基于PWM滤波的数模转换电路的开发与设计

Development and design of digital analog conversion circuit based on PWM filter

文中针对现阶段单片机微处理器未有D/A转换器或自带D/A转换器精度过低，使得交流伺服电机需要额外外接高速高精度D/A转化器而使电路成本上升，面积增大的问题，开发与设计了基于PWM滤波的数模转换电路。其利用单片机微处理器内部自带的定时器产生PWM波，然后经过隔离，滤波，放大后形成－10~10 V的模拟信号，满足了交流伺服电机的工作要求。同时降低了成本，避免了额外的电路面积。仿真结果表明，该电路转换速度快，误差小，具有较高的D/A转换特性。

This paper in view of the present stage microprocessor no D/A converter or comes with low accuracy of the D/A converter additional external high speed and high precision D/A converter and makes the circuit costs rise and area increase in the AC servo motor, develop and design the digital to analog conversion circuit based on filtered PWM, the microprocessor built-in timer to generate PWM wave and after isolation, filtering, amplification formation simulation signal-10v to 10V, to meet the requirements of AC servo motor, while reducing the cost, avoid the additional circuit area. The simulation results show that the proposed circuit has high conversion speed, small error and high D/A conversion characteristics.