Freescale Semiconductor M68HC08 manual Dimmable Light Ballast Input and PFC

Page 27

System Modules

signal of the comparator (Comp Out) controls the power switch Q1 through the output buffer, which consists of transistors Q2, Q3, and Q4, resistors R10, R13, R34, R35, R36, and R37, and capacitor C7.

For discontinuous conduction mode the comparator output is disconnected from the Q4 transistor gate. The PWM1 pin is connected to the Q4 transistor gate.

Digital PFC is driven by the MCU. The MC68HC908LB8 peripherals used for PFC are listed below:

AD converter — channels ADC1 and ADC2

PWM0 for generating sine wave

comparator

IRQ pin for zero-crossing detection

The PFC control algorithm

converts the sensed output voltage to a digital value

provides software PI regulator for a voltage feedback loop

programs its PWM channel to create the pattern of the input current

synchronizes operation with the mains frequency using mains zero-crossing detection

The control algorithm is described in 5.2 Control Algorithm Description.

DC-BUS VOLTAGE OUTPUT AND SENSING

INPUT EMI FILTER AND BRIDGE RECTIFIER

 

 

1

1

4

 

 

 

C1

 

J1

 

 

10nF 275V X2

 

PM100-INP_CONN-6

2

2

3

I6

6

 

 

L6

5

 

 

CMFIL2

I5

 

 

4

 

 

 

NC

 

 

 

3

 

 

 

I3

 

 

 

2

 

 

 

I2

1

2

 

1

 

I1

 

 

 

 

 

 

 

 

C5

 

 

 

4n7 250/1000V Y2

 

 

 

 

GND

 

1

R11

3K0

2

R14 2K0

PFC Current Sense

C8 82pF

GND

 

 

 

 

 

 

2.7mH

 

BOOST CONVERTER

 

 

 

JP6

 

 

 

 

 

 

L1B

 

 

 

 

 

 

1

 

U1

 

 

C2

 

PFCIND3

 

 

 

 

 

 

2

 

DF1510S

 

150nF 275V X23

 

 

5

D1

 

 

 

 

 

4 AC2

DC+ 1

 

 

 

 

 

 

DCB

CONN/HDR/2X1

1

 

 

 

 

 

 

 

 

MURS160T3

 

 

 

 

 

RV1

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

1

 

 

 

D

 

C3

1

 

R1

 

275V

 

 

 

 

 

 

 

 

 

C4

 

 

 

 

 

 

 

 

 

 

 

10nF 630V TC356 +

560K

 

 

 

 

 

2

 

 

 

G

 

 

 

22uF 450V

GND

2

 

 

 

 

PFC Gate

Q1

 

2

 

2

 

 

 

 

 

 

 

 

 

 

1

 

3

 

 

2

 

1

 

2

S

 

 

 

 

AC1

DC-

 

 

IRF820A

 

 

 

R2

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4

2R7

 

 

 

 

 

 

R3

 

 

 

 

 

 

 

 

GND

 

560K

 

 

 

 

 

 

 

 

 

 

 

 

 

 

220K

 

 

 

 

 

PFC Current Sense

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

R6

 

1

 

 

 

 

 

 

 

15V

 

 

 

 

 

R5

 

 

 

 

 

 

 

 

 

 

 

510K

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

220K

 

 

 

 

 

 

 

 

 

 

 

2

 

2

 

MAINS ZERO CROSSING SENSING

 

 

 

 

 

 

DCB Divider

 

 

 

 

 

 

 

 

1

 

15V/1

 

 

1

 

1

 

 

 

 

 

 

 

 

R35

 

C6

R8

 

 

 

 

 

 

Zero Detect

 

 

 

 

R7

 

 

 

 

 

0R

 

 

18K

 

 

 

 

1

 

 

 

 

 

 

100nF

 

220K

D15

 

 

 

 

 

R36 0R

R37 0R

 

 

 

 

R9

 

 

 

 

 

 

 

 

 

 

BAT48

C27

 

 

2

 

 

 

 

2

 

2

 

 

 

47K

1n5

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

R34

 

 

GND

GND

 

 

 

 

 

GND

GND

 

 

 

0R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D2

 

 

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BZV55C5V6

 

 

 

C7

 

 

 

 

 

 

 

GND

 

 

1

 

 

100nF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R10

 

 

 

6K8

 

5V

 

GND

C

 

2

B

 

 

Q2

 

 

 

BC846B

 

C10

 

E

 

R13

PFC Gate

 

220nF

 

 

 

1

620R

E

 

 

B

Q3

GND

R12

 

BC856B

 

10K

 

C

 

D

 

 

 

 

2

 

 

 

G

BUFFER CIRCUIT

Comp -

Comp Out

Q4

 

 

 

 

SMMBF0201

COMPARATOR CIRCUIT

GND

GND

Figure 4-3. Dimmable Light Ballast — Input and PFC

Dimmable Light Ballast with Power Factor Correction, Rev. 1

Freescale Semiconductor

27

Image 27
Contents Dimmable Light Ballast with Power Factor Correction Page Designer Reference Manual Dimmable Light Ballast with Power Factor CorrectionDraft 2 for Review Chapter Hardware Design Contents Chapter IntroductionChapter Control Theory Chapter Reference DesignAppendix B. References Chapter Demo SetupAppendix A. Schematics and Part List Chapter Software DesignIntroduction Benefits of this SolutionMC68HC908LB8 Microcontroller MC68HC908LB8 Microcontroller Freescale Semiconductor Fluorescent Lamp Operation Fluorescent Lamp Control TheoryTypical Low Pressure Fluorescent Tube I/V Characteristic Typical Fluorescent Tube Equivalent Circuit in Steady State Controlling the Fluorescent LampControl Theory PFC Control Theory Main Characteristics of the Dual Switch TopologiesDigital Power Factor Concept Hysteresis Current Control Mode Hysteresis Current Control Mode Current Waveform Digital Power Factor Concept Discontinuous Conduction ModeDiscontinuous Conduction Mode Principle Generated Input Current Waveform Concept SummaryFreescale Semiconductor Application Outline Dimmable Light Ballast CharacteristicsApplication Description Light Ballast CharacteristicsLight Ballast Control Power Factor CorrectionSoftware Specification Software SpecificationHardware Specification Protection FeaturesSystem Modules Hardware ImplementationInput and PFC Dimmable Light Ballast Input and PFC Inverter Dimmable Light Ballast Inverter Microcontroller J1 Luminance Header Dimmable Light Ballast MicrocontrollerJ2 Interface Header Supplied Voltages Power SupplyFreescale Semiconductor Control Algorithm Description Chapter Software DesignDC-bus Voltage Control Power Factor Correction ControlTube Start Mode Roundi tmin ⋅ AD max ⁄ i max Software Implementation Initialization SetupPWM Setup PWM Frequency = BusFrequency Hz Hz Main Program Loop Sine Wave Generation Interrupt Routine Synchronization Interrupt RoutineFlow Chart Sine Wave Generation Interrupt Routine Fault Detection and Processing Detailed Software Description Flow Chart timovISR and faultISRFlow Chart Main Flow, Part Reference sine gain Yes Is preheat frequency reached? Has 1ms gone? 10. Flow Chart Main Flow, Part Memory Usage Microcontroller UsageMicrocontroller Peripheral Usage Program and Data Memory UsageDefinitions of Constants and Variables 3 I/O UsageI/O Usage System Setup Definitions Represents the number of fault states during tube ignition Defines the minimum HRP frequency in kHz during run modeDefines the maximum HRP frequency in kHz during run mode Represents the number of fault states during run modeExtern tSWFLAGS Swflags System Constants and VariablesExtern tU08 CurrT1 Building and Uploading the Application Hardware SetupSoftware Setup Required Software Tools\Sources\main.c, main program Executing the ApplicationProject Files \prm\P&EFCSlinker.prm, linker program fileSchematics Appendix A. Schematics and Part List7mH 7mH Figure A-3. Inverter TOP BOT TOP Figure A-6. Power supply Table A-1. Printed Circuit Board Parts List Parts ListInternational IRF830A Dimmable Light Ballast with Power Factor Correction, Rev Appendix B. References Dimmable Light Ballast with Power Factor Correction, Rev Page How to Reach Us
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M68HC08 specifications

Freescale Semiconductor, known for its innovative solutions in the field of embedded systems, developed the M68HC08 microcontroller family, which includes the MC68HC908QT2. This 8-bit microcontroller is engineered to meet the demands of diverse applications, including automotive, industrial, and consumer electronics.

The MC68HC908QT2 is designed around Freescale’s M68HC08 core, which is renowned for its efficient and reliable performance. This microcontroller integrates a powerful instruction set, enabling developers to create high-performance applications with relatively low power consumption. The device operates at a clock frequency of up to 3 MHz, which is adequate for various control tasks.

One of the key features of the MC68HC908QT2 is its memory architecture. It includes a 2 KB Flash memory for program storage, representing a significant advantage for developers requiring non-volatile memory. Additionally, it encompasses 128 bytes of EEPROM memory, allowing for data retention even after power loss. The microcontroller also has 256 bytes of RAM for efficient data manipulation during operation.

In terms of input/output capabilities, the MC68HC908QT2 supports a variety of interfacing options. The microcontroller features up to 20 general-purpose I/O pins for flexibility in connecting with peripheral devices. Additionally, it provides multiple analog-to-digital converters (ADC) and timers that facilitate efficient analog signal processing and precise control through timing functions.

The architecture of the MC68HC908QT2 also incorporates sophisticated on-chip peripherals, enhancing its functionality. These peripherals include PWM (Pulse Width Modulation) outputs, which are essential for applications requiring motor control and other precise duty cycle processes. The integrated watchdog timer ensures reliable operation by resetting the system in the event of an application failure.

Moreover, the MC68HC908QT2 is equipped with an efficient power management system, enabling operation in a low-power mode, ideal for battery-powered applications. This microcontroller is packaged in a compact 28-pin dual in-line package (DIP), making it suitable for space-constrained designs.

In summary, the Freescale Semiconductor MC68HC908QT2 microcontroller is distinguished by its robust performance, extensive memory options, and versatile I/O capabilities. Its advanced features, including built-in timers, ADC, and a power management system, make it an exceptional choice for developers seeking to implement reliable and efficient embedded solutions. With its comprehensive architecture, the MC68HC908QT2 remains a popular choice in the landscape of 8-bit microcontrollers.