Transcript MASTERs 07 Slide Template

11091 PS6
Advanced SMPS Applications
using the dsPIC®
DSC SMPS Family
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Class Objective

When you finish this class you will:
 Understand design considerations for a
High Power Converter
 Know how to implement digital control
loops using the dsPIC® DSC
 Understand the benefits of Digital Power
Conversion
 View a demonstration of the AC/DC
Reference Design
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Overview of the
AC/DC Reference
Design
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Overview of AC/DC
Reference Design


Total Output Power Rating of 350 W
Multiple DC Outputs:
 3.3V, 69A (max)
 5V, 23A (max)
 12V, 28A (max)

Universal Operating Voltage
 85V – 265V AC, 45-65 Hz

Digital PFC Implementation
 PF > 0.98
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Overview of AC/DC
Reference Design




Automatic Fault Handling
Flexible Start-up Capability
Remote Power Management
Capability
Full Digital Control
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
AC/DC Reference Design
Block Diagram
Isolation
Barrier
Rectified
Sinusoidal
Voltage
400Vdc
12Vdc
Phase Shift ZVT Converter
EMI Filter
and Bridge
Rectifier
PFC
Boost
Converter
ZVT
Full-Bridge
Converter
3.3Vdc
69A
Multi-Phase
Buck Converter
Synchronous
Rectifier
85-265Vac
45-65Hz
dsPIC
30F2023
© 2007 Microchip Technology Incorporated. All Rights Reserved.
OptoCoupler
11091 PS6
dsPIC
30F2023
5Vdc
23A
Single-Phase
Buck Converter
Slide
‹#›
dsPIC® DSC SMPS Features


30 MIPS MCU + DSP core
Intelligent Power Peripherals
 High Speed A/D: 10-bit, 2 MSPS
 High Resolution PWM – 1.05ns
 High Speed Analog Comparators






Internal Fast RC oscillator + PLL
Small footprint package - 6 x 6 mm
Flash-based controller
CodeGuard™ Security Enabled
Extended Temp (125°C) Operation
Additional Information in 11089_PS4
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
AC/DC Reference
Design Architecture
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Stage Architecture
Isolation
Barrier
Rectified
Sinusoidal
Voltage
EMI Filter
and Bridge
Rectifier
PFC
Boost
Converter
85-265Vac
45-65Hz
dsPIC
30F2023

AC/DC
ZVT
Synchronous
Full-Bridge
Reference
Rectifier
Converter
Design
OptoCoupler
3.3Vdc
69A
Multi-Phase
Buck Converter
5Vdc
23A
Single-Phase
Buck Converter
dsPIC
30F2023
Multi-stage design simplifies
design of each stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Stage Architecture
Rectified
Sinusoidal
Voltage
EMI Filter
and Bridge
Rectifier
Isolation
Barrier
PFC
Boost
Converter
3.3Vdc
69A
Multi-Phase
Buck Converter
ZVT
Full-Bridge
Converter
Synchronous
Rectifier
85-265Vac
45-65Hz
dsPIC
30F2023

OptoCoupler
dsPIC
30F2023
5Vdc
23A
Single-Phase
Buck Converter
Multiple Outputs and multiple
loads can be controlled
Independently
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Stage Architecture
Rectified
Sinusoidal
Voltage
EMI Filter
and Bridge
Rectifier
Isolation
Barrier
PFC
Boost
Converter
Single-Phase
Buck Converter
Single-Phase
Multi-Phase
Buck Converter
ZVT
Half-Bridge
Push-Pull
Full-Bridge
Converter
Converter
Synchronous
Full-Wave
Rectifier
3.3Vdc
69A
Single-Phase
Buck Converter
85-265Vac
45-65Hz
Single-Phase
Boost
Buck Converter
Converter
dsPIC
30F2023

OptoCoupler
5Vdc
23A
dsPIC
30F2023
Modular Architecture enables
swapping of stages with dropin topologies
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Choice of PFC Topology
v1
Buck Converter
S
+
ωt
L
i
D
v1
V2 < V1
C
+
v2
i1
-
ωt
-
0
V2 > V1
Buck-Boost Converter
v1
S
V2 < V1
D
+
v1
ωt
i
L
C
-
+
v2
ωt
0
-

i1
Buck and Buck-Boost Topologies operate with
discontinuous Current
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Why PFC Boost Converter?
V2 > V1
Boost Converter
L
v1
D
+
ωt
i
v1
S
C
+
v2
i1
-
ωt
0
-

Boost Converter operates with
continuous input current at high
loads
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Choice of Switching
Methodology
Hard Switching
Soft Switching
Fixed Frequency Operation
Variable/Fixed Frequency
Operation
Fewer Components Required
More Components Required
Simpler Control
Complex Control
High Switching Losses
Low Switching Losses
Used in Designs with Low
Power and Low Performance
Requirements
Used in Designs with High
Power and High Performance
Requirements
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Output Isolation and Safety
Requirements
Isolation
Barrier
Low Voltage
Output
High
Voltage
Input

dsPIC
30F2023
dsPIC
30F2023
Live Bias
Supply
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Output
Isolation is
provided by:
 Transformers
 Optocouplers
Isolated
Bias Supply
11091 PS6
Slide
‹#›
Considerations for Choice of
Architecture





Number of Stages
Choice of PFC Topology
Switching Methodology
Output Isolation requirements
Requirements of Output Stage
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Output Stage Requirements
Multi-Phase Synchronous
Buck Converter
Buck Converter
L
O
A
D
Synchronous
Buck Converter
L
O
A
D

Output Design Specifications
determine Choice of Converter
Topology
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Summary

Overview of AC/DC Reference
Design
 Design Specifications
 Features of dsPIC® DSC SMPS Family

AC/DC Reference Design
Architecture
 Block Diagram
 Rationale Behind Chosen Architecture
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Power Factor
Correction
Additional Information Available in 11092_PFC
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Why is PFC needed?





Reduce Peak Current Ratings
Reduce Component Overheating
Efficiently utilize available Power
Comply with Regulations
Avoid Penalties from Utility
Company
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
What is Power Factor ?
Un-utilized
power
Applied Voltage
Resulting Current
Φ
Φ
Applied Voltage
Resulting Current
Useful power
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›


Diode ON
Diode ON
Diode ON
Diode
OFF
With no Power Factor
Correction, the input
current is highly distorted
Induces Noise in the Power
Grid
Higher current rating
device is required
Diode
OFF

Diode
OFF
Power Factor Correction
Diode ON
Input Voltage
Output Voltage
AC
Input Current
Load
Current is not
sinusoidal
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Power Factor Correction
Iin
Vin
Boost
Circuit
Input Voltage
Vhb
AC
Load




Input Current
P.F. = Real (Active) component of Power/Total Power
Need to sense Vin, Inductor Current and Vhb
Maintains a Noise-free power grid
Reduce rms and peak current required by the system
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Forced
Sinusoidal input
current
Slide
‹#›
Common PFC Methods



Discontinuous
Current Mode
Input Current
Critical Conduction
Current Mode
Continuous
Current Mode
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Input Current
Input Current
11091 PS6
Slide
‹#›
PFC Boost Converter
Boost
Diode
PFC
Inductor
L1
Primary (Live) Side
D1
+HV_BUS
R4
R1
Vac
Q1
PWM1H
+
~
~
R2
-
C3
R5
C2
|VAC|
VHV Sense
Sense
R6
R3
C4
C1
LIVE_GND
Rsense
IPFC
sense
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
-HV_BUS
PFC
MOSFET
Slide
‹#›
PFC Control Scheme
Voltage
Reference
+
Voltage Error
Compensator
∑
X
|VAC|MEAN
Calculated
Current
Reference
Rectified
AC Mains
Voltage
+
∑
Vout
Current Error
Compensator
PFC
Choke
PWM
-
1
V2
Current
Feedback
Voltage Feedback
PFC
Current
sense
1011001010
1001011011
ADC
© 2007 Microchip Technology Incorporated. All Rights Reserved.
S&H
11091 PS6
VOUT
Sense
S&H
Slide
‹#›
Resources Required for Digital
PFC
IPFC
VHV_BUS
|VAC|
k1
k3
VAC
ADC
Channel
k2
FET
Driver
ADC
Channel
PWM
Output
ADC
Channel
dsPIC30F2023
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
PFC Resource Allocation
Signal Name
Type of
Signal
dsPIC® DSC
Resource Used
VOUT
Analog Input
AN5
IPFC
Analog Input
AN4
|VAC|
Analog Input
AN6
MOSFET Gate
Drive
Drive Output
PWM4L
Current Loop
Trigger
dsPIC® DSC
Internal Signal
PWM4 Trigger to
Sample PFC Current
Voltage Loop
Trigger
dsPIC® DSC
Internal Signal
Timer2
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
PFC Control Software
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
PFC Software Overview




ADC Conversions are initiated by the
PWM Trigger Feature
The Current Control Loop is
Executed in the ADC Interrupt
Routine
The Voltage Loop is Executed in a
Timer Interrupt
Faults are handled by the PWM
Module using the on-chip Analog
Comparators
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start

Initialization




© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Initialize PWM
Initialize ADC
Setup Timer
Configure
Interrupts
Initialize Control
Loop Variables
Slide
‹#›
Structure of the PFC Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize PWM
 Configure PWM Mode,
Output Polarity, Period,
initial Duty Cycle
 Setup PWM Faults and
Fault Thresholds
 Setup PWM Triggers
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize ADC
 Setup ADC Speed
 Configure desired
ADC channels as
analog inputs
 Choose ADC Trigger
Sources
 Configure ADC Data
Format
 Choose Simultaneous
or Sequential
Sampling
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start
Initialization

Configure Timer
 Use Timer to trigger
Voltage Control Loop

Setup Interrupts
 PWM Interrupt for
Fault Handling
 ADC Interrupt to
trigger Current Control
Loop
 Timer Interrupt to
trigger Voltage Control
Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start
Initialization

Initialize Control
Loop Variables
 Initialize PID Gain
Terms in X-memory
 Initialize Measured
signals in Y-memory
 Initialize pointers to
Control Loop Inputs
and Outputs
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start

Initialization
 Enable Timer
 Enable ADC
 Enable PWM
Enable Peripherals
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Enable
Peripherals
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start

Check for Faults

Initialization
Enable Peripherals


Fault
Presen
t?

© 2007 Microchip Technology Incorporated. All Rights Reserved.
Fault Loop

Fault
Loop

11091 PS6
The PWM Module is
setup to detect Faults
and Shutdown all
Outputs
The PWM Fault Interrupt
sets the Fault Flag
The Main Routine
Checks the Fault Flag
The Fault Indicator LED
is enabled
Any other Fault Handling
Routines can be placed
in this loop
Slide
‹#›
Structure of the PFC Software
Start

Initialization
 Input AC Voltage
Measurement
 Power Management
Routines
 Check Temperature
 Other Auxiliary
Features
Enable Peripherals
Fault
Presen
t?
Idle Loop
(Normal
Operation)
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Idle Loop
(Low Priority)
Fault
Loop
11091 PS6
Slide
‹#›
Structure of the PFC Software
Start

ADC Interrupt
(High Priority)

Initialization
PFC Current Loop

Enable Peripherals


Fault
Presen
t?
Idle Loop
(Normal
Operation)

Timer Interrupt
(Medium Priority)

Fault
Loop
PFC Voltage Loop


ADC Interrupt
PFC Current
Measurement
Current PID
Calculations
Update PWM Duty
Cycle

VOUT Measurement
Voltage PID
Calculations
Update PFC Current
Reference
Timer Interrupt
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Demonstration #1
Digital Power Factor
Correction
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Zero Voltage and
Zero Current Switching
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Zero Voltage Switching

Vds
At transition period from one state to
another state of the switch, the voltage is
zero, hence no losses
D
Vds(t)
G
Id(t)
S
Id
ZVS
t
PWM
t
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Switching Methodology

Zero Voltage Switching :
 Eliminates V*I losses in switching device
during transitions
 Reduces Noise in the system hence
better EMI performance
 Eliminates MOSFET output capacitor
(Coss) loss during switch Turn-ON
 Preferred in high voltage high power
system
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Zero Current Switching

At transition period from one state to
another state of the switch, current is
zero, hence no losses
Ir(t)
D
Vds(t)
G
Vds
S
ZCS
t
PWM
t
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Switching Methodology

Zero Current Switching:
 Eliminates V*I losses in switching device
during transitions
 Reduces Noise in the system hence
better EMI performance
 Can be implemented at switch Turn ON
as well as Turn OFF
 RMS Current through switch increases
and therefore higher conduction losses
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Soft Switching Topologies

 Zero Transition
Resonant Mode
 ZVT – Zero Voltage
 SRC – Series Resonant
Transition
 PRC – Parallel
Resonant
 LLC Resonant
Full Bridge ZVT
Converter
+Vin
+Vin
Series Resonant Half Bridge
Converter
PWM1H
PWM1L
LR
CR
T1
PWM1H
Vout
L1
PWM1L
Resonant
Circuit
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Vout
T1
L
m
PWM2H
PWM2L
Phase Shift
Element
11091 PS6
Slide
‹#›
Full-Bridge ZVT Converter
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Full-Bridge Converter
+Vin
PWM1H
Ts
PWM1L
T1
L1
Ts/2
Vout
PWM1H
Ipri
PWM1L
Vpri
ton
t
PWM1H
PWM1L
t
Vpri

Full bridge converter






t
Buck derived isolated converter
Push Pull mode of PWM gate pulses
Ipri
Each half-bridge produces square wave
voltage
Duty cycle ratio controls the power flow
Turn ON as well as Turn OFF losses in the
MOSFET
Popular for high power application
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
t
Slide
‹#›
Full-Bridge Phase Shift ZVT
Converter
+Vin
PWM2H
PWM1H
T1
Ipri
PWM1L

L1
Vout
Vpri
PWM2L
Full-bridge Phase Shift ZVT converter





Complementary, fixed duty cycle PWM gate pulses
Phase shift in gate pulse of two legs control the power flow
Zero Voltage Switching, hence Turn ON losses in the
MOSFET eliminates
Parasitic of MOSFET and Transformer used to achieved
ZVT
A popular converter for very high power application
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Full-Bridge Phase Shift ZVT
Converter
A
Vout
T1
C
A
B
E
Ipri
+Vin
L1
D
VT
F
C
D
B
VT
Right leg transition


VT

Terminates the power delivery interval

Reflected load current is driving ZVS

Transition is linear

End of this period transformer primary is short
circuited
Ipri
Left leg transition

Begins after freewheeling state to initiate the
power delivery

Energy stored in the inductor drives the ZVS

Transition is resonant and non linear
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Full-Bridge Phase Shift ZVT
Converter

The right leg transition period is given by:

Time required to charge and discharge the output capacitor of
MOSFET C and MOSFET D
dt  Cr 

dv
Ip
The left leg transition period is given by:

Resonant time between L1 and output capacitor of MOSFET (A+B)
dt 

2
 L1  C r
Where, dt = transition time
Ip = primary current when the MOSFET D turns OFF
L1 = Leakage inductance of transformer
Cr = equivalent capacitor of MOSFET two MOSFET and transformer
parasitic capacitor (Cxfmr)
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
ZVT Control Scheme
Calculated
Current
Reference
Voltage
Reference
+
∑
-
Voltage Error
Compensator
+
∑
Current Error
Compensator
-
PWM
Phase
S&H
Current
Feedback
1011001010
ZVT
Xformer
ZVT
Current
sense
1001011011
1001001001
S&H
Voltage Feedback
ADC
Optocoupler
S&H
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Vout
Rectifier
11091 PS6
VOUT
Sense
Slide
‹#›
Resources Required for Digital
ZVT Converter
Isolation
Barrier
VHV_BUS
VOUT
IZVT
PWM
FET
Driver
PWM
PWM
PWM
FET
Driver
k2
FET
Driver
k1
ADC
ADC
Channel Channel
ADC
Channel
PWM
dsPIC30F2023
dsPIC30F2023
PWM
UART
RX
© 2007 Microchip Technology Incorporated. All Rights Reserved.
UART
TX
11091 PS6
Slide
‹#›
ZVT Resource Allocation
Signal Name
Type of
Signal
dsPIC® DSC
Resource Used
IZVT1
Analog Input
AN0
IZVT2
Analog Input
AN2
VOUT
UART Input
U1RX
ZVT Gate Drive
Drive Outputs
Sync. Rectifier
Gate Drive
Current Loop
Trigger
Voltage Loop
Trigger
Drive Outputs
PWM1H, PWM1L
PWM2H, PWM2L
PWM3H, PWM3L
© 2007 Microchip Technology Incorporated. All Rights Reserved.
dsPIC® DSC
Internal Signal
dsPIC® DSC
Internal Signal
11091 PS6
PWM1, PWM2 Triggers
to Sample ZVT Current
UART1
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
ZVT Control Software
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
ZVT Software Overview


ADC Conversions are initiated by the
PWM Trigger Feature
The Current Control Loop is Executed in
the ADC Interrupt Routine
 Additional Check for Transformer Primary
Current Balance to prevent Flux Walking


The Voltage Loop is Executed from a
UART Receive Interrupt
Faults are handled by the PWM Module
using the on-chip Analog Comparators
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start

Initialization





© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Initialize PWM
Initialize ADC
Setup Timers
Setup UART
Configure
Interrupts
Initialize Control
Loop Variables
Slide
‹#›
Structure of the ZVT Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize PWM
 Configure PWM
Mode, Output
Polarity, Period,
Duty Cycle and
Phase Shift
 Setup PWM Faults
and Fault
Thresholds
 Setup PWM Triggers
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize ADC
 Setup ADC Speed
 Configure desired
ADC channels as
analog inputs
 Choose ADC Trigger
Sources
 Configure ADC Data
Format
 Choose Simultaneous
or Sequential
Sampling
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start

Configure Timers
 Use Timer to trigger
Voltage Control Loop
Initialization

Configure UART
 Use UART to receive
VOUT feedback signal

Setup Interrupts
 PWM Interrupt for Fault
Handling
 Timer Interrupt to trigger
Voltage Control Loop
 ADC Interrupt to trigger
Current Control Loop
 UART Receive Interrupt
to Execute the Voltage
Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start
Initialization

Initialize Control
Loop Variables
 Initialize PID Gain
Terms in X-memory
 Initialize Measured
signals in Y-memory
 Initialize pointers to
Control Loop Inputs
and Outputs
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start

Initialization




Enable Peripherals
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Enable
Peripherals
11091 PS6
Enable Timers
Enable UART
Enable ADC
Enable PWM
Slide
‹#›
Structure of the ZVT Software
Start

Check for Faults

Initialization
Enable Peripherals


Fault
Presen
t?

© 2007 Microchip Technology Incorporated. All Rights Reserved.
Fault Loop

Fault
Loop

11091 PS6
The PWM Module is
setup to detect Faults
and Shutdown all
Outputs
The PWM Fault Interrupt
sets the Fault Flag
The Main Routine
Checks the Fault Flag
The Fault Indicator LED
is enabled
Any other Fault Handling
Routines can be placed
in this loop
Slide
‹#›
Structure of the ZVT Software
Start

Initialization
 Check Input
Voltage
 Check
Temperature
 Power
Management
Routines
 Other Auxiliary
Features
Enable Peripherals
Fault
Presen
t?
Idle Loop
(Normal
Operation)
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Idle Loop
(Low Priority)
Fault
Loop
11091 PS6
Slide
‹#›
Structure of the ZVT Software
Start

ADC Interrupt
(High Priority)

Initialization
ZVT Current Loop

Enable Peripherals


Fault
Presen
t?
Idle Loop
(Normal
Operation)


Fault
Loop
UART Interrupt
(Medium Priority)

ZVT Voltage Loop


ADC Interrupt

UART Interrupt
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
ZVT Current
Measurements
Check for Current
Imbalance
Current PID
Calculations
Update Phase Shift
VOUT Measurement
ZVT Voltage PID
Calculations
Update ZVT Current
Reference
Slide
‹#›
Additional Guidelines
for Primary side
®
dsPIC DSC Software
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Full-Bridge Phase Shift ZVT
Converter
Phase
Shift
PWM1H
Vout
T1
PWM2H
PWM1L
E
+Vin
Ipri
L1
PWM2H
VT
Duty Cycle
F
PWM1L
PWM1H
PWM2L
PWM2L
Ipri

ZVT Current #1
Trigger Instant

Trigger at start of
PWM1H Pulse

ZVT Current #2 Trigger Instant

© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Trigger on PWM2H at
(Duty Cycle + Phase Shift)
Slide
‹#›
Sequence of Current Loop
Triggers
ZVT Current 1
Trigger:
Once every 8
ZVT cycles
ZVT Current 2
Trigger:
Once every 8
ZVT cycles
ZVT Current 1
Trigger:
Once every 8
ZVT cycles
PWM1H
PWM1L
Phase
Shift
PWM2H
PWM2L
PWM4L
Execute
ZVT
Current
Loop #1
Sample
and
Convert
AN0, AN1
Idle
Loop
Execute
ZVT
Current
Loop #2
Idle
Loop
Sample
and
Convert
AN2, AN3
© 2007 Microchip Technology Incorporated. All Rights Reserved.
PFC Current
Trigger:
Once every 4
PFC cycles
Execute
ZVT
Current
Loop #1
Sample
and
Convert
AN4, AN5
Idle
Loop
Sample
and
Convert
AN0, AN1
Execute
PFC
Current
Loop
11091 PS6
Slide
‹#›
Time Management
ZVT Current 2
Trigger:
Once every 8
ZVT cycles
ZVT Current 1
Trigger:
Once every 8
ZVT cycles
PWM1H
PWM1L
Phase
Shift
PWM2H
PWM2L
PWM3L

Execute
ZVT
Current
Loop #1
Sample
and
Convert
AN0, AN1
Execute
ZVT
Current
Loop #2
Idle
Loop
Sample
and
Convert
AN2, AN3
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Idle time between
execution of consecutive
ZVT Current Loops should
be large enough to prevent
multiple simultaneous ADC
Triggers
Worst Case Condition is
Maximum Phase Shift
11091 PS6
Slide
‹#›
Time Management
ZVT Current 2
Trigger:
Once every 8
ZVT cycles
ZVT Current 1
Trigger:
Once every 8
ZVT cycles

PWM1H
PWM1L
Phase
Shift
PWM2H
PWM2L
PWM3L
PWM4L
Execute
ZVT
Current
Loop #1
Sample
and
Convert
AN0, AN1
Idle
Loop
Execute
ZVT
Current
Loop #2
Idle
Loop
Sample
and
Convert
AN2, AN3
© 2007 Microchip Technology Incorporated. All Rights Reserved.
PFC Current
Trigger:
Once every 4
PFC cycles
Sample
and
Convert
AN4, AN5

Execute
PFC
Current
Loop
11091 PS6
The Idle time
after execution
of the second
ZVT Current
Loop should be
enough to
prevent multiple
simultaneous
ADC Triggers
Worst Case
condition is zero
Phase Shift
Slide
‹#›
Time Management
ZVT Current 2
Trigger:
Once every 8
ZVT cycles
ZVT Current 1
Trigger:
Once every 8
ZVT cycles

PWM1H
PWM1L
Phase
Shift
PWM2H
PWM2L
PWM3L
PWM4L
Execute
ZVT
Current
Loop #1
Sample
and
Convert
AN0, AN1
Idle
Loop
Execute
ZVT
Current
Loop #2
Idle
Loop
Sample
and
Convert
AN2, AN3
© 2007 Microchip Technology Incorporated. All Rights Reserved.
PFC Current
Trigger:
Once every 4
PFC cycles
The Idle time after
PFC Current Loop
Execution utilized
for executing the
Voltage Loops and
auxiliary functions
Sample
and
Convert
AN4, AN5
Idle
Loop
Execute
PFC
Current
Loop
11091 PS6
Slide
‹#›
Control Loop Execution
Error
Signal
PID Control Loop
Kp
Reference
Input
x(n)
e(n)
+
+ -
Ki Σe(n)
Kdde(n) /dn
PID
Command
(correction)
up(n)
ui(n)
+
u(n)
PWM
y(n)
ud(n)
Measured
Output
u(n) = up(n) + ui(n) + ud(n)
where,
up(n) = Kp*e(n)
ui(n) = Ki*[e(n) + e(n-1)]
ud(n) = Kd*[e(n) - e(n-1)]
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Auxillary Tasks




AC Input Voltage Measurement
Check if Soft Start is required
Temperature Measurement
Communication Routines
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Demonstration #2
ZVT Operation
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Summary

Power Factor Correction
 Overview of PFC
 Control Scheme for Digital PFC
 Structure of Control Software

Zero Voltage Transition





ZVS and ZCS and Full-Bridge Converter
ZVT Phase Shift Converter
Control Scheme for ZVT Converter
Structure of Control Software
Additional Guidelines for Primary Side
dsPIC® DSC Control Software
 Time Management
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Phase Buck
Converter
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Basic Theory of a Buck
Converter
Switch ON
Step down converter
Charging inductor
IL
IQ
ILoad
+Vin
L1
Q1
Cin
PWM
D1
Vout
Cout
Iripple
ON
IL
PWM
Ton
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Toff
Period
11091 PS6
Slide
‹#›
Basic Theory of a Buck
Converter
Switch OFF
Discharging inductor
Step down converter
IL
ILoad
+Vin
L1
Q1
Cin
PWM
D1
ID
Vout
Cout
Iripple
OFF
IL
PWM
Ton
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Toff
Period
11091 PS6
Slide
‹#›
PWM Pulse Width vs.
Buck Output Voltage
Vout = Vin  D
Where:
D = PWM dutycycle = Ton / (Ton +Toff)
Note: range of duty cycle = 0 to 1
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Synchronous Buck
Converter
ILOAD + Iripple
Q1
+Vin
Vout
L1
Q2
Cin
PWMH
PWML
Cout
ILOAD
Iripple
Period
PWMH
PWML
Iripple
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Phase Buck Converter
3.3V
Output
12V Input
Q1
Q2
Drive Signals
are Phase
Shifted by 120°
120° 120° 120°
Q1
Q3
Q4
Q3
Q5
Q5
Q6
© 2007 Microchip Technology Incorporated. All Rights Reserved.
GND
11091 PS6
Slide
‹#›
Why the Multi-phase Buck
Converter?





Each Phase is rated for less Power
Semiconductor Devices have lower
current rating
Smaller MOSFETs usually mean better
switching speed
Higher Output Ripple Frequency
decreases size of output filter
Ripple magnitude is reduced
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
5V Buck Converter Control
Scheme
Calculated
Current
Reference
Vref
+
Buck
Current
sense
Analog
Comparator
Voltage
Reference
+
∑
Voltage Error
Compensator
Current Limit
Shutdown
1001011011
ADC
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Buck
Inductor
PWM
Voltage Feedback
VOUT
11091 PS6
VOUT
Sense
S&H
Slide
‹#›
3.3V Buck Converter Control
Scheme
+
Calculated
Current
Reference
Vref
Analog
Comparator
+
Vref
Analog
Comparator
Voltage
Reference
+
Vref
Buck
Current
sense 1
VOUT
Buck
Current
sense 2
Phase 1
Inductor
Buck
Current
sense 3
Analog
Comparator
+
∑
Voltage Error
Compensator
-
Current Limit
Shutdown
Phase 2
Inductor
Phase 3
Inductor
PWM
1001011011
VOUT
Sense
Voltage Feedback
ADC
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
S&H
Slide
‹#›
Resources Required for Digital Buck
Converters
I3.3V_1
12V
Input
I5V
Analog ADC
Comp. Channel
dsPIC30F2023
UART
TX
© 2007 Microchip Technology Incorporated. All Rights Reserved.
k6
k2
PWM
PWM
k1
FET
Driver
I3.3V_3
PWM
PWM
ADC
Channel
PWM
PWM
k7
FET
Driver
I3.3V_2
5V
Output
FET
Driver
3.3V
Output
PWM
PWM
Analog
Comp.
Analog
Comp.
Analog
Comp.
ADC
Channel
11091 PS6
FET
Driver
k3
k4
k5
Slide
‹#›
Buck Converters Resource
Allocation
Signal Name
Type of
Signal
dsPIC® DSC
Resource Used
I5V
Analog Input
CMP1A
5V Output
Analog Input
AN1
I3.3V_1
Analog Input
CMP2A
I3.3V_2
Analog Input
CMP3A
I3.3V_3
Analog Input
CMP4A
3.3V Output
Analog Input
AN3
5V Buck Gate
Drive
Drive Outputs
PWM4H, PWM4L
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Buck Converters Resource
Allocation
Signal Name
Type of
Signal
dsPIC® DSC
Resource Used
3.3V Buck Gate
Drive
Drive Outputs
5V Current Loop
Trigger
3.3V Current Loop
Trigger
12V Bus Sense
dsPIC® DSC
Internal Signal
dsPIC® DSC
Internal Signal
Analog Input
PWM1H, PWM1L
PWM2H, PWM2L
PWM3H, PWM3L
PWM4 Trigger to Sample
5V Buck Voltage
PWM1 Trigger to Sample
3.3V Buck Voltage
AN5
12V Digital
Feedback
Temperature
Sense
UART
Transmission
Analog Input
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
U1TX
AN8
Slide
‹#›
Agenda



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Phase Buck Converter
Control Software
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Multi-Phase Buck Converter
Software Overview


ADC Conversions are initiated by the
PWM Trigger Feature
Peak Current Control is implemented
using the Analog Comparators
 Additional Check Desired for Current Imbalance
between the three phases


The Voltage and Current Loops are
executed at the same speed
The UART Transmission for 12V digital
feedback is executed from a Timer
Interrupt
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

Initialization






© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Initialize PWM
Initialize ADC
Initialize Analog
Comparators
Setup Timers
Configure UART
Configure
Interrupts
Initialize Control
Loop Variables
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize PWM
 Configure PWM Mode,
Output Polarity, Period,
Duty Cycle and Phase
Shift
 Setup PWM Current
Limit Sources
 Setup PWM Triggers
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start
Initialization
© 2007 Microchip Technology Incorporated. All Rights Reserved.

Initialize ADC
 Setup ADC Speed
 Configure desired
ADC channels as
analog inputs
 Choose ADC Trigger
Sources
 Configure ADC Data
Format
 Choose Simultaneous
or Sequential
Sampling
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start
Initialization

Initialize Analog
Comparators
 Configure Correct
Analog Comparator
Inputs
 Choose Voltage
Reference Source
 Setup Initial DAC
Reference
 Choose Comparator
Output Polarity
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start
Configure UART
 Use UART to transmit
12V Bus Data to Primary
Side dsPIC® DSC
Initialization

Setup Interrupts
 PWM Interrupt for Fault
Handling
 Timer Interrupt to trigger
Voltage Control Loop
 ADC Interrupt to trigger
Current Control Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start
Initialization

Initialize Control
Loop Variables
 Initialize PID Gain
Terms in X-memory
 Initialize Measured
signals in Y-memory
 Initialize pointers to
Control Loop Inputs
and Outputs
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

Initialization
 Enable Analog
Comparators
 Enable ADC
 Enable PWM
 Enable UART
Enable Peripherals
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Enable
Peripherals
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

Check for Faults

Initialization
Enable Peripherals


Fault
Presen
t?

© 2007 Microchip Technology Incorporated. All Rights Reserved.
Fault Loop

Fault
Loop

11091 PS6
The PWM Module is
setup to detect Faults
and Shutdown all
Outputs
The PWM Fault Interrupt
sets the Fault Flag
The Main Routine
Checks the Fault Flag
The Fault Indicator LED
is enabled
Any other Fault Handling
Routines can be placed
in this loop
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

Initialization
 Transmit 12V Bus
Data
 Power
Management
Routines
 Check
Temperature
 Other Auxiliary
Features
Enable Peripherals
Fault
Presen
t?
Idle Loop
(Normal
Operation)
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Idle Loop
(Low Priority)
Fault
Loop
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

Initialization
ADC Interrupt
(High Priority)

Buck Current Loop

Enable Peripherals


Fault
Presen
t?
Idle Loop
(Normal
Operation)
VOUT Measurement
Calculate Current
Reference
Update Analog
Comparator DAC
References
Fault
Loop
ADC Interrupt
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Structure of the Multi-Phase
Buck Software
Start

ADC Interrupt
(High Priority)

Initialization
Buck Current Loop


Enable Peripherals

VOUT Measurement
Calculate Current
Reference
Update Analog
Comparator DAC
References
Fault
Presen
t?
Idle Loop
(Normal
Operation)
Fault
Loop

Timer Interrupt
(Medium Priority)

Buck Voltage Loop

ADC Interrupt
Transmit 12V Digital
Feedback Signal
Timer Interrupt
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Sequence of Current Loop
Triggers
5V Buck
Voltage Trigger
3.3V Buck
Voltage Trigger
3.3V Buck
Voltage Trigger
5V Buck
Voltage Trigger
5V Buck
Voltage Trigger
3.3V Buck
Voltage Trigger
PWM1H
PWM1L
PWM2H
PWM2L
PWM3H
PWM3L
PWM4H
PWM4L
Execute
5V Buck
Control
Loop
Sample
and
Convert
AN1
Execute
5V Buck
Control
Loop
Idle
Loop
Sample
and
Convert
AN3
Execute
3.3V
Buck
Control
Loop
Idle
Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Execute
5V Buck
Control
Loop
Sample Idle
and
Loop
Convert
AN1
Sample
and
Convert
AN3
11091 PS6
Execute
3.3V
Buck
Control
Loop
Idle
Loop
Sample
Idle
and
Convert Loop
AN1
Execute
3.3V
Buck
Control
Loop
Sample
and
Convert
AN3
Slide
‹#›
Sequence of Current Loop
Triggers
5V Buck
Voltage Trigger
3.3V Buck
Voltage Trigger
5V Buck
Voltage Trigger
PWM1H
PWM1L
PWM2H
PWM2L
PWM3H
PWM3L
PWM4H
PWM4L
Execute
5V Buck
Control
Loop
Sample
and
Convert
AN1
Execute
5V Buck
Control
Loop
Idle
Loop
Sample
and
Convert
AN3

Execute
3.3V
Buck
Control
Loop
Current Loop
Execution must
finish before next
ADC Trigger
Idle
Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Sequence of Current Loop
Triggers
5V Buck
Voltage Trigger
3.3V Buck
Voltage Trigger
5V Buck
Voltage Trigger
PWM1H
PWM1L
PWM2H
PWM2L
PWM3H
PWM3L
PWM4H
PWM4L
Execute
5V Buck
Control
Loop
Sample
and
Convert
AN1
Execute
5V Buck
Control
Loop
Idle
Loop
Sample
and
Convert
AN3

Execute
3.3V
Buck
Control
Loop
Perform Auxiliary
Tasks during the
Idle Times
Idle
Loop
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Control Loop Execution
Error
Signal
PID Control Loop
Kp
Reference
Input
x(n)
e(n)
+
+ -
Ki Σe(n)
Kdde(n) /dn
PID
Command
(correction)
up(n)
ui(n)
+
u(n)
PWM
y(n)
ud(n)
Measured
Output
u(n) = up(n) + ui(n) + ud(n)
where,
up(n) = Kp*e(n)
ui(n) = Ki*[e(n) + e(n-1)]
ud(n) = Kd*[e(n) - e(n-1)]
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Auxillary Tasks





12V Bus Voltage Measurement
Communication Routines
Load Sharing Routines
Temperature Measurement
Power Management Routines
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Demonstration #3
High Power Operation
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
PFC Sinusoidal Reference
Voltage
Reference
+
∑
Sinusoidal Reference
can be generated
using a lookup table
in software
Rectified
AC Mains
Voltage
Voltage Error
Compensator
X
-
+
∑
Vout
Current Error
Compensator
PFC
Choke
PWM
-
Sync signal for
detecting Zero
Crossings
Current
Feedback
Voltage Feedback
PFC
Current
sense
1011001010
1001011011
ADC
© 2007 Microchip Technology Incorporated. All Rights Reserved.
S&H
11091 PS6
VOUT
Sense
S&H
Slide
‹#›
HV Bias Supply
+13V
High Voltage
Bus (400V)
LIVE_GND
Live Digital
Supply
+7V
LIVE_GND
Live Drive
Supply
+HV_BUS
+17V
Digital Supply
GND
+7V
Drive Supply
Energy
Efficient
Switching
Converter
GND
D
TNY277
-HV_BUS
© 2007 Microchip Technology Incorporated. All Rights Reserved.
F/B
Bias
Supplies
S
11091 PS6
Slide
‹#›
DSC to DSC Communication

© 2007 Microchip Technology Incorporated. All Rights Reserved.
dsPIC30F2023

Perform status
checks
Report Fault
Conditions to
protect Hardware
Implement Data
Logging and
Remote
Monitoring
11091 PS6
Isolation
Barrier
Secondary
(Isolated)
Side
U1RX
U1T
X
U1TX
U1RX
Slide
‹#›
dsPIC30F2023

Primary
(Live)
Side
Power Supply Sequencing
sequential
simultaneous
V
5.0v
3.3v
V
5.0v
3.3v
T
T
offset
ratio metric
V
5.0v
V
3.3v
5.0v
3.3v
T
T

Choose method that meets system
requirements
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Output Protection Schemes

A number of protection schemes can
be implemented





Constant Current Limiting
Constant Power Limiting
Output Over-voltage Shutdown
Input Under-voltage Shutdown
All shutdown schemes can be
configured for immediate or delayed
shutdown
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Remote Monitoring Capability
Isolation
Barrier
Rectified
Sinusoidal
Voltage
EMI Filter
and Bridge
Rectifier
400Vdc
12Vdc
Synchronous ZVT Converter
PFC
Boost
Converter
ZVT
Full-Bridge
Converter
Multi-Phase
Buck Converter
3.3Vdc
69A
Single-Phase
Buck Converter
5Vdc
23A
Synchronous
Rectifier
85-265Vac
45-65Hz
dsPIC
30F2023
OptoCoupler
dsPIC
30F2023
+V
GND
SDA
SCK

PICkit™
Serial
Analyzer
Power monitoring can be implemented using a
Serial I2C™ interface provided on the
Secondary (Isolated) side
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Load Sharing Issues



Multiple power modules share load
Component and wiring differences cause some
modules to work harder than others
The heavily loaded modules get hotter and
reliability drops causing failures – Domino
Effect
Buck
Phase 1
Load Equalization
Routine
© 2007 Microchip Technology Incorporated. All Rights Reserved.
Buck
Phase 2
Load
Buck
Phase 3
11091 PS6
Slide
‹#›
Benefits of Digital Control








Reduce Component Count
Flexibility of Design
Flexibility of Control
Protect Intellectual Property
Implement non-linear and adaptive
control
Control Multiple Stages
Error logging capability
Flexible Fault handling
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Summary



Overview of AC/DC Reference Design
AC/DC Reference Design Architecture
Power Factor Correction
 PFC Control Software

Zero Voltage Transition
 ZVT Control Software

Multi-phase Buck Converters
 Multi-phase Buck Control Software

Enhanced Features
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
AC/DC Reference Design

Availability



Q4 2007
Contact Local Sales office for more
information
Visit Microchip’s Intelligent Power
Supply Design Center for our full
product offering

www.microchip.com/smps
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
References







C.K. Tse, “Circuit Theory of Power Factor Correction in switching
converters”
A. Hofmann, A.Baumuller, T. Gerhardt, M. Marz, E. Schimanek, “A
robust digital PFC control method suitable for low-cost
microcontroller”
L. Rossetto, G.Spiazzi, P. Tenti, “Control Techniques for Power
Factor Correction Converters”
L.Rossetto, G.Spiazzi, “Design Considerations on Current-Mode
and Voltage-Mode control methods for Half-Bridge Converters”
W.Gu, J.Abu-Qahouq, S.Luo, I.Batarseh, “A ZVT-PWM single stage
PFC converter with an active snubber”
M. Brown, “Power Supply Cookbook”
M. Kazimierczuk, D. Czarkowski, “Resonant Power Converters”
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Development Tools Used in
this Class

Hardware Tools
 AC/DC Reference Design (not released)
 MPLAB® REAL ICE™ Emulator
(DV244005)
 MPLAB ICD2 (DV164005)

Software Tools
 MPLAB IDE 7.61 (SW007002)
 MPLAB C30 v3.01 (SW006012)
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›
Trademarks
The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KeeLoq,
KeeLoq logo, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, rfPIC
and SmartShunt are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
AmpLab, FilterLab, Linear Active Thermistor, Migratable Memory, MXDEV,
MXLAB, SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM,
dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM,
fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi,
MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit, PICDEM,
PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool,
REAL ICE, rfLAB, Select Mode, Smart Serial, SmartTel, Total Endurance,
UNI/O, WiperLock and ZENA are trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their respective
companies.
© 2007 Microchip Technology Incorporated. All Rights Reserved.
11091 PS6
Slide
‹#›