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Freescale Semiconductor M68HC08 manual Light Ballast Control, Tube Start Mode

Models: M68HC08

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5.2.2 Light Ballast Control

Control Algorithm Description

is higher than the generated sine waveform, then the comparator output is in log.1 and PWM1 is switched off. This happens every PWM period and this process is called cycle by cycle limiting. PWM1 operates at a 40 kHz frequency with variable duty cycle. For safety reasons, the comparator is enabled when the microcontroller is initialized and mains voltage synchronization is provided.

5.2.2 Light Ballast Control

Light Ballast Control controls the fluorescent tubes. The control process consists of two parts (modes), tube start mode and tube run mode. Figure 5-2shows the software control time diagram during start mode and run mode.

Figure 5-2. Dimmable Light Ballast — Control Time Diagram

5.2.2.1 Tube Start Mode

When the DC-bus voltage reaches the required value, the HRP is enabled at maximum ballast frequency and kept for a set time. Then the ballast frequency is ramped down to the preheat frequency and kept for a set time. This procedure preheats the filaments. In the next stage, the ballast frequency is ramped down until the lamps are ignited. During the lamp ignition procedure, the frequency and tube currents are controlled (see Reference [4]).

5.2.2.2 Luminance Level Control (Tube Run Mode)

Luminance Level Control is active after tube ignition. The actual values of the tube currents are sensed by the AD converter. Average value of currents is compared with required current value after luminance

Dimmable Light Ballast with Power Factor Correction, Rev. 1

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Freescale Semiconductor M68HC08 manual Light Ballast Control, Tube Start Mode, Luminance Level Control Tube Run Mode

Contents

M68HC08 Microcontrollers Designer Reference ManualDRM067 Rev. 1 12/2005 Page Designer Reference Manual Freescale Semiconductor Draft 2 for ReviewChapter Control Theory Contents Chapter IntroductionChapter Reference Design Chapter Hardware DesignAppendix A. Schematics and Part List Chapter Demo SetupChapter Software Design Appendix B. ReferencesChapter Introduction 1.2 Benefits of this Solution1.1 Introduction 1.3 The MC68HC908LB8 Microcontroller 7-bitkeyboard interrupt Freescale Semiconductor Introduction2.1 Introduction Chapter Control Theory2.1.1 Fluorescent Lamp Control Theory 2.1.2 Fluorescent Lamp OperationGas filling mixture Freescale Semiconductor 2.1.3 Controlling the Fluorescent LampFreescale Semiconductor 2.2.1 Introduction 2.2PFC Control TheoryFreescale Semiconductor Freescale Semiconductor Control Theory MCU PWM PWM1 FAULT PINDC Bus Voltage ZeroFigure 2-8.Generated Input Current Waveform 2.2.4 Concept SummaryFreescale Semiconductor Control TheoryChapter Reference Design 3.2 Dimmable Light Ballast Characteristics3.1 Application Outline Table 3-1.Light Ballast Characteristics 3.3 Application Description3.3.1 Light Ballast Control 3.3.2 Power Factor CorrectionCONTROL BOARD MC68HC908LB83.5 Hardware Specification 3.4 Software Specification3.3.3 Protection Features 4.1 Hardware Implementation Chapter Hardware Design4.2 System Modules Hardware Design 4.2.1 Input and PFCFigure 4-3.Dimmable Light Ballast - Input and PFC Freescale Semiconductor 4.2.2 InverterSystem Modules Figure 4-4.Dimmable Light Ballast - InverterFreescale Semiconductor HALF BRIDGE4.2.3 Microcontroller System Modules SignalPin number TOP BOT Comp Comp Out Zero DetectTable 4-2.J2 Interface Header SignalHardware Design Pin numberFigure 4-6.Dimmable Light Ballast - Power Supply 4.2.4 Power SupplyTable 4-3.Supplied Voltages Freescale Semiconductor Hardware Design5.1 Introduction Chapter Software Design5.2 Control Algorithm Description 5.2.1.2 Phase Shift Synchronization 5.2.1 Power Factor Correction Control5.2.1.4 Generation of Output PFC Control SIgnal 5.2.1.1 DC-busVoltage Control5.2.2.1 Tube Start Mode 5.2.2 Light Ballast Control5.2.2.2 Luminance Level Control Tube Run Mode ireq = A ⋅ ek ⋅ ireqAD + q q = itADmin - A ⋅ ek ⋅ ADminrounditmin ⋅ ADmax ⁄ imax rounditmax ⋅ ADmax ⁄ imax5.3 Software Implementation 5.3.1 Initialization Setup5.3.1.1 PWM Setup PWM Frequency = 5.3.1.2 HRP SetupBusFrequency Hz Hz5.3.2 Main Program Loop 5.3.4 Sine Wave Generation Interrupt Routine 5.3.3 Synchronization Interrupt RoutineFreescale Semiconductor Software Design Set 1ms flag and reset 1ms counterinterrupt void pwmISRvoid Read new PWM value from table * sineGain5.3.4.1 Fault Detection and Processing Figure 5-6.Flow Chart - timovISR and faultISR 5.4 Detailed Software DescriptionSoftware Design Stop HRPDetailed Software Description Figure 5-7.Flow Chart - Main Flow, PartSoftware Design Figure 5-8.Flow Chart - Main Flow, PartFreescale Semiconductor Detailed Software Description Figure 5-9.Flow Chart - Main Flow, PartFreescale Semiconductor Software Design Figure 5-10.Flow Chart - Main Flow, PartFreescale Semiconductor 5.5.1.4 Timer Interface Module TIM 5.5.1.1 High Resolution PWM HRP5.5 Microcontroller Usage 5.5.1 Microcontroller Peripheral Usage5.5.3 I/O Usage 5.6 Definitions of Constants and VariablesSoftware Design I/O pin5.6.1 System Setup Definitions defines the minimum HRP frequency in kHz 5.6.2 System Constants and Variables Page 6.1 Hardware Setup Chapter Demo Setup6.2 Software Setup 6.2.1 Required Software Tools6.2.4 Project Files 6.2.3 Executing the Application\prm\P&E FCS linker.prm, linker program file \Sources\pi controller.c, PI regulators fileA.1 Schematics Appendix A. Schematics and Part ListPFC Current Sense 2.7mHComp PFC GateComp PFC Current SensePFC Gate Zero DetectDCB TOP BOT Figure A-3.InverterO1 O2 O3 O4 O5 O6 O7 O8 COM LOSerial Data TOP BOT Comp - Comp Out Zero DetectSerial Data DCB Divider Tube Current Tube Current Tube Voltage differenceSerial Data5 GNDSerial Data DCB Divider Tube Current Tube Current Tube Voltage differenceFigure A-6.Power supply DESIGNATORS A.2 Parts ListQUANTITY DESCRIPTIONQUANTITY DESIGNATORSDESCRIPTION MANUFACTURERFreescale Semiconductor Appendix B. References Freescale Semiconductor Page Home Page How to Reach UsE-mail USA/Europe or Locations Not Listed