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Power Design Engineer for Lighting

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Presentation on theme: "Power Design Engineer for Lighting"— Presentation transcript:

1 Power Design Engineer for Lighting
Bringing light to life Najmi Kamal Power Design Engineer for Lighting March 2012

2 TI Solid State Lighting (SSL) Core Competencies
Applications General Illumination Retrofit Commercial Professional Back Lighting Portable Monitor Digital TV Automotive Exterior Lighting Full System Solutions Power Management Multi-String Single-String Multi-Stage Single-Stage Monitoring Communication High Performance Solution Expertise AC/DC Analog Digital DC/DC Linear Wireless & PLC Light Measurement Resources EVMs Cook Book Ref. designs Sample software Application reports Local design services Lighting training support Lighting Know-How

3 High Power Wide Area LM340x
Market Segment Focus Downlighting LM3464,LM3466 High Power Wide Area LM340x Street Lights Parking Lights Ext. Building Energy Saving intelligent Lights Public Buildings Commercial Energy Saving LED Lamp LM3445,TPS92310 Cost driven High Light quality Cost driven Fast growth Automotive LM342x, LM3409

4 TI Lighting System Solution
NSC + TI = strong system level know-how

5 Lighting Summary Lighting Portfolio LED driver Architecture Dimming techniques LED driver MR16 LED bulb design Controller, Ref design High brightness LEDs driver Off line LED Bulb/T8 Ref design Multi Channel LED driver System solutions ( Triac, DALI, 0 to 10V) WEBENCH Architect

6 Texas Instrument’s Current LED Driver Solutions
Quick Selection guide

7 DC/DC Buck Converters for LED Lighting
2A 1.5A 1A 0.5A 0.35A 10 20 30 40 50 60 70 80 90 TPS92510 (RTM:10/2011) LM3406 LM3406HV LM3414 LM3414HV MAX LED Current LM3404 LM3404HV LM3405 A LM3402 LM3402HV TPS92501 (RTM:12/2011) LM3407 Input Voltage (V)

8 With current (high end system)
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

9 N or P FET

10 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: This section of a block diagram is from the LM3404, but it applies to the LM3402 and LM3406 as well. Do you have an idea why we didn’t use in the past P mosfet but N mosfte driver? The lower the switching frequency, fSW, the closer VO-MAX is to VIN

11 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 The LM3401 and LM3409/09HV are all PFET bucks

12 Dimming

13 Various dimming techniques
4/14/2017 Various dimming techniques Dimming using PWM signal White LEDs change Colour over Current! Solution: Maintain Current and Change ON-Time = PWM

14 Two different PWM dimming methods
4/14/2017 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)

15 Output capacitor for a Buck topology

16 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 + - VIN C O + D Vo - Do we need an output cap for driving LEDs ? Since we need a current source and not voltage source. In CCM mode you can leave without cap but big inductor and EMI PB In DCM mode small inductor and big cap. The best is in between. + R FB V FB -

17 BUCK - To Cap or Not to Cap
No Output Capacitor No output cap provides high output impedance Saves a component Leads to higher LED ripple current May generate more electromagnetic interference (EMI) With Output Capacitor Adding an output cap reduces ripple current Small cap + small inductor is smaller than one large inductor Slows pulse-width modulation (PWM) dimming Must be rated to VIN in case of output open circuit

18 BUCK - To Cap or Not to Cap
No Output Cap With Output Cap Note inductor height as well 4.5mm 1.4mm

19 Three Pieces of the Puzzle
Optical – Just as critical, must be integrated into the mechanical design of the lamp Thermal – Critical. Good designs integrate heat sinking into the design of the lamp LED Driver – Critical. Must be good designs. (Efficient, small size, EMI/Safety proved)

20 LED Drivers

21 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 The LM3409 and LM3409HV are buck PFET controllers that extend the input voltage range of the LM3401 and provide several new features at the same time. These controllers use a constant off-time control scheme which naturally combines the safety current limit with peak current control. Like the LM3401 the LM3409 is capable of a true 100% duty cycle, but it adds two important features. First, the current sensing is done on the high side. Within National, “high-side” current sensing means that the current sense resistor is placed before the anode of the first LED. The principal advantage of this is the simplification of the wiring. LED current returns through system ground, and this eases the design of systems with wiring harnesses, especially those where the LEDs are placed on a separate PCB or are physically distant from the drive electronics. The second addition to the LM3409 is the IADJ pin, which is designed for linear adjustment of the LED current. A 5 μA current source flows from IADJ, allowing the user to set the current sense voltage by placing a resistor from IADJ to ground. The user can also apply a control voltage to IADJ, which then directly sets the current sense voltage. Both methods allow the user to make the tradeoff between power dissipation in the current sense resistor and the accuracy of the LED current. Linear dimming also opens the door to simple temperature or ambient light feedback loops.

22 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 VIN can also be used for PWM dimming when a logic signal is not available. In this mode of operation DIM should be connected to VIN through a 10 kΩ resistor. There is typically 10 us of startup delay time when using VIN for dimming. Depending on the application, this de-lay limits the maximum dimming frequency to typically several hundred Hz. When 100% duty, Vo=Vin, I_LED is fixed to I_LED_MAX (L is a short). HYST control  Vo goes between Vref – HYS and Vref + HYS Rsns ADJUST THE OUTPUT CURRENT Hyst adjust the hysterisys CS detect the max peak current and switch off the mosfet I lim adjust the peak current Applications: Automotive Lighting, General Illumination, MR16 replacement, Industrial Lighting, Gaming, High-end LCD Backlighting

23 Hysteretic Control (LM3401)
4/14/2017 Fast load Transient / no compensation required Fsw changes with VIN and VOUT ILED Ripple constant 23

24 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

25 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 LM COT: in CCM, fsw costant enough with the Vin - ton inv. Proportionally to Vin - 1W LM COT: in CCM, fsw costant enough with the Vin - ton inv. Proportionally to Vin W LM COT: in CCM, fsw costant enough with the Vin - ton inv. Proportionally to Vin -5W Adding an external input diode and using the internal VINS comparator allows the LM3406/06HV to sense and respond to dimming that is done by PWM of the input voltage. If the VINS pin voltage falls 70% below the VIN pin voltage, the LM3406/06HV disables the internal power FET and shuts off the current to the LED array. The support circuitry (driver, bandgap, VCC) remains active in order to minimize the time needed to the turn the LED back on when the VINS pin voltage rises and exceeds 70% of VIN. This minimizes the response time needed to turn the LeD array back on. he LM3402, 04 and 06 all feature internal power MOSFETs, giving them the advantage of reduced component count, smaller solution footprint, and built in safety features such as current limit and thermal shutdown. Because power LED currents have coalesced around several discrete points, each member of the LM340x family specifies a minimum current limit over the full temperature range that takes into account both the average current and gives headroom for a wide LED ripple current. These minimum current limit thresholds have been set to allow the ripple currents to be 30% or more peak to peak. All the members of the LM340x family operate over National´s industrial temperature range of minus 40 to plus 125 degrees celsius, which means that the lighting designer can count on getting the full drive current plus ripple even in harsh thermal conditions. This is a constant on time ARCHITECTURE ,which means that Ton TIME IS FIXED BY rON, ton time is inversly prportional to vin and vout. Comp pin make the systeme stable for high dimming. High transient Applications: Automotive Lighting, General Illumination, Industrial Lighting, Arcitectual

26 Fsw is constant with VIN
COT Control (LM3402/4/6) 4/14/2017 Fast load Transient / no compensation required Ton is inversely proportional to VIN Fsw is constant with VIN ILED Ripple is variable TON 26

27 COT Control Revised: LM3406
4/14/2017 The LM3406 has the switching frequency constant not only with respect to the input voltage but also to the output voltage Instead of having a fixed reference, this timer references VOUT so that frequency is truly fixed. 27

28 LM3405A 1A LED Driver Key Features SOT23-6 eMSOP-8
VIN Range from 3V to 22V Low 205mV Feedback Voltage Self-Adjusting Output to deliver Constant 1A Current PWM Dim Pin Low Side Current Sense With External Resistor Low 30nA Shutdown Current Internal NFET for reduced parts count 1.6 MHz Switching Frequency Tiny 6 Lead TSOT package Current Mode Control with internal compensation SOT23-6 Existing SOT-23 pkg (LM3405AXMK) can drive ~ 600mA for an MR16 application eMSOP8 version of the LM3405A can drive ~ 1A in an MR16 application eMSOP-8

29 LM3414/14HV Low Side Converter for High Power LED Drives
4/14/2017 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 active component 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 Internal mosfet The mosfet is a N MOSF,we do not need a Boost cap. No Rseens resitor. Few external componentrs

30 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 LML Module

31 An Evolution of Simple 350mA LED Buck Driver Solution (TO-MOD-7 Module)
10.16mm 8.64mm 14.35mm LED+ IADJ GND LED- DIM 4th Gen LED Buck DC-DC Driver SMT Module+1Cs 3rd Gen LED Buck DC-DC Driver (Higher Integration) IC+L+D+2Rs+2Cs National 3.0 Conference [insert presenter’s name(s)]

32 Retrofit MR16

33 LED MR16 Replacement Solutions
AC Transformer for MR16 Reference Designs LED MR16 Replacement Solutions Issue: Resistive load = PF Doesn’t switch off at 0v input Small form factor mr16 HALOGENE are driven by two kind of transformer.electronic and 50hz transformer To make an LED bulb working with 50 hz is easy bridge cap and driver , to make it run with ELECTRONIC TRANSFORMER is more complexe that why you will find in the market MR16 WORKING ONLY WITH 50HZ transformer and some with 50 hz and not all electronic transformer. If you go to shop and buY led MR16 you should know what you have in your selling. A good MR16 design has the following criteria: Cost effective Fits into a standard MR16 enclosure No electrolytic Operates well (no flicker) with most of the common electronic transformers (non-dimming) Good efficiency (system > 80%) Mitigation of high input current spikes to reduce failure of electronic transformer or MR16 diode bridge

34 Automotive Lighting, General Illumination, Industrial Lighting
LM A 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 One of our solution for low current. Standard LED Driver with pulse width modulation No loop compensation Internal mosfet Fs:FHZ ISNS: I SENSE PIN ANODE OF LED TO PLUS VIN Applications: Automotive Lighting, General Illumination, Industrial Lighting

35 Architecture of the LM3407

36 LM 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

37 Halogen MR16 vs. SSL MR16 waveforms
Issue #1 - The two scope captures above illustrate the SSL MR16 technical challenges. Figure one shows typical Halogen MR16 waveforms, and figure two is common MR16 replacement bulbs waveforms. The SSL replacement bulb looks capacitive to the ELVT; therefore large current spikes charge the energy storage device within the SSL MR16 bulb. The switching converter within the bulb then processes the input power from the energy storage element to the LED load. At this time the minimum load requirement of the ELVT is not satisfied, and the ELVT turns off. Once the energy is depleted within the MR16 converter, the ELVT will start up, and the process cycles. The turning off/on of the ELVT will manifest itself as visible flicker. Issue #2 – The maximum input current to the Halogen bulb is approximately 4.25A. The maximum input current to the SSL bulb is approximately 12A. The large magnitude spike associated with charging the SSL MR16 input capacitor can cause premature failures within the SSL bulb, or even the ELVT.

38 First schematic draft for MR 16

39 Final schematic of the MR16
4/14/2017 Final schematic of the MR16

40 Plots of the LM3409 BUCK BOOST
4/14/2017 CH4: Inductor current CH2: Rectified input voltage CH3: Input current CH3: LED current   

41 MR16 in design with electronic transformer

42 LM3401 MR16 Reference Design Vin: 12VAC Vout: 6.2V (2 series LEDs)
4/14/2017 LM3401 MR16 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)

43 LM3401 MR16 Reference Design

44 TPS40211 Sepic Reference Design

45 LM3444 Boost Reference Design

46 LM3444 BUCK BOOST Reference Design

47 Controller/ Regulator/ Ref design

48 Why Not More Internal FET Boosts?
Boost and Buck-boost The buck is the only switching converter where average output current (LED current) is equal to average inductor current. In every other converter the average inductor current is different from LED current. Any time the circuit is boosting, be it the boost topology or one of the buck-boost topologies, the inductor current will be higher than the output current. How much higher depends upon the topology and upon both input and output voltage. Internal FET regulators are very limiting because their current limits are almost always fixed. Even within the very few internal FET boosts or buck-boosts that have adjustable current limits, power dissipation and self heating limit the true maximum current. To make matters worse, current limits detect peak current, not average current. This means that output current, input and output voltage, and also inductance must all be taken into account when designing a circuit. Exemple 10v out 1a out Vin 5v 2A average on the coil. SEPIC and Flyback

49 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

50 TPS61500 3A, Boost High Brightness LED Driver
Features Benefits Operating Voltage Ranges: VIN: V VOUT: VIN to 38V Suitable for Use in Battery,12V, or 15V Systems 3A Peak Switch Current Can be Used to Drive High Current LEDs Adjustable Switching Frequency: 200k-2.2MHz with up to 93% Efficiency Allows Designed to be Optimized for Efficiency or Size Dimming: PWM or PWM-to-Analog Use PWM for No LED Color Shift. Use Analog to Eliminate Audible Noise from Pulsed Currents. UVLO, Over-Voltage, Current Limit and Thermal Shutdown Protects Against Abnormal and Fault Conditions Applications LED General Illumination LED Flashlights LED Backlighting TPS61500EVM-369 TOOLS

51 TPS40211 4.5V to 52V Current Mode N-Ch Controller
Features Benefits Supports Boost, Flyback and SEPIC Topologies Suitable for a Wide Variety of LED Lighting Applications 4.5 to 52V Input Voltage Range Can Drive Up To 14 Series HB LEDs Programmable Switching Frequency (35kHz to 1MHz) Flexible Filter Design Frequency Synchronization (with External Components) Can Operate with an External Clock 260mV Internal Voltage Reference Reduces Power Dissipation in Sense Resistor Integrated Low-Side Driver Reduces Component Count Programmable Over-Current Limit and Internal UVLO Protects Against Fault and Abnormal Operating Conditions Applications High Current LED Drivers (Street Lighting, High Bay) LED Based MR-16 Light Bulb Replacement LED Backlighting TPS40211EVM-352 TOOLS

52 LM3429: Low Side N-MOSFET Controller for Constant Current LED Drivers
High side current sense. A “low side” controller is a switching power regulator that uses an external power MOSFET whose source is connected to system ground. The LM3421, 3423 and 3429 are a family of low side N-MOSFET controllers designed specifically to drive LEDs with a constant current. While the boost regulator is the most common circuit built with low side controllers, they are also capable of SEPIC converters and transformer-based flyback converters. Like the LM3409 buck controller, the LM342X family feature integrated, differential, high-side current sensing. In addition to simplifying the system wiring, this differential current sense allows them to be used in two more topologies. These are the Vin-referenced buck and the Vin-referenced buck-boost. As the names imply, these are converter topologies that perform step-down and step up-and-down functions, respectively. The difference is that the output current flows back to the input voltage as opposed to ground. In the case of a current source driving LEDs, a load that connects between output voltage and input voltage is perfectly OK in many applications.

53 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 The circuit shown in this slide is possible thanks to differential current sensing. Other names for this topology are “floating buck-boost”, “negative buck-boost” and “Vin referenced flyback”. Current flows from the input, through the inductor and through the external power FET while the FET is on. When the FET turns off, the current commutates through the Schottky diode, through the LEDs, and back to the input. At first glance it appears that this circuit should have a continuous input current, since the inductor is connected to Vin. This is not the case, however. Like the classic buck-boost and the flyback, this circuit has a discontinuous input current and a discontinuous output current. One principal advantage of this topology is the power efficiency. While not as good as the buck or boost, it is higher than the SEPIC or the flyback. The voltage designated “Vo” on this slide is equal to the input voltage plus the voltage across the LED string, so the user must be aware that the 75V limit for the IS, HSP and HSN pins is reached more easily. This can be alleviated by moving the current sense resistor to between Vin and the cathode of the last LED in the chain, and by using an external peak current sense resistor between ground and the source of the power FET Q1.

54 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

55 LM3429: Features VIN range: 4.5V to 75V: runs from 12V, 24V, 48V rails
Adjustable current sense voltage: 50 mV to 1.24V Allows linear (analog) dimming without changing the current sense resistor User can make tradeoff between average current accuracy and power dissipation in RSNS High-side current sense: LED current returns through system GND Input for PWM (digital) dimming Precision output over-voltage protection Disables the regulator if an LED fails open circuit or the LED array is disconnected Input under-voltage lockout Switching frequency as high as 2 MHz Thermally enhanced TSSOP-14 EP package Runs at high frequency and drives N-FETs with large gate charge A “low side” controller is a switching power regulator that uses an external power MOSFET whose source is connected to system ground. The LM3421, 3423 and 3429 are a family of low side N-MOSFET controllers designed specifically to drive LEDs with a constant current. While the boost regulator is the most common circuit built with low side controllers, they are also capable of SEPIC converters and transformer-based flyback converters. Like the LM3409 buck controller, the LM342X family feature integrated, differential, high-side current sensing. In addition to simplifying the system wiring, this differential current sense allows them to be used in two more topologies. These are the Vin-referenced buck and the Vin-referenced buck-boost. As the names imply, these are converter topologies that perform step-down and step up-and-down functions, respectively. The difference is that the output current flows back to the input voltage as opposed to ground. In the case of a current source driving LEDs, a load that connects between output voltage and input voltage is perfectly OK in many applications.

56 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 Nuventix SynJet active cooling 1500 lumens at 50 lm/W This is a tunable white with high CRI .(Excelent colour rending.)

57 PAR-38 Spot Light – Block Diagram
4/14/2017 57 57

58 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 Nuventix SynJet active cooling Dimmable using buck boost topology

59 LM3429 MR-16 Buck-boost Schematic

60 - Automotive Backlight
LM Channel Constant Current LED Driver with Integrated Boost Controller Product Overview: The LM3492 is a 2-channel linear current controller combined with a boost switching controller ideal for driving LED backlight panels. Key Features: VIN Range: 4.5V to 65V Drive two individual PWM dimmable LED strings up to 65V total 15W (around 230mA) 2 individually dimmable output channel No Loop compensation required > 15000:1 contrast ratio for 200Hz dimming frequency Near constant adjustable switching frequency up to 1 MHz LED driver Over-Power protection for short to supply scenario Dynamic Headroom Control Precision Enable pin Versatile COMM I/O pin for FAULT reporting (LED rail Power- Good, Short-FAULT, Open-FAULT and Over-Temperature Alert) and Digital Tune for switching frequency Individual LED string voltage diagnosis mode eTSSOP-28 package Applications: - Automotive Backlight - 6.5”-10” LCD display backlight applications up to 36 LEDs which requires ultra-high contrast ratio

61 LM3433 HB LED Driver LM3434 Common Anode Capable
real High Brightness LED drivers

62 LM3433 Common Anode Capable HB LED Driver
Key Features:COT Operating Input voltage Range: -9V to -14V w.r.t. LED Anode Control inputs are referenced to the LED anode Output current > 6A Greater than 30 kHz PWM Dimming frequency No output capacitor required Programmable up to 1 MHz switching frequency Low IQ, 1 mA typical Soft start “Intelligent” constant ON time allows for constant ripple current LLP-24 package Output configuration allows the anode of the LED to be tied directly to the ground reference chassis for maximum heat sink efficiency Applications: LCD Backlighting, Projection Systems, Solid State Lighting, Automotive Lighting

63 Synchronous Buck HB LED Driver with Common Anode Capability
Negative Buck Approach offers Negative output voltage capability allows common anode LED modules LED mounted directly to chassis for Maximum heat sink efficiency!! Directly mounted on projector chassis Here shows the application circuits of LM3433 Buck LED driver, which is designed for driving common anode LED modules in projector application. If you compared the conventional Buck LED driver shown in previous slides p.9, there are two main differences of LM3433 from conventional Buck LED driver. First, the LM3433 application circuits, as shown in here, configures as negative buck approach. This offers Negative output voltage capability which allows common anode LED modules to be tied directly to chassis without any insulation layer for maximizing heat sink efficacy!! As you can see in this block diagram, the reference ground of LED driver is at the same electrical potential as the LED anode. Therefore, this point can be connected to the chassis (earth) without any safety issue.

64 LED Offline products Retrofit E27 T8 tube non retrofit High power bay (multi string)

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