LM3466 www.ti.com SNOSB96F –JUNE 2011–REVISED NOVEMBER 2013 Multi-String LED Current Balancer for Use with Constant-Current Power Supplies Check for Samples: LM3466 1FEATURES DESCRIPTION The LM3466 integrates a linear LED driver for lighting 2• Easy to Design for Lighting Systems Consisting of Multiple LED Strings (Supports systems which consist of multiple LED strings Modular Design) powered by a constant current power supply. It balances the current provided by the supply in a pre- • Automatically Balances the Current of Every set ratio for each active LED string, where an active Active LED String, even the Forward Voltage string is a fully turned on LED string, regardless of of Each String is Different the number of strings connected to the supply or the • Easy to Pre-Set and Fine-Tune Current Ratio forward voltage of each LED string. If any LED string Among LED Strings (e.g., color temperature opens during operation, the LM3466 automatically adjustment or CRI Enhancement) balances the supply current through all of the remaining active LED strings. As a result, the overall • ±1% Current Accuracy at Room Temperature brightness of the lighting system is maintained even if and ±1.5% Over Temperature some LED strings open during operation. • Maintains Constant Output Power if Some The LM3466 lighting system is simple to design Strings Open (inactive) by Automatically owing to a proprietary control scheme. To minimize Balancing the Current of Remaining Active the component count, the LM3466 integrates a 70-V, LED Strings 1.5-A, N-channel power MOSFET with a current limit • Works with a Constant Current Power Supply of 2.06 A. To add one more LED string to the system, (ac/dc or dc/dc), and no Communication only a single resistor, a capacitor, and a LM3466 are to/from the Constant Current Power Supply is required. Other supervisory features of the LM3466 Required include under-voltage lock-out, fault reporting, thermal latch off, and thermal shutdown protection. • Operates with Minimum Voltage Overhead to Maximize Power Efficiency The LM3466 consists of only linear circuitry so that the EMI of the application circuit is not deteriorated. • Wide Input Voltage Range from 6 V to 70 V The LM3466 lighting system is EMI friendly if the • Fault Status Output constant current power supply used is complied to • Thermal Shutdown EMI standards. The LM3466 is available in the DDA- 8 exposed thermal pad and TO220-7 packages. • Integrated 70-V, 1.5-A MOSFET with 2.06 A Current Limit SIMPLIFIED APPLICATION • Maximum 70-V per LED String, 20 LEDs VIN • Linear Circuitry Does Not Deteriorate EMI Connect to CIN • DDA-8 Exposed Thermal Pad and TO220-7 VIN pin of another Packages LM3466 APPLICATIONS Connect to • Street Lamps VEQ pin of LM3466 another • Solid State Lighting Systems LM3466 ILED VEQ Connect to VIN COMM pin COMM REQ CLED of another SEN LM3466 SRC GND CEQ RSEN 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. 2All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Copyright © 2011–2013, Texas Instruments Incorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. LM3466 SNOSB96F –JUNE 2011–REVISED NOVEMBER 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. ABSOLUTE MAXIMUM RATINGS (1) If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/ Distributors for availability and specifications. MIN MAX UNIT VIN, ILED to GND –0.3 75 V COMM to GND –0.3 7 V SEN, SRC, VEQ to GND –0.3 5 V ESD Rating (2), Human Body Model –2 2 kV Storage Temperature Range –65 150 °C Junction Temperature (TJ) 150 °C (1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. (2) The human body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin. RECOMMENDED OPERATING CONDITIONS(1) MIN MAX UNIT Supply Voltage Range (VIN) 6 70 V Junction Temperature Range (TJ) −40 125 °C (1) Recommended Operating conditions are those under which operation of the device is intended to be functional. For specifications and test conditions, see the Electrical Characteristics table. THERMAL INFORMATION SO PowerPAD TO-220 THERMAL METRIC DDA NEC(1) UNITS 8 PINS 7 PINS (2) θJA Junction-to-ambient thermal resistance 50.7 32.2 (3) θJCtop Junction-to-case (top) thermal resistance 56.1 36.4 (4) θJB Junction-to-board thermal resistance 28.9 25.2 (5) °C/W ψJT Junction-to-top characterization parameter 9.8 6.2 (6) ψJB Junction-to-board characterization parameter 28.8 23.8 (7) θJCbot Junction-to-case (bottom) thermal resistance 3.3 0.3 (1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. (2) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as specified in JESD51-7, in an environment described in JESD51-2a. (3) The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC- standard test exists, but a close description can be found in the ANSI SEMI standard G30-88. (4) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB temperature, as described in JESD51-8. (5) The junction-to-top characterization parameter, ψJT, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA, using a procedure described in JESD51-2a (sections 6 and 7). (6) The junction-to-board characterization parameter, ψJB, estimates the junction temperature of a device in a real system and is extracted from the simulation data for obtaining θJA , using a procedure described in JESD51-2a (sections 6 and 7). (7) The junction-to-case (bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88. Spacer 2 Submit Documentation Feedback Copyright © 2011–2013, Texas Instruments Incorporated Product Folder Links: LM3466 LM3466 www.ti.com SNOSB96F –JUNE 2011–REVISED NOVEMBER 2013 ELECTRICAL CHARACTERISTICS –40°C ≤ TJ ≤ 125°C, VIN = 48 V (unless otherwise stated) PARAMETER CONDITIONS MIN TYP MAX UNITS VIN pin under-voltage lockout (UVLO) V Input voltage increasing 4.06 4.78 5.30 V IN-UVLO-UPPER upper threshold VIN-UVLO-HYS VIN pin UVLO hysteresis Input voltage decreasing, TA = 25°C 0.52 V IIN Operating current to the VIN pin 550 640 µA VEQ = 200 mV, TA = 25°C 197.1 200 201.0 VSEN SEN pin voltage regulation mV VEQ = 200 mV 195.6 200 201.5 ISEN SEN pin bias current out VSEN = 0 V 9.35 10.29 11.23 µA ILED-OFF ILED pin off current VILED = 70 V 0.1 0.6 µA Integrated power MOSFET on- R I = 300 mA 0.5 1.2 Ω DS(on) resistance ILED VSRC-OPEN SRC pin open circuit threshold VSEN = VSRC, VCOMM = 0 V 25 31 37 mV ILIMIT Current limit VSEN = VSRC = 0 V, VILED = 3 V 1.75 2.06 2.35 A COMMILOW COMM pin pull-low current VCOMM = 5 V 34 54 µA COMM pin to ground through a 10-kΩ COMM COMM pin pull-high voltage 6.0 V VHIGH resistor TSD Thermal shutdown 150 °C Connection Diagrams Figure 1. DDA (SO PowerPAD) Package, 8 Pins Figure 2. NEC (TO-220) Package, 7 Pins (Top View) (Top View) PIN DESCRIPTIONS PINS NAME I/O DESCRIPTION DDA NEC Open-drain status output. Indicates the status of the LM3466 including startup, LED string COMM 2 6 O active/inactive, thermal shutdown. GND 5 4 — Ground. Connects to ground. Current regulator input. Connects to the drain of the integrated power MOSFET. Connects this pin to ILED 1 5 I the cathode of an LED string. Connects a capacitor from this pin to ground to minimize noise if the connecting cable to the LED string is long. SEN 6 2 I Current sense input. Senses the voltage of an external current sensing resistor. 7 Source of power MOSFET. Connects to the source of the integrated power MOSFET. Connect this SRC 3 O 8 pin to an external current sensing resistor. Control voltage. Connects to the VEQ pin of other LM3466 with a 51-Ω resistor in series with a 1-µF VEQ 4 1 O capacitor to ground. Input voltage supply. Connects to voltage supply from 6 V to 70 V. Connects a 10-nF capacitor from VIN 3 7 I this pin to ground for decoupling. Thermal Pad — Thermal connection pad. Connects to a ground plane. Copyright © 2011–2013, Texas Instruments Incorporated Submit Documentation Feedback 3 Product Folder Links: LM3466 LM3466 SNOSB96F –JUNE 2011–REVISED NOVEMBER 2013 www.ti.com TYPICAL CHARACTERISTICS Unless otherwise specified the following conditions apply: TJ = 25°C, VIN = 48V with configuration in the additional application circuit for ILED = 0.35A shown in this datasheet. 600 580 25°C 560 125°C A) ( IN I 540 520 -40°C 500 0 10 20 30 40 50 60 70 VIN(V) Figure 3.