AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT NEW PRODUCT Description Pin Assignments The AL3157 is a low noise, constant frequency charge pump DC/DC converter that uses a Dual mode load switch (1x), and doubling (2x) conversion for driving white LEDs. Low external part count (one 1µF flying capacitor and two 2.2µF capacitors at VIN and VOUT) make this part ideally suited for small, battery-powered applications The AL3157 drives 3 channels at up to 30mA for small screen backlighting and an additional channel up to 210mA for LED Flash or LED Flashlight – All from a 2.7V to 5.5V input. The AL3157 uses two control inputs (EN1/2) to enable/disable it and PWM dim the LED current. EN2 controls/PWM dims the backlight LEDs at 30mA per channel and EN1 controls/PWM dims the Flash/Flashlight LEDs at 210mA. Each output is equipped with built-in protection for VOUT short circuit and auto-disable for LED failure conditions. Built-in soft-start circuitry prevents excessive in-rush current during start-up and mode switching. A low-current shutdown feature disconnects the load from VIN to reduce quiescent current less than 1µA. The AL3157 is available in a lead-free, space-saving thermally enhanced 12-pin 3x3mm DFN package. ( Top View ) EN2 • • • • • • • • Notes: 12 D1 PGND 2 11 EN1 CN 3 10 D2 4 9 GND CP 5 8 D3 VOUT 6 7 D4 VIN Exposed Pad U-DFN3030-12 Features • • 1 Applications • • • Dual-Mode 1x and 2x Charge Pump Up to 300mA drive capability o 3-channel for backlight – 30mA/ch o 1-channel for Flight/light – 210mA VIN Range: 2.7V to 5.5V Two simple PWM dimming control inputs up to 50kHz 1.2 MHz Constant Switching Frequency Built-In Thermal, Open-Circuit and VOUT short circuit Protection Soft Start for reducing in-rush current IQ <1µA in Shutdown Thermally-Enhanced DFN3030-12 Package: Available in “Green” Molding Compound (No Br, Sb) Lead Free Finish/ RoHS Compliant (Note 1) Smart Touch Phone LED Backlighting PDA White LED backlighting Backlighting + Torch light 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html Typical Application Circuit VIN 4 Flash/ Light (EN1) VIN 2.2µF CIN 5 1µF C1 3 EN1 EN2 11 1 VOUT CN D1 EN2 2 Document number: DS35116 Rev. 1 - 2 2.2µF COUT 12 10 D2 8 D3 7 D4 EN1 PGND AL3157 6 CP AL3157 Backlight (EN2) GND 9 1 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT NEW PRODUCT Pin Descriptions Pin Name Pin Number EN2 1 Enable Pin 2: Controls outputs D2, D3 and D4 Description PGND 2 Charge Pump Switch Ground: Connect to GND CN 3 Negative Terminal of Flying Capacitor VIN 4 Input Power Supply. Decouple with a 2.2µF capacitor between this pin and ground. CP 5 Positive Terminal of Flying Capacitor VOUT 6 Charge pump output to drive D1~D4 load circuit. Decouple with a 2.2µF capacitor between this pin and ground. D4 7 Current sink input #4. Drive up to 30mA LED current. Connect to VOUT when un-used. D3 8 Current sink input #3. Drive up to 30mA LED current. Connect to VOUT when un-used. GND 9 Ground D2 10 Current sink input #2. Drive up to 30mA LED current. Connect to VOUT when un-used. EN1 11 Enable Pin 1: Controls output D1 D1 12 Current sink input #1. Drive up to 210mA LED current. Connect to VOUT when un-used. EP EP PAD Exposed Pad (bottom). Connect to GND directly underneath the package. Functional Block Diagram CN CP VOUT VIN SHORT CIRCUIT PROTECTION CHARGE PUMP SWITCHES OVER VOLTAGE PROTECTION EN1 DIGITAL CONTROL BLOCK EN2 D1 BANDGAP D2 OSCILLATOR D3 OVER TEMPERATURE PROTECTION CURRENT CONTROL D4 UNDER VOLTAGE LOCKOUT GND AL3157 Document number: DS35116 Rev. 1 - 2 2 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT NEW PRODUCT Absolute Maximum Ratings (Note 2) Symbol ESD HBM ESD MM VIN VEN1,2,3 IOUT TJ TLEAD Notes: Description Human Body Model ESD Protection Machine Model ESD Protection Input Voltage EN1, EN2, EN3 to GND Voltage Maximum DC Output Current Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Rating 2 200 -0.3 to 6 -0.3 to VIN +0.3 300 125 300 Unit kV V V V mA °C °C 2. Exceeding Absolute Maximum Ratings will cause permanent damage to the device. Recommended Operating Conditions Symbol VIN VENL(1, 2) VENH(1,2) TA Parameter Input Voltage EN1,2 Threshold Low EN1,2, Threshold High Operating Ambient Temperature Min 2.7 0 1.4 -40 Max 5.5 0.4 VIN 85 Unit V V V °C Electrical Characteristics VIN = 4V, CIN = COUT = 2.2µF, C1 = 1µF; TA = 25°C unless otherwise noted. Symbol Parameter Test Conditions 1x Mode, 3.0≤VIN≤5.5, Active, No Load Current IQ Quiescent Current 2x Mode, 3.0≤VIN≤5.5, Active, No Load Current ISHDN Shutdown Current EN1, EN2 = 0 Backlight LED Drive Sink Current ID2~4 IDX = 30mA Accuracy (Note 3) Flash/light LED Drive Sink Current ID1 ID1 = 210mA Accuracy (Note 3) Current Matching Between Any ID-Match Two Backlight LED Drive Current VF: D2:D4 = 4V Sink Outputs (Note 4) Rout VTH-Dx VTH-D1 VHS tSS fSW tEN1,2 UVLO IEN1,2 TSHDN THYS θJA Notes: Charge Pump VOUT Open Loop Resistance 5. Typ. Max 0.3 0.6 2 5 Unit mA 1 µA 28.5 30 31.5 mA 199.5 210 220.5 mA 1 2 % 1x mode 0.5 2x mode 4.5 1x to 2x Transition Threshold at ID = 30mA D2, D3 and D4 Pins 1x to 2x Transition Threshold at D1 ID1 = 210mA Pin Mode Transition Threshold Soft-Start Time Switching Frequency EN1,2 Off Timeout VIN Under-Voltage Lockout EN1, 2 Input Leakage Thermal Shutdown Protection Thermal Shutdown Hysteresis Thermal Resistance U-DFN3030-12 (Note 5) Junction-to-Ambient 3. 4. Min Ω 150 mV 150 mV 500 100 1.2 1.8 -1 2 160 10 55.29 20 2.2 1 mV µs MHz ms V µA o C o C o C/W Determined by the mean of channels 2,3 and 4 currents, EG (ID2 + ID3 + ID4)/3 Determined by the maximum sink current (MAX), the minimum sink current (MIN), and the average sink current (AVG). Two matching numbers are calculated as (MAX-AVG)/AVG and (AVG-MIN)/AVG. The largest number of the two (worst case) is as the matching data. Device mounted on FR-4 substrate, 2"*2", 2oz, copper, double-sided PC board. AL3157 Document number: DS35116 Rev. 1 - 2 3 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT Typical Performance Characteristics Turn-On in 1x Mode Turn-On in 2x Mode EN1,2 2V/div NEW PRODUCT EN1,2 2V/div Vout 2V/div Vout 2V/div Iin 300mA/div Iin 300mA/div VIN=4.2V TA=25°C VIN=3.0V TA=25°C 100us/div 100us/div Turn-Off in 1x Mode Turn-Off in 2x Mode VIN=4.2V TA=25°C VIN=3.0V TA=25°C EN1,2 2V/div Vout 2V/div EN1,2 2V/div Vout 2V/div Iin 300mA/div Iin 300mA/div 200ms/div 200ms/div Load Characteristics in 2x Mode PWM Dimming Control (Duty Cycle=50%) Vin 100mVAC/div Vout 100mVAC/div VIN=3.0V TA=25°C EN 2V/div VIN=4V Freq=20kHz Duty Cycle=50% Document number: DS35116 Rev. 1 - 2 TA=25°C Iin 300mA/div Iin 100mAAC/div 500ns/div AL3157 Id1 200mA/div 10us/div 4 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT Typical Performance Characteristics (Continued) VIN=4V VF=3.27V TA=25°C NEW PRODUCT Channels 2 to 4 TA=25°C VIN=4V Channels 2 to 4 VEN(H) VIN=2.7V VIN=4.0V AL3157 Document number: DS35116 Rev. 1 - 2 5 of 9 www.diodes.com VEN(L) March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT Functional Description The AL3157 is a dual-mode high efficiency charge pump (1x and 2x) device, driving 3-channel standard backlight LEDs and one high-current Flash/Torch LED, intended for white LED backlight applications. An internal comparator circuit compares the voltage at each constant current sink input against a reference voltage. To ensure maximum power efficiency, the most appropriate switching mode (1x and 2x) is automatically selected. NEW PRODUCT The APL3157 requires only three external components: one 1µF ceramic flying capacitor (C1) for the charge pump, one 2.2µF ceramic input capacitor (CIN), and one 2.2µF ceramic charge pump output capacitor (COUT). The each output channel of the AL3157 can drive three individual LEDs with a maximum current of 30mA per channel and a Flash/Torch LED with a maximum current of 210mA. These can be paralleled to give a total output current of 300mA. LED Control Table EN1 0 0 1 1 EN2 0 1 0 1 D1 OFF OFF ON ON D2, D3, D4 OFF ON OFF ON Disabled Current Sinks Unused current channels must be disabled by connecting the sinks to VOUT with only a small sense current flowing through the disabled channel. Soft-Start Soft-start is incorporated to prevent excessive in-rush current during power-up, mode switching, and transitioning out of stand-by mode. Short-Circuit Protection Short-circuit protection function is incorporated to prevent excessive load current when either flying cap terminals or output pin electrically tied to a very lower voltage or ground. Over-Voltage Protection Over-Voltage Protection function is incorporated to limit the output voltage under a safe value to avoid on-chip device breakdown. Under-Voltage Lockout Under-Voltage lockout feature disables the device when the input voltage drops below UVLO threshold. Thermal Auto Shutdown When the die temperature exceeds the thermal limit, the device will be disabled and enter stand-by mode. The operation resumes whenever the die cools off sufficiently. PWM Dimming Control The AL3157 provides simple PWM dimming control through ENx pins, and the current is adjusted by the duty cycle of the signal applied on ENx pin. The recommended PWM frequency is from 200Hz to 50kHz depending on applications. . AL3157 Document number: DS35116 Rev. 1 - 2 6 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT Ordering Information Device AL3157F-7 Notes: 7. Package Packing F : U-DFN3030-12 7 : 7” Tape & Reel Package Code F 7” Tape and Reel Quantity Part Number Suffix 3000/Tape & Reel -7 Packaging (Note 7) U-DFN3030-12 Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at http://www.diodes.com/datasheets/ap02001.pdf Marking Information (1) U-DFN3030-12 ( Top View ) XX Y WX XX : B7 : AL3157 Y : Year : 0~9 W : Week : A~Z : 1~26 week; a~z : 27~52 week; z : represents 52 and 53 X : A~Z : Green Part Number Package Identification Code AL3157F U-DFN3030-12 B7 Package Information 0.57/0.63 (1) Package type: U-DFN3030-12 0.15max. 0.10 C 0.25 A 2.9 / 3.1 2.3 / 2.5 2x 0/0.05 0.08 C B 2x- 0.25 B Seating plane C A 3 0.45typ 0.25/0.55 1.5 / 1.7 R0. 2.9 / 3.1 NEW PRODUCT AL3157 X - 7 0.18/0.28 0.10 M C A B Bottom View AL3157 Document number: DS35116 Rev. 1 - 2 7 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT NEW PRODUCT Tape Orientation (Note 8) Notes: 8. The taping orientation of the other package type can be found on our website at http://www.diodes.com/datasheets/ap02007.pdf AL3157 Document number: DS35116 Rev. 1 - 2 8 of 9 www.diodes.com March 2011 © Diodes Incorporated AL3157 HIGH EFFICIENCY 1x/2x CHARGE PUMP LED DRIVER FOR SMALL SCREEN BACKLIGHTING AND FLASHLIGHT IMPORTANT NOTICE NEW PRODUCT DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. 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