UNISONIC TECHNOLOGIES CO.,

Transcription

1 UNISONIC TECHNOOGIES CO., WHITE ED STEP-UP CONVERTER 3 2 DESCRIPTION The UTC is a STEP-UP DC/DC Converter and designed for driving white EDs with a constant current. It can drive several EDs in series by a i-ion cell. UTC switches at a high frequency.2mhz, so it can allowing the use of tiny external components. The output capacitor can be as small as.22µf, saving space and cost compare with alternative other solutions. The low 9mV feedback voltage minimizes power loss in the current setting resistor can have better efficiency. SOT-2 SOT-363 FEATURES * Inherently Matched ED Current * High Efficiency: 83% Typical * Drives Up to Four EDs from a 3.2V Supply * Drives Up to Six EDs from a V Supply * 36V Rugged Bipolar Switch *.2MHz Switching Frequency * Uses Tiny mm Tall Inductors * Output Capacitor can be small to only.22µf *Pb-free plating product number: ORDERING INFORMATION Ordering Number Normal ead Free Plating Package Packing -AF-R -AF-R SOT-2 Tape Reel -AN3-R -AN3-R SOT-363 Tape Reel Copyright 2 Unisonic Technologies Co., QW-3-2,A

2 PIN DESCRIPTION PIN NO. SOT-2 SOT-363 PIN NAME SYMBO FUNCTION Switch Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. 2 2/ Ground Connect directly to local ground plane. 3 3 Feedback FB Reference voltage is 9mV. Connect cathode of lowest ED and resistor here. Calculate resistor value according to the formula: R FB = 9mV/I ED Shutdown SHDN Connect to.v or higher to enable device;.v or less to disable device. 6 Input Supply V IN Input Supply Pin. Must be locally bypassed. BOCK DIAGRAM Pin (SOT-2) Pin 6 (SOT-363) FB 3 VREF.2V 9mV - + A - + Rc Cc A2 R S Q DRIVER Q Σ RAMP GENERATOR.2MHz TIME CONTRO SHUTDOWN Slope compensation + -.2Ω SHDN 2 Pin 2/ (SOT-363) Pin 2 (SOT-2) UNISONIC TECHNOOGIES CO., TD 2 QW-3-2,A

3 ABSOUTE MAXIMUM RATINGS PARAMETER SYMBO RATINGS UNIT Input Voltage V IN 2 V Switch Voltage V 36 V Feedback Voltage V FB 2 V Shutdown Voltage V SHDN 2 V Operating Temperature T OPR ~ +7 Junction Temperature T J +2 Storage Temperature T STG - ~ + EECTRICA CHARACTERISTICS (Ta=2, V IN =3V, V SHDN =3V, unless otherwise specified.) PARAMETER SYMBO TEST CONDITIONS MIN TYP MAX UNIT Operating Voltage V IN 2. 2 V Feedback Voltage V FB I =ma, Duty Cycle=66% 87 9 mv Shutdown Voltage ON V ON. V Shutdown Voltage OFF V OFF.3 V Switch V CESAT V CESAT() I =2mA 36 mv Switch Current imit I 32 ma Supply current Icc SHDN=V.8. Switch eakage Current I (OFF) V =V. µa Shutdown Pin Bias Current I SHDN 6 µa Feedback Pin Bias Current I FB na Switching Frequency f OSC MHz Maximum Duty Cycle DC 8 9 % 2.. ma µa UNISONIC TECHNOOGIES CO., TD 3 QW-3-2,A

4 TYPICA APPICATION CIRCUIT 86 Two ED Efficiency 3V ~ V CIN μf 22μH D 9k k 2Ω COUT.22μF EFFICIENCY(%) =3V =3.6V i-ion to Two White EDs ED CURRENT (ma) 3V ~ V CIN μf 22μF D COUT.22μF 9 8 Three ED Efficiency 9k k 6.3Ω ma EFFICIENCY (%) =3V =3.6V i-ion to Three White EDs ED CURRENT (ma) UNISONIC TECHNOOGIES CO., TD QW-3-2,A

5 TYPICA APPICATION CIRCUIT (cont.) Four ED Efficiency 8 3V ~ V C IN µf 22 µh D 9 k k Ω C OUT. 22µF EFFICIENCY (%) 8 7 V IN=3V =3.6V 7 i- Ion to Four White EDs 6 2 OAD CURRENT (ma) Five ED Efficiency 3V ~ V CIN μf 22μH D COUT.22μF 8 8 9k k Ω EFFICIENCY(%) 7 =3V =3.6V 7 i-ion to Five White EDs OAD CURRENT (ma) UNISONIC TECHNOOGIES CO., TD QW-3-2,A

6 TYPICA APPICATION CIRCUIT (cont.) Seven ED Efficiency 8 V IN V C IN µf V IN 22µ H D 9 k k Ω C OUT. 22µF EFFICIENCY (%) V to Seven White EDs 6 OAD CURRENT (ma) UNISONIC TECHNOOGIES CO., TD 6 QW-3-2,A

7 TYPICA CHARACTERISTICS 2.2 Quiescent Current 3 Current imit vs Duty Cycle IQ (ma) CURRENT IMIT (ma) (V) DUTY CYCE (%) 8 * UTC is guaranteed the operating temperature range of ~7. UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOOGIES CO., TD 7 QW-3-2,A