Single or Multiple Cell Li-ion Battery Powered 4-Channel and 6-Channel LED Drivers ISL97692, ISL97693, ISL97694A The ISL97692, ISL97693, ISL97694A are Intersil’s highly integrated 4- and 6-channel LED drivers for display backlighting . These parts maximize battery life by featuring only 1mA quiescent current, and by operating down to 2.4V input voltage, with no need for higher voltage supplies. The ISL97692 has 4 channels and provides 8-bit PWM dimming with adjustable dimming frequency up to 30kHz. The ISL97693 has 6 channels with Direct PWM dimming control. The ISL97694A has 6 channels and provides 8-, 10-, or 12-bit PWM dimming with adjustable dimming frequency up to 30kHz, 7.5kHz, or 1.875kHz, respectively, controlled with I2C or PWM input. ISL97692 and ISL97694A feature phase shifting that may be enabled optionally, with a phase delay between channels optimized for the number of active channels. In ISL97694A, phase shifting can multiply the effective dimming frequency by 6 allowing above-audio PWM dimming with 10-bit dimming resolution. The ISL97692/3/4A employ adaptive boost architecture, which keeps the headroom voltage as low as possible to maximize battery life while allowing ultra low dimming duty cycle as low as 0.005% at 100Hz dimming frequency in Direct PWM mode. The ISL97692/3/4A incorporate extensive protection functions including string open and short circuit detections, OVP, and OTP. The ISL97692/3 are offered in the 16 Ld 3mmx3mm TQFN package and ISL97694A is offered in the 20 Ld 3mmx4mm TQFN package. All parts operate in ambient temperature range of -40°C to +85°C. Features • 2.4V Minimum Input Voltage, No Need for Higher Voltage Supplies • 4 Channels, up to 40mA Each (ISL97692) or 6 Channels, up to 30mA Each (ISL97693/4A) • 90% Efficient at 6P5S, 3.7V and 20mA (ISL97693/4A) • Low 0.8mA Quiescent Current • PWM Dimming Control with Internally Generated Clock - 8-bit Resolution with Adjustable Dimming Frequency up to 30kHz (ISL97692/4A) - 12-bit Resolution with Adjustable Dimming Frequency up to 1.875kHz (ISL97694A) - Optional Automatic Channel Phase Shift (ISL97692/4A) - Linear Dimming from 0.025%~100% up to 5kHz or 0.4%~100% up to 30kHz (ISL97692/4A) • Direct PWM Dimming with 0.005% Minimum Duty Cycle at 100Hz • ±2.5% Output Current Matching • Adjustable Switching Frequency from 400kHz to 1.5MHz Applications • Tablet, Notebook PC and Smart Phone Displays LED Backlighting Related Literature (Coming Soon) • AN1733 “ISL97694A Evaluation Board User Guide” • AN1734 “ISL97693 Evaluation Board User Guide” • AN1735 “ISL97692 Evaluation Board User Guide” 10 L1 VIN: 2.4V~5.5V D1 10µH VOUT: 24.5V, 6 x 20mA 4.7µF 4.7µF 4.7µF 10 1 VIN LX COMP 100pF 470k OVP 15nF 2.2nF 12k ILED (mA) 1µF 23.7k ISL97694A ISET 53k PGND 0.1 0.01 AGND fPWM: 200Hz SDA/PWMI SCL CH1 EN CH2 0.001 fPWM: 100Hz CH3 FPWM CH4 291k FSW CH5 0.0001 0.001 CH6 143k FIGURE 1. ISL97694A TYPICAL APPLICATION DIAGRAM July 19, 2012 FN7839.2 1 0.01 0.1 1 INPUT DIMMING DUTY CYCLE (%) 10 FIGURE 2. ULTRA LOW PWM DIMMING LINEARITY CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2012. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. ISL97692, ISL97693, ISL97694A Typical Application Circuits L1 VIN: 2.4V~5.5V D1 10µH VOUT: 24.5V, 4 x 20mA 4.7µF 4.7µF 4.7µF 10 VIN 1µF LX COMP 100pF 470k OVP 15nF 2.2nF 23.7k 12k ISL97692 ISET 53k PGND AGND ENPS CH1 PWMI CH2 EN CH3 FPWM CH4 291k FSW 143k FIGURE 3. ISL97692 TYPICAL APPLICATION DIAGRAM L1 VIN: 2.4V~5.5V D1 10µH VOUT: 24.5V, 6 x 20mA 4.7µF 4.7µF 4.7µF 10 VIN 1µF LX COMP 100pF 470k OVP 15nF 2.2nF 12k 23.7k ISL97693 ISET 53k PGND AGND PWMI EN CH1 CH2 CH3 FSW 143k CH4 CH5 CH6 FIGURE 4. ISL97693 TYPICAL APPLICATION DIAGRAM 2 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Typical Application Circuits (Continued) L1 VIN: 2.4V~5.5V D1 10µH VOUT: 24.5V, 6 x 20mA 4.7µF 4.7µF 4.7µF 10 VIN 1µF LX COMP 100pF 470k OVP 15nF 2.2nF 12k 23.7k ISL97694A ISET 53k PGND AGND SDA/PWMI SCL CH1 EN CH2 CH3 FPWM CH4 291k FSW CH5 CH6 143k FIGURE 5. ISL97694A TYPICAL APPLICATION DIAGRAM 3 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Block Diagrams 24V, 4x40mA VIN: 2.4V~5.5V OPTIONAL FUSE 10µH VIN LX O/P SHORT EN REG INTERNAL BIAS OVP OVP FSW OSC & RAMP COMP PWM/ PFM LOGIC FET DRIVERS IMAX ILIMIT PGND COMP GM AMP + - ISET 8-BIT DAC HIGHEST VF STRING DETECT DYNAMIC HEADROOM CONTROL + - OPEN CKT, SHORT CKT DETECTION CH1 CH2 CH3 CH4 1 2 REF GEN 3 REF_OVP REF_VSC + - PWMI 8-BIT DIGITIZER FPWM ENPS 4 DIRECT PWM DETECT PHASE SHIFT & PWM DIMMING CONTROLLER ISL97692 TEMP SENSOR FIGURE 6. ISL97692 BLOCK DIAGRAM 4 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Block Diagrams (Continued) 24V, 6x30mA VIN: 2.4V~5.5V OPTIONAL FUSE 10µH VIN LX O/P SHORT EN INTERNAL BIAS REG OVP OVP FSW OSC & RAMP COMP PWM/ PFM LOGIC FET DRIVERS IMAX ILIMIT PGND GM AMP COMP 8-BIT DAC HIGHEST VF STRING DETECT DYNAMIC HEADROOM CONTROL + - + - OPEN CKT, SHORT CKT DETECTION 1 2 REF GEN ISET CH1 CH2 CH3 CH4 CH5 CH6 3 4 5 REF_OVP REF_VSC + - PWMI 6 PWM DIMMING CONTROLLER ISL97693 TEMP SENSOR FIGURE 7. ISL97693 BLOCK DIAGRAM 5 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Block Diagrams (Continued) 24V, 6x30mA VIN: 2.4V~5.5V OPTIONAL FUSE 10µH VIN LX O/P SHORT EN REG INTERNAL BIAS OVP OVP FSW OSC & RAMP COMP PWM/ PFM LOGIC FET DRIVERS IMAX ILIMIT PGND GM AMP COMP 8-BIT DAC HIGHEST VF STRING DETECT DYNAMIC HEADROOM CONTROL + - + - OPEN CKT, SHORT CKT DETECTION 1 2 REF GEN ISET CH1 CH2 CH3 CH4 CH5 CH6 3 4 5 REF_OVP REF_VSC SCL SDA/PWMI + - I2C CONTROLLER 6 PHASE SHIFT & PWM DIMMING CONTROLLER FPWM DIRECT PWM DETECT ISL97694A TEMP SENSOR FIGURE 8. ISL97694A BLOCK DIAGRAM 6 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Pin Configurations s CH2 CH1 14 13 CH1 13 CH3 CH2 14 16 CH4 CH3 15 16 CH4 15 ISL97693 (16 LD TQFN) TOP VIEW ISL97692 (16 LD TQFN) TOP VIEW AGND 1 12 OVP CH5 1 12 OVP COMP 2 11 FSW CH6 2 11 FSW VIN 8 EN 7 PWMI 6 ISET 5 FPWM 8 VIN 7 EN 6 PWMI 5 9 LX COMP 4 9 LX ENPS 4 10 PGND AGND 3 10 PGND ISET 3 CH5 CH4 CH3 CH2 ISL97694A (20 LD TQFN) TOP VIEW 20 19 18 17 AGND 2 15 OVP COMP 3 14 FSW ISET 4 13 NC SCL 5 12 PGND NC 6 11 LX 7 8 9 10 FPWM CH1 VIN 6 16 EN 1 SDA/PWMI CH6 Pin Descriptions PIN NAME ISL97692 ISL97693 ISL97694A AGND 1 3 2 Analog Ground for precision circuits. CH5 1 20 Channel 5 current sink and channel monitoring. Tie pin to GND if channel unused. CH6 2 1 Channel 6 current sink and channel monitoring. Tie pin to GND if channel unused. DESCRIPTION COMP 2 4 3 External compensation. Fit a series RC comprising 12kΩ and 15nF from COMP to GND. ISET 3 5 4 Channel current setting. The LED channel current is adjusted from 2mA to 40mA (ISL97692) or to 30mA with (ISL97693/4A) resistor RSET from ISET pin to GND ENPS 4 PWMI 5 Enable Phase Shift PWM Dimming Control. High = Enable. Low = Disable. 6 PWM Input Signal for ISL97692/3/4A for brightness control. SCL 5 I2C serial clock input. Mode selection to PWMI input when tied to GND for ISL97694A. SDA/PWMI 7 I2C serial data input and output. PWMI input when SCL tied to GND for ISL97694A. 7 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Pin Descriptions (Continued) PIN NAME ISL97692 ISL97693 ISL97694A DESCRIPTION EN 6 7 8 Enable Input. High = Normal operation. Low = Shutdown. VIN 7 8 9 Input Supply Voltage. FPWM 8 10 Tie FPWM to VIN to select Direct PWM mode. In Direct PWM mode, the channel outputs follow the PWMI pin’s frequency and pulse width. Connect resistor RFPWM from FPWM to GND to select PWM dimming frequency adjustment. In this mode, the channel outputs follow the PWMI pin’s PWM duty, and the LED PWM dimming frequency is set by the value of resistor RFPWM. LX 9 9 11 Input to boost switch. PGND 10 10 12 Power ground (LX, CIN, and COUT Power return). FSW 11 11 14 Switching Frequency Adjustment. The boost switching frequency is adjusted from 400kHz to 1.5MHz with resistor RFSW from FSW pin to GND. OVP 12 12 15 Overvoltage protection input. CH1 13 13 16 Channel 1 current sink and channel monitoring. Tie pin to GND if channel unused. CH2 14 14 17 Channel 2 current sink and channel monitoring. Tie pin to GND if channel unused. CH3 15 15 18 Channel 3 current sink and channel monitoring. Tie pin to GND if channel unused. CH4 16 16 19 Channel 4 current sink and channel monitoring. Tie pin to GND if channel unused. NC 6, 13 Not connected. Ordering Information PART NUMBER (Notes 1, 2, 3) PART MARKING ISL97692IRTZ TEMP RANGE (°C) PACKAGE (Pb-free) PKG. DWG. # 7692 -40 to +85 16 Ld 3mmx3mmx0.75mm TQFN L16.3x3D ISL97693IRTZ 7693 -40 to +85 16 Ld 3mmx3mmx0.75mm TQFN L16.3x3D ISL97694AIRTZ 694A -40 to +85 20 Ld 3mmx4mmx0.8mm TQFN L20.3x4A ISL97692IRTZ-EVALZ Evaluation board ISL97693IRTZ-EVALZ Evaluation board ISL97694AIRT-EVZ Evaluation board NOTES: 1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications. 2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate - e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 3. For Moisture Sensitivity Level (MSL), please see device information page for ISL97692, ISL97693 ISL97694A. For more information on MSL please see tech brief TB363. 8 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Table of Contents Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Typical Performance Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 PWM Boost Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Dimming Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Direct PWM Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Phase Shift Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 PWM Dimming Frequency Adjustment (ISL97692/4A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Current Matching and Current Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Dynamic Headroom Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Soft-Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Operation with Input Voltage Greater than 5.5V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Power-Off Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 SMBus/I2C Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Read Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Slave Device Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 SMBus/I2C Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Component Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Input Capacitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Overvoltage Protection (OVP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Boost Output Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Inductor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Output Capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Schottky Diode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Unused LED Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 High Current Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 PCB Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 PCB Layout with TQFN Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 General Power PAD Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Fault Protection and Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Short Circuit Protection (SCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Open Circuit Protection (OCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Overvoltage Protection (OVP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Undervoltage Lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Over-Temperature Protection (OTP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 9 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Absolute Maximum Ratings (Note 4) Thermal Information VIN, ISET, COMP, OVP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V PWMI, FPWM, FSW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V EN, ENPS, SCL, SDA/PWMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V CH1 to CH6, LX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 28V PGND, AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V Maximum Average Current Into LX Pin . . . . . . . . . . . . . . . . . . . . . . . . . .2.6A ESD Ratings Human Body Model (Tested per JESD22-A114F) . . . . . . . . . . . . . . . . 2kV Machine Model (Tested per JESD22-A115C) . . . . . . . . . . . . . . . . . . 200V Charged Device Model (JESD22-C101E) . . . . . . . . . . . . . . . . . . . . . . . 1kV Latch Up (Tested per JESD-78B; Class 2, Level A) . . . . . . . . . . . . . . 100mA Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) 16 Ld TQFN (Notes 5, 6) . . . . . . . . . . . . . . . 51 4.6 20 Ld TQFN (Notes 5, 6) . . . . . . . . . . . . . . . 45 3.0 Thermal Characterization (Typical) PSIJT (°C/W) 16 Ld TQFN (Note 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.11 20 Ld TQFN (Note 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 Maximum Continuous Junction Temperature . . . . . . . . . . . . . . . . .+125°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp Operating Conditions Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. NOTES: 4. Voltage Ratings are all with respect to the AGND pin. 5. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech Brief TB379. 6. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside. 7. PSIJT is the PSI junction-to-top thermal characterization parameter. If the package top temperature can be measured with this rating then the die junction temperature can be estimated more accurately than the θJC and θJC thermal resistance ratings. Electrical Specifications All of the following specifications are characterized at TA = -40°C to +85°C; VIN = EN = 3.3V, RISET = 26.7kΩ (ISL97692) or RISET = 35.5kΩ (ISL97693/4A), unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +85°C. PARAMETER DESCRIPTION CONDITION MIN (Note 8) TYP MAX (Note 8) UNIT 5.5 V GENERAL VIN IVIN_Standby IVIN Backlight Supply Voltage, (Notes 9, 10) TA = +25°C Standby current EN = Low, LDO disabled 2.4 VIN Active Current, ILED = 40mA (ISL97692) All channels 100% duty 30mA (ISL97693/4A) All channels 0% duty VOUT Output Voltage VUVLO Undervoltage Lockout Threshold VUVLO_HYS Undervoltage Lockout Hysteresis ENLow EN Input Low Voltage ENHi EN Input High Voltage 1 µA 2.5 mA 0.8 mA VIN ≥ 2.7V, ILED = 40mA (ISL97692) 30mA (ISL97693/4A) 2 2.15 26 V 2.35 V 150 mV 0.5 1.5 V V BOOST SWITCHING REGULATOR SS SWILimit rDS(ON) Eff_peak Soft-start 100% LED Duty Cycle Boost FET Current Limit 2.7V< VIN < 5.5V, fSW = 600kHz, L = 10µH, TA ≤ +55°C Internal Boost Switch ON-Resistance TA = +25°C 212 mΩ Peak Efficiency VIN = 5.5V, VOUT = 21V, TA = +25°C, RFSW = 144kΩ, ICH1-CH6 = 20mA, L = 10µH with DCR ≤ 150mΩ 90 % VIN = 2.7V, VOUT = 21V, TA = +25°C, RFSW = 144kΩ, ICH1-CH6 = 20mA, L = 10µH with DCR ≤ 150mΩ 74 % 10 7 2.45 2.8 ms 3.2 A FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Electrical Specifications All of the following specifications are characterized at TA = -40°C to +85°C; VIN = EN = 3.3V, RISET = 26.7kΩ (ISL97692) or RISET = 35.5kΩ (ISL97693/4A), unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +85°C. (Continued) PARAMETER DMAX DMIN fSW DESCRIPTION Boost Maximum Duty Cycle Boost Minimum Duty Cycle Boost Switching Frequency CONDITION MIN (Note 8) MAX (Note 8) UNIT FSW = 400kHz 93.5 % FSW = 1.5MHz 93 % FSW = 400kHz 11 % FSW = 1.5MHz 15 % RFSW = 216kΩ 360 RFSW = 72.1kΩ RFSW = 57.7kΩ ILX_leakage TYP 400 440 kHz 1.2 1.35 1.5 MHz 1.65 MHz 10 µA LX Leakage Current LX = 26V Channel-to-Channel DC Current Matching ILED = 20mA -2.5 +2.5 % Current Accuracy ILED = 20mA -3 +3 % 9.25 V REFERENCE IMATCH IACC FAULT DETECTION VSC Channel Short Circuit Threshold Vtemp Over-Temperature Threshold VOVPlo Overvoltage Limit on OVP Pin OVPfault 6.75 8 1.180 1.22 150 OVP Short Detection Fault Level °C 1.245 V 75 mV 300 mV CURRENT SOURCES Vheadroom Dominant Channel Current Source Headroom at CH Pin ILED = 20mA TA = +25°C ILED(max) Maximum LED Current per Channel 2.7V < VIN < 5.5V, VOUT = 21V (ISL97692) 40 mA 2.7V < VIN < 5.5V, VOUT = 21V (ISL97693 and ISL97694A) 30 mA PWM GENERATOR VIL Guaranteed Range for PWM Input Low Voltage VIH Guaranteed Range for PWM Input High Voltage 1.5 PWMI Input Frequency Range 100 FPWMI 0.5 V V 30,000 Hz DPWMACC Direct PWM Dimming Output Resolution (ISL97692, ISL97693 and ISL97694A) 80 ns tDPWM_ON_MIN Direct PWM Dimming Minimum On-Time (ISL97692, ISL97693 and ISL97694A) 350 ns PWMACC PWM Dimming with Adjustable Dimming Frequency Output Resolution (ISL97692, ISL97694A) 12 bit FPWM Generated PWM Dimming Frequency Range (ISL97692, ISL97694A) 2 SMBus/I C INTERFACE (ISL97694A only) VIL Guaranteed Range for Data, Clock Input Low Voltage VIH Guaranteed Range for Data, Clock Input High Voltage VOL SMBus/I2C Output Data Line Logic Low Voltage IPULLUP = 4mA Input Leakage On SDA/SCL Measured at 4.8V ILEAK 11 100 1.5 -10 30,000 Hz 0.5 V VDD V 0.17 V 10 µA FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Electrical Specifications All of the following specifications are characterized at TA = -40°C to +85°C; VIN = EN = 3.3V, RISET = 26.7kΩ (ISL97692) or RISET = 35.5kΩ (ISL97693/4A), unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +85°C. (Continued) PARAMETER DESCRIPTION 2 SMBus/I C TIMING SPECIFICATIONS (ISL97694A only) tEN-SMBus/I2C FSCL CONDITION Minimum Time between VIN>UVLO and SMBus/I2C Enabled MIN (Note 8) Bus Free Time Between Stop and Start Condition t2 tHD:STA Hold Time After (Repeated) START Condition tSU:STA Repeated Start Condition Setup Time tSU:STO MAX (Note 8) 2 SCL Clock Frequency t1 TYP UNIT ms 400 kHz 1.3 µs After this Period, the First Clock is Generated 0.6 µs t5 0.6 µs Stop Condition Setup Time 0.6 µs tHD:DAT Data Hold Time 300 ns tSU:DAT Data Setup Time 100 ns t3 Low Period of SCL Clock 1.3 µs t4 High Period of SCL Clock 0.6 µs tF Clock/data Fall Time 300 ns tR Clock/data Rise Time 300 ns NOTES: 8. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization and are not production tested. 9. At maximum VIN of 5.5V, minimum VOUT is 6V. Minimum VOUT can be lower at lower VIN. 10. Limits established by characterization and are not production tested. 12 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Typical Performance Curves 95 92 6P5S LEDs 85 6P6S LEDs EFFICIENCY (%) EFFICIENCY (%) 88 86 84 6P7S LEDs 82 70 65 78 55 3.7 4.2 4.7 50 5.2 6P7S LEDs 75 60 3.2 6P6S LEDs 80 80 76 2.7 6P5S LEDs 90 90 0 20 40 60 80 100 PWM DIMMING (%) INPUT VOLTAGE (V) FIGURE 9. EFFICIENCY vs VIN (ICH: 20mA, fDIM: 200Hz, FOR LEDs: 6P5S, 6P6S, 6P7S) FIGURE 10. EFFICIENCY vs PWM DIMMING (VIN: 3.7V, ICH: 20mA, fDIM: 200Hz, FOR LEDs: 6P5S, 6P6S, 6P7S) 2.5 MATCHING ACCURACY (%) LED CURRENT (mA) 20 15 10 5 0 0 20 40 60 80 100 1.5 IC#3 0.5 -0.5 IC#2 -1.5 -2.5 IC#1 0 FIGURE 11. PWM DIMMING LINEARITY (VIN: 3.7V, VOUT: 21V FOR 6P7S, fDIM: 200Hz) IL VOUT VOUT VLX VLX VCH VCH 13 2 3 4 5 6 7 FIGURE 12. CHANNEL MATCHING ACCURACY (VIN: 3.7V, VOUT: 21V FOR 6P7S, ICH: 20mA) IL FIGURE 13. START-UP (100% DIRECT PWM DIMMING, VIN: 3.7V, ICH: 20mA, LEDs: 6P7S, fDIM: 200Hz) 1 CHANNEL NUMBER INPUT DIMMING DUTY CYCLE (%) FIGURE 14. START-UP (100% DECODED PWM DIMMING, VIN: 3.7V, ICH: 20mA, LEDs: 6P7S, fDIM: 200Hz) FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Typical Performance Curves (Continued) IL IL VOUT VOUT VLX VLX VCH VCH FIGURE 15. START-UP (50% DIRECT PWM DIMMING, VIN: 3.7V, ICH: 20mA, LEDs: 6P7S, fDIM: 200Hz) FIGURE 16. START-UP (50% DECODED PWM DIMMING, VIN: 3.7V, ICH: 20mA, LEDs: 6P7S, fDIM: 200Hz) S:Start R/W A A A P:Stop SCL PWM INPUT SDA ICH Slave address:01011010 Command code (8bit) Brightness(100%): 11111111 I_CH FIGURE 17. MINIMUM DIMMING DUTY CYCLE (0.003% DIRECT PWM DIMMING MODE, fDIM: 100Hz) FIGURE 18. I2C CONTROL TIMING AND CHANNEL CURRENT (100% DIMMING, ISL97694A) IL I_L IL VLX V_LX V LX V_CH1 VCH1 V CH 1 VCH2 V_CH2 V CH 2 FIGURE 19. DECODED PWM DIMMING WITH PHASE SHIFT (VIN: 3.7V, ICH: 20mA, DIM: 17%, fDIM: 250Hz, LEDs: 6P6S) 14 FIGURE 20. DIRECT PWM DIMMING WITHOUT PHASE SHIFT (VIN:3.7V, ICH: 20mA, DIM:17%, fDIM: 250Hz, LEDs: 6P6S) FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Theory of Operation The reciprocal of this calculation gives the effective resolution of the PWM control per Equation 4: PWM Boost Converter The current mode PWM boost converter produces the minimal voltage needed to enable the LED stack with the highest forward voltage drop to run at the programmed current. The ISL97692/3/4A employs current mode control boost architecture that has a fast current sense loop and a slow voltage feedback loop. This architecture achieves the fast transient response, which is essential for portable product backlight applications where the backlight must not flicker when the power source is changed from a drained battery to an AC/DC adapter. (EQ. 4) For example, for a 200Hz input PWM frequency, the minimum duty cycle is: Min Duty Cycle = 350ns × 200Hz = 0.007% (EQ. 5) The effective resolution at 200Hz is 13½ bits: 1 PWM Resolution = -------------------------------------- = 14286 = 13.5bits 80ns × 200Hz (EQ. 6) Phase Shift Control The number of LEDs that can be driven by ISL97692/3/4A depends on the type of LED chosen in the application. The maximum output is 26V at 40mA from 2.7V input. Enable Take the EN input high to enable the ISL97692/3/4A for normal operation and low to enter low-power shutdown. Dimming Controls The ISL97692/3/4A allows the LED current to be programmed in the range 2mA to 40mA (ISL97692) or 2mA to 30mA (ISL97693/4A) by RSET per Equation 1: 1066 I LEDmax = --------------R SET 1 PWM Resolution = ------------------------------------------------------------------------------80ns × Input PWM Frequency (EQ. 1) The ISL97692/4A are capable of delaying the phase of each current source. Conventional LED drivers exhibit the worst load transients to the boost circuit by turning on all channels simultaneously, as shown in Figures 21 and 23. In contrast, the ISL97692/4A phase shift each channel by turning them on once during each PWM dimming period, as shown in Figures 22 and 24. At each dimming duty cycle (except at 100%) the sum of the phase shifted total current will be less than a conventional LED drivers’ total current. For ISL97692/4A, the channels are separated by 360°/N, where N is number of channels enabled. For example, if 3 channels are enabled, they will be separated by 120°. If the channels are combined for higher current application, the phase shift function must be disabled by connecting the ENPS pin to ground. Where: - RSET is the resistor from ISET pin to GND (Ω) - ILEDmax is the peak current set by resistor RSET (A) For example, if the required LED current (ILEDmax) is 40mA, then the RSET value needed is: R SET = 1066 ⁄ 0.04 = 26.65kΩ ILED1-20mA ILED2-20mA ILED3-20mA (EQ. 2) ILED4-20mA Choose the nearest standard resistor: 26.65kΩ, 0.1% Direct PWM Dimming ILED_Total_80mA The ISL97693 always operates in Direct PWM dimming mode. The ISL97692 and ISL97694A can be selected to operate in Direct PWM dimming mode by connecting the FPWM pin to VIN and the SCL pin of ISL97694A must be tied to GND. With Direct PWM, the channel outputs follow the input PWM signal’s frequency and pulse width, as provided to the PWMI pin. When PWMI is high, all channels sink the current set by the RSET resistor. When PWMI is low, all channels are high-Z. 5 10 TIME (ms) 15 FIGURE 21. CONVENTIONAL 4-CH LED DRIVER WITH 10% PWM DIMMING CHANNEL CURRENT (UPPER) AND TOTAL CURRENT (LOWER) The maximum allowed input PWM frequency at PWMI is 30kHz. The minimum duty is calculated by Equation 3 according to the input PWM frequency, and is set by the minimum channel on-time of 350ns. Min Duty Cycle = 350ns × Input PWM Frequency 15 (EQ. 3) FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A PWMI ILED1-20mA 60% 40% tPWMIN tFPWM (tPWMOUT) tOFF tON 40% 60% ILED2-20mA ILED1 ILED3-20mA ILED2 ILED4-20mA ILED3 ILED_Total_20mA ILED4 5 10 TIME (ms) FIGURE 22. ISL97692 PHASE SHIFT 4-CH LED DRIVER WITH 10% PWM DIMMING CHANNEL CURRENT (UPPER) AND TOTAL CURRENT (LOWER) ILED1 FIGURE 25. ISL97692 4 CHANNELS PHASE SHIFT TIMING ILLUSTRATION PWM Dimming Frequency Adjustment (ISL97692/4A) ILED4-20mA The ISL97692 and ISL97694A can use an internal oscillator to generate the PWM dimming frequency. In this mode, the duty of the signal at PWMI pin is measured with 8- or 12-bit resolution, and applied to the internally generated PWM dimming frequency. The dimming frequency is set by an external resistor RFPWM at the FPWM pin for ISL97692 and ISL97694A, per Equation 7: ILED3-20mA ILED2-20mA ILED1-20mA 6 58.1 ×10 R FPWM = -----------------------F PWM ILED_Total_80mA 5 10 TIME (ms) FIGURE 23. CONVENTIONAL LED DRIVER PWM DIMMING CHANNEL AND TOTAL CURRENT AT 50% DUTY CYCLE (EQ. 7) Where: - FPWM is the required PWM dimming frequency (Hz) - RFPWM is the resistor from FPWM pin to GND (Ω) For example, to set the PWM dimming frequency to 480Hz: 6 58.1 ×10 R FPWM = ------------------------ = 121kΩ 480 (EQ. 8) The maximum allowed PWM dimming frequency varies according to the PWM resolution, per Table 1. This is configurable for the ISL97694A by the En12Bit and En10Bit bits in register 0x01. ILED4-20mA ILED3-20mA TABLE 1. MAX PWM DIMMING FREQUENCY SET BY RFPWM ILED2-20mA ILED1-20mA PART ISL97692 ILED_Total_40mA 5 10 TIME (ms) FIGURE 24. ISL97692 PHASE SHIFT LED DRIVER PWM DIMMING CHANNEL AT 50% DUTY CYCLE 16 ISL97694A MAX FREQUENCY (kHz) PWM RESOLUTION (Bit Mode) 30 8 30 8 7.5 10 1.875 12 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Current Matching and Current Accuracy Each channel of the LED current is regulated by a current sink circuit. The LED peak current is set by the external RSET resistor according to Equation 1. The current sink MOSFETs in each LED driver channel output are designed to run at ~300mV to optimize power loss versus accuracy requirements. The sources of errors of the channel-to-channel current matching come from internal amplifier offsets, internal layout and reference accuracy. These parameters are optimized for current matching and absolute current accuracy. Absolute accuracy is also determined by the external resistor RSET, and so a 0.1% tolerance resistor is recommended. Dynamic Headroom Control The ISL97692/3/4A feature a proprietary Dynamic Headroom Control circuit that detects the highest forward voltage string or effectively the lowest voltage on any of the channel pins. When this lowest channel voltage is lower than the short circuit threshold, VSC, such voltage will be used as the feedback signal for the boost regulator. The boost makes the output to the correct level, such that the lowest channel pin is at the target headroom voltage. Since all LED stacks are connected to the same output voltage, the other channel pins will have a higher voltage, but the regulated current source circuit on each channel will ensure that each channel has the same current. The output voltage will regulate cycle-by-cycle and it is always referenced to the highest forward voltage string in the architecture. Note that there will be also an initial in-rush current to COUT when VIN is applied. This is determined by the ramp rate of VIN and the values of COUT and L. UVLO VIN VO SOFT-START (7ms) 17 FEEDBACK REGULATION ESTABLISHED EN PWMI ICHn Power-Off Sequence VIN VO Soft-Start Once the ISL97692/3/4A is powered up and the EN pin is taken high, the boost regulator will begin to switch and the current in the inductor will ramp-up. The current in the boost power switch is monitored and the switching is terminated in any cycle where the current exceeds the current limit. The ISL97692/3/4A includes a soft-start feature where this current limit starts at a low value (350mA). This is stepped up to the final 2.8A current limit in 7 further steps of 350mA. These steps will happen over typically 7ms, and will be extended at low LED PWM frequencies if the LED duty cycle is low. This allows the output capacitor to be charged to the required value at a low current limit and prevents high input current for systems that have only a low to medium output current requirement. (RISING) VUVLO - 150mV BOOST CONVERTER TURNED OFF tOFF AFTER REACHING {VUVLO - 150mV} EN DEPENDS ON APPLICATION PWMI ICHn Operation with Input Voltage Greater than 5.5V The ISL97692/3/4A boost regulator can operate from an input voltage higher than 5.5V, and up to 23V, as long as an additional supply voltage between 2.4V and 5.5V is available for the VIN pin. Please refer to Figure 26 for a typical application schematic adopting this solution. FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A L1 VBATT: 2.4V~21.8V D1 10µH VOUT: 24.5V, 6 x 20mA 4.7µF 4.7µF 4.7µF 2.4V~5.5V VIN LX COMP 100pF 470k OVP 15nF 2.2nF 12k 23.7k ISL97694A ISET 53k PGND AGND SDA/PWMI SCL CH1 EN CH2 CH3 FPWM CH4 291k FSW CH5 CH6 143k FIGURE 26. LED DRIVER OPERATION WITH INPUT VOLTAGE UP TO 26V SMBus/I2C Communications Slave Device Address The ISL97694A is controlled by SMBus/I2C for PWM dimming, and The slave address contains 7 MSB plus one LSB as R/W bit, but these 8 bits are usually called Slave Address bytes. As shown in Figure 27, the high nibble of the Slave Address byte is 0x5 or b’0101’ to denote the “backlight controller class”. Bit 0 is always the R/W bit, as specified by the SMBus/I2C protocol. If the device is in the write mode where bit 0 is 0, the slave address byte is 0x5A or b’01011010’. If the device is in the read mode where bit 0 is 1, the slave address byte is 0x5B or b’01011011’. powers up in the shutdown state. The ISL97694A is enabled when both the EN pin is high and the BL_CTL bit in register 0x01 is programmed to 1. Write Byte The Write Byte protocol is only three bytes long. The first byte starts with the slave address followed by the “command code,” which translates to the “register index” being written. The third byte contains the data byte that must be written into the register selected by the “command code”. A shaded label is used on cycles during which the slaved backlight controller “owns” or “drives” the Data line. All other cycles are driven by the “host master.” MSB 0 1 0 1 1 0 1 R/W 18 EB DEVICE ADDRESS /W R IT DEVICE IDENTIFIER RE AD As shown in Figure 30, the four byte long Read Byte protocol starts out with the slave address followed by the “command code”, which translates to the “register index.” Subsequently, the bus direction turns around with the rebroadcast of the slave address with bit 0 indicating a read (“R”) cycle. The fourth byte contains the data being returned by the backlight controller. That byte value in the data byte reflects the value of the register being queried at the “command code” index. Note the bus directions, which are highlighted by the shaded label that is used on cycles during which the slaved backlight controller “owns” or “drives” the Data line. All other cycles are driven by the “host master.” IT Read Byte FIGURE 27. SLAVE ADDRESS BYTE DEFINITION FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A SMBus/I2C Register Definitions When the ISL97694A is configured to 10-bit or 12-bit operation, be sure to write the PWM Brightness Control Register LSB (address 0x02) first. The subsequent write of PWM Brightness Control Register MSB (address 0x00) updates the contents of both registers to the PWM engine. The backlight controller registers are Byte wide and accessible via the SMBus/I2C Read/Write Byte protocols. Their bit assignments are provided in Figures 29 and 30 with reserved bits containing a default value of “0”. SMBCLK tLOW tF tR VIH VIL tHIGH tHD:DAT tHD:STA tSU:STA tSU:DAT tSU:STO SMBDAT VIH VIL P tBUF S P S NOTES: SMBus/I2C DESCRIPTION S = START CONDITION P = STOP CONDITION A = ACKNOWLEDGE A = NOT ACKNOWLEDGE R/W = READ ENABLE AT HIGH; WRITE ENABLE AT LOW FIGURE 28. SMBUS/I2C INTERFACE for ISL97694A 1 7 1 1 8 1 8 1 1 S SLAVE ADDRESS W A COMMAND CODE A DATA BYTE A P MASTER TO SLAVE SLAVE TO MASTER FIGURE 29. WRITE BYTE PROTOCOLfor ISL97694A 1 7 1 1 8 1 1 8 1 1 8 1 1 S SLAVE ADDRESS W A COMMAND CODE A S SLAVE ADDRESS R A DATA BYTE A P MASTER TO SLAVE SLAVE TO MASTER FIGURE 30. READ BYTE PROTOCOL for ISL97694A 19 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A TABLE 2. I2C REGISTER ALLOCATIONS FOR ISL97694A ADDRESS REGISTER BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 DEFAULT VALUE SMBUS/I2C PROTOCOL 0x00 PWM Brightness Control Register MSB BRT11 BRT10 BRT9 BRT8 BRT7 BRT6 BRT5 BRT4 0xFF Read and Write 0x01 Device Control Register - - - - PS_EN BL_CTL 0x00 Read and Write 0x02 PWM Brightness Control Register LSB BRT3 BRT2 BRT1 BRT0 - - 0xF0 Read and Write En12Bit En10Bit - - TABLE 3. I2C REGISTER FUNCTIONS FOR ISL97694A ADDRESS REGISTER DATA BIT DESCRIPTIONS 0x00 PWM Brightness Control Register MSB BRT[11..4] = DPWM duty cycle brightness control In 8 bit PWM data mode, PWM data is BRT[11..4] In 10 bit PWM data mode, PWM data is BRT[11..2] In 12 bit PWM data mode, PWM data is BRT[11..0] 0x01 Device Control Register PS_EN = Phase shift On/Off (1: Phase shift enabled, 0: Phase shift disabled) BL_CTL = Backlight On/Off (1: driver enabled if EN pin is high, 0 = driver shut down) {En12Bit, En10Bit} = {0,0} to select 8 bit PWM data mode {En12Bit, En10Bit} = {0,1} to select 10 bit PWM data mode {En12Bit, En10Bit} = {1,0} to select 12 bit PWM data mode 0x02 PWM Brightness Control Register LSB BRT[3..0] = DPWM duty cycle brightness control (10 and 12 bit PWM data modes only). Note: this data is saved, but the PWM engine is only updated with BRT[11..0] or BRT[11..2] when the PWM Brightness Control Register MSB 0x00 is written Component Selection The design of the boost converter is simplified by an internal compensation scheme allowing easy design without complicated calculations. Please select your component values using the following recommendations. Input Capacitor It is recommended that a 4.7µF to 10µF X5R/X7R or equivalent ceramic input capacitor is used. Overvoltage Protection (OVP) The integrated OVP circuit monitors the boost output voltage, VOUT, and keeps the voltage at a safe level. The OVP threshold is set as Equation 9: R1 + R2 V OVP ( min ) = 1.22V × ---------------------R2 (EQ. 9) Where: - VOVP is the maximum boost output voltage, VOUT (V) - R1 is the resistor from OVP pin to the boost output (Ω) - R2 is the resistor from OVP pin to GND (Ω). The total R1 plus R2 series resistance should be high to minimize power loss through the resistor network. For example, choosing R1 = 470kΩ and R2 = 23.7kΩ per the Typical Application Circuits on page 2 and Block Diagrams on page 4. Set VOVP(typ) to 25.41V (Equation 10). 470 + 23.7 V OVP ( typ ) = 1.22V × ---------------------------- = 25.41V 23.7 20 (EQ. 10) The OVP threshold, R1, and R2 tolerances should also be taken into account (Equations 11 and 12). R1min + R2max V OVP ( min ) = 1.18V × ---------------------------------------------R2max (EQ. 11) R1max + R2min V OVP ( max ) = 1.24V × ---------------------------------------------R2min (EQ. 12) Calculating VOVP using the OVP threshold range (1.18V to 1.24V) and 0.1% resistor tolerances gives an actual VOVP range of 24.53V to 25.88V for the 25.4V previous example (Equations 13 and 14). ( 470 × 0.999 ) + ( 23.7 × 1.001 ) V OVP ( min ) = 1.18V × -------------------------------------------------------------------------------- = 24.53V ( 23.7 × 1.001 ) (EQ. 13) ( 470 × 1.001 ) + ( 23.7 × 0.999 ) ( max ) = 1.24V × -------------------------------------------------------------------------------- = 25.88V ( 23.7 × 0.999 ) (EQ. 14) V OVP It is recommended that parallel capacitors are placed across the OVP resistors such that R1/R2 = C2/C1. Using a C1 value of at least 30pF is recommended. These capacitors reduce the AC impedance of the OVP node, which reduces noise susceptibility when using high value resistors. Boost Output Voltage Range The working range of the boost output voltage, VOUT is from 40% to 100% of the maximum output voltage, VOVP, set by resistors R1 and R2, as described in the previous section. The target applications should be considered carefully to ensure that VOVP is not set unnecessarily high. For example, using R = 470kΩ and R2 = 23.7kΩ per the “Typical Application Circuits” on page 2 sets VOVP to between 24.53V to 25.88V when tolerances are considered. FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A The minimum voltage, VOVP(min) = 24.53V, sets the maximum number of LEDs per channel because this is the worst case minimum voltage that the boost converter is guaranteed to supply. Output Capacitor The maximum voltage, VOVP(max) = 25.88V, sets the minimum number of LEDs per channel because it sets the lowest voltage that the boost converter is guaranteed to reach: 40% x 25.88V = 10.35V. Schottky Diode Using LEDs with a VF tolerance of 3V to 4V, this VOVP example is suitable for strings of 4 to 6 LEDs. If fewer than 4 LEDs per channel are specified, VOVP must be reduced. Compensation Switching Frequency The boost switching frequency is adjusted by resistor RFSW (Equation 15): 10 ( 8.65 ×10 ) f SW = -------------------------------R FSW (EQ. 15) It is recommended that a two of 4.7µF X5R/X7R or equivalent ceramic output capacitor is used. The Schottky diode should be rated for at least the same forward current as the inductor, and for a reverse voltage equal to at least the maximum output voltage, OVP. The ISL97692/3/4A’s boost regulator uses a current mode control architecture with a standardized external compensation network connected to the COMP pin. The component values shown in the “Typical Application Circuits” on page 2, should be used. The network comprises a series RC of 12kΩ and 15nF from COMP to GND. Applications Where: - fSW is the desirable boost switching frequency (Hz) - RFSW is resistor from FSW pin to GND (Ω) Unused LED Channels Inductor High Current Applications Choose the inductance according to Table 4: Each channel of the ISL97692 supports 40mA continuous sink current. Each channel of the ISL97693/4A supports 30mA continuous sink current. For applications that need higher current, multiple channels can be paralleled (Tables 5 and 6). Connect unused LED channels to GND. TABLE 4. INDUCTOR SELECTION BOOST FREQUENCY INDUCTANCE (µH) 400kHz to 700kHz 10 to 15 700kHz to 1MHz 6.8 to 10 1MHz to 1.5MHz 4.7 to 8.2 1.5MHz 3.3 to 4.7 TABLE 5. PARALLELING ISL97692 CHANNELS FOR HIGHER CURRENT TOTAL CHANNELS The inductor saturation current rating should be as provided by Equation 16: 1.35 × V OUT × I LED I L = ----------------------------------------------------V IN (EQ. 16) Where: - IL is the minimum inductor saturation current rating (A) - VOUT is the maximum output voltage set by OVP (V) - ILED is the sum of the channel currents (A) - VIN is the minimum input voltage (V) If the calculation produces a current rating higher than the 3.08A maximum boost switch current limit, then a 3A inductor current rating is adequate. For example, for a system using 4 LED channels with 30mA per channel and a maximum output voltage (OVP) of 24.53V with an input supply of 2.7V minimum as shown by Equation 17: 1.35 × 24.53 × ( 4 × 0.03 ) I L = ----------------------------------------------------------------- = 1.47A 2.7 21 CHANNEL CURRENT CHANNEL CONNECTIONS 4 40mA per channel CH1, CH2, CH3, CH4 2 80mA per channel {CH1 & CH2}, {CH3 & CH4} 1 160mA {CH1 & CH2 & CH3 & CH4} TABLE 6. PARALLELING ISL97693/4A CHANNELS FOR HIGHER CURRENT TOTAL CHANNELS CHANNEL CURRENT CHANNEL CONNECTIONS 6 30mA per channel CH1, CH2, CH3, CH4, CH5, CH6 3 60mA per channel {CH1 & CH2}, {CH3 & CH4}, {CH5 & CH6} 2 90mA per channel {CH1 & CH2 & CH3}, {CH4 & CH5 & CH6} 1 180mA {CH1 & CH2 & CH3 & CH4 & CH5 & CH6} Figure 31 shows CH1 and CH2 paralleled. (EQ. 17) FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A pin. The AGND connection of the lower OVP components is critical for good regulation. 4. The COMP network and the rest of the analog components (on ISET, FPWM, FSW, etc.) should be reference to AGND. 5. The heat of the chip is mainly dissipated through the exposed thermal pad so maximizing the copper area around is a good idea. A solid ground is always helpful for the thermal and EMI performance. CH1 CH2 6. The inductor and input and output capacitors should be mounted as tight as possible, to reduce the audible noise and inductive ringing. FIGURE 31. PCB Layout Considerations PCB Layout with TQFN Package Great care is needed in designing a PC board for stable ISL97692/3/4A operation. As shown in the typical application diagram (Figures 3, 4 and 5 on pages 2, and 3) the separation of PGND and AGND is essential, keeping the AGND referenced only local to the chip. This minimizes switching noise injection to the feedback sensing and analog areas, as well as eliminating DC errors form high current flow in resistive PC board traces. PGND and AGND should be on the top and bottom layers respectively in the two layers PCB. A star ground connection should be formed by connecting the LED ground return and AGND pins to the thermal pad with vias (Figures 32, 33). The ground connection should be into this ground net, on the top plane. The bottom plane then forms a quiet analog ground area that both shields components on the top plane, as well as providing easy access to all sensitive components. For example, the ground side of the ISET resistor can be dropped to the bottom plane, providing a very low impedance path back to the AGND pin, which does not have any circulating high currents to interfere with it. The bottom plane can also be used as a thermal ground, so the AGND area should be sized sufficiently large to dissipate the required power. For multi-layer boards, the AGND plane can be the second layer. This provides easy access to the AGND net, but allows a larger thermal ground and main ground supply to come up through the thermal vias from a lower plane. Figure 34 shows the example of the PCB layout of ISL97694A. This type of layout is particularly important for this type of product, resulting in high current flow in the main loop’s traces. Careful attention should be focused in the following layout details: General Power PAD Design Considerations Figures 32 and 33 show an example of how to use vias to remove heat from the IC. We recommend you fill the thermal pad area with vias. A typical via array would be to fill the thermal pad foot print with vias spaced such that the centre to centre spacing is three times the radius of the via. Keep the vias small, but not so small that their inside diameter prevents solder wicking through the holes during reflow. FIGURE 32. VIA PATTERN OF ISL97692/3 TQFN FIGURE 33. VIA PATTERN OF ISL97694A TQFN 1. Boost input capacitors, output capacitors, inductor and Schottky diode should be placed together in a nice tight layout. Keeping the grounds of the input, and output connected with low impedance and wide metal is very important to keep these nodes closely coupled. 2. If possible, try to maintain central ground node on the board and use the input capacitors to avoid excessive input ripple for high output current supplies. The filtering capacitors should be placed close by the VIN pin. 3. For optimum load regulation and true VOUT sensing, the OVP resistors should be connected independently to the top of the output capacitors and away from the higher dv/dt traces. The OVP connection then needs to be as short as possible to the 22 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A ISL97694A INDUCTOR CH1‐6 PVIN DIODE OVP RESISTORS COUT CIN COUT TOP LAYER(PGND) PGND PGND BOTTOM LAYER(AGND) PVOUT TOP VIEW BOTTOM VIEW FIGURE 34. EXAMPLE OF PCB LAYOUT 23 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Fault Protection and Monitoring Overvoltage Protection (OVP) The ISL97692/3/4A features extensive protection functions to handle failure conditions automatically. Refer to Figure 35 and Table 7 for details of the fault protections. The integrated OVP circuit monitors the boost output voltage, VOUT, and keeps the voltage at a safe level. The OVP threshold is set as Equation 18: The LED failure mode is either open or short circuit. An open circuit failure of an LED only results in the loss of one channel of LEDs without affecting other channels. Similarly, a short circuit condition on a channel that results in that channel being turned off does not affect other channels. Due to the lag in boost response to any load change at its output, certain transient events (such as LED current steps or significant step changes in LED duty cycle) can transiently look like LED fault modes. The ISL97692/3/4A use feedback from the LEDs to determine when it is in a stable operating region and prevents apparent faults during these transient events from allowing any of the LED stacks to fault out. See Table 7 for more details. Short Circuit Protection (SCP) The short circuit detection circuit monitors the voltage on each channel and disables faulty channels, which are above the short circuit protection threshold, nominally 8V (the action taken is described in Table 7). OVP = 1.22V × ( RUPPER + R LOWER ) ⁄ R LOWER (EQ. 18) Where: - VOVP is the maximum boost output voltage, VOUT (V) - RUPPER is resistor from OVP pin to the boost output (Ω) - RLOWER is resistor from OVP pin to GND (Ω) Undervoltage Lockout If the input voltage falls below the VUVLO level of ~2V, the ISL97692/3/4A will stop switching and be reset. Operation will restart only if the VIN is back in the normal operating range. Over-Temperature Protection (OTP) The ISL97692/3/4A have an over-temperature protection threshold set to +150°C. If this threshold is reached, the boost stops switching and the ISL97692/3/4A output current sinks are switched off. The ISL97692/3/4A can be restarted by toggling VIN to below the VUVLO level of ~2V, then back up to the normal input voltage level, or by power recycling VIN. Open Circuit Protection (OCP) When one of the LEDs becomes open circuit, it can behave as either an infinite resistance or a gradually increasing finite resistance. The ISL97692/3/4A monitors the current in each channel such that any string, which reaches the intended output current is considered “good”. Should the current subsequently fall below the target, the channel will be considered an “open circuit”. Furthermore, should the boost output of the ISL97692/3/4A reaches the VOVP limit, all channels which are not “good” will immediately be considered as “open circuit”. Detection of an “open circuit” channel will result in a time-out before disabling of the affected channel. 24 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A LX VOUT VIN LX FAULT O/P SHORT DRIVER OVP IMAX ILIMIT FET DRIVER LOGIC VSC CH1 FAULT FLAG CHx THRM SHDN REF OTP T2 TEMP SENSOR T1 FAULT DETECT LOGIC DC2 DC1 Q1 PWM/OC1/SC1 Qx PWM/OCx/SCx PWM GENERATOR FIGURE 35. ISL97692/3/4A SIMPLIFIED FAULT PROTECTIONS TABLE 7. ISL97692/3/4A PROTECTIONS TABLE CASE FAILURE MODE DETECTION MODE FAILED CHANNEL ACTION VOUT REGULATED BY OTHER CHANNELS ACTION 1 CH1 Short Circuit Upper Over-Temperature Protection limit (OTP) not triggered and CH1 < 8V CH1 ON and burns power. 2 CH1 Short Circuit OTP triggered Boost converter and channels are shut down until VIN is cycled - 3 CH1 Short Circuit OTP not triggered, CH1 > 8V CH1 disabled after 6 PWM cycle time-out Normal Operation Highest LED string VF of other channels 4 CH1 Open Circuit with OTP not triggered, infinite resistance CH1 < 8V VOUT will ramp to OVP. CH1 will time-out after 6 PWM cycles and switch off. VOUT will then reduce to normal level Normal Operation Highest LED string VF of other channels 5 Output LED stack voltage too high Any channel that is below the target current will time-out after 6 PWM Highest LED string VF cycles while VOUT is regulated at VOVP, and VOUT will then return to the of channels above target current normal regulation voltage required for other channels VOUT = VOVP 25 Normal Operation Highest LED string VF of other channels FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you have the latest Rev. DATE REVISION CHANGE June 28, 2012 FN7839.2 - Modified title on page 1 - IVIN typ lowered to 0.8mA - tENLow typ removed - Added “Operation with Input Voltage Greater than 5.5V” on page 17. - Updated Figure 20 - Added Figure 26, “LED DRIVER OPERATION WITH INPUT VOLTAGE UP TO 26V,” on page 18. -Removed “Coming Soon” from ISL97694A parts in “Ordering Information” on page 8. May 25, 2012 FN7839.1 Corrected LX pin connection in Figures 1, 3, 4 and 5. Moved tie point in between L1 and D1. Changed Title in Figure 12 from “Accuracy vs WPM Dimming” to “Channel Matching Accuracy” Revised Figures 9 and 10. April 16, 2012 FN7839.0 Initial release Products Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks. Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a complete list of Intersil product families. For a complete listing of Applications, Related Documentation and Related Parts, please see the respective device information page on intersil.com: ISL97692, ISL97693, ISL97694A To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff FITs are available from our website at: http://rel.intersil.com/reports/search.php For additional products, see www.intersil.com/product_tree Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 26 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Package Outline Drawing L16.3x3D 16 LEAD THIN QUAD FLAT NO-LEAD PLASTIC PACKAGE Rev 0, 3/10 4X 1.50 3.00 A 12X 0.50 B 13 6 PIN 1 INDEX AREA 16 6 PIN #1 INDEX AREA 12 3.00 1 1.60 SQ 4 9 (4X) 0.15 0.10 M C A B 5 8 16X 0.40±0.10 TOP VIEW 4 16X 0.23 ±0.05 BOTTOM VIEW SEE DETAIL “X” 0.10 C 0.75 ±0.05 C 0.08 C SIDE VIEW (12X 0.50) (2.80 TYP) ( 1.60) (16X 0.23) C 0 . 2 REF 5 0 . 02 NOM. 0 . 05 MAX. (16X 0.60) TYPICAL RECOMMENDED LAND PATTERN DETAIL "X" NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to ASME Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal ± 0.05 4. Dimension applies to the metallized terminal and is measured between 0.15mm and 0.25mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be 7. JEDEC reference drawing: MO-220 WEED. either a mold or mark feature. 27 FN7839.2 July 19, 2012 ISL97692, ISL97693, ISL97694A Package Outline Drawing L20.3x4A 20 LEAD THIN QUAD FLAT NO-LEAD PLASTIC PACKAGE Rev 0, 6/10 3.00 0.10 M C A B 0.05 M C 4 20x 0.25 +0.05 17 -0.07 A B A 16x 0.50 6 PIN #1 INDEX AREA 20 16 1 6 PIN 1 INDEX AREA 4.00 2.65 +/0.10 -0.15 11 6 0.10 (4X) A 10 VIEW "A-A" TOP VIEW 7 1.65 +0.10 -0.15 20x 0.40+/-0.10 BOTTOM VIEW SEE DETAIL "X" 0.10 C SEATING PLANE 0.08 C 0.80 MAX C SIDE VIEW (3.80) (2.65) (16x 0.50) (20x 0.25) (20x 0.60) 0 . 2 REF C (1.65) (2.80) 0 . 00 MIN. 0 . 05 MAX. TYPICAL RECOMMENDED LAND PATTERN DETAIL "X" NOTES: 1. Dimensions are in millimeters. Dimensions in ( ) for Reference Only. 2. Dimensioning and tolerancing conform to ASME Y14.5m-1994. 3. Unless otherwise specified, tolerance : Decimal ± 0.05 4. Dimension applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 5. Tiebar shown (if present) is a non-functional feature. 6. The configuration of the pin #1 identifier is optional, but must be located within the zone indicated. The pin #1 identifier may be 7. JEDEC reference drawing: MO-220VEGD-NJI. either a mold or mark feature. 28 FN7839.2 July 19, 2012