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3. Richtek LED lighting driver IC Jan 2011 - Richtek Technology

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3. Richtek LED lighting driver IC Jan 2011 - Richtek Technology Powered By Docstoc
					LED Lighting Driver IC Introduction




 Robin Liao
 January 2011



 http://www.richtek.com/LED
Contents

  LED Lighting Driver IC Overview
  AC input to constant current LED
  driver -- Isolated
  AC input to constant current LED
  driver -- Non-isolated
  DC to CC Solution
  Applications
  Selection Guide

                                     2
LED Lighting Driver IC Overview




                                  3
LED Lighting Driver IC Overview

                                      E26/E27/E17, T5/T8
                         Isolated
                                      Par30/Par38, Street light


               AC/CC

                                      GU10, E26/E27/E17
                       Non-isolated
                                      T5/T8, Par30/Par38
LED Lighting

                         With ET      MR16, AR111

               DC/CC


                                      Street light, car light, desk
                       Without ET     light, freeze light, projector
                                      Emergency light

                                                                       4
AC input to constant current
   LED driver -- Isolated




                               5
AC Input Solution -- Isolated

• Application
 • E27, GU10 …. Bulb, Par 30, Par 38
 • T5, T8 …. Light bar, Freeze light
 • Street light, Desk light…


• Richtek advantage
 • High-precision constant current control to limit current accuracy in +/-
   5% range on mass production.
 • Small package and high integrated solution with less external
   components to fit into a small bulb or light bar
 • Very low quiescent current
 • Dimming on secondary side to provide better accuracy

                                                                              6
Secondary side CC/CV controller
AC to CC – Isolated – secondary side CC/CV controller & dimming

  RT8456         Single channel CC/CV controller


  RT8457         Single channel CC/CV controller with dimming


  RT8454         Multi-channel CC/CV controller with dimming



      Easily work with any kind of primary side topology.
      Provide high precision LED current.
     LED current accuracy does not vary with the accuracy of transformer.
     OVP support

                                                                             7
RT8456 Secondary-side constant Current Controller


                            Secondary side LED current
                            regulation
                            Support LED voltage up to 45V
                            High accuracy LED current
                            threshold control over wide input
                            voltage and temperature range
                            0.6mA operation current
                            Programmable LED current through
                            60mV sense resister
                            Programmable OVP
                            Easily connected to different kinds
                            of primary side solutions
                            TSOT 23-6
                                                                   8
RT8457: Dimmable secondary side constant current controller


                                LED voltage up to 45V
                                Support Triac dimming, PWM
                                dimming, analog dimming
                                High accuracy LED current
                                threshold control over wide input
                                voltage and temperature range
                                Programmable LED current through
Dimming
                                60mV sense resister
Input
                                Programmable OVP
                                Easily connected to different kinds
                                of primary side solutions
                                SOP-8

                                                                       9
RT8454 AC-CC 6-Ch Current Regulators

                   Vcc up to 50V
                   Programmable channel current
                   3% current sense amplifier input
                   offset
                   Easy dimming
                   Programmable soft start and OVP
                   Automatic detecting unconnected
                   AND/OR broken channel to avoid
                   output over voltage
                   Vcc under voltage lockout and
                   Thermal shutdown
                   One LDO controller embedded

                                                       10
RT8454 AC-CC One-Stage Driving Scheme




                                        11
Application Tip: RT8454Channel Number Extension
AC Power Lines


                 AC to DC Primary Side Circuit




                                                                Vaux




                                                 Opto-Coupler




                                                                       12
    Applications: Isolated E26/27, T5/T8, PAR30/38…..

•        Primary side solution example
    1.       Flyback: R7912 (MOS inside) R7732(MOS ext.)
              Low PF, small output current ripple, good efficiency, good for no-PF requirement condition.
    2.       Valley-fill PFC+Flyback
              For small power (<10W), PF at 0.7~0.9 range. Small output current ripple, good for small
               power and PF>0.7 application.
    3.       Active PFC+Flyback
              High PF (>0.9), lower efficiency, small output current ripple, good for high power design.
    4.       PFC single stage
              High PF (>0.9), low cost, need big output cap to reduce current ripple. Good for small power,
               low cost design.
    5.       LLC
              High efficiency, high cost. Good for high power, high performance design.
    6.       Primary side constant current : R7710
              Current accuracy is suffered from transformer accuracy. Good for current accuracy <+/-10%
               application
                                                                                                            13
Applications: Isolated E26/27, T5/T8, PAR30/38…..


• Secondary side solution
 • RT8456, RT8457, RT8454 can work with any kind of primary side
   topologies and become constant current LED drivers except (6)
 • Maintain current accuracy at +/-5% independent of the variation of
   transformer
  Non-dimmable: Primary side + RT8456
  Dimmable: (bleeder)+ Primary side + RT8457
    • Support Triac dimming with external bleeder added
    • Support PWM, analog, wireless… dimming on secondary side with
      accurate current control.
    • Using MCU for Traic dimming can provide the best compatibility of
      dimmer.



                                                                          14
Valley-fill PFC+R7732+RT8456




                               15
AC input to constant current
LED driver -- Non-isolated




                               16
AC-CC non-isolated product roadmap

AC to CC – non-isolated

   RT8458        High-side buck CC LED driver


            RT8459        High-side PFC buck CC LED driver


                                    High-side PFC inverting buck-boost CC
        MOS           RT8460        LED driver
        inside



            RT8469


   RT8468
                                                                            17
RT8458 floating buck LED driver for non-isolated
application


                                   Unique self-biasing floating buck
                                   driver topology
                                   True average LED current sense
                                   High efficiency (>90% possible)
                                   Cheap and simple external components
                                   Very wide input voltage range
                                   (16V~400V or higher)
                                   Stable LED current over wide input
                                   voltage range
                                   Works with standard series drum choke
                                   inductors
                                   Support OVP & OCP
                                   Small PCB to to fit GU10, E17…..


       The best way to drive LEDs from AC power input!!
                                                                            18
 Three RT8458 applications
1.   Typical application
        Advantage
          Very good line regulation. LED current variation between 110V/220V AC input is
            minor. (<+/-2%)
          Small input/Output cap
          Simple external components
          Good for application do not need PFC.
        Disadvantage
          Low PF (About 0.6)
2.   Valley-fill PFC+RT8458
        Advantage
          PF at 0.7~0.9 for low power application (<10W)
          Good for small power, PF>0.7 design
        Disadvantage
          Big cap for high power or high PF application.
3.   Active PF + RT8458
        Advantage
          High PF (>0.95)
          Good for high power, high PF design
        Disadvantage
          Higher cost
          Lower efficiency                                                                 19
RT8458 typical application circuit
                                OVP option




                                         Vout>31V




          EMI improvement



                                                    20
High-efficiency universal input design


Vin.ac (V)   Pin(W)   V-LED (V)   I-LED (A)   Pout (W)   Eff. (%)

   90        10.25      36.20      0.257       9.303      90.76

   110       10.22      36.29      0.257       9.327      91.26

   130       10.29      36.19      0.257       9.300      90.38

   180       10.19      36.02      0.257       9.257      90.85

   220       10.21      36.02      0.257       9.257      90.67

   260       10.23      36.06      0.257       9.267      90.59



                                                                    21
RT8458 efficiency vs. LEDs




               LED current=350mA

                                   22
RT8459 High PF, floating buck LED driver for
non-isolated application

                         Unique self-biasing floating buck driver
                         topology
                         True average LED current sense for
                         high PF application
                         Cheap and simple external components
                         Very wide input voltage range
                         (16V~400V or higher)
                         Stable LED current over wide input
                         voltage range with high PF support
                         Works with standard series drum choke
                         inductors
                         Support OVP & OCP
                         Small PCB to to fit GU10, E17…..



                                                                     23
RT8459 typical application circuit




                                     24
RT8459 test result with universal input

                                8459 Vout=44V//200mA/15LEDs

Vin.ac (V)   Vo (V)   Io (mA)     Pin (W)   Po (W)    PF      Eff. (%)   current offset (%)

   90        43.33     194          9.3      8.41    0.980     90.39          -1.02%

   110       43.37     196         9.26      8.50    0.981    91.80           0.00%

   130       43.35     195         9.19      8.45    0.985     91.98          -0.51%

   180       43.31     191         9.03      8.27    0.972     91.61          -2.55%

   220       43.36     194         9.23      8.41    0.955    91.14           -1.02%

   264       43.41     196         9.42      8.51    0.932     90.32          0.00%




  ** Good line regulation for universal input with high PF support
  ** NOTED: Higher output current ripple & big output cap. for PFC single stage
  design                                                                                      25
How to choose the driving topology?

                   NO
  Need PFC?                   RT8458 typical application


 Small output      NO
                              RT8459 typical application
 current ripple?




                   Valley-fill PFC+RT8458 good for small power, PF in 0.7~0.9



                   Active PFC + RT8458, good for high power design or PF>0.9


                                                                                26
DC to CC Solution



                    27
Richtek’s Product -- DC to Constant Current

 Converter     RT8450B      RT8453B      RT8470   RT8471


 Controller     RT8452       RT8482      RT8480   RT8488



• Application
 •   MR16, AR111
 •   Street light, Desk light, Freeze light
 •   Car light, Projector lamp
 •   Solar lighting, Emergency light



                                                           28
Richtek’s Product -- DC to Constant Current

• Richtek advantage
 • Cover wide input/output voltage range and support different
   kinds of topology include buck, boost, buck-boost, SEPIC
 • Accurate output current over wide temperature range
 • Stable output current vs. input/output voltage change
 • Easy Dimming : Analog, PWM or PWM Converting to Analog
   with One External Capacitor, Triac dimming
 • Support high-speed PWM dimming up to 50kHz
 • Better reliability with bipolar process
 • Cost competitive



                                                                 29
Selection Guide for DC to CC Products
                                    DC Input to Constant Current
                                                                   Max
                                                LED current per   Efficie    LED
Part Number        Vin(V)         Max Vout(V)                                           Topology
                                                  string (mA)      ncy      String
                                                                   (%)

                                                                                     Buck,Boost,Buck-
 RT8450A      4.5~40+Zener drop       50           UP to 1.5A      > 95       1
                                                                                          Boost

                                                                                     Buck,Boost,Buck-
 RT8450B      4.5~40+Zener drop       50           UP to 1.5A      > 95       1
                                                                                          Boost

                                                                                     Buck,Boost,Buck-
  RT8452      4.5~36+Zener drop       48        External MOSFET    > 95       1
                                                                                          Boost

  RT8453           4.5~40             38           UP to 1.5A      > 95       1           Buck

                                  Limited by
  RT8480      4.5~40+Zener drop    external     External MOSFET    > 93       1        Boost, SEPIC
                                   MOSFET

                                                                                     Buck,Boost,Buck-
  RT8482      4.5~36+Zener drop       48        External MOSFET    > 95       1
                                                                                          Boost

  RT8470            7~30              28           UP to 1A        >95        1           Buck
  RT8488      7~36+Zener drop     Limited by    External MOSFET    >92        6           Boost
                                   external
                                   MOSFET
                                                                                                        30
Applications



               31
Applications: MR16
• Major solutions
 •   RT8470 low cost solution
     • Lowest cost solution
     • About 70% Electronic Transformer (ET) compatibility
     • Different brightness with different ET connected
     • Very popular in China
 •   RT8453 high ET compatibility solution
     • Very high ET compatibility
     • Keep same brightness with different ET connected
• Special applications
 •   RT8453 dimmable solution
     • Dimmable with minor cost added from the previous solution
     • Same performance as the previous solution without dimmer connected
     • ET limited
     • With selected ET, about 50% dimmer can dim pretty well
 • RT8453 non electrolytic cap solution
     •   High ET compatibility with square wave output
 • RT8453 three-step dimming
     •   Support three-step dimming with three-step dimming controller added   32
     •   Use ON/OFF break to switch between three steps
Application: MR16 (RT8470 BUCK---a typical low cost design)




                                                              33
MR16—RT8470 Buck




 CH1: Vin                                           CH1: LED voltage
            Average LED current will be different
 CH4: Iin   with different ET connected             CH4: LED current
                                                                       34
Application: RT8453 MR16

 Excellent electronic transformer compatibility
 High efficiency, stable output LED current
 Support Triac dimming with selected ET and
 Dimmer but no extra cost added
 No flicker with most of the ET




                                                   35
Application: RT8453 MR16




 CH1: Vin                                            CH1: LED voltage
            Very stable LED current with different
 CH4: Iin   ET connected                             CH4: LED current
                                                                        36
Applications: Street Light (I)

         PFC
            +
 AC                                    RT8454
        AC2DC
Power
                                                     ….
        Primary
          Side                       Vbase
         Circuit                                     6 CHs

                                     Opto

                              Vaux                  6 Current
                                             FBx6
                                                    Sources
                                             Gx6
                        MCU          Dim
                                             CSx6
                                                    ….
                    Other
                   Control    NTC
                   Signals
                             Sense LED Temp.
                                                                37
 Applications : Street Light (II)

    AC Power              DC 12V~48V


                                             RT8488
  PFC AC2DC

(Either one or both)
                                 Vaux
                                           Gbias
                                                   Gate    ….
                                                           6 CHs
                             MCU                 Sense
    LiFePO3
    Batteries                              Dim

                        Other                             6 Current
                                                   FBx6
                       Control                            Sources
                                   NTC
                                                   Gx6
    Solar Cell         Signals
                                   Sense
                                                   CSx6
                                                          ….
                                    LED
                                   Temp.


                                                                      38
Applications : Street Light (III)

     AC Power           DC 12V~48V

                                                RT8480
   PFC AC2DC
                                                                    Up to
                              Vaux                    Gate        40xLEDs
 (Either one or both)                         Gbias                (160V)
                                                    Sense
     LiFePO3
     Batteries
                           MCU                Dim
                                                    PWMO     Dimming
     Solar Cell          Other      Thermal           IFB
                        Control    Feedback                  Current FB
                        Signals
                                   NTC

                                  Sense LED Temp.
                                                                            39
Application: Thermal protection




                                  40
Selection guide



                  41
LED Lighting Selection Guide Sorted by Application

                             LED Lighting Selection Guide Sorted by Application
Application                      Topology                       Richtek Solution
Solid-State Lighting AC or DC Input
MR16                             Buck, Buck-Boost, Boost        RT8450B,RT8482,RT8453, RT8470
AR111                            Boost                          RT8450B,RT8482
GU10, E27,PAR30,PAR38            Flyback, non-isolated          RT8458, RT8456, RT8457
Office Lamp                      Boost, Flyback, non-isolated   RT8450B,RT8482, RT8456, RT8458
Decoration Light                 Boost                          RT8450B,RT8482
Street Light, Solar Light        Buck, Boost, flyback           RT8450B,RT8482,RT8488,RT8454
Emergency Light                  Boost                          RT8450B,RT8482
T5, T8 Light Bar                 Flyback, non-isolated          RT8456, RT8457, RT8458
RGB Light                        Buck                           RT8453, RT8470
Freeze Light                     Buck, Flyback, non-isolated    RT8450B,RT8453, RT8456, RT8470, RT8458
Projector                        Synchronous Buck               RT8452
Automotive Application
Interior Light                   Buck, SEPIC, Buck-Boost        RT8450B,RT8482, RT8488, RT8480
Exterior Light                   Buck, SEPIC, Buck-Boost        RT8450B,RT8482, RT8488, RT8480
Automotive Light                 Buck, SEPIC, Buck-Boost        RT8450B,RT8482, RT8488, RT8480           42
http://www.richtek.com/LED

				
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