电流型功率放大器保护电路设计

Design of Protection Circuit for Current-mode Power Amplifier

电流型功率放大器工作在高电压、大电流情况下,因此保护电路更为重要。分析了功率放大器中功率管容易损坏的情况,研制了避免功放损坏的电路。死区硬件产生电路可以防止因程序故障造成的死区时间减小而导致桥臂短路损坏;当出现上下桥臂同时导通的信号时,防误导通电路可以中止功率驱动芯片IR2110的信号输出;当出现干扰信号导致全桥电路同侧导通时,短路保护电路中止功率驱动芯片的输出,同时还具有过流保护的功能。经过实验验证,这些电路在实际应用中效果良好。

Protection circuit is important when current-mode power amplifier works in high-voltage and high-current circumstance.This paper analyzes the conditions which will resuh in power amplifier destruction.Dead-time cireuit,antiwrong start station and short-protection circuit were designed to avoid the damage of the circuit.Dead-time circuit could prevent the short-arm bridge from damaging caused by the reducing of dead-time due to program failures.When the two MOSFETs of one side given the same signal of turning on,anti-wrong circuit would stop the output signal of the drive IC IR2110.If the disturbance signal lead to the turning on of the two MOSFETs of one side of the full bridge circuit at the same time, short-cireuit protection might hold back the output signals of the power drive chip, it also had the function of over-current protection.These circuits are validated by experiment and applied in machine successfully.