LM3492HCMHX/NOPB

Product Folder Sample & Buy Support & Community Tools & Software Technical Documents LM3492HC-Q1, LM3492HC SNVS797B – MARCH 2012 – REVISED OCTOBER 2015 LM3492HC/-Q1 Two-Channel, Individual Dimmable, LED Driver With Boost Converter and Fast Current Regulator 1 Features 2 Applications • • 1 • • Boost Converter – Automotive Grade Product, Q100 Grade-1 Qualified – Very Wide Input Voltage Range: 4.5 V to 65 V – Programmable Soft-Start Period – No Loop Compensation Required – Stable with Ceramic and Other Low ESR Capacitors with No Audible Noise – Nearly Constant Switching Frequency Programmable from 200 kHz to 1 MHz Current Regulator – Programmable LED Current: 50 mA to 250 mA – 10000:1 Contrast Ratio, 300-ns Minimum Pulse Width – Two Individual Dimmable LED Strings up to 65 V, Total 15 W (Typically 28 LEDs at 150 mA) – Dynamic Headroom Control Maximizes Efficiency – Over-Power Protection – ±3% Current Accuracy Supervisory Functions – Precision Enable – COMM I/O Pin for Diagnostic and Commands – Thermal Shutdown Protection – Thermally Enhanced PWP, 20-Pin Package • Ultra-High Contrast Ratio 6.5” to 10” LCD Display Backlight up to 28 LEDs Automotive or Marine GPS Display 3 Description The LM3492HC/-Q1 device integrates a boost converter and a two-channel current regulator to implement a highly efficient and cost effective LED driver. This device drives two individually dimmable LED strings with a maximum power of 15 W and an output voltage of up to 65 V. The boost converter employs a proprietary projected-on-time control method to give a fast transient response with no compensation required. The nearly constant switching frequency can be set to a level from 200 kHz to 1 MHz. Ceramic capacitors stabilize the application circuit and produce no audible noise on dimming. The programmable peak current limit and soft-start features reduce current surges at start-up. An integrated, 190-mΩ, 3.9-A, N-Channel MOSFET switch minimizes the solution size. The fast slew rate current regulator allows high frequency and narrow pulse width dimming signals to achieve a very high contrast ratio of 10000:1. The LED current can be set from 50 mA to 250 mA by a single resistor. Device Information(1) PART NUMBER LM3492HC PACKAGE PWP (20) LM3492HC-Q1 BODY SIZE (NOM) 6.50 mm × 4.40 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Application L1 LM3492HC LM3492HC-Q1 VIN SW CIN RRT CDHC CCDHC VCC CVCC EN RT CFB RFB1 VOUT COUT FB RIREF RCOMM PGND GND IREF RFB2 ILIM COMM LGND DIM1/CLK IOUT1 DIM2 IOUT2 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM3492HC-Q1, LM3492HC SNVS797B – MARCH 2012 – REVISED OCTOBER 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Description (continued)......................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 3 4 7.1 7.2 7.3 7.4 7.5 7.6 4 4 4 5 5 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 11 8.1 Overview ................................................................. 11 8.2 Functional Block Diagram ....................................... 11 8.3 Feature Description................................................. 12 8.4 Device Functional Modes........................................ 17 8.5 Programming .......................................................... 18 9 Application and Implementation ........................ 19 9.1 Application Information............................................ 19 9.2 Typical Application ................................................. 19 10 Power Supply Recommendations ..................... 22 11 Layout................................................................... 22 11.1 Layout Guidelines ................................................. 22 11.2 Layout Example .................................................... 22 12 Device and Documentation Support ................. 23 12.1 12.2 12.3 12.4 12.5 Related Links ........................................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 23 23 23 23 23 13 Mechanical, Packaging, and Orderable Information ........................................................... 23 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision A (May 2013) to Revision B • 2 Page Added Pin Configuration and Functions section, ESD Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1 Submit Documentation Feedback Copyright © 2012–2015, Texas Instruments Incorporated Product Folder Links: LM3492HC-Q1 LM3492HC LM3492HC-Q1, LM3492HC www.ti.com SNVS797B – MARCH 2012 – REVISED OCTOBER 2015 5 Description (continued) To maximize the efficiency, dynamic headroom control (DHC) automatically adjusts the output voltage to a minimum. The DHC also facilitates a single BOM for different number of LED in a string, which is required for back-light panels of different size, thereby reducing overall development time and cost. The LM3492HC device includes a COMM pin that serves as a bidirectional I/O pin. The versatile COMM pin interface with an external micro-controller unit (MCU) is used for the following functions: power-good, overtemperature, IOUT overvoltage and undervoltage indications, switching frequency tuning, and channel 1 disabling. Other supervisory functions of the device include precise enable, VCC undervoltage lockout, current regulator over-power protection, and thermal shutdown protection. The device is available in the thermally enhanced PWP, 20-pin package. 6 Pin Configuration and Functions PWP Package 20 Pin HTSSOP Top View EN VIN SW SW VOUT RT FB GND IOUT2 IOUT1 1 2 3 4 5 6 7 8 9 10 Exposed Thermal Pad ILIM VCC PGND PGND DIM2 DIM1/CLK LGND COMM IREF CDHC 20 19 18 17 16 15 14 13 12 11 NC – No internal connection Pin Functions PIN TYPE (1) DESCRIPTION NAME NO. CDHC 11 I Dynamic headroom control. An external capacitor connected to this pin sets the DHC sensitivity. At start-up, a 12- µA internal current source charges an external capacitor to provide a soft-start function. COMM 13 I/O Bidirectional logic communication. This pin is open drain for various indications (power-good, overtemperature, IOUT overvoltage and undervoltage) and command sending (switching frequency tuning and channel 1 disabling). DIM1/CLK 15 I/O Dimming control of channel 1. Control the on and off of the current regulator of channel 1. This pin is internally pulled low by a 5-µA current. This pin also serves as a clock signal for latching input and output data of the COMM pin. DIM2 16 I Dimming control of channel 2. Control the on and off of the current regulator of channel 2. This pin is internally pulled low by a 5-µA current. EN 1 I Enable input. Contains an internal pullup. Connect to a voltage higher than 1.63 V to provide precision enable for the device. FB 7 I Output voltage feedback. The output voltage is connected to this pin through a feedback resistor divider for output voltage regulation. The voltage of this pin is from 1.05 V to 2.5 V. GND 8 G Analog signal ground. Connect to the exposed pad directly beneath the device. ILIM 20 I Peak current limit adjust. Connecting an external resistor from the ILIM pin to the VCC pin reduces peak current limit. Connect the ILIM pin to ground to obtain the maximum current limit. IOUT1 10 I Current regulator input for channel 1. Input of the current regulator of channel 1. The regulated current is programmable (see the IREF pin). IOUT2 9 I Current regulator input for channel 2. Input of the current regulator of channel 2. The regulated current is programmable (see the IREF pin). IREF 12 I Current setting pin for the current regulators. An external resistor connected from this pin to ground programs the regulated current of the current regulator of channels 1 and 2. (1) I = Input, O = Output, G = Ground Copyright © 2012–2015, Texas Instruments Incorporated Product Folder Links: LM3492HC-Q1 LM3492HC Submit Documentation Feedback 3 LM3492HC-Q1, LM3492HC SNVS797B – MARCH 2012 – REVISED OCTOBER 2015 www.ti.com Pin Functions (continued) PIN NAME NO. LGND 14 TYPE (1) 17 PGND 18 RT 6 3 SW 4 DESCRIPTION G Current regulator ground. Must be connected to the GND pin and exposed pad for normal operation. The LGND and GND pins are not internally connected. G Integrated MOSFET ground. Must be connected to the GND pin and exposed pad for normal operation. The PGND and GND pins are not internally connected. I Frequency control pin. An external resistor from the VOUT pin to this pin sets the switching frequency. I Switch node. Internally connected to the drain of the integrated MOSFET. VCC 19 O Internal LED regulator output. Nominally regulated to 5.5 V. Connect a capacitor of 0.47-μF or larger between the VCC and GND pins. VIN 2 I Input supply voltage pin. Input voltage range is from 4.5 V to 65 V. VOUT 5 I Output voltage sense pin. Senses the output voltage for nearly constant switching frequency control. G Thermal connection pad. Connect to a ground plane. Exposed Pad 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) Input voltage Output voltage (1) VIN, RT, VOUT to GND, SW to GND MIN MAX −0.3 67 V −2 SW to GND (transient