LED Drivers for LCD Backlights Backlight LED Driver for Small LCD Panels (Charge Pump Type) BD82103GWL No.11040EBT34 ●Description BD82103GWL is charge pump type 2 light or 3 light parallel LED driver for the portable instruments. This IC not only ensures efficient boost by automatically changing the boost rate but also works as a constant current driver in 16 steps, so that the driving current can be adjusted finely. This IC is best suited to turn on white LEDs that require high-accuracy LED brightness control. ●Features 1) 2light or 3light parallel LED driver is mounted 2) 16-step LED current adjust function 3) Inter-LED relative current accuracy: 5% or less 4) Driving control via a single-line digital control interface 5) Automatic transition charge pump type DC/DC converter (×1,×1.5, x2) 6) High efficiency achieved (Maximum over 93%) 7) It transits for the most suitable power operating by the LED terminal process of the 3rd light when 2 light driving 8) Various protection functions such as output voltage protection and thermal shutdown circuit are mounted. 9) Package : UCSP50L1 (Thick 0.55mm MAX, Pin pitch 0.4mm) CSP11pin package ●Absolute Maximum Ratings (Ta=25℃) Parameter Symbol Ratings Unit Power supply voltage VMAX 7 V Vdin GND-0.3 ~ VBAT+0.3 V Pd 730 mW Operating temperature range Topr -30 ~ +85 ℃ Storage temperature range Tstg -55 ~ +150 ℃ Input voltage ( EN ) Power dissipation Note 1) The measurement value which was mounted on the PCB by ROHM. When a glass epoxy substrate (70mm × 70mm × 1.6mm) has been mounted, this loss will decrease 5.84mW/℃ if Ta is higher than or equal to 25℃. ●Operating Conditions (Ta = -30 ~ 85 ℃) Parameter Symbol Ratings Unit Operating power supply voltage VBAT 2.7 ~ 5.5 V *This chip is not designed to protect itself against radioactive rays. *This material may be changed on its way to designing. *This material is not the official specification. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1/9 2011.06 - Rev.B BD82103GWL Technical Note ●Electrical Characteristics (Unless otherwise noted, Ta = +25℃, VBAT=3.6V) Limits Parameter Symbol Unit Min. Typ. Max. Condition Current Consumption Quiescent Current Iq - 0.1 1 μA EN=0V Current Consumption1 Idd1 - 1.0 2.4 mA x1.0 Mode, Except LED current Current Consumption2 Idd2 - 2.0 3.5 mA x2.0 Mode, Except LED current fOSC 0.56 0.85 1.14 MHz LED maximum current ILED-max 18 20 22 mA LED current accuracy ILED-diff - - 10.0 % LED current matching ILED-match - 0.5 5.0 % VLED - 0.15 0.25 V Low threshold voltage VIL - - 0.4 V EN High threshold voltage VIH 1.4 - - V EN High level Input current IIH - 0 1 μA EN=Vin Low level Input current IIL -1 0 - μA EN=0V Minimum EN High time THI 0.05 - 100 μsec Described in Fig.5 Minimum EN Low time TLO 0.3 - 100 μsec Described in Fig.5 EN Off Timeout TOFF 1 - - msec Described in Fig.5 Latch time TLAT 1 - - msec Described in Fig.5 Access available time Tacc 1 - - msec Described in Fig.5 Charge Pump Oscillator frequency Current Source LED control voltage VBAT≥3.0V When LED current 10.0mA setting and LED terminal voltage 1.0V When LED current 10.0mA setting and LED terminal voltage 1.0V minimum voltage at LED1~LED3 pins Logic control terminal www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/9 2011.06 - Rev.B BD82103GWL Technical Note C2P C2N C1P C1N ●Block Diagram ×1, ×1.5, ×2 Charge pump VBAT VOUT Over Voltage Protect Charge Pump Mode Control EN OSC Enable/ Brightness Control Vout Control TSD LED1 LED2 LED3 DET LED3 4 Current DAC GND Pin number 11pin Fig. 1 Block Diagram www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 3/9 2011.06 - Rev.B BD82103GWL Technical Note ●Pin Configuration [Bottom View] C LED1 GND VBAT C1N EN C1P index B LED2 A LED3 VOUT C2N C2P 1 2 3 4 Fig. 2 Pin Configuration ●Pin Descriptions Pin No. Terminal No. Pin name In/Out Type Function 1 C3 VBAT - A Power supply 2 B4 C1P A Flying capacitor pin positive (+) side 3 C4 C1N In/Out In/Out B Flying capacitor pin negative (-) side 4 A4 C2P In/Out A Flying capacitor pin positive (+) side 5 A3 C2N In/Out B Flying capacitor pin negative (-) side 6 A2 VOUT Out A Charge pump output 7 B3 EN In ON/OFF and dimming control 8 C1 LED1 Out C A LED current driver output 1 9 B1 LED2 Out A LED current driver output 2 LED current driver output 3 GND 10 A1 LED3 Out A 11 C2 GND - D ●Pin ESD Type Type A Type B PAD PAD VBAT Type C VBAT Type D VBAT PAD PAD GND GND GND Fig. 4 Pin ESD Type www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 4/9 2011.06 - Rev.B BD82103GWL Technical Note ●Separate Function Description (1) LED driver ・Register access control protocol LED current is controlled by only EN terminal. It is possible to access the register inside of this chip by using the protocol below. LED driver ON/OFF, selecting the mode is operated by accessing the registers with using this protocol. TLAT THI Tacc TOFF TLO EN 1 n-1 2 LED Current Setting n (N≦16) 0 n 0 Fig.5 Register access protocol Tacc TLAT TLAT TLAT TLAT EN 16pulse 15pulse 14pulse 13pulse 1mA 0.5mA LED Current OFF 0.25mA 0.125mA Fig.6 Slope control example ( Note ) ・In the case of N > 16, BD82103GWL selects the mode of N = 16. ・LED current is changed by the pulse of EN pin. Be careful to noise of EN signal. ・Reset BD82103GWL when the set is unusual. (Keep EN=L over Toff time.) ・LED current level The interface records rising edges of the EN pin and decodes them into 16 different indicated in following table. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. Data Output current [mA] Data Output current [mA] 1 20.0 9 5.0 2 17.0 10 4.0 3 14.0 11 3.0 4 12.0 12 2.0 5 10.0 13 1.0 6 8.5 14 0.5 7 7.0 15 0.25 8 6.0 16 0.125 5/9 2011.06 - Rev.B BD82103GWL Technical Note (2) Charge pump a) Description of operations Pin voltage comparison takes place at Vout control section, and then Vout generation takes place so that the LED cathode voltage with the highest Vf is set to 0.2V. A boost rate is changed automatically to a proper one at the Charge Pump Mode Control section so that operation can take place at possible low boost rate. In addition, if the output voltage falls below 1.5V, this IC is reset for short-circuit at output. b) Soft start function BD82103GWL have a soft start function that prevents the rush current. TOFF EN/LED* VOUT ILED Soft Start Ordinal mode Fig.7 Soft Start c) Automatic boost rate change The boost rate automatically switches to the best mode. * (×1 mode ×1.5 mode) or (×1.5 mode ×2 mode) If a battery voltage drop occurs BD82103GWL cannot maintain the LED constant current, and then mode transition begins. * (×1.5 mode ×1 mode) or (×2 mode ×1.5 mode) If a battery voltage rise occurs, VOUT and VBAT detection are activated, and then mode transition begins. (3) UVLO (Under Voltage Lock Out) If the input voltage falls below 2.2V, BD82103GWL is shut down to prevent malfunction due to ultra-low voltage. (4) OVP (Over Voltage Protection) This circuit protects this IC against damage when the C/P output voltage (VOUT) rises extremely for some external factors. (5) Thermal shutdown (TSD) To protect this IC against thermal damage or heat-driven uncontrolled operations, this circuit turns off the output if the chip temperature rises over 175℃. In addition, it turns on the output if the temperature returns to the normal temperature. Because the built-in thermal protection circuit is intended to protect the IC itself, the thermal shutdown detection temperature must be set to below 175℃ in thermal design. (6 ) Power sequence EN signal must be released after VBAT voltage enough rise up. Prohibit the VBAT rise up during EN=”H”. VBAT EN Fig.8 www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. Power sequence 6/9 2011.06 - Rev.B BD82103GWL Technical Note ●Application Circuit Example (3 light) C2 C2P C1N C1P C2N C1 Battery ×1, ×1.5, ×2 Charge pump VBAT Cin =1μF VOUT Cout =1μF Over Voltage Protect Charge Pump Mode Control EN Pulse Generator OSC Enable/ Brightness Control Vout Control LED1 TSD LED2 LED3 LED3 DET 4 Current DAC GND Fig.9 Application Circuit Example 1 C2 C1P C2N C1N C1 C2P ●Application Circuit Example (2 light) Battery ×1, ×1.5, ×2 Charge pump VBAT Cin =1μF VOUT Cout =1μF Over Voltage Protect Charge Pump Mode Control EN Pulse Generator OSC Enable/ Brightness Control Vout Control LED1 TSD LED2 LED3 LED3 DET 4 Current DAC GND Fig.10 Application Circuit Example 2 www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/9 2011.06 - Rev.B BD82103GWL Technical Note ●Notes for use (1) Absolute Maximum Ratings An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety measures including the use of fuses, etc. (2) Power supply and ground line Design PCB pattern to provide low impedance for the wiring between the power supply and the ground lines. Pay attention to the interference by common impedance of layout pattern when there are plural power supplies and ground lines. Especially, when there are ground pattern for small signal and ground pattern for large current included the external circuits, please separate each ground pattern. Furthermore, for all power supply pins to ICs, mount a capacitor between the power supply and the ground pin. At the same time, in order to use a capacitor, thoroughly check to be sure the characteristics of the capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the constant. (3) Ground voltage Make setting of the potential of the ground pin so that it will be maintained at the minimum in any operating state. Furthermore, check to be sure no pins are at a potential lower than the ground voltage including an actual electric transient. (4) Short circuit between pins and erroneous mounting In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between pins or between the pin and the power supply or the ground pin, the ICs can break down. (5) Operation in strong electromagnetic field Be noted that using ICs in the strong electromagnetic field can malfunction them. (6) Input pins In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the input pin. Therefore, pay thorough attention not to handle the input pins, such as to apply to the input pins a voltage lower than the ground respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to the input pins when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is applied, apply to the input pins a voltage lower than the power supply voltage or within the guaranteed value of electrical characteristics. (7) External capacitor In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc. (8) Thermal shutdown circuit (TSD) This IC builds in a thermal shutdown (TSD) circuit. When junction temperatures become detection temperature or higher, the thermal shutdown circuit operates and turns a switch OFF. The thermal shutdown circuit, which is aimed at isolating the IC from thermal runaway as much as possible, is not aimed at the protection or guarantee of the IC. Therefore, do not continuously use the IC with this circuit operating or use the IC assuming its operation. (9) Thermal design Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in actual states of use. (10) LDO Use each output of LDO by the independence. Don’t use under the condition that each output is short-circuited because it has the possibility that an operation becomes unstable. (11) About the pin for the test, the un-use pin Prevent a problem from being in the pin for the test and the un-use pin under the state of actual use. Please refer to a function manual and an application notebook. And, as for the pin that doesn't specially have an explanation, ask our company person in charge. (12) About the rush current For ICs with more than one power supply, it is possible that rush current may flow instantaneously due to the internal powering sequence and delays. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of wiring. (13) About the function description or application note or more. The function description and the application notebook are the design materials to design a set. So, the contents of the materials aren't always guaranteed. Please design application by having fully examination and evaluation include the external elements. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/9 2011.06 - Rev.B BD82103GWL Technical Note ●Ordering part number B D 8 Part No. 2 1 0 3 G Part No. W L - Package GWL: UCSP50L1 E 2 Packaging and forming specification E2: Embossed tape and reel UCSP50L1 (BD82103GWL) <Tape and Reel information> 0.1±0.05 1.8±0.05 A 0.05 A B Tape Embossed carrier tape Quantity 3000pcs Direction of feed S E2 The direction is the 1pin of product is at the upper left when you hold ( reel on the left hand and you pull out the tape on the right hand ) 0.35±0.05 0.08 S 11-φ0.2±0.05 (φ0.15)INDEX POST 0.55MAX 1.5±0.05 1PIN MARK B C A 1 0.3±0.05 2 3 4 P=0.4×3 P=0.4×2 B 1pin Reel (Unit : mm) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 9/9 Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. 2011.06 - Rev.B Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. The content specified herein is for the purpose of introducing ROHM's products (hereinafter "Products"). If you wish to use any such Product, please be sure to refer to the specifications, which can be obtained from ROHM upon request. Examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the Products. The peripheral conditions must be taken into account when designing circuits for mass production. Great care was taken in ensuring the accuracy of the information specified in this document. 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