BCRU LED Driver Features LED drive current of Output current adjustable up to 5 with external resistor 5 3 Supply voltage up to V Easy paralleling of drivers to increase current Low voltage overhead of.v High current accuracy at supply voltage variation No EMI High power dissipation of 75mW Reduced output current at higher temperatures - Negative thermal coefficient of -.% / K RoHS compliant (pb-free) small and robust SC-7 package Qualified according to AEC Q Applications Channel letters for advertising, LED strips for decorative lighting Aircraft, train, ship illumination Retrofits for general lighting, white goods like refrigerator lighting Medical lighting Automotive applications like CHMSL and rear combination lights General Description The BCRU is a cost efficient LED driver to drive low power LED s. The advantages towards resistor biasing are: homogenous light output despite varying forward voltages in different LED strings homogenous light output of LED s despite voltage drop across long supply lines homogenous light output independent from supply voltage variations longer lifetime of the LED s due to reduced output current at higher temperatures (negative thermal coefficient) The advantages towards discrete solutions are: lower assembly cost smaller form factor better quality due to less soldering points higher output current accuracy due to pretested LED drivers Dimming is possible by using an external digital transistor at the ground pin. The BCRU can be operated at higher supply voltages by putting LED s between the power supply +VS and the power supply pin of the LED driver. You can find further details in the application note AN97. The BCRU is a perfect fit for numerous low power LED applications by combining small form factor with low cost. These LED drivers offer several advantages to resistors like significantly higher current control at very low voltage drop ensuring high lifetime of LED s. 9-7-3
BCRU Pin Configuration Typical Application GND BCRU Rext BCR U Rext (optional) +Vs Vdrop Out 5 Out Out 3 Vs Is,3,5 Type Marking Pin Configuration Package BCRU Ls = GND ;3;5 = Out = V S = R EXT SC7 Maximum Ratings Parameter Symbol Value Unit Supply voltage V S V Output current I out 5 Output voltage V out 38 V Reverse voltage between all terminals V R.5 Total power dissipation, T S = C P tot 75 mw Junction temperature T j 5 C Storage temperature T stg -5... 5 Thermal Resistance Parameter Symbol Value Unit Junction - soldering point ) R thjs 5 K/W For calculation of RthJA please refer to Application Note Thermal Resistance 9-7-3
BCRU Electrical Characteristics at T A =5 C, unless otherwise specified Parameter Symbol Values Unit min. typ. max. Characteristics Collector-emitter breakdown voltage V BR(CEO) - - V I C =, I B = Supply current I S 3 5 µa V S = V DC current gain h FE 7 - I C = 5, V CE = V Internal resistor R int 7 9 Ω I Rint = Output current I out 9 V S = V, V out = 8. V Voltage drop (V S - V E ) I out = V drop.8.9. V DC Characteristics with stabilized LED load Lowest sufficient battery voltage overhead I out >8 Output current change versus T A V S = V Output current change versus V S V S = V V Smin -. - V / - -. - %/K / - - %/V 3 9-7-3
BCRU Total power dissipation P tot = f (T S ) Permissible Pulse Load R thjs = f (t p ) mw K/W 8 Ptot 7 RthJS 5 3.5...5...5 D = 8 C 5 T S - -7 - -5 - -3 - s t p Permissible Pulse Load P totmax / P totdc = f (t p ) 3 Ptotmax / PtotDC - D =.5...5...5-7 - -5 - -3 - s t p 9-7-3
BCRU Output current versus supply voltage I out = f (V S ); R ext = Parameter V S - V out =. V Supply current versus supply voltage I S = f(v S ) T A = Parameter. A IS.... 8 C C - C open Ohm 7 Ohm 33 Ohm Ohm 8 Ohm 5 Ohm 5 5 5 3 V V S.8... 5 5 5 3 35 V 5 VS Output current versus supply voltage I out = ƒ(v S ), T A = C V S -V out as Parameter Output current versus supply voltage I out = ƒ(v S ), V S -V out =. V T A = Parameter. - V - C 5 C 85 C 5 C.5 V 9.5 9 8.5 8 7.5 7 5 5 5 3 35 V 5 V S 5 5 5 3 V V S 5 9-7-3
BCRU Output current versus external resistor I out (R ext ), V S = V, V S -V out =. V T A = Parameter Output current I out (T S ), V S = V, V S -V out =. V R EXT = Parameter 7 5 Ohm 5 8 Ohm - C 5 C 85 C 5 C 3 Ohm 33 Ohm 7 Ohm Ohm open OHM R ext -5-5 5 5 75 C 5 T S Reference Voltage (Vdrop) versus I out = µa... Reference Voltage (Vdrop) versus I out =... 5 9-7-3
BCRU Application circuit: Stand alone current source Application circuit: Boost mode current source with external power transistor BCR U +Vs BCR U +Vs Rext (optional) Vdrop Rext (optional) Vdrop I LED Is,3,5 Is,3,5 R R Application hints BCRU serves as an easy to use constant current source for LEDs. In stand alone application an external resistor can be connected to adjust the current from to 5. Rext can be determined by using the diagram 'Output current versus external resistor', or by refering to diagram 'Reference voltage versus output current'. Look for your desired output current on the x axis and read out the corresponding Vdrop. Calculate Rext: Rext = Vdrop / ( -(Vdrop/Rint)) Please take into account that the resulting output currents will be slightly lower due to the self heating of the component and the negative thermal coefficient. In boost mode configuration the LED current can be extended to drive high power LEDs. Select the power trasistor according the power dissipation and output current requirements. (e.g. BC87SU or BCX8-5, etc.) Dimension R to reduce the transistor current transfer ratio to... 5. For ILED / =5 e.g. ILED= 35, is 7. R = VbeON /. Dimension R for minimum supply voltage condition: R = (Vsmin -.V -VbeON)/. Please visit our web site for application notes: www.infineon.com/lowcostleddriver AN77 gives hints to thermal design AN97 helps in case of high supply voltages AN gives an overview to LED biasing 7 9-7-3
SC7 Package BCRU Package Outline.9 ±. (.5) B (.35) +..5 -.. MAX. Pin marking 5 3 +..35 -.5.95.9. M B x ±. ±..5.5 MAX.. M A MAX.. MAX.. A ±. Foot Print.5.9.9.95 Marking Layout (Example) Small variations in positioning of Date code, Type code and Manufacture are possible. Manufacturer 5, June Date code (Year/Month) Pin marking Laser marking BCWH Type code Standard Packing Reel ø8 mm = 3. Pieces/Reel Reel ø33 mm =. Pieces/Reel For symmetric types no defined Pin orientation in reel...7 8 Pin marking 3.5.5 8 9-7-3
BCRU Published by Infineon Technologies AG 87 München, Germany Infineon Technologies AG 7. All Rights Reserved. Attention please! The information given in this data sheet shall in no event be regarded as a guarantee of conditions or characteristics ( Beschaffenheitsgarantie ). With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. 9 9-7-3