IS31BL3229 8-LED BACKLIGHT DRIVER October 2012 GENERAL DESCRIPTION FEATURES The IS31BL3229 with a smart charge-pump circuit is a parallel white-LED driver with eight matched 20mA current outputs. It can supply a total output current of 160mA over an input voltage range of 2.7V to 5.5V. IS31BL3229 typically draws less than 1µA when placed in shutdown, and 0.7mA when operating in the no-load and 1X mode condition. If any of the outputs are not used, leave the pin(s) unconnected. Brightness can be controlled by simple-series-control techniques and external PWM signal. IS31BL3229 is available in QFN-20 (3mm × 3mm). It operates from 2.7V to 5.5V over the temperature range of -40°C to +85°C. Supply voltage: 2.7V ~ 5.5V 1X, 1.5X operating mode fade in and fade out mode Output current can be 25mA 32 current level and PWM intensity control Low input current ripple, low EMI 90% high efficiency No inductors, low noise operation Over voltage protection on output Built-in thermal protection Automatic soft start Built-in thermal protection QFN-20 (3mm × 3mm ) package APPLICATIONS Cell phone, smart phone, PDA Mp3, Mp4, PMP White LED backlighting TYPICAL APPLICATION CIRCUIT Figure 1 Typical Application Circuit Note 1: PWM pin should be pulled high if modulated by EN pin only. EN pin should be pulled high if modulated with PWM pin only. Please refer to Page 8 for detail information. Note 2: The fade in and fade out mode is only available when shut down and enable the IC by EN pin. Note 3: D1 must be connected and others can be floating in less than 8 LEDs application. Note 4: The IC should be placed far away from the mobile antenna in order to prevent the EMI. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 1 IS31BL3229 PIN CONFIGURATION 20 CN1 19 CP1 18 OUT 17 D1 16 D2 RSET 7 OPT 8 GND 9 D8 10 Pin Configuration (Top View) PWM 6 Package QFN-20 PIN DESCRIPTION No. Pin Description 1 NC No connection. 2 VCC Power supply input, requires 0.1μF and 1μF capacitor connect between this pin and ground pin. 3 CP2 Flying capacitor positive terminal 2. 4 CN2 Flying capacitor negative terminal 2. 5 EN Shutdown and output current control pin. Pull low to shutdown the IC. 6 PWM PWM control pin. Adjust the LED intensity by PWM duty cycle. Pull low at least 128ms (Typ.), the IC should be shutdown. 7 RSET 8 OPT Option pin. Floating to operating in FIFO mode. Pull low to disable FIFO. 9 GND Ground. 10~17 D8~D1 White LED channel 8~1. D1 must be connected and others can be floating in less than 8 LEDs application. 18 OUT Charge pump output to drive load circuits, Requires 1μF capacitor connected between this pin and ground pin. 19 CP1 Flying capacitor positive terminal 1. 20 CN1 Flying capacitor negative terminal 1. Thermal Pad Connect to GND. External resistor for bias current. I MAX 1.25 / RSET 1600 Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 2 IS31BL3229 ORDERING INFORMATION Industrial Range: -40°C to +85°C Order Part No. Package QTY/Reel IS31BL3229-QFLS2-TR QFN-20, Lead-free 2500 Copyright © 2012 Integrated Silicon Solution, Inc. All rights reserved. ISSI reserves the right to make changes to this specification and its products at any time without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and before placing orders for products. Integrated Silicon Solution, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless Integrated Silicon Solution, Inc. receives written assurance to its satisfaction, that: a.) the risk of injury or damage has been minimized; b.) the user assume all such risks; and c.) potential liability of Integrated Silicon Solution, Inc is adequately protected under the circumstances Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 3 IS31BL3229 ABSOLUTE MAXIMUM RATINGS Supply voltage, VCC Voltage at any input pin Junction temperature, TJMAX Storage temperature range, TSTG Operating temperature ratings, TA -0.3V ~ +6.0V -0.3V ~ VCC+0.3V 150°C -65°C ~ +150°C −40°C ~ +85°C Note: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS VCC = 2.7V ~ 5.5V, TA = 25°C, unless otherwise noted. Typical value are TA = 25°C, VCC = 3.6V. Symbol Parameter VCC Operation range ICC Operating current ISD Shutdown current IOUT Output current ILED LED current for each channel I(D-Match) VTH Condition Min. Typ. 2.7 1x mode, no load Max. Unit 5.5 V 0.7 1.5x mode, no load 2 VEN = 0V 1 mA μA 200 RSET = 100kΩ Current matching between any two outputs mA 20 mA 1 % Transition threshold (D1 pin) VD1 falling 180 mV VUVLO Input under voltage lockout threshold VCC rising or falling. 100mV hysteresis 2.4 V VSET Bias voltage for RSET pin 1.25 V VOVP Over voltage protect 5.5 V tFI Fade in time FIFO Mode(Note 5) 400 ms tFO Fade out time 400 ms RDS_ON Output resistor 160 °C TOTP Over temperature protection FIFO Mode(Note 5) 1x mode: (VCC-VOUT)/IOUT (Note 6) THYS Over temperature protection hysteresis (Note 6) 40 °C 1 Ω Charge Pump Characteristics tST Soft-start time (Note 6) 150 μs fCLK Clock frequency (Note 6) 1 MHz Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 4 IS31BL3229 ELECTRICAL CHARACTERISTICS (Continue) VCC = 2.7V ~ 5.5V, TA = 25°C, unless otherwise noted. Typical value are TA = 25°C, VCC = 3.6V. Symbol Parameter Condition Min. Typ. Max. Unit 0.4 V EN, PWM Pin Characteristics VIL Enable threshold low VCC = 2.7V VIH Enable threshold high VCC = 5.5V 1.4 tLO EN low time (Note 6) 0.5 75 μs tHI EN high time (Note 6) 0.5 75 μs tOFF EN off time (Note 6) 500 μs tLAT EN latch time (Note 6) 500 μs fPWM Input frequency for PWM pin tOFF_PWM PWM off time V 0.1 (Note 7) 50 128 kHz ms Note 5: Typical value. Note 6: Guaranteed by design. Note 7: As the PWM pin is pulled low at least 128ms, the IS31BL3229 will be shutdown. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 5 IS31BL3229 TYPICAL PERFORMANCE CHARACTERISTIC 100 25 20 80 70 Efficiency(%) Output Current(mA) 90 15 10 5 60 50 40 30 VEN = VPWM = 3.6V VF = 3.2V ILED = 20mA RSET = 100kΩ 20 VEN = VPWM = 3.6V RSET = 100kΩ 0 2.7 3 10 4 3.5 4.5 0 2.7 5 3 3.5 5 Supply Voltage vs. Efficiency Figure 3 100 18 90 16 80 14 70 Duty Cycle(%) Output Current(mA) Supply Voltage vs. Output Current 20 12 10 8 6 RSET = 100kΩ VEN = VCC = 3.6V fPWM = 1kHz 60 50 40 30 20 4 RSET = 100kΩ VPWM = VCC = 3.6V 2 0 4.5 Supply Voltage(V) Supply Voltage(V) Figure 2 4 1 4 8 10 12 16 20 24 28 32 0 0 5 EN Level Figure 4 EN pin dimming Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 10 15 20 Output Current(mA) Figure 5 PWM pin dimming 6 IS31BL3229 FUNCTION BLOCK Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 7 IS31BL3229 APPLICATION INFORMATION GENERAL DESCRIPTION The IS31BL3229 with a smart charge-pump circuit is a parallel white-LED driver with eight matched 20mA current outputs. CHARGE PUMP The built-in charge pump converter switches on automatically to ensure constant current output when the voltage of channel 1 (VD1) is below the threshold voltage VTH (180mV). The charge pump converter only needs three external components: supply decoupling capacitor, output bypass capacitor and flying capacitor. Table 1 Current Level Setting (Typical) VCC = 3.6V, RSET = 100kΩ, PWM pin is high. ILED ILED Pulse Pulse Pulse (mA/Ch) (mA/Ch) 1 20.0 12 13.125 23 2 3 19.375 18.75 13 14 4 18.125 5 17.5 6 16.875 17 7 16.25 18 8 15.625 19 8.75 ILED (mA/Ch) 6.25 12.5 11.875 24 25 5.625 5 15 11.25 26 4.375 16 10.625 27 3.75 10 28 3.125 9.375 29 2.5 30 1.875 Choose low ESR capacitors to ensure the best operating performance and place the capacitors as close as possible to the IS31BL3229. 9 15 20 8.125 31 1.25 10 14.375 21 7.5 ≥32 0.625 OUTPUT CURRENT SETTING 11 13.75 22 6.875 The maximum current (IMAX) of each LED can be set by the extra resister RSET follow the Equation (1) below. I MAX 1.25 / RSET 1600 (1) For example, in Figure 1, RSET = 100kΩ, So, I MAX 1.25 / 100k 1600 20mA FADE IN AND FADE OUT MODE By floating the OPT pin the fade in and fade out mode enable. When the EN pin is pulled high to enable the IC, LED fade in. When the EN pin is pulled low at last tOFF to shutdown the IC, LED fade out. Pulling OPT pin low to disable this mode (Figure 6). The recommended minimum RSET is 82kΩ, then the maximum IMAX is 24mA. The recommended maximum RSET is 110kΩ, then the minimum IMAX is 18mA. FUNCTIONAL DESCRIPTION The LED intensity can be modulated by pulse count or PWM signal. Figure 6 FIFO Function EN DIMMING MODE TIMING CONTROL The current level magnitude is controlled by Pulse Count Control (PCC wire) serial interface. The interface records rising edges of the EN pin and decodes them into 32 different states. The 32 current level settings available are indicated in Table 1. The PWM pin should be pulled to high if modulated by EN pin only. The EN pin should be configured as the Figure 7. tLAT is the latch time. High level should be at last tLAT to active the pulse signal. tOFF is the shutdown time. EN pin is pulled low at last tOFF the IC will be shutdown. PWM SIGNAL DIMMING MODE The PWM pin of the IS31BL3229 can accept a PWM signal to implement LED dimming by changing the PWM duty cycle. Recommended PWM frequency is in the range of 100Hz ~ 50kHz. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 Figure 7 EN pin timing 8 IS31BL3229 THERMAL PROTECTION The IS31BL3229 has a thermal protection circuit that will shut down the chip if the die temperature rises above the thermal limit until the temperature falls down. DESIGN NOTE The decoupling capacitors should be placed close to the VCC pin. A 0.1μF ceramic and an 1μF capacitors are recommended. The flying capacitor should be placed close to the CN and CP pins. The output capacitor should be placed close to the OUT pin and the traces of OUT pin connected to the capacitor should be as possible as short and wide. Trace width should be at least 0.75mm when the current reaches 1A. Trace width should be at least 1.0mm for the power supply and the ground plane. The thermal pad and the GND pin should connect directly to a strong common ground plane for heat sinking. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 9 IS31BL3229 CLASSIFICATION REFLOW PROFILES Profile Feature Pb-Free Assembly Preheat & Soak Temperature min (Tsmin) Temperature max (Tsmax) Time (Tsmin to Tsmax) (ts) 150°C 200°C 60-120 seconds Average ramp-up rate (Tsmax to Tp) 3°C/second max. Liquidous temperature (TL) Time at liquidous (tL) 217°C 60-150 seconds Peak package body temperature (Tp)* Max 260°C Time (tp)** within 5°C of the specified classification temperature (Tc) Max 30 seconds Average ramp-down rate (Tp to Tsmax) 6°C/second max. Time 25°C to peak temperature 8 minutes max. Figure 8 Classification profile Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 10 IS31BL3229 PACKAGE INFORMATION QFN-20 Note: All dimensions in millimeters unless otherwise stated. Integrated Silicon Solution, Inc. – www.issi.com Rev.A, 09/17/2012 11