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LX1745 DUAL OUTPUT BOOST LED DRIVER/LCD BIAS New Product Information and Sales Kit Manufactured by: Microsemi Integrated Products Garden Grove Telephone: 714-898-8121 More than solutions – enabling possibilities LX1745 Dual Output Boost – LED Driver/LCD Bias INTRODUCTION WWW . Microsemi .C OM CONFIDENTIAL INFORMATION This new product introduction guide is intended for use only by Microsemi’s sales people and authorized representatives and distributors. This material can be adapted for customer presentations, but the sales strategy and summary [pricing, availability, etc.] is confidential and should not be shown to customers DESCRIPTION The LX1745 is a compact high efficiency step-up boost regulator for driving white or color LED’s in LCD lighting applications plus two integrated LCD Bias generator within one package. Featuring a pseudo-hysteretic pulse frequency modulation topology, the LX1745 was designed for maximum efficiency, reduced board size, and minimal cost making it ideal for PDA and digital camera applications. Utilizing an internal N-Channel FETs for LCD Bias generation minimizes PCB board space, whereas the use of an external N-Channel MOSFET for the higher current LED regulator portion results in maximum electrical efficiency. With a shutdown (Sleep) current of less than 1µA, the LX1745’s is optimized for portable battery powered systems. The input voltage ranges from 1.6V to 6.0V, allowing for a wide selection of system battery voltages. Start-up is guaranteed at 1.6V input, with sustained operation to as little as 1.1V. LED drive currents are easily programmed using one external current sense resistor in series with the LED’s. In this configuration, LED current provides a feedback signal to the FB pin, maintaining constant current regardless of varying LED forward voltage (VF). Depending on the MOSFET selected, the LX1745 is capable of achieving an LED drive power in excess of 1W. The LX1745 is available in the 20-Pin TSSOP SUMMARY The LX1745 is a small, cost effective solution that combines two Boost LDC bias supplies and a LED driver. Copyright © 2002 Rev. 1.0 8/22/03 Page 2 New Product Information and Sales Kit SALES KIT The LX1745 has an additional feature for simple dynamic adjustment of both the LED drive current (0% to 100% full range dimming) and the LCD Bias output voltages (up to ±15% typ). Incorporating an internal RC filter, designers can make this adjustment via a direct PWM input signal or an analog reference signal applied to the ADJx pin. Any PWM amplitude is easily accommodated with a single external resistor. LX1745 Dual Output Boost – LED Driver/LCD Bias KEY PRODUCT INFORMATION LFB Control Logic Driver DRV SRC Reference Logic BRT 50pF GND Current Limit 2.5MΩ WWW . Microsemi .C OM BLOCK DIAGRAM CS LSHDN Shutdown Logic IN SHDNx OVP FBx Control Logic REF SWx Driver Reference Logic ADJx 50pF Current Limit 2.5MΩ Voltage Reference FBx Control Logic Driver SWx Reference Logic ADJx Current Limit 50pF SALES KIT 2.5MΩ Copyright © 2002 Rev. 1.0 8/22/03 Page 3 New Product Information and Sales Kit LX1745 Dual Output Boost – LED Driver/LCD Bias > 90% Maximum Efficiency Low Quiescent Supply Current Externally Programmable Peak Inductor Current Limit For Maximum Efficiency Logic Controlled Shutdown < 1µA Shutdown Current Dynamic Output LED Current and Two LCD Bias Voltage Adjustment Via Analog Reference Or Direct PWM Input 20-Pin TSSOP WWW . Microsemi .C OM KEY FEATURES APPLICATIONS Pagers Smart Phones PDAs Handheld Computers General LCD Bias Applications SALES KIT Copyright © 2002 Rev. 1.0 8/22/03 Page 4 New Product Information and Sales Kit LX1745 Dual Output Boost – LED Driver/LCD Bias TYPICAL APPLICATIONS ILED = 20mA to 0mA VBAT = 1.6V to 6.0V 47µH 1206 Case Size - VLCD C1 4.7µF DRV IN SRC SW1 VLCD1 = VIN to 25V OVP LFB FB1 CS LX1745 LSHDN ON OFF SW2 RSET 15Ω BRT REF SHDN1 FB2 GND VLCD2 = VIN to 25V WWW . Microsemi .C OM L1 ON OFF ADJ1 SHDN2 ADJ2 ON OFF LED Driver with Full-Range Dimming plus Two LCD Bias With Contrast Adjustment Via PWM Input ILED = 20mA to 0mA L1 VBAT = 1.6V to 6.0V 47µH 1206 Case Size - VLCD C1 4.7µF DRV IN SRC SW1 VLCD1 = VIN to 25V OVP LFB FB1 CS LX1745 LSHDN REF ON OFF SW2 REF FB2 GND VLCD2 = VIN to 25V RSET 15Ω BRT REF SHDN2 SHDN1 ON OFF ADJ1 ADJ2 LED Driver with Full-Range Dimming plus LCD Bias With Contrast Adjustment Via Analog Voltage Input The component values shown are only examples for a working system. Actual values will vary greatly depending on desired parameters, efficiency, and layout constraints. Copyright © 2002 Rev. 1.0 8/22/03 Page 5 New Product Information and Sales Kit SALES KIT ON OFF LX1745 Dual Output Boost – LED Driver/LCD Bias COMPETITIVE ANALYSIS LX1745 Device Topology Input Supply Range Package Temperature Range Microsemi LX1745 PFM/COT* 1.6 to 6V 20 pin TSSOP -40 to 85°C Linear Tech LT1944 PFM/COT 1.2 to 15V 10 pin MSOP -40 to 85°C Texas Instruments TPS61045 1.8 to 6V 8 pin QFN -40 to 85°C Maxim MAX629 2.7 TO 5.5V 8 pin SOIC -40 to 85°C Bias Only 28V Max National Semiconductor LM2703 2.2 to 7V SOT23-5 -40 to 125°C Bias Only 20V Max PFM/ COT/MOT PFM/ COT/MOT PFM/COT Notes SMT Boost LED and Two Boost Bias 25V Max SMT Boost LED and Boost Bias 34V Max Bias Only 28V Max DAC output control WWW . Microsemi .C OM Competitor *COT = Constant or fixed off –time, MOT = Maximum on-time MICROSEMI ALTERNATIVE Competitor Microsemi Device Topology Input Supply Range Package Temperatur e Range Notes LX1744 PFM 1.6 to 6V 14 pin TSSOP/ 16 pin MLPQ -40 to 85°C SMT Boost LED and Boost Bias 25V Max SALES KIT Copyright © 2002 Rev. 1.0 8/22/03 Page 6 New Product Information and Sales Kit LX1745 Dual Output Boost – LED Driver/LCD Bias SALES STRATEGY • Portable Display Products • LED LCD panels • Step up conversion for both LCD bias and LED drive • Two Cell Alkaline, NiCd and NiMH Battery sources WWW . Microsemi .C OM Find Sockets Positioning • Choice of small low profile packages • Guaranteed startup voltage of 1.6V • Useful over wide temperature range • High efficiency PFM topology • Low frequency direct PWM bias and LED adjust Important Facts to Remember • No pin-for-pin competition SALES KIT Copyright © 2002 Rev. 1.0 8/22/03 Page 7 New Product Information and Sales Kit LX1745 Dual Output Boost – LED Driver/LCD Bias SUMMARY Device Package LX1745CPW 20pin TSSOP DC 1000+ $2.07 Contact Factory Note: WWW . Microsemi .C OM Pricing Availability Samples: Production: LX1745CPW Released Options Temperature: C Packages: PW Commercial 16-Pin -40 to 85°C Tape & Reel [MOQ 2500pcs] Technical Support Datasheet: Application Note: Evaluation Board: See Microsemi’s Website See Datasheet LX1745 Evaluation Board (LX1745Eval Kit) Factory Contacts Technical Questions: Bruce Ferguson (714) 372-8094 mailto:[email protected] Marketing Manager: Paul Pickle (714) 372-8365 Copyright © 2002 Rev. 1.0 8/22/03 SALES KIT mailto:[email protected] Page 8 New Product Information and Sales Kit
