PMW low pass filtering


Pulse width modulation (PWM) amplifiers often require low-pass filtering of the output to demodulate the PWM carrier. These filters can be as simple as a single inductor to multiple LC nodes depending on the application. In some motor and solenoid applications, the load can act as its own filter. Deciding on the type and size of a filter can be time consuming since the calculations can be tedious and often give component values that are not easily obtainable. This application note is an effort to reduce filter calculation time.