SLOS754C June 2012 – August 2016 DRV2603
With no output filter, the output waveform from the DRV2603 looks similar to Figure 1. The output signal contains both a high frequency PWM component and a fundamental drive component which causes motion in the actuator. To measure or observe the fundamental drive component, a low-pass filter must be used to eliminate the PWM component. The digital filter function on a digital oscilloscope was utilized in the rest of the Typical Characteristic figures. A 1st order, low-pass filter corner between 1 kHz and 3.5 kHz is recommended.
If a digital oscilloscope with digital filtering is not available, a 1st order, low-pass, RC filter network can be used instead. Care must be taken not to use a filter impedance that is too low. This can interfere with the back-EMF behavior of the actuator and corrupt the operation of the auto resonance function. A recommended circuit is shown in Figure 8.