at full duty 330 410 ns C_OUT Output Resistance RC_OUT Source and sink 15 20 Ω 140 151.2 kHz Output Resistance RSINK Output Resistance 250 Switching Frequency Oscillator Switching Frequency Tolerance OSCINPWM Max Oscillator Frequency OSCMAX_LLC LLC Frequency Control Current Source TA = 25°C, Frequency of AOUT, BOUT in PWM mode, CC_R=330pF, RC_R = 15K. TA = 25°C, Frequency of AOUT, BOUT in LLC mode, CC_R=330pF, RC_R = 15K. VENABLE < 2.8V 128.8 1 0 MHz 200 µA Ramp Valley Voltage OSCVV 0.5 V Ramp Peak Voltage OSCPV 2.5 V Ratio of UVS/SYN input over C_R oscillator free run frequency 1.05 TA = 25°C, input, Corresponds to 2V after 4.75X internal amplifier. 414.6 ISNS Linear Input Range Linear operation range for internal circuit 800 BRTA Input Range 4.75 times of ISNS signal. Input outside the range is clamped at upper or lower limit internally. 0.5 Synchronization Range 3 Ratio 426.4 mV LED Dimming Control Pre-Amplifier Gain Error Amp Output Capacity ISNSREF KPRAMP 421 mV 2.0 V 4.75 Source and Sink 100 µA Page 3 Copyright  2012 Rev. 0.3_03-27-2013 Microsemi Analog Mixed Signal Group One Enterprise Aliso Viejo, CA 92656 USA LX27901 ISNS Reference LX27901 ® TM Multipurpose High Performance LED Controller P RELIMINARY D ATASHEET ELECTRICAL CHARACTERISTICS Unless otherwise listed, the following specifications apply over the operating ambient temperature of -40°C < Temp < 85°C, and VIN = 7.5V to 27V, except where otherwise noted and the following test conditions: VIN = 12V, C C_R = 330pF, RC_R= 15K Symbol DIM Input Voltage Range PWM Dimming Mode Control Threshold Test Conditions/Comments MIN Effective for duty from 0 to 100% 0.5 Voltage level of FAULT pin, in ACU_BRITE PWM dimming mode when below threshold; in conventional PWM dimming mode when above threshold. 2.8 VSNSTH Fault when above the threshold 1.8 ICLAMP Pull down source at COMP pin VDIM VPDMODETH TYP MAX Units 2.0 V 3.0 3.2 V 2.0 2.2 V Fault Monitoring and Protection VSNS Threshold VSNS Clamping Current Source UVS/SYN Threshold UVS/SYNTH Fault when below the threshold, positive and negative input Functional operation range, positive and negative input 160 0.35 0.4 0.45 V 4 V UVS/SYN Input Range VUVS/SYN ISNS Fault Threshold VISNSTH Fault when below the threshold 85 100 115 mV Over Current Threshold OCTH Upper threshold for ISNS input 550 600 650 mV Short Circuit Threshold SCTH Upper threshold for ISNS input 870 930 990 mV Fault Count FC Fault reset Interval -0.5 µA At clock frequency of AOUT, BOUT FRESET Fault Output Sinking Capacity FSINK Fault Output Open Impedance RF Interval for resetting fault counter, At clock frequency of AOUT, BOUT VFAULT ≤ 0.8V, TA = 25°C 4 When in open state 5 256 Count 32768 Count 6 mA W W W. Microsemi .CO M Parameters MΩ Bias & References Internal Master Reference Voltage VREF Soft Start Charging Source ISSC C_B Charging source at start up 1.2 V 2 µA Power-Up Sequencing Power On Reset Time Start up Time Out Pin # TSTART After UVLO of VDD released After POR 50 µs 32768 Count FUNCTIONAL PIN DESCRIPTION Description VIN 1 Input voltage pin. A built-in regulator is connected to this pin to step down the input voltage to the internal operating voltage VDD. This pin can accept input voltage from 10V to 27V to provide the flexibility of interfacing with either 12V or 24V system supply. A low ESR decoupling capacitor of not less than 1µF should be connected from this pin to GND with low impedance traces. ENABLE 2 Enable pin to control the on/off operation of the controller. A logic low signal 2V sets the dimming operation in continuous analog mode. A PWM signal of low level 2V will force the PWM dimming operation to follow the PWM signal directly. Input level 2V activates the controller operation. The DC signal level on this pin also sets the drive mode of the controller. When 2V