Were using the DRV8842 as a amplifier to drive a voice coil type actuator (2mH 8Ohms) with a 24V supply. The current regulation is disabled (Rsense = 0Ohm) and we use the DRV8842 as a voltage amplifier.
What we see is non-linear behavior from -3V to +3V.
This curve is different with every individual DRV8842 and can't be characterized. We have used multiple PWM modes and the result is always the same. A thing to notice is we see the PWM output edges jitter when the inputs (IN1,IN2) are stable microcontroller timer produced.
We expect the large dead-times or blanking times (dynamic) to be the problem. When i connect a H-bridge with a small dead time setting the output is linear around 0V.
Are we doing something wrong or is the linearity around 0V output just this unpredictable?
Thanks, Matthew