Download Harmonic Current - Renesas e

Increasing the Performance of PFC and
LED Driver Applications
Renesas Electronics America Inc.
© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Technology & Solution Portfolio
2
© 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
3
© 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.*
*
4
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)
5
© 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
6
© 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
7
© 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!
8
© 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
9
© 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
10
© 2012 Renesas Electronics America Inc. All rights reserved.
Why Replace Incandescent and CFL Bulbs?
 Efficiency
 Lifetime
 Maintenance Costs
•Online e-conolight.com brochure
11
© 2012 Renesas Electronics America Inc. All rights reserved.
Why Replace Incandescent and CFL Bulbs?
 Efficiency
 Lifetime
 Maintenance Costs
 From EDN Joke Contest
12
© 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.
13
© 2012 Renesas Electronics America Inc. All rights reserved.
Why Replace Incandescent and CFL Bulbs?
14
© 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.
15
© 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
16
© 2012 Renesas Electronics America Inc. All rights reserved.
Efficiency
 Efficiency = Useful Power Output / Total Power consumed
Often and herein denoted by Greek symbol h
17
© 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
18
© 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?
19
© 2012 Renesas Electronics America Inc. All rights reserved.
Non-Linear Loads
 Non-linear load: The current flow is non-proportional to the
applied voltage.
20
© 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!
21
© 2012 Renesas Electronics America Inc. All rights reserved.
Real Power
V(t)
PAC (Watts) =
22
© 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
23
© 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
24
© 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)
25
© 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
26
© 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)…
27
© 2012 Renesas Electronics America Inc. All rights reserved.
Total Harmonic Distortion
 Harmonic current: Total harmonic distortion quantifies the
magnitude of the harmonics:
39
THD 
28
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
29
© 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
30
© 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
31
© 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
32
© 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
33
© 2012 Renesas Electronics America Inc. All rights reserved.
Agenda






34
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







35
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
36
© 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
37
© 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
38
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)
39
© 2012 Renesas Electronics America Inc. All rights reserved.
Hi-Side Drive Merits are Efficiency and Cost
40
© 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
41
© 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
42
© 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
43
© 2012 Renesas Electronics America Inc. All rights reserved.
t[s]
As inductor value changes,
LED current isn’t pronounced
Complete Circuit Implementation
44
© 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.
45
© 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
46
© 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
47
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
48
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
49
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
50
© 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
51
© 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
52
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
53
© 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
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.
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
56
© 2012 Renesas Electronics America Inc. All rights reserved.
Questions?
57
© 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
58
© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Electronics America Inc.
© 2012 Renesas Electronics America Inc. All rights reserved.