Increasing the Performance of PFC and LED Driver Applications Tad Keeley Sr. Marketing Director Class ID: AC04B Renesas Electronics America Inc. © 2012 Renesas Electronics America Inc. All rights reserved. Tad Keeley : Sr. Marketing Director Renesas Electronics America Senior Marketing Director for Analog and Power 12 years with Renesas in Marketing roles for non-MCU products 7 prior years in Semiconductor Process Engineering BA Physics from Reed College MBA Stanford GSB 2 © 2012 Renesas Electronics America Inc. All rights reserved. Renesas Technology & Solution Portfolio 3 © 2012 Renesas Electronics America Inc. All rights reserved. Discrete and Integrated Power Products 30V-1500V in Application Optimized Processes Low voltage family optimized for x Rds(on)LCDs LEDQgd Backlight Separate family optimized for pure Rds(on) performance 600V Super Junction MOSFETs for SMPS 300V-1350V Discrete Devices Class-leading turn-off loss High-speed, short-circuit rated, and low Vce(on) optimized using thin wafers Multiple package options and bare die option available Broad Line-up of Packages and Devices Current ratings from 0.8A to 30A rms Voltage ratings from 600V to 1500V Junction temperature to 150°C 4 © 2012 Renesas Electronics America Inc. All rights reserved. SiC, Fast Recovery, SBD and Others SiC Schottky barrier diodes for very high switching speeds 3A to 30A, 600V parts available SBD optimized for high switching speeds Optimized for Highest Efficiency & Compactness Dr MOS solutions for > 93% peak efficiency, up to 1.5MHz PFC ICs for solutions up to 98% peak efficiency Smallest CSP packages for POL, Battery Charger and Fuel Gauge Applications ‘Enabling The Smart Society’ Challenge: Enable LED’s to reduce energy consumption towards lighting. The US has an installed base of 5 billion bulbs. These are primarily either incandescent or compact fluorescent Together, these consume 18% of total US electricity! LED retrofitting should reduce the energy requirement by half.* * 5 DOE Estimates by 2030 © 2012 Renesas Electronics America Inc. All rights reserved. ‘Enabling The Smart Society’ Challenge: Designing efficient LED supplies presents circuit challenges: Compact conversion of AC line power to DC Efficiency > 85% PF > 0.9 Stringent harmonics, ripple, dimming, reliability and cost requirements. •Example from Lamp-wallpaper.com (vendor unknown) 6 © 2012 Renesas Electronics America Inc. All rights reserved. ‘Enabling The Smart Society’ Solution: Renesas extends PFC product family for LED applications to develop single stage PFC buck circuit using a hi-side switch to replace incumbent low side switch topologies to improve performance across the requirement spectrum 7 © 2012 Renesas Electronics America Inc. All rights reserved. Agenda LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch improves upon incumbent topologies Results and data Summary Q&A 8 © 2012 Renesas Electronics America Inc. All rights reserved. What is the Retrofit Market? & Replace this And this With these The US has 5 billion light bulbs installed, and about 2 billion light bulbs are sold in the US each year! 9 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Efficiency LED in Development ‘10 LED 2007 - 2010 CFL 27 – 40 W CFL 5 – 26 W Standard Incandescent •IESNA Lighting Handbook, Ninth Edition p 26-3 and Wikipedia 10 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Efficiency Lifetime 25K hours per LED How many incandescent and CFL bulbs to reach 25K hours? Incandescents 1K hours per CFLs 10K hours per LED 25K hours per •OSRAM Online Study 4.08.2009 11 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Efficiency Lifetime Maintenance Costs •Online e-conolight.com brochure 12 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Efficiency Lifetime Maintenance Costs From EDN Joke Contest 13 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Efficiency Lifetime Maintenance costs Regulatory compliance Energy Independence and Security Act of 2007 ● Requires ~ 25 percent more efficiency for household light bulbs. ● Effectively phases out household incandescent bulbs (but not CFL’s and specialty lamps) . ● Was signed by then President Bush in 2007. 14 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? 15 © 2012 Renesas Electronics America Inc. All rights reserved. Why Replace Incandescent and CFL Bulbs? Question: Why regulate power factor for LED lighting down to 25W, when other equipment less than 75W is exempted from Power Factor regulations? Answer: Related to the 5B Bulbs installed in the US, 18% of US electricity consumption; each US households averages 40 active bulbs, so in aggregate low PF LEDs will contribute a lot of harmonic current to the AC lines in even residential buildings. 16 © 2012 Renesas Electronics America Inc. All rights reserved. Agenda LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch improves upon incumbent topologies Results and data Summary Q&A 17 © 2012 Renesas Electronics America Inc. All rights reserved. Efficiency Efficiency = Useful Power Output / Total Power consumed Often and herein denoted by Greek symbol h 18 © 2012 Renesas Electronics America Inc. All rights reserved. Linear Loads Linear load: A load in which a sinusoidal voltage draws a sinusoidal current with the same frequency. Examples Resistor: V= I*R Resistive Loads – Incandescent Bulb – Electric Heater 19 © 2012 Renesas Electronics America Inc. All rights reserved. Linear Loads Question: Resistive loads, defined by Ohm’s law, are clearly, linear. How about purely inductive or capacitive load, is it linear as well? 20 © 2012 Renesas Electronics America Inc. All rights reserved. Non-Linear Loads Non-linear load: The current flow is non-proportional to the applied voltage. 21 © 2012 Renesas Electronics America Inc. All rights reserved. Linear Loads Question: Resistive loads, defined by Ohm’s law, are clearly, linear. How about purely inductive or capacitive load, is it linear as well? Answer: Yes! 22 © 2012 Renesas Electronics America Inc. All rights reserved. Real Power V(t) PAC (Watts) = 23 © 2012 Renesas Electronics America Inc. All rights reserved. R Vrms * Irms = I2rms*R Reactive Power V(t) L R = Zero Ohms. So real power transfer is zero, instead the circuit has a reactive power. Q= I2rms* Z Units = Volt * Amperes Reactive Common Reactive Components Q 24 © 2012 Renesas Electronics America Inc. All rights reserved. Apparent Power Apparent Power (S) = volt*amperes = I2Z Reactive Power (Q) = volt*amperes reactive = I2(XL-XC) Q Real Power (P) = Watts = I2R 25 © 2012 Renesas Electronics America Inc. All rights reserved. Power Factor: Incomplete Definition Power factor = Real Power / Apparent Power = COS (Q) Apparent Power (S) Reactive Power (Q) Q Real Power (W) 26 © 2012 Renesas Electronics America Inc. All rights reserved. Power Factor: Incomplete Definition Non-linear load example: SMPS. The angle between V & I is zero, so PF = COS ( 0 ) = 1 ? Wrong: In fact we need another term, THD, to the PF equation 27 © 2012 Renesas Electronics America Inc. All rights reserved. Harmonic Current Harmonic current: Harmonic currents are integer multiples of the fundamental frequency (e.g. 60 Hz in the US). Harmonic currents are created by non-linear loads. by converting the signal on the fundamental supply frequency. 120 Hz (2nd harmonic), 180 Hz (3rd harmonic), 240 Hz (4th harmonic)… 28 © 2012 Renesas Electronics America Inc. All rights reserved. Total Harmonic Distortion Harmonic current: Total harmonic distortion quantifies the magnitude of the harmonics: 39 THD 29 2 I n 3 I1 © 2012 Renesas Electronics America Inc. All rights reserved. I1: RMS value of AC current fundamental In: RMS value of AC current nth harmonic Waveform Distortion by Harmonic Currents AC voltage (sinusoidal) This current wave is distorted by odd order (3rd, 5th, 7th…) harmonic current PF << 1 Harmonic current [A] AC current 6 5 Fundamental = 50 Hz 4 3 2 1 0 3rd 5th 7th 9th (150 Hz) (250 Hz) (350 Hz) (450 Hz) Order of harmonic current 30 © 2012 Renesas Electronics America Inc. All rights reserved. A Complete Power Factor Definition Power factor, a complete definition: Power Factor (PF) = Real Power / Apparent Power = COS (Q) * Irms(fundamental) / Irms = COS (Q) * 1/(1+THD)2 31 © 2012 Renesas Electronics America Inc. All rights reserved. Example: Incandescent Light Bulb +100 V AC voltage (AC 100 V) -100 V In phase & Proportional +0.5 A AC current (AC 0.5 A) -0.5 A Power Factor = 1 32 © 2012 Renesas Electronics America Inc. All rights reserved. Example: Incandescent Light Bulb with Dimmer AC current controlled With a dimmer, even an incandescent bulb PF << 1 by dimmer 33 © 2012 Renesas Electronics America Inc. All rights reserved. LED Characteristics I*V curve for a diode: For bright LED’s On voltage will be ~ 3.3V Intensity will be ~ 60 lm/Watt – Compare to ~ 20lm/W for an incandescent bulb Intensity will, approximately, scale linearly with current •Drawing from Wikipedia 34 © 2012 Renesas Electronics America Inc. All rights reserved. Agenda 35 LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch Results and data Summary Q&A © 2012 Renesas Electronics America Inc. All rights reserved. LED Drive Requirements for Retrofit Market 36 h > 85% PF > 0.9 THD < 20% Leading Edge Dimming Compatibility Trailing Edge Dimming Compatibility Maintenance Costs Regulatory Compliance © 2012 Renesas Electronics America Inc. All rights reserved. LED Driver Circuit Background Common LED drive circuits combine CRM PFC function With a low-side MOS Gate Drive circuit filter Driver IC Buck-boost low side 37 © 2012 Renesas Electronics America Inc. All rights reserved. LED Driver Circuit Background PFC operation is CRM di(t)= v(t) dt L filter Vac Iac IL Ton Toff IC Buck-boost low side GD Ramp level shift COMP RAMP Gate off timing 38 © 2012 Renesas Electronics America Inc. All rights reserved. LED Driver Circuit Background An alternate is high side gate drive (High side driver IC will float versus ground, and be more susceptible to noise.) Gate di(t)= R2A20135 v(t) dt L Vac Iac IL Ton Toff GD Gate Gate Drive ramp Ramp level shift COMP RAMP Amplifier Gate off timing Phase compensation 39 Smoothing Peak current © 2012 Renesas Electronics America Inc. All rights reserved. Hi-Side Drive Merits are Efficiency and Cost di(t)= v(t) dt L Vac Iac IL Ton Toff GD Ramp level shift COMP RAMP Gate off timing VL = L* (di/dt) 40 © 2012 Renesas Electronics America Inc. All rights reserved. Hi-Side Drive Merits are Efficiency and Cost 41 © 2012 Renesas Electronics America Inc. All rights reserved. Hi-Side Drive Merit includes Current Precision High side drive has more precise current accuracy MOS low-side drive MOS high-side drive MOS Current Driver MOS Current f IC Driver IC Diode Current Diode Current Only MOS current Controlled by CS resistor !!! Diode current I[A] Both MOS current and Diode current Controlled by CS resistor !!! MOS current Diode current I[A] 10% 6% t[s] As inductor value changes, LED current changes 42 © 2012 Renesas Electronics America Inc. All rights reserved. t[s] As inductor value changes, LED current isn’t pronounced Hi-Side Drive Merit includes Current Precision High side drive has more precise current accuracy Question: What typical circumstance may change the inductance value? Answer : Temperature change. L = m0mrN2A / l m0 permeability of free space mr rel permeability of core N = number of turns A = cross section of coil l = length of coil 43 © 2012 Renesas Electronics America Inc. All rights reserved. Hi-Side Drive Merit includes Current Precision High side drive has more precise current accuracy MOS low-side drive MOS high-side drive MOS Current Driver IC Driver MOS Current IC Diode Current Diode Current Only MOS current Controlled by CS resistor !!! Diode current I[A] 10% Both MOS current and Diode current Controlled by CS resistor !!! MOS current Diode current I[A] Better! 6% t[s] As inductor value changes, LED current changes 44 © 2012 Renesas Electronics America Inc. All rights reserved. t[s] As inductor value changes, LED current isn’t pronounced Complete Circuit Implementation 45 © 2012 Renesas Electronics America Inc. All rights reserved. Power Factor Tradeoff Considerations Power Factor improvement options Reduce input capacitor to decrease charge current pulse Reduce VF (load) to decrease zero conduction period length. 46 © 2012 Renesas Electronics America Inc. All rights reserved. Agenda LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch improves upon incumbent topologies Results and data Summary Q&A 47 © 2012 Renesas Electronics America Inc. All rights reserved. Circuit Performance: Power Factor Higher than 0.9 over a 90Vac to 132Vac input range Vac vs PF 1.00 0.95 0.90 PF>0.9 0.85 PF 0.80 0.75 0.70 0.65 0.60 0.55 0.50 80 48 90 100 © 2012 Renesas Electronics America Inc. All rights reserved. 110 Input voltage[Vac] 120 130 140 Circuit Performance : Efficiency Higher than 85% over a 90Vac to 132Vac input range Vac vs Efficiency(η) R13=12kΩ R13=100kΩ 100 95 90 85 η>85% η[%] 80 75 70 65 60 55 50 80 49 90 100 © 2012 Renesas Electronics America Inc. All rights reserved. 110 Input voltage[Vac] 120 130 140 Circuit Performance: THD Under 20% over a 90V to 132Vac input range Vac vs THD 50 45 40 THD[%] 35 30 25 THD<20% 20 15 10 5 0 80 50 90 100 © 2012 Renesas Electronics America Inc. All rights reserved. 110 Input voltage[Vac] 120 130 140 Circuit Performance : Leading Edge Dimming Dimming from nearly 0% to 100% with 100 to 120 Vac Dimmer type WN575159(Panasonic denko 500VA) Leading dimmer AC100V AC110V AC120V 0.25 Bridge Voltage T2 T1 Iout [A] 0.20 0.15 0.10 time ratio[%] = 100×(T2/T1) 0.05 0.00 0 51 © 2012 Renesas Electronics America Inc. All rights reserved. 10 20 30 40 50 time ratio [%] 60 70 80 90 Circuit Performance : Trailing Edge Dimming Dimming from 4% to 100% with 100 to 120 Vac Dimmer type DVELV-300P(LUTRON 300W) Min-Max of time ratio is the operation range of dimmer control 調光特性 AC100V AC110V AC120V 0.25 Bridge Voltage T2 T1 Iout [A] 0.20 0.15 10% - 100% area 0.10 time ratio[%] = 100×(T2/T1) 0.05 4% 0.00 0 52 © 2012 Renesas Electronics America Inc. All rights reserved. 10 20 30 40 50 time ratio [%] 60 70 80 90 Demo Board Line-up 調光特性 AC100V AC110V AC120V 0.25 Bridge Voltage T2 T1 Iout [A] 0.20 0.15 0.10 10% - 100% area time ratio[%] = 100×(T2/T1) 0.05 Improvement in design efficiency, inventory management cost reduction. *Input range : 90 to264V *PF>0.9 within 90 to264V *efficiency>85% within 90 to264V *Iout ripple<30% within 90 to264V *THD<30% within 90 to264V 53 High efficiency 4% dimmable solution. *Input range : 90 to132V 0.00 *PF>0.90 10 20 30 40 50 *efficiency>85% time ratio [%] *Iout ripple<30% *THD<30% © 2012 Renesas Electronics America Inc. All rights reserved. Improvement in design efficiency, inventory management cost reduction. *Input 60 range 70 : 9080to264V 90 *PF>0.97 within 90 to264V *efficiency>81% within 90 to264V *Iout ripple<30% within 90 to264V *THD<30% within 90 to264V Agenda LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch improves upon incumbent topologies Results and data Summary Q&A 54 © 2012 Renesas Electronics America Inc. All rights reserved. Summary Potential benefits of LED retrofit lighting include Halving US energy consumption for lighting Reducing maintenance costs by 80%+ Design challenges of LED retrofit lighting include Meeting PF regulatory requirements Meeting size and efficiency constraints Achieving compatibility with existing dimmers PFC with driver for high side switch is an excellent solution Has inherent efficiency and cost advantages Enables excellent dimming performance Meets PF requirements 55 © 2012 Renesas Electronics America Inc. All rights reserved. Summary Potential benefits of LED retrofit lighting include Halving US energy consumption for lighting Reducing maintenance costs by 80%+ Design challenges of LED retrofit lighting include Meeting PF regulatory requirements Meeting size and efficiency constraints Achieving compatibility with existing dimmers PFC with driver for high side switch is an excellent solution Has inherent efficiency and cost advantages Enables excellent dimming performance Meets PF requirements 56 © 2012 Renesas Electronics America Inc. All rights reserved. Agenda LED retrofit opportunity and requirements Pertinent terms and definitions Single stage PFC buck circuit with high side switch improves upon incumbent topologies Results and data Summary Q&A 57 © 2012 Renesas Electronics America Inc. All rights reserved. Questions? 58 © 2012 Renesas Electronics America Inc. All rights reserved. ‘Enabling The Smart Society’ Challenge: Enable LED’s to reduce energy consumption towards lighting by meeting circuit challenges. Today lighting consumes 18% of total US electricity! LED retrofitting should reduce the energy requirement by half. Design challenges for size, efficiency, PF, cost must be overcome. Solution: Renesas extends PFC product family for LED applications to develop single stage PFC buck circuit using a hi-side switch to replace incumbent low side switch topologies to improve performance across the requirement spectrum 59 © 2012 Renesas Electronics America Inc. All rights reserved. Please Provide Your Feedback… Please utilize the ‘Guidebook’ application to leave feedback or Ask me for the paper feedback form for you to use… 60 © 2012 Renesas Electronics America Inc. All rights reserved. Renesas Electronics America Inc. © 2012 Renesas Electronics America Inc. All rights reserved.