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Bringing light to life. Najmi Kamal Power Design Engineer for Lighting. March 2012. TI Lighting System Solution. NSC + TI = strong system level know-how . Lighting Summary.
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Bringing light to life Najmi Kamal Power Design Engineer for Lighting March 2012
TI Lighting System Solution • NSC + TI = strong system level know-how
Lighting Summary Lighting Portfolio LED driver Architecture Dimming techniques LED driverMR16 LED bulb designController, Ref designHigh brightness LEDs driverOff line LED Bulb/T8 Ref designMulti Channel LED driverSystem solutions ( Triac, DALI, 0 to 10V)WEBENCH Architect
Texas Instrument’s Current LED Driver Solutions Quick Selection guide
How to drive LEDs? • With current (high end system) • Light output is proportional to forward current • Brightness AND color can change with current • With power(low end system) • Bulb
Duty Cycle Limits Max VO in Bucks High Side N-MOSFETs (internal or external FETs) Must turn off for ~200 ns each cycle to recharge CBOOT The max number of LEDs is then: The lower the switching frequency, fSW, the closer VO-MAX is to VIN
PFET Bucks Can Provide 100% Duty Cycle Gate is driven below source to turn the PFET ON Gate can drive to VCC indefinitely PFET can stay on indefinitely True 100% duty cycle capability Buck is better than buck-boost Better efficiency Less parts Faster dimming • High Side P-MOSFETs
Variousdimmingtechniques • Dimming using PWM signal • White LEDs change Colour over Current! • Solution: Maintain Current and Change ON-Time = PWM
Two different PWM dimming methods • First method: Dim 1: Continuous inductor current (Good EMC, extra Mosfet ) • Second method: Dim 2: more efficient (2khz dim max)
Buck (step-down) DCM or CCM • Vo Limited by VIN • Cout not needed • Continuous output current, low EMI • Easy to stabilize, if needed • Inherent protections against failure L I o Δ I + L Δ I V C F + - C VIN O + Vo D - + R V FB FB -
LM3409/09HV: High-Side PFET Buck Controller • VIN 6V to 42V (LM3409) • VIN 6V to 75V (LM3409HV) • External power PFET • 100% Duty Cycle Capable • Output Currents up to 4A • Differential, high-side current sense • Simplifies system wiring • PWM dimming and analog dimming at 1000:1 • Thermally enhanced eMSOP-10 package • No control-loop compensation
LM3401 Hysteretic PFET controller HB LED Driver Key Features • VIN Range: 4.5V – 35V • Output range: 0.2V (Vfb) to VIN, adjusts to deliver constant current to up to 9 HB LEDs in series with scalable LED current > 2A • No output cap, no compensation components • Logic level dimming 1% to 100%, 70nS delay • Controlled start up allows PWM at Vin for dimming • PFET driver 100% duty cycle capable • Adjustable Dual Side Hysteresis • Adjustable ripple current • Flexible inductor selection • Fine tuning of switching frequency up to 1.5MHz • MSOP-8 package Applications: Automotive Lighting, General Illumination, MR16 replacement, Industrial Lighting, Gaming, High-end LCD Backlighting
Ref design: LM3401 - 20 Cent-Sized PCB • Runs from 6V to 35V • Drives one white LED in at 800 mA • High-side PFET topology can do 100% duty cycle
LM3402/4/6 and LM3402HV/4HV/6HV 0.5A/1.0A/1.5A HB LED Driver Key Features: COT • VIN Range: • LM340X: 6V – 42V, Buck • LM340XHV: 6V – 75V, Buck • True average current control • Two PWM LED dimming options: • Fast logic pin PWM dimming • LM3406: 2-wire dimming by VIN pin-70% • Feedback Voltage = 200mV • Internal NFET for reduced parts count • Switching Frequency up to 1MHz • Exposed pad eTSSOP-14 package • Drives 1W, 3W, and higher powered LEDs Fast PWM Dim 2-Wire Dim Applications: Automotive Lighting, General Illumination, Industrial Lighting, Arcitectual
LM3414/14HV Low Side Converter for High Power LED Drives • Support LED power up to 60W*: 18x 3W HBLEDs • Patented True Average Current Control Provides ±3% Accuracy to Average LED Current • Requires NO external current sensing resistor • Up to 96% efficiency ,1 activecomponent • High contrast ratio • (Minimum dimming current pulse width <10 µS) • Adjustable Constant LED current from 350mA to 1000mA • ±3% LED current accuracy • Support PWM /analog dimming and thermal fold-back • Wide input voltage range: • 4.5V to 42V (LM3414) • 4.5V to 65V (LM3414HV) • Constant Switching Frequency • adjustable from 250 kHz to 1000 kHz • Thermal shutdown protection • ePSOP-8 or LLP-8 package
TPS92550 (LML416504)LED Driver Module • Wide Input Voltage Range : 4.5V - 65V • Can drive up to 18 LEDs in series with 65V input • LED current accurately trimmed to +/-3% • 450mA LED current + fine tuning by external resistor (= analog dimming!) • Integrated shielded inductor and power components • Efficiency up to 95% • Input Under-Voltage Lock-Out (UVLO) • Stable with ceramic and low ESR capacitors • Low radiated and conducted emissions • LED open and short circuit protection • Thermal Shutdown • Only 3 external passive components needed • Simple PCB layout and high Power Density • RoHS Compliant Actual LML416504 Module
AC Transformer for MR16 Reference Designs LED MR16 Replacement Solutions • Issue: • Resistive load = PF • Doesn’t switch off at 0v input • Small form factor
LM3407 0.35A HB LED Driver Key Features: floating buck • VIN Range: 4.5V to 30V • Less than ±10% load current variation • Adjustable switching frequency from 150 kHz to 1 MHz • Internal low side NFET for reduced parts count • Feedback Voltage = 200mV • Fast PWM dimming enabled • Exposed pad eMSOP-8 package • Drives 1W LEDs Applications: Automotive Lighting, General Illumination, Industrial Lighting
LM3407 - MR-16 Retrofit • Runs from low voltage: 11VAC to 20VAC or 14V to 30VDC • Magnetic transformers only • Nominal 12VAC or 24VDC inputs • Drive three white LEDs in series at 350 mA±10% • 1 MHz switching frequency for minimum inductor size • Low-side buck topology uses small, efficient N-MOSFET • Complete solution including a diode bridge and holdup capacitor fits in standard MR-16 bulb housing
LM3401MR16 Reference Design • Vin: 12VAC • Vout: 6.2V (2 series LEDs) • Iout: 1A • Pout: 6.2W • Efficiency: 81% • PF: 0.85 • Dimmable with electronic low voltage dimmers/electronic transformers • LED Agnostic • Demo board, reference design, CAD design files available online (RD-188) http://www.national.com/rd/RDhtml/RD-188.html
Why Not More Internal FET Boosts? Boost and Buck-boost SEPIC and Flyback
LM3410 Boost and SEPIC LED Driver Key Features • Input voltage range of 2.75 to 5.5V • Output voltage range of 3 to 24V • Switch current up to 2.1A guaranteed over temperature • Low, 190mV feedback voltage • Option of 520 or 1600 kHz switching frequency • PWM Dim pin • 160mΩ switch resistance • Current Mode control with internal compensation Applications: Portable Illumination/Flashlight, Personal Navigation Device, Portable Measurement Equipment, Automotive Control/Entertainment Console, Portable DVD Player LLP-6 eMSOP-8 SOT23-5
TOOLS TPS615003A, Boost High Brightness LED Driver • TPS61500EVM-369
LM3429: Low Side N-MOSFET Controller for Constant Current LED Drivers
LM342x Controls the Floating Buck-Boost VO controlled with respect to VIN Adjustable, precision threshold protection for LEDs that fail open-circuit Linear IF control
LM3423: Adds Fault Flag, Powergood Flag, and Input Disconnect • FLT pin is for error signaling or for input disconnect via PFET • TIMR sets the delay between when LED current is out of spec and when FLT flag goes logic HIGH • DPOL selects the polarity of the nDIM pin when PWM dimming • LRDY is a powergood pin for signaling a system microprocessor
Ref design: LM3429 PAR-38 Spotlight • DC Input Voltage 12V to 30V • SEPIC circuit bucks or boosts as needed • ILED up to 1.5A • 6 White and one yellow LED for CCT adjustment • All LEDs in series • Yellow LED has separate shunt NFET dimming • 250Hz PWM dimming • LM26675 supplies 5V for NuventixSynJet active cooling • 1500 lumens at 50 lm/W
Ref Design:LM3429 MR-16 retrofit with active cooling • DC Input Voltage 9V to 36V • Buck-boost circuit runs from 12VDC or 24VDC rails • ILED up to 1A • Powers 1 to 12 LEDs in series • Accepts standard 0-10V linear dimming signals and adjusts LED current down to zero • LM2842 supplies 5V for NuventixSynJet active cooling
LED Offline products • Retrofit E27 • T8 tube non retrofit • High power bay (multi string)