Microprocessor based temperature and DC protection control

Abstract

The aim of this project is using a microprocessor to protect an amplifier and speaker. They are very weak and easy to damage. Therefore, the microprocessor could control the power of amplifier and speaker. The most of audio amplifier circuit, a transistor must be included. In fact, the transistor's characteristics have changed and affect the performance at higher temperatures. Therefore, we use a fan to cool down the temperature when the temperature is over 30 degree C. After the microprocessor gets the environment temperature, it uses the PWM method to change the speed of fan. Moreover, the current temperature has displayed on two 7-segment LEDs. The microprocessor has other functions, which included AC loss detection, DC fault protection, clipping detection and re-triggerable monostable controller, to protect the amplifier. The monostable method can protect the speaker even if the microprocessor fails. All the functions are made sure the amplifier, which could be safe during operation. If the microprocessor detects any error in the circuit, it will cut off the power of speaker immediately.