Transcript AC04B_TadKeeley_LEDPFC_finalx - Renesas e

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
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Renesas Technology & Solution Portfolio
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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
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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.*
*
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DOE Estimates by 2030
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‘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)
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‘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
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© 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
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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!
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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
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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
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Why Replace Incandescent and CFL Bulbs?
 Efficiency
 Lifetime
 Maintenance Costs
•Online e-conolight.com brochure
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Why Replace Incandescent and CFL Bulbs?
 Efficiency
 Lifetime
 Maintenance Costs
 From EDN Joke Contest
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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.
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Why Replace Incandescent and CFL Bulbs?
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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.
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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
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Efficiency
 Efficiency = Useful Power Output / Total Power consumed
Often and herein denoted by Greek symbol h
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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
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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?
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Non-Linear Loads
 Non-linear load: The current flow is non-proportional to the
applied voltage.
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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!
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Real Power
V(t)
PAC (Watts) =
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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
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Apparent Power
Apparent Power (S)
= volt*amperes = I2Z
Reactive Power (Q)
= volt*amperes reactive
= I2(XL-XC)
Q
Real Power (P) = Watts = I2R
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Power Factor: Incomplete Definition
 Power factor = Real Power / Apparent Power = COS (Q)
Apparent Power (S)
Reactive Power (Q)
Q
Real Power (W)
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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
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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)…
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Total Harmonic Distortion
 Harmonic current: Total harmonic distortion quantifies the
magnitude of the harmonics:
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THD 
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2
I
n
3
I1
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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
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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
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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
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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
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Example: Incandescent Light Bulb with Dimmer
AC current controlled
With a dimmer, even an incandescent
bulb PF << 1
by dimmer
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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
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Agenda






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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







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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
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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
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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
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Smoothing Peak current
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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)
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Hi-Side Drive Merits are Efficiency and Cost
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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
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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
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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
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t[s]
As inductor value changes,
LED current isn’t pronounced
Complete Circuit Implementation
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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.
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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
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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
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90
100
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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
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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.
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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
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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
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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
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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
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*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…
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© 2012 Renesas Electronics America Inc. All rights reserved.