Abstract: The present invention relates to a system for diagnosis and management of indoor air quality, and more particularly to a system for diagnosis and management of indoor air quality which is capable of obtaining and analyzing air quality data by measuring the indoor air quality of a vehicle or accommodation space and of detecting smoking or non-smoking, the type of smoking, and an abnormal situation by diagnosing at least one of indoor smoking and smoking types. In addition, the present invention relates to a technology for facilitating the management of accommodation by efficiently diagnosing indoor air quality.

Abstract: A power protecting apparatus and method of a power amplifier for removing backward voltages and preventing a hard damage within a circuit by connecting an output terminal of a DC-DC converter with an input terminal of a filter using diodes when an excessive backward voltage is generated due to physical characteristics of an inductor within the circuit at the time of applying high power level and low power level to the power amplifier using switching devices within a power circuit in order to optimize power consumption.

Abstract: A power protecting apparatus and method of a power amplifier for removing backward voltages and preventing a hard damage within a circuit by connecting an output terminal of a DC-DC converter with an input terminal of a filter using diodes when an excessive backward voltage is generated due to physical characteristics of an inductor within the circuit at the time of applying high power level and low power level to the power amplifier using switching devices within a power circuit in order to optimize power consumption.