Freescale Semiconductor M68HC08 Chapter Hardware Design, Hardware Implementation, System Modules

Chapter 4

Hardware Design

4.1 Hardware Implementation

This chapter covers the system hardware implementation. The dimmable light ballast board is shown in Figure 4-1.

Figure 4-1. Dimmable Light Ballast - Demo Board

4.2 System Modules

The light ballast system hardware is shown in the block diagram in Figure 4-2. It incorporates the controller board, powered from AC line and fluorescent tubes. As can be seen, the controller board contains four major parts:

•Input and PFC (Input EMI Filter, Bridge Rectifier, Boost topology PFC circuit, DC-bus Voltage, DC-bus Sensing, Mains Zero Crossing Sensing, Comparator Circuit, Buffer Circuit)

•Inverter (Half-bridge Drive, Resonant Circuit, Output Inductance Circuity, Different Voltage Sensing, Tube Currents Sensing)

•Microcontroller (MC68HC908LB8)

•Power Supply (Switch Mode Power Supply)

Detailed descriptions of the individual parts of the controller boards follows. Note that the reference design includes the PCB design files and bill of materials (BOM).

Dimmable Light Ballast with Power Factor Correction, Rev. 1

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