| As an important component for police car, the warning lightbar plays a vital role at hazard and accident scenes by alerting casual people to the situation at hand. This in turn promotes safety and efficiency at the scene of the emergency and helps to mitigate the damage that has been done.The requirements for the warning lightbar are durability, small volume and high reliability. Therefore, according to the existing shortcomings of these products, a novel warning lightbar with characteristics of high power and multifunction was proposed in this dissertation. This warning lightbar has characteristics of high output power, multifunction, long life-span and intelligence.The key of flashing light circuit is flyback DC-DC converter. Although this converter has simple structure, the peak current of this converter is very high, and this high peak current may impact the battery. Thus, the flashing light circuit based on interleaving technique was designed, and the peak current of flashing light circuit can be reduced dramatically, which can effectively protect the product from failure. Moreover, a novel flyback DC-DC converter based on autotransformer was designed. Therefore, the converter's size and leakage inductance are' reduced effectively compared to the tranditional flyback DC-DC converters.As to the power amplifier, a switch-mode power amplifier based on TL494 was designed. With an unique output stage, the efficiency of this switch-mode power amplifier can be improved dramatically.As to the power LED constant current driver, a switch-mode constant current driver, which can control the forward-current of power LED strictly, was designed in this dissertation. Therefore, it guarantees the reliable operation of the power LED. In addition, observed experimental results for each part were also given.
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