Medium & High Power LED Driver Solutions

1

Medium and High Power Drivers

2 • Template • Nov-12 Confidential Proprietary2

Medium/High Power LED Lighting

• Broad power range (20 – 400 W)• Replace HID or Fluorescent• Power architecture based on:

– End product and application needs– Many LED configurations– 1-3 power conversion stages

Large Array LEDs, 2 Independent Drivers Modular Strips of LEDs


Trends in High Power Lighting

• Decision to use LEDs is based on total cost of operation– Upfront Purchase Cost– Maintenance Cost– Energy Cost

• Controls that allow dimming, reduce energy cost and improve payback time

• Drivers + Sensors + Communication = “Intelligent Control”– Occupancy and activity sensors– Ambient Light Sensors– Constant Light output– Autonomous (µC/Sensor) or Networked (wired/wireless)


Example: Intelligent Bi-level Lighting

• LEDs are easy to dim in discrete levels of light tied to motion or activity

• Typical dimming step can be at 20-30% which give significant energy savings

• Many different uses– Outdoor Parks– Petrol station canopies– Parking structures – Stairways – Refrigerator case lighting– Security Lights


High Lumen Lighting Considerations

• For large area lighting, many LEDs are required (40-100+ 1W LEDs) to get lumen output

• New high power LEDs are simplifying drivers by only needed to drive single string

LEDModulew/ CCR

PWM

DimmingControl

LEDLampw/CCR

PWM

LEDLampw/CCR

PWM

Power Supply

PFC IsolatedDC-DC

AC

3 Loss producing stagesPFC + DC/DC + LED Driver

Overall Efficiency may be 85-88%

DCOutput

(48-60V)

Courtesy:

CREE XP-G2 Series450 lumens @ 1.5 A (Vf = 3.1V)

http://www.siteco.de/de/home.html


ON has a Broad Range of Power Solutions• Power Factor Correction Controllers

• Flyback Controllers and Switchers– Quasi-resonant– Fixed Frequency

• Buck Controllers and Switchers

• Half Bridge Drivers and Resonant LLC Controllers

• Secondary Side Controllers (Linear and Sync Rectification)

• Application Specific Products Combos


Wide Range of Topologies Used

* Fixed voltage drivers typically have 24-55 V output and need DC-DC Buck LED Driver like NCL30160/1, NCL30105, or CAT4201

Single Stage PFC

Isolated Flyback

Non-isolated Buck-boost, Buck or Boost

PFC (CrM/CCFF/CCM)

Non-isolated buck

Isolated Flyback or LLC

Constant CurrentFixed Voltage*

Constant CurrentFixed Voltage*

Constant Current

Constant CurrentMulti-Stage


Hi-PF Drivers – Single versus Two Stage

• Advantages– Direct current drive– Single switch and magnetic

• Disadvantages– 100 / 120 Hz ripple– Higher MOSFET Stress– Wider Duty Cycle

– Limited to ~ 100-150 W

• Advantages– Primary energy storage

means low output ripple– Easy to scale in power/size– Easy to provide secondary

bias power

• Disadvantages– Two magnetics, at least 2

power switches

Flyback or

LLCor

Buck


25 W Hi-PF Single Stage Design•NCL30000 Constant On Time CrM Flyback Control

– 90 – 305 Vac Input– Efficiency > 87%– Input current THD: <15%/PF > 0.97– LED power: 25 W (Vf = 36 Vdc)

– LED current: 700 mA +/- 4%– Maximum LED voltage: 44 Vdc

230 Vac 50 Hz: 447 mA pk-pk2 470 uF Caps

DN05031 Design Note


NCL30001 100 W Single Stage LED Driver

• Constant Current Output up to 3 A

• > 2:1 VF range from 90-265 Vac

• CCM Avg Current Control Flyback

• EMI Frequency Jittering AND8427 App Note

Demo Board

HV Startup

MultiplierInput

AdjustableConstant

Frequency


NCL300001 Efficiency Versus PoutIout = 1A

80%

82%

84%

86%

88%

90%

20 25 30 35 40 45 50

Pout (W)

Eff

icie

nc

y (

%)

120 Vac

230 Vac


PFC Solutions for 2 Stage Architectures

Power Factor Controllers

Variable Frequency

Discontinuous

Mode

NCP1605

CCFF

NCP1611

NCP1612

NCP1615

Interleaved

PFC

NCP1631

CrM

MC33262

NCP1607

NCP1608

Fixed Frequency

Continuous

Mode

NCP1653/4

Single Stage

PFC

NCP1652A

NCL30001

PFC Handbook

“Patent Pending” Current Controlled Frequency Foldback (CCFF) control improves efficiency across line /load. Ideal for Dimmable LED Drivers


How the NCP1611/12 CCFF Approach Works

With classic CrM / BCM control– As the load is reduced, the switching

frequency increases– At light loads the controller may enter

“burst mode” resulting in noise

With CCFF control:– As the load is reduced, the switching

frequency decreases reducing losses– At light loads the controller’s lower

frequency can be clamped above audible frequency band

– Skip mode operation at very light load (can be disabled for better THD)

Valley turn on further improves efficiency and reduces EMI

Operating in “Skip”


NCP1611 Typical Application Schematic

Brownout Frequency Foldback/Skip Control

Skip can be easily disabled

Loop Compensation

ZCD and Current sense (CS) are multiplexed onto one pin with low cost 1N4148 diode

Two Versions:

A - Startup at 10.5 Vdc (typ) with soft start for auxiliary biased applications

B - Higher startup of 17 Vdc (typ) with normal startup for self-biased applications allowing smaller Vcc capacitor

Output Feedback Sense


Frequency Fold-back Operation• Current flow from FFcontrol is proportional

to the input line current

• The voltage on FFcontrol pin determines the operating condition

– VFF > 2.50 V …. CrM

– VFF < 0.65 V …. Skip mode

– Otherwise …. Frequency fold-foldback

• RFF selection determines the point where frequency foldback is initiated

• Normally, a small capacitor is placed in parallel with RFF to filter noise on the pin but not distort the waveform

• See 5 Step Design Application Note for details

– AND9062 – NCP1611– AND9065 – NCP1612

NCP1611EVB – Full load, 115 Vac Input

http://www.onsemi.com/pub_link/Collateral/AND9062-D.PDF

http://www.onsemi.com/pub_link/Collateral/AND9065-D.PDF


NCP1611/2 CCFF Comparison

• Improved efficiency in light load over traditional CrM PFC as switching frequency is reduced at light load

• Significant efficiency gain for wide mains starting at ~ 50% load• Improved reliability and safety without extra components

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100

0 10 20 30 40 50 60 70 80 90 100

Eff

icie

ncy

(%)

Relative Output Power (%)

CCFF with Skip

CCFF with Skip Off

CRM

Vin= 115 Vac, Pout(max) = 160 W85

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100

0 10 20 30 40 50 60 70 80 90 100

Eff

icie

ncy

(%)

Relative Output Power (%)

CCFF with Skip

CCFF with Skip Off

CRM

Vin= 230 Vac, Pout(max) = 160 W

Efficiency vs Load @ 115Vac Efficiency vs Load@ 230Vac

By forcing VFF, efficiency gain can be easily evaluated


Optimizing the FFcontrol Filter for Best THDVFF > 2.50 V …. CrMVFF < 0.65 V …. Skip modeOtherwise …. Frequency fold-foldback


Harmonic Content at Light LoadJIS/EN61000-3-2 Class C > 25 W Pout Limits

Note: For 230 Vac, a 8.2 MΩ between from VCC to FFcontrol ensures that the NCP1611 does not enter skip mode

100 Vac Nominal 230 Vac Nominal

With skip inhibited, even at <20% of full loadharmonics and THD are excellent


US Line Voltage PerformanceTHD < 20% across wide load range

277 Vac Nominal, Full Load 277 Vac Nominal, 16% of Full Load

115 Vac Nominal, 20% of Full Load115 Vac Nominal, Full Load


Other Key Features of NCP1611/12• Performance

– Dynamic Response Enhancer for fast line/load transient response– Wide Vcc Range to 35 V with Gate Voltage Clamp– 20 µA typical startup, 50 µA maximum – Vcc startup at 10.5V (A version) or 17 V (B Version)– Line Range Detection to adjust optimize loop gain – NCP1612 has PFC Okay and Independent bulk monitoring

• Safety– Over-current protection for saturated inductor or shorted bypass diode– Output over-voltage (soft and fast) and under-voltage protection– Input line brownout protection – Open feedback disable and open ground fault monitoring


NCP1611/2 Collateral• The following items are available to allow easy evaluation

and simplify the design process:– NCP1612GEVB – 160 W Demo Board:

• Schematic and BOM• Gerber Files• Evaluation Board Manual

– Safety Evaluation App Note– Step-by-Step Design Guide– NCP1612 Excel® based Design Tool

< 13 mm height

Design ToolDemo Board Manual


HV DC/DC Second Stage

• Single switch architecture, good efficiency, typically < 100 W

• ON is a leader in fixed frequency and quasi-resonant control– HV Startup– QR Valley locking– Robust fault protection– Wide range of product offering down

to 6 pin controllers

• Soft switching needed for highest efficiency and lowest EMI generation

Flyback

Resonant Half Bridge


AC-DC Quasi-Resonant Flyback Controller Evolution

| 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013

NCP1207-DSS

NCP1377- No DSS

NCP1378

- Lower UVLO

1st Generation High Voltage Controllers

Fe

atu

res

an

d E

ffic

ien

cy

3rd Generation Major Leap in Light Load

Efficiency

4th Generation Improved No Load

Power Consumption

NCP1351 (VF)-Dual OCP for peak

power

2nd Generation Advance Protection

Features

NCP1308- OVP on

Vcc

Industry first QR AC-DC controllers with Direct

Connection to High Voltage Line

-Brown Out Protection-Overpower Compensation

-Frequency Foldback-NCP1380 Introduces Valley Lockout

NCP1380

NCP1379- UVLO

NCP1337

NCP1338- Better for Aux SMPS

NCP1381-PFC Go To

Standby

-Fault Timer

-Voltage Ref

NCP1382

-Latch Threshold

- Active X2 Discharge- Power Savings Mode

NCP1339<10 mW No Load

NCP1385- No HV

NCP1336- HV Startup

NCP1937 (Combo)

CrM PFC + QR


+

_

Driver90-305 Vac

Input

500 mA

• Constant Current Output• Higher voltage, lower current can

improve efficiency• Single string, no current mis-match• 100 watts example

– 20 LED = 60V (30 W)– 60 LED = 180V (90 W)

– DC-DC Stage Eliminated (+)– Requires UL Class 1 in US >60 V– Increased fixture safety design

Isolated High Voltage Driver Topology

PFC+Flyback


HV DC/DC Second Stage

• Single switch architecture, good efficiency

• ON is a leader in fixed frequency and quasi-resonant control– HV Startup– QR Valley locking– Robust fault protection– Wide range of product offering down

to 6 pin controllers

• Soft switching needed for highest efficiency and lowest EMI generation

Flyback

Resonant Half Bridge


Benefits of an LLC series resonant converter

• Type of serial resonant converter that allows operation in relatively wide input voltage and output load range when compared to the other resonant topologies

• Limited number of components: resonant tank elements can be integrated to a single transformer – only one magnetic component needed

• Zero Voltage Switching (ZVS) condition for the primary switches under all normal load conditions

• Zero Current Switching (ZCS) for secondary diodes, no reverse recovery losses

Cost effective, highly efficient and EMI friendly solutionfor high and medium output voltage commonly used in LED Driver topologies


An upgraded version of the NCP1397, the NCP1398 offers the same high performance and protection features. In addition it also improves the Rt pin robustness, open/short pin protection and Brown out feature.

Built-in drivers Adjustable & accurate

minimum frequency

Fast and slow fault detection, Broken FB loop detection

Compact design Keeps the converter in

the right region & ease the design

Robust and rugged power supply & help to be compliant with safety standards

Latch input, brownout Adjustable dead-time Adjustable soft start Easy no-Load operation and low standby power due

to programmable skip cycle Enable capability

Others Features

Ordering & Package InformationMarket & Applications

NCP1398 High Performance Resonant Controller

NCP1398ADR2G (SOIC-16) = Auto-recovery NCP1398BDR2G (SOIC-16) = Latch

Flat TVs High power AC adapters Desktop PCs / Servers High Power LED Drivers

Application DataUnique Features Benefits

Value Proposition

http://www1.us.dell.com/content/products/category.aspx/desktops?c=us&cs=19&l=en&s=dhs


NCP1398 5th Generation LLC Controller• High-frequency operation from 50 kHz up to 750 kHz• Adjustable minimum switching frequency with 3% accuracy• Adjustable dead-time• Externally adjustable soft-start• Precise and high impedance Brown-out protection• Latched input for severe fault conditions, e.g. over temperature or OVP• Timer-based auto-recovery over-current protection• Latched output short circuit protection• Open feedback loop protection for NCP1398B version• Disable input for ON/OFF control• Skip mode with adjustable hysteresis• Vcc operation up to 20 V• Common collector opto-coupler connection for easier ORing• Internal temperature shutdown• 600 V Half-Bridge driver with 1 A / 0.5 A sink / source drive capability


Typical Application Schematic


Resonant Mode Topology is a High EfficiencySolution for LED Drivers

• CrM PFC + LLC– Ex: NCP1607 + NCP1397– 8 pin + 16 pin SOIC

• Power control is based on changing LLC frequency– Lower frequency = more power

• Very flexible to support wide range of Vin and Vout

• Regulates out 100/120 Hz ripple

• CrM PFC + Fixed Frequency Resonant Half Bridge– Single SOIC16

• Power control is based on changing PFC bulk– Higher bulk = more power

• Limitation is dynamic range of bulk voltage

• Great to simplify Fixed Voltage LED Driver Designs

Classical Approach NCL30051 Approach


NCL30051 is a combination of a PFC and half bridge resonant controller which has all functionality to implement a high efficiency driver in a small low form factor. Regulation is achieved by varying PFC bulk voltage

Half bridge driver with 600 V high side gate drive

Resonant controller with fixed frequency and soft-skip

PFC with constant on-time controller & error amp

No need for external level shifter or transformer

Increases efficiency at light load. Reduces EMI

Excellent PF at mains with low ripple

LED Drivers and Supplies Applications include Wall packs, street lights, outdoor

area lights, low and high bay lighting NCL30051DR2G: SOIC-16

NCL30051 – Resonant Controller with integrated Fixed On-Time CRM PFC

Others Features

Ordering & Package InformationMarket & Applications

Pb

Disable Input to half bridge 50 ns max rise and fall time on the high and low side gate

drive 500 ns min fixed crossover dead time between drives No electrolytic outputs needed for output filtering

Unique Features Benefits

Value Proposition

Block Diagram


Simplified Application Schematic

Simple fixed frequency resonant

half bridge step down operation:• As output voltage varies at A• Feedback signal is generated at B• PFC voltage at point C changes to regulate output

Half Bridge can be disabled for PWM dimming

PFC Stage Resonant Half Bridge

High Voltage Startup simplifies biasing

A

C

B


• Universal Input 90 – 265 Vac

• Pout Maximum 60 W (board limited to 120 W) but the NCL30051is capable of power up to 250 W

• Power Factor PF > 0.9 (50-100% of load with dimming) and IEC61000-3-2 class C compliance

• CC Iout Range 0.7 - 1.5 A (3 A with component changes)

• Vout Range 35 - 50 V

• Protection Features• Output Open and Short Circuit Protection• Over Temperature• Over Current Protection - auto recovery• Over Voltage Protection – input (OVP bulk voltage)

• Dimming• Two-step bi-level analog• PWM dimming

Dimming range > 20:1• 1-10 V analog voltage input

NCL30051LEDGEVB Available

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34 38 42 46 50

Effici

ency

(%)

LED Forward Voltage (Vdc)

120 Vac

230 Vac

>90% Efficient35 - 45 W (Iout = 1A)

PWM orAnalog Dimming

Interface


Example: Advanced Lighting Application

(2x) …Two strings to implement white LED

color control

MCU forDimming and

Control

IRControl

NCP1607

NCL30105Buck LED Driver

WholeRoom Light

40-80 W80 lm/W


Summary

• LED Lighting is evolving requiring new solutions that can support the latest generations of LEDs on the market

• Topology choices are evolving to improve efficiency and reduce overall system cost

• Intelligent control can enhance energy saving and extend operation lifetime even if more complex drivers are needed to support

• We have only begun to harness what is possible with Solid State General Lighting


Appendix


CCFF PFC Feature Comparison to NCP1608NCP1608 NCP1611 NCP1612 Benefit

Fast Overvoltage Protection (F-OVP) o o oUndervoltage Protection o o o

Soft OVP o o Improved transient response when load is reduced

Dynamic Response Enhancer o o Dramatically improved transient response

Bulk Undervoltage Protection (BUV) o Informs downstream controller when Bulk is too low

Independent Sensing of FOVP & BUV o Enhanced Fault Protection

Cycle-by-cycle Over Current Protection o o o Fault Protection

Shorted Boost or Bypass Diode o o System Robustness, Safety Testing

Saturated Inductor Detection o o Fault Protection

Vcc - UVLO o o o Ensures proper operation of controller

UVLO Gate Driver Pulldown o o o Ensures FET is off during turn on and turn off

Line Range Gain Selection o o Optimizes control loop for wide mains applications

AC Line Brownout o o Improves system robustness to line faults

FB o o oCS/ZCD o o

GND o oFOVP/BUV o

Disable o o o Simplifies PFC ON/OFF Sequencing

Soft Start A Version A Version Reduced component stress at startup

High Vcc Startup Threshold/Low Icc B Version B Version Reduces Vcc capacitor size & startup time

Skip Mode Disable o o Eliminates audible noise, improves THD & PF at light load

Thermal Shutdown o o Enhanced Fault Protection

PFC Okay o Sequencing control for downstream converter

Latch Input o Enhanced fault control, easy to implement thermal latchoff

Simplifies safety testing

Protects supply under abnormal operation

Monitoring

Control

Open Pin Protection

Protection and Control Features

Bulk Sensing

Current Sense

Business

Medium & High Power LED Driver Solutions