Research And Design Of The Low Frequency Pulse Power Amplifier Based On Adaptive Power Supply

With the improvement of people’s safety awareness during industrial production, low-frequency pulse power amplifiers are widely used in industrial alarm. As the most important section of all kinds of ships, police cars and other transportation facilities, low-frequency pulse amplifier is an effective means to protect the safety of people traveling and working. Designing a pulse power amplifier with a high efficiency and adjustable output power to solve various safety problems has a practical significance to industrial production. However, how to make power section only use one stage DC-DC conversion to achieve boost-buck function to improve the conversion efficiency is still a challenge for power, which used one stage DC-DC conversion to realize the boost-buck function, and power driver stage work in the wide voltage range. The problems that current power driver stage’s working voltage is immutable and power output efficiency is low was solved in this design. It can be widely applied in different industrial alarm.Firstly, an adaptive power was designed on the basis of the operating theory of the flyback converter. Boost-buck power supply was designed by using UC3843power chip and the operating theory of the flyback converter,12-24V was inputted, output2.3-60V and it can be continuously adjustable. Optoelectronic coupler PC817and comparator HA17358was used as the regulated power supply feedback loop. It is exponential relationship between output voltage and variable resistance.Secondly, pulse power amplifier driver stage was designed based on bootstrap diode and MOSFET hybrid driver. The system could work under the wide voltage range of adaptive output power. And two same groups of hybrid driver composited BTL type with source-drain pressure drop of MOSFET is very small when saturated conductivity and schottky diode’s pressure drop is small when it conducts, achieving the goal of power driver stage the characteristics of high efficiency which reached to95%and simple circuit.In this dissertation, the adaptive power has achieved the function of boost-buck voltage after one stage DC-DC converter, and current detection used the method based on MOSFET’s body resistance, so adaptive power has high efficiency which is between89%-95%. Power amplifier driver stage worked under wide range of voltage, and overcame the disadvantages of low efficiency, circuit complexity and tone changes when volume changes of current pulse width way to adjust output power. The whole machine efficiency of pulse power amplifier is between87%～92%. According to the index features between pulse power amplifier output power and variable resistance and the logarithmic features of the human ear hearing, pulse power amplifier achieved the goal of the human ear hearing induction linearization.