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DRV2605: How can I get the normal Waveform as the reference

Robin Zhou
Intellectual 625 points
Part Number: DRV2605

Dear TI Expert,

There are several question about DRV2605. 

1.Is the output of DRV2605 sinusoidal or square? Is there a selection mechanism or how to set it up?

2.Waveform 1 and 3 in LRA Library of ROM. The values of OD_Clamp and Rate_Voltage registers are unchanged. I observed on the oscilloscope that the voltage amplitudes of the two waveforms are similar, but the waveform density of 1 is just higher than that of 3. But the data sheet says that 100% is higher than 30% of the voltage. What is the reason for this?

3. In the case of LRA mode and internal trigger, I2C communication. Can the output voltage amplitude be modified by OD_Clamp and Rate_Voltage registers when the waveform is output?

4. Are there some Reference materials  for the registers' settings and Waveforms?

  • 0
    TI__Guru* 84915 points
    Hi, Robin,

    Please take a look at my answers below and let me know if you have more questions or comments on this.

    1.- The output of DRV2605 is a differential PWM form that depend of the analog input. In order to get a sinusoidal output waveform, I would suggest to use an external RC filter (100Kohms, 470pF). This will filter the high-frequency content of the PWM signal to measure or analyze it with the help of a scope.

    2.- The OD_Clamp and Rate_Voltage don't affect the LRA library effects. These parameters are only used for other modes such the PWM and RTP modes. The library effects are predefined waveforms and the OD_Clamp and Rate-Voltage won't have any effect. The only parameters that can be modified are explained in the 7.3.5.2.2 section of datasheet ( www.ti.com/.../drv2605.pdf ).

    3.- Yes, in this case, these parameters can be modified and they will have an effect at the output.

    4.- Yes, please take a look at the following links:

    www.ti.com/.../sloa189.pdf
    www.ti.com/.../sloa194.pdf
    www.ti.com/.../getliterature.tsp

    Best regards,
    Luis Fernando Rodríguez S.