Download What is Power Factor? - Renesas E

Power Factor Correction –
Why and How?
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.
Microcontroller and Microprocessor Line-up
2010
2013
1200 DMIPS, Superscalar
32-bit
 Automotive & Industrial, 65nm
 600µA/MHz, 1.5µA standby
1200 DMIPS, Performance
 Automotive, 40nm
 500µA/MHz, 35µA deep standby
500 DMIPS, Low Power
 Automotive & Industrial, 90nm
 600µA/MHz, 1.5µA standby
165 DMIPS, FPU, DSC
 Industrial, 40nm
 242µA/MHz, 0.2µA standby
165 DMIPS, FPU, DSC
 Industrial, 90nm
 242µA/MHz, 0.2µA standby
8/16-bit
25 DMIPS, Low Power
 Industrial, 90nm
 1mA/MHz, 100µA standby
 Industrial & Automotive, 150nm
 190µA/MHz, 0.3µA standby
44 DMIPS, True Low Power
10 DMIPS, Capacitive Touch
 Industrial & Automotive, 130nm
 144µA/MHz, 0.2µA standby
 Industrial
Automotive, 130nm
Wide
Format&LCDs
 350µA/MHz, 1µA standby
3
Embedded Security, ASSP
© 2012 Renesas Electronics America Inc. All rights reserved.
Enabling the Smart Society
 Energy efficiency is key to a Smart Society
Energy
harvesting
Home
Automation
Smart
Metering
Industrial
Motors
 Power quality is key to efficient energy management
4
© 2012 Renesas Electronics America Inc. All rights reserved.
Agenda
 Market drivers for Power Factor Correction
 What is Power Factor and why do we need to correct it?
 Definition of Power Factor (PF)
 What causes PF degradation
 Impacts of bad PF on power distribution and billings
 How do we correct bad Power Factor?
 Basic PFC topologies
 Renesas PFC Solutions
 Analog and Digital Solutions
 Implementation with Renesas MCU and Analog & Power devices
 Summary
5
© 2012 Renesas Electronics America Inc. All rights reserved.
PFC Market Drivers
6
© 2012 Renesas Electronics America Inc. All rights reserved.
What Drives the PFC Market?
 Some energy is delivered but not used due to bad PF
 Consumers
 Some consumers are charged for energy they don’t use
 Power utilities
 Need to cover consumers who are not charged for bad PF
 Need to compensate by over-sizing:
– Distribution lines, Transformers, Energy production
 Harmonics can disrupt other consumers
 Government regulations
7
© 2012 Renesas Electronics America Inc. All rights reserved.
What is Power Factor?
Ammeter
Wattmeter
A
A
A
P
5.1 A
120V
60Hz
AC Motor
~
 Real Power:
P = 400 W (Watts)
 Apparent Power:
S = 120V x 5.1A = 612 VA (Volt Ampere)
 Power Factor:
PF = 400/612 = 0.653
8
400W
© 2012 Renesas Electronics America Inc. All rights reserved.
P (W )
PF 
S (VA)
What is Power Factor?
 Where did the power go?
P (W)
AC voltage
Inductive Load
φ
AC current
S’
φ
S (VA)
Displacement
P(W )
DPF 
S (VA)
Range: 0 – 1
Q(VAR): Reactive Power
DPF = 1 when Q = 0
9
© 2012 Renesas Electronics America Inc. All rights reserved.
DPF  cos 
Q (VAR)
What is Power Factor?
 Total Harmonic Distortion (THD)
 Non-linear loads distort original AC current
AC current
Distortion
AC voltage
φ
Displacement
39
THD 
I
3
I1
2
n
I1: RMS value of AC current fundamental
In: RMS value of AC current nth harmonic
 Total Power Factor
 Combination of Displacement Power Factor
(DPF) and Distortion Power Factor (THD)
10
© 2012 Renesas Electronics America Inc. All rights reserved.
TPF  DPF
1
1  THD 2
What causes PF degradation?
 Inductive loads store reactive power and cause current lag
 Non-linear loads with switching elements distort the
original AC current and introduce harmonics
 Total Power Factor
1
TPF  DPF
1  THD 2
 Bad PF:
TPF  1
11
© 2012 Renesas Electronics America Inc. All rights reserved.
Question 1
What causes PF degradation?
A. Resistive loads
B. Inductive loads
C. Capacitive loads
D. Non-linear loads
E. B, C, D
F. None of the above
12
© 2012 Renesas Electronics America Inc. All rights reserved.
Why Power Factor < 1 is bad?
 Reactive energy is not used to produce real power
 Utilities need to compensate by over sizing:
 Distribution lines
 Transformers
 Energy production
 Harmonic distortion can disrupt other consumers
13
© 2012 Renesas Electronics America Inc. All rights reserved.
Power Factor Correction
14
© 2012 Renesas Electronics America Inc. All rights reserved.
Power Factor Correction
AC current
AC voltage
φ
Displacement
 PFC makes the load look like a resistor!
 Need to control current to match the shape and phase of the
voltage
AC voltage
15
© 2012 Renesas Electronics America Inc. All rights reserved.
AC current
Power Factor Correction Methodologies
 Passive PFC
 Passive components to compensate for reactive energy loss
 Active PFC
 Active components to drive solid state switches with PWM
signals in combination with passive reactive components such as
inductors
+
-
16
© 2012 Renesas Electronics America Inc. All rights reserved.
Passive Power Factor Correction
 Passive PFC
 Control harmonic current using filter
 Expensive large high-current inductor
 No automatic adjustment for wider AC input power
 DC output varies with AC input voltage
17
© 2012 Renesas Electronics America Inc. All rights reserved.
Active Power Factor Correction
 Active PFC
 Input current is controlled to follow the shape and phase of
input AC voltage
Q
 Transistor Q is switched ON/OFF at a PWM rate
 Most common configuration – Boost converter
 Efficiency is affected by Q switching losses and diode recovery
18
© 2012 Renesas Electronics America Inc. All rights reserved.
Active PFC Topologies
 Critical Conduction Mode (CRM)
Rectified, unfiltered
AC voltage
Inductor ripple current
Average AC current
Q
 Q switched on when inductor current reaches zero
 Inductor ripple current - High
 Low power applications
 No recovery loss through diode
19
© 2012 Renesas Electronics America Inc. All rights reserved.
Active PFC Topologies
 Continuous Conduction Mode (CCM)
Rectified, unfiltered
AC voltage
Inductor ripple current
Average AC current
Q
 Q switched on before the inductor current reaches zero
 Inductor ripple current – Low
 High power applications
 Recovery loss through the diode
20
© 2012 Renesas Electronics America Inc. All rights reserved.
Implementation Example of Active CRM PFC
PFC Boost Converter
DC BUS
Rectified, unfiltered
AC voltage
Average AC current
Critical
Conduction
Mode
Timer
CMP+
A/D
Interlock
Internal
Vref
21
(CRM)
ANI0
Zero current
detection
TMX00
T1
TMX00
(PFC output)
PFC-ON
pulse width
MCU
© 2012 Renesas Electronics America Inc. All rights reserved.
PFC-off
pulse width
CMP+
(Zero current
detection)
Active PFC Topologies
 Single channel
120V
AC
D1
~
Q1
L1
Q1
C
IL1
PFC
Cb
 Two channel interleaved
D2
Q1
L2
120V
AC
Q2
D1
~
IL1
L1
Q1
C
PFC
Q2
Cb
IL2
IL1+IL2
 Reduced current ripple
22
© 2012 Renesas Electronics America Inc. All rights reserved.
Effect of High-frequency Switching
 Harmonics and inductor current ripple can disrupt other
consumers
 Regulation standards apply – IEC61000-2-2
L
120V
AC
~
C
C
L
Q
 Higher ripple current will require better filters with multiple
stages
23
© 2012 Renesas Electronics America Inc. All rights reserved.
Advantages of Interleaving
 Reduced current ripple
 Size and number of input filters can be reduced
 Size of inductors, capacitor, switching devices can be reduced
 Overall efficiency is increased
24
© 2012 Renesas Electronics America Inc. All rights reserved.
Interleaved PFC Versus Single Channel
 Single channel
 Inductor ripple current affects size of:
– Inductor, Bulk Capacitor and input EMI filter
 High current through IGBT/MOSFET cause conduction losses
 Two channel interleaved
 Two sets of smaller and less expensive components:
– Inductor, Diode, Capacitor and IGBT/MOSFET
 180° out of phase switching
– Inductor ripple currents cancel out each other
– Further reduction in bulk capacitor size and EMI filter
 Better efficiency due to reduced conduction losses
 Multiple interleaving can further reduce the size of components
25
© 2012 Renesas Electronics America Inc. All rights reserved.
Interleaved PFC versus Single Channel
 CCM topology for large power application (>300W)
26
Item
Single Channel
2-Ch Interleaved
Ripple current
Large
Small
Inductor
1 large
2 small (less $)
Transistor
1 large
2 small (less $)
Diode
1 large (SiC?)
2 small (less $)
Bulk capacitor
Large
Small
EMI filter
Large
Small
Efficiency
Good
Better
© 2012 Renesas Electronics America Inc. All rights reserved.







Typical Application - Motor Control and PFC
L
D
Fast
Recovery
Diode ( SiC)
3 Phase Inverter stage
C
3 Phase Motor
90 – 264
VAC
T
AC voltage,
DC voltage
current
PWM
PFC
Control
IC
27
© 2012 Renesas Electronics America Inc. All rights reserved.
Current,
voltage,
temperature,
OC-detection
MCU
PWM
Gate Driver
PWM
Speed,
Position
Digital PFC for Motor Control Inverter
L
D
Fast
Recovery
Diode ( SiC)
3 Phase Inverter stage
C
3 Phase Motor
90 – 264
VAC
T
AC voltage,
DC voltage
current
Current,
voltage,
temperature,
OC-detection
PWM
MCU
28
© 2012 Renesas Electronics America Inc. All rights reserved.
PWM
Gate Driver
PWM
Speed,
Position
Renesas PFC Solutions
Renesas offers a variety of analog and digital devices to support PFC
 Analog: PFC Controller ICs
 Single channel and interleaved
 CCM and CRM topologies
 Internal MOSFET/IGBT driver
 Digital: MCUs with integrated peripherals
 High performance CPU with FPU and 10ns flash access
 Internal PGAs and Comparators
 High-speed ADC with multiple S&H
 Fast over-current protection by hardware
 Fast interrupt response
29
© 2012 Renesas Electronics America Inc. All rights reserved.
Analog PFC Solutions
30
© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Offers Complete Analog PFC Solutions
 PFC Controllers
– CCM (Continuous Conduction Mode)
– CRM (Critical Conduction Mode)
 PFC Boost Switch
– Super Junction MOSFETs for high frequency (> 50 kHz), up to
2.5 kW
– High Speed, Low Vceon, IGBTs for lower frequency (< 40 kHz)
and above 2.5 kW
 PFC Boost Diode (SiC)
 Support and Collateral
 Datasheet
 Evaluation Boards
 Technical Support
31
© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Analog PFC Controller Solutions
CCM
CRM
32
Mode
Part #
Features
Interleaved
R2A20114
R2A20104
Small current ripple Server
Average SW noise
Air conditioner
More complex circuit Induction heating
Single
R2A20115
Large current ripple
Large SW noise
Simple circuit
Interleaved
R2A20132
R2A20118A
R2A20117
R2A20112
Small current ripple Air conditioner
Average SW noise
Plasma TV
More complex circuit PC
Office automation
Single
R2A20113
Large current ripple
Large SW noise
Simple circuit
© 2012 Renesas Electronics America Inc. All rights reserved.
Applications
Plasma TV
PC
Office automation
LCD monitor
AC adaptor
LCD projector
CCM Interleaved PFC Controllers
 2A20114/20104
 Phase drop control input
 Internal / external clock can be used
 20104 can use current transformer
Current transformers
33
© 2012 Renesas Electronics America Inc. All rights reserved.
CRM Interleaved PFC Controllers
 2A20132
 Phase drop control input
 OTC – prevents increase of switching frequency at light loads
— Increased efficiency at light loads
 Protection circuits: Brownout, ZCD pin opening
34
© 2012 Renesas Electronics America Inc. All rights reserved.
CCM Interleaved PFC Controllers
R2A20118/117/112
 Protection features
 ZCD open/short
 OCP timer latch
 RAMP charge
current
 Brownout
 Soft start
 Gate drivability
 VFB 1.5%
35
© 2012 Renesas Electronics America Inc. All rights reserved.
Digital PFC Solutions
36
© 2012 Renesas Electronics America Inc. All rights reserved.
PFC Control Functions
85 – 264VAC
PF > 0.9
400V DC
PFC Hardware
Gate
PWM
Inductor
ripple
current
VAC
VREF
37
© 2012 Renesas Electronics America Inc. All rights reserved.
OC/OV
Detection
VDC
PFC Controller
PFC Control Functions – Input/Output
Control function
Input
Output
Output voltage
Feedback voltage
Constant DC bus voltage
AC voltage range
AC voltage
Adjust to 85-264VAC
IGBT current
Inductor current
AC voltage
Over-current
Hardware protection
Over-voltage
Under-voltage
38
© 2012 Renesas Electronics America Inc. All rights reserved.
Inductor current
amplitude
Synchronize with AC
voltage phase
Disable IGBT gate
signals
Digital PFC for Motor Control Inverter
L
D
Fast
Recovery
Diode ( SiC)
3 Phase Inverter stage
C
3 Phase Motor
90 – 264
VAC
T
AC voltage,
DC voltage
current
PWM
Rx62T MCU
39
© 2012 Renesas Electronics America Inc. All rights reserved.
Current,
voltage,
temperature,
OC-detection
PWM
Gate Driver
PWM
Speed,
Position
Interleaved PFC Reference Design
Auxiliary
power
DC/DC converter
395V
3.8A
output
85-264
VAC input
Rx62T MCU
board
40
© 2012 Renesas Electronics America Inc. All rights reserved.
PFC
CH1
PFC
CH2
SIC
Diodes
Complete PFC Solution from Renesas
Diode:
RJS6005TDPP-EJ
(target)
IGBT:
RJH60F4DPK
IGBT:
RJH60F4DPK
RX62T/100pin
R5F562TAADFP
41
© 2012 Renesas Electronics America Inc. All rights reserved.
System Specification
1 MCU
R5F562TAADFP (RX62T)
(Flash: 256kB, RAM: 32kB, CLK: 100MHz, VCC: 5V )
2 Circuit system
Continuous Conduction Mode / 2-phase interleaved
3 Switching device
4 Input voltage
AC 85 to 264 V
5 Output voltage
DC 395 V
6 Maximum output current
3.8 A
7 Maximum output power
1.5 kW
8 PWM frequency
9 Efficiency
10 Power factor
42
IGBT (RJH60F4DPK: 600V/50A)
© 2012 Renesas Electronics America Inc. All rights reserved.
35 kHz / 1 phase x 2
> 96 %
> 0.96
PFC Controller System Block Diagram
PFC OUT
390V
RX62T
Multiplyer
INPUT
AC85～264V
×
Deviation
Voltage
Controller
Deviation
Current
Controller
Duty 1
Duty 2
Protection
Controller
ADC
10bit
Gate
Driver
PWM
Timer2
OUT2
Gate
Driver
CS1
ADC
12bit
+
VAC
OUT1
OCP
setting
-
Voltage
Reference
PWM
Timer1
CS2
FB
OVP
Setting
OSC
Controller
CLK:100MHz
CLK:50MHz
GND
HW
43
© 2012 Renesas Electronics America Inc. All rights reserved.
SW
Protection
Controller Implementation
CS1
CC1
GD1
CS2
CC2
GD2
VAC
VFB
CS1,2
VAC
VFB
CC1,2
VC
44
VC
- Current sensing Ch1,2
- AC Input voltage
- DC Output voltage
- Current controller 1,2
- Voltage controller
© 2012 Renesas Electronics America Inc. All rights reserved.
Control loops:
Two-stage IIR filter
Program Flow
Main
ADC conversion interrupt
Main
 Conversion start by GPT
Interrupt
10-Bit ADC
VAC
12-Bit ADC
CS
FB
ADC to voltage calculation
 Voltage reference calculation
Voltage controller
 Voltage IIR filter controller
Current controller
 Current IIR filter controller
PWM update
45
 Conversion complete interrupt
© 2012 Renesas Electronics America Inc. All rights reserved.
 GPT PWM duty update
RX62T MCU Resources Used
Signal name
46
MCU Peripheral
Pin Name
I/O
Resolution
Functions
GD1
GPT0
GTIOC0A-A
OUT
20ns
PWM for IGBT1 gate
GD2
GPT1
GTIOC1A-A
OUT
20ns
PWM for IGBT1 gate
VFB
12-Bit ADC0
AN000
IN
12bit
Output DC voltage sensing
CS2
12-Bit ADC0
AN001
IN
12bit
IGBT1 current sensing
CS2
12-Bit ADC0
AN002
IN
12bit
IGBT2 current sensing
VAC
10-Bit ADC
AN2
IN
10bit
Input AC voltage sensing
© 2012 Renesas Electronics America Inc. All rights reserved.
RX62T Peripherals used for PFC
RX 62T
390VDC
RX CPU
(100 MHz)
Flash up to 256KB
FPU
Data Flash 8KB
(30k times E/W)
Multiplier, Divider,
Multiply, Accumulate
~
IL2
GPT
16-bit PWM Timer GPT0
Ch 6&7
3-ph PWM
16-bit PWM Timer GPT1
47
CS1
0.02Ω
GD1
GD2
GD2
uPC844G2
16-bit PWM Timer GPT2
0.02Ω
16-bit PWM Timer GPT3
Ch 0
Hall / BEMF Input
16-Bit CMT
4 channel
Multi purpose timer
FB
uPC844G2
Ch 3&4
3-ph PWM
Ch 5
Dead-time compensation
uPC844G2
RAM 16KB
16-Bit MTU3
Ch 1&2
2 Encoder Inputs
IL1
12bit ADC
4-ch
3 PGA
3 Comp
x2
x2
10bit ADC
12-ch
© 2012 Renesas Electronics America Inc. All rights reserved.
CS2
CS1
VFB
VAC
CS2
Gate Drive, Synchronized ADC sampling
Average coil current 1
Duty set 1
IL1
uPC844G2
Timer count 1
VFB
FB
GD1
GD1
uPC844G2
IL2
CS1
CS1
0.02Ω
180deg phase shift
IGBT current 2
Average coil current 2
GD2
GD2
Duty set 2
uPC844G2
Timer count 2
0.02Ω
CS2
CS2
GD2
GD1 period
GD2 period
CS1 ADC sampling
CS2 ADC sampling
FB ADC sampling
48
© 2012 Renesas Electronics America Inc. All rights reserved.
Tn
Tn+1
Tn
Tn+2
Tn+1
Tn+2
Overvoltage Protection by Hardware
- Example of PFC and DC/DC converter
PFC-OUT
+5V
2MΩ
10k
PFC-FB
3.33V
18.56kΩ
OVP_PFC
PWM-OUT
20kΩ
5.1kΩ
2kΩ
PWM-FB
OVP_PWM
PFC-OUT
3.33V
* 2 POE0#
*1
PFC-GD1
MTIOC3B
RX62T
PFC-GD2
MTIOC4A
PWM-GD
MTIOC4B
R5F562TAADFP
* 1. Protection by external hardware
* 2. Protection by internal hardware by POE function
49
© 2012 Renesas Electronics America Inc. All rights reserved.
PWM-OUT
Feedback Signal Measurement by 12-Bit ADC
ADC unit 0
AN000/AN101
PGA
S/H
VCSPF1_IN
AN001/AN101
PGA
S/H
VCSPF2_IN
AN002/AN102
VAC_IN
AN003/AN103
PGA
S/H
Data Register 0
Multiplexer
VFBPF_IN
Data Register 1
ADC
Data Register 2
Data Register 3
 Three S&H for sensing currents and voltage for interleaved PFC.
 PGA (Programmable Gain Amp) with selectable gain
 1 usec conversion time per channel at AVCC0=AVCC=4.0 to 5.5V.
50
© 2012 Renesas Electronics America Inc. All rights reserved.
Implementation with General Purpose Timers
 4-Channels, 16-Bit counters, 100 MHz count clock
 Phase shifted operation – 180° for interleaved PFC
 Triangular wave with center aligned PWM
 ADC conversion start trigger by timer
AD trigger
CPU Interrupt
GTIOC0A-A/B
GPT0
GTIOC0B-A/B
AD trigger
CPU Interrupt
GPT1
GTIOC1B-A/B
GPT3
GTIOC3A
ON
OFF
ON
OFF
GPT1.GTCNT
GTCCRA1
GTIOC3B
POE3
CPU interrupt for POE
51
OFF
GTIOC2B-A/B
Output protect
CPU Interrupt
GTIOC0A-A
GTIOC2A-A/B
GPT2
AD trigger
GTCCRA0
GTIOC1A-A/B
AD trigger
CPU Interrupt
GPT0.GTCNT
© 2012 Renesas Electronics America Inc. All rights reserved.
GTIOC1A-A ON
OFF
1. GTPR0,1:
2. GTCCRA0,1:
ON
OFF
PWM frequency（35kHz)
PWM duty
ON
Example of PFC Control Trigger by GPT0
GPT0.GTCNT
Counter value
GTP0.GTPR
PFC Cycle
hhhh
ffff
eeee
dddd
cccc
bbbb
aaaa
Time
Register write
GTP0.GTCCRC
PFC Duty Cycle
Register write
ffff
Register write
dddd
Buffer transfer at crest
bbbb
hhhh
Buffer transfer at through
ffff
GTIOC0A output
PFC gate drive
GTADTRA
ADC Trigger
ADC conversion
start
PFC control start
52
ADC conversion
end
ADC conversion
end interrupt
∆t
© 2012 Renesas Electronics America Inc. All rights reserved.
Register write
PFC control end
dddd
Buffer transfer at crest
hhhh
CPU BW for Interleaved PFC: 32% @35KHz
Control loop processing:
9us
4.5us
PFC
control
timing
28us
GD1
53
© 2012 Renesas Electronics America Inc. All rights reserved.
(32%)
4.5us
AC Current Waveforms @1.5KW – 100V AC input
1.5KW @ 100V AC Input
Input AC voltage
Input AC current
Inductor current
Output voltage
ripple
54
© 2012 Renesas Electronics America Inc. All rights reserved.
Rx62G High Resolution PWM Timer
 Each GPT channel can generate HR-PWM for two outputs independently
 Minimum resolution is 1/32 of normal resolution:
 312.5psec @100MHz
rising
falling
 390.0psec @80MHz
GTDLYRA GTDLYFA
GTDBU
GTDVU
GTPBR
GTPR
High
resolution
Controller
GTCNT
AD
trigger
Comparator
CPU
Interrupt
GTADTRA GTADTRB GTCCRB
GTCCRA
GTADTBRA GTADTBRB GTCCRE
GTCCRC
GTCCRF
GTCCRD
GTADTDBRA
GTADTDBRB
CPU interrupts
Output protect
GTDBD
GTDVD
Output control Input control
GTPDBR
Comparator
input
GTTCRA GTTCRA
External
Trigger.
GTIOCA
PWM1
GTDLYRA
GTDLYFA
PWM2
POEx
15
Upper 16bit
4 Lower 5bit 0
0
+
GTDLYRA
GTTCRA
+
GTDLYFA
55
© 2012 Renesas Electronics America Inc. All rights reserved.
Question 2
 What PFC method is used in the Renesas digital reference
design?
A. Single-channel PFC in Critical Conduction Mode (CRM)
B. Single-channel PFC in Continuous Conduction Mode (CCM)
C. Dual-channel interleaved in Continuous Conduction Mode (CCM)
D. None of the above
56
© 2012 Renesas Electronics America Inc. All rights reserved.
Summary
 Market drivers for Power Factor Correction
 What is Power Factor and why do we need to correct it?
 Definition of Power Factor (PF)
 What causes PF degradation
 Impacts of bad PF on power distribution and billings
 How do we correct bad Power Factor?
 Basic PFC topologies
 Renesas PFC Solutions
 Analog and Digital Solutions
 Implementation with Renesas MCU and Analog & Power devices
57
© 2012 Renesas Electronics America Inc. All rights reserved.
Questions?
58
© 2012 Renesas Electronics America Inc. All rights reserved.
Enabling the Smart Society
 Energy efficiency is key to a Smart Society
Energy
harvesting
Home
Automation
Smart
Metering
Industrial
Motors
 Power quality is key to efficient energy management
59
© 2012 Renesas Electronics America Inc. All rights reserved.
Renesas Electronics America Inc.
© 2012 Renesas Electronics America Inc. All rights reserved.