DRV595 Distortion

William Tribley

Other Parts Discussed in Thread: DRV595, DRV595EVM

I have a simple application simulating an AC generator. The requirement is to drive a 4 ohm load with about 0.6A RMS (2.4W) max (zero up to that level) at frequencies between 55 and 65 Hz. I selected a DRV595 and purchased the DRV595EVM evaluation board. Using this board at 12VDC power with a signal generator at 60hz, the output fidelity into 33 ohms is terrible, the output into 4 ohms is better but not radically so, the peaks are defined but the transitions have noise and do not follow the input very well. It cleans up a little at 100Hz but not much.

Should I have selected a Class-D audio amp instead like the TPA3130? Any suggestions appreciated.

Thanks,

Bill

over 10 years ago

0 Don Dapkus over 10 years ago

TI__Guru**** 189399 points

Hi, Bill,

I took the liberty to move your post to the Motor Drive forum...

Anyway, I am surprised at this. Can you post some plots of the distortion that you are seeing?

-d2

0 William Tribley over 10 years ago in reply to Don Dapkus

Prodigy 50 points

Hi Don,

Thank you for your response. I have attached a description of our setup and resultant waveforms.

Regards,

Bill

tribley navsea drv595 nonlinearity description.pdf

0 William Tribley over 10 years ago in reply to Don Dapkus

Prodigy 50 points

Don,

The waveforms have been posted for a day and a half. Management is all over me to solve this, at this point I may just go with a Maxim class D audio amp solution.

Regards,

Bill

0 William Tribley over 10 years ago in reply to Don Dapkus

Prodigy 50 points

Hi Don,

I called application support, they indicated that things were delayed due to the Good Friday holiday. Standing by for any comment you may have on this.

Thanks,

Bill

0 Don Dapkus over 10 years ago in reply to William Tribley

TI__Guru**** 189399 points

Hi, Bill,

Sorry for the delay. There is something definitely wrong here. I am thinking your input biasing is the problem, but I am working to confirm that.

Try bringing the common mode voltage closer to ground. Right now, you have it around 6V which is probably too high.

-d2

0 William Tribley over 10 years ago in reply to Don Dapkus

Prodigy 50 points

Hi Don,

That was it. Set it to 3.25V and everything lit up. Went back to the data sheet, I should have noticed this:

VICM Input common-mode range 0.5 to 4.5V

I'll probably set it to 2.5V. Thanks for the help.

Bill

Motor drivers

Motor drivers forum

DRV595 Distortion