Introduction

•Energy saving

•Ease of adapting software for different lamps

•Ease of re-programming the system behavior

•Software can simplify the hardware

•Diagnostic functions — fault state, tube end-of-life, ignition fault, tube removed

•Open to innovation

The MC68HC908LB8 is designed for light ballast applications. It contains a HRP that is assigned to control a lamp ballast circuit using half-bridge topology. The HRP provides two complementary outputs for controlling a half-bridge drive. Pulse Width Modulation (PWM) with constant duty cycle is used for light ballast control. The HRP frequency can be adjusted easily by software in range 40 kHz to 120 kHz in 256 steps. Dimming levels down to 5% are possible.

The PFC circuit uses an on-chip comparator on the MC68HC908LB8. This peripheral simplifies the dimming light ballast solution with PFC, since it eliminates the need of external components and thus decreases the system cost.

The reference design is intended for all geographic regions, so 110V/60Hz and 230V/50Hz input voltage supplies are supported.

The application can be debugged using the MON08 CYCLONE debug tool in monitor mode.

WARNING

Since the application runs at high voltage, it is dangerous to connect development tools directly to the board. Therefore, it is recommended to use an opto-isolation monitor mode board. This separate board provides an opto-isolated interface for the MON08 debug tool, using the MON08 standard connector. This allows the user to safely debug or examine code in-circuit.

1.3 The MC68HC908LB8 Microcontroller

The MC68HC908LB8 is a member of the low-cost, high performance MC68HC08 Family of 8-bit MCUs. All MCUs in the family use the enhanced MC68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.

Standard features of microcontroller MC68HC908LB8 are:

•8 MHz internal bus frequency

•Trimmable internal oscillator:

–4.0 MHz internal bus operation

–8-bit trim capability

–25% untrimmed

–2% trimmed

•8K bytes of 10K write/erase cycle typical on-chip in application programmable FLASH(1) memory with security option

•128 bytes of on-chip random access memory (RAM)

1.Non volatile memory that retains its data when the power is removed.

Dimmable Light Ballast with Power Factor Correction, Rev. 1

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Freescale Semiconductor

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Freescale Semiconductor M68HC08 manual MC68HC908LB8 Microcontroller
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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.
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