DRV632: The diconnected audio signal of wireless microphone receiver

Hi, Wesley,

Could you describe which circuit configuration you are using on the DRV632? It is actually not related to any of the functional modes described in the datasheet.

Best regards,
Luis Fernando Rodríguez S.

Hi team,

 1. It's a low-pass second-order filter circuit and it is adapted according to our experience.

 2. But I personally feel that this part of the circuit has nothing to do with the technical problems in the wireless microphone receiver, because the AD22650 works normally under the same circuit. 

 3.  What makes me curious is why the received signal of FM chip will be affected after changing to DRV632, so that the signal will be disconnected occasionally?  Could you please help me analysis that?

Best regards

Wesley Huang

Hi, Wesley,

What is the PVDD level at the DRV632?

In addition, could you try leaving floated the UVP pin? Does it have the same results?

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

1. The PVDD level is 3.0V.

2. When I leave floated the UVP or pull EN to ground, It works normal and doesn't appear the same results.

Best regards,
Wesley Huang

Hi, Wesley,

Thank you for your response. It seems that the UVP feature could be enabling the device protection. What is your purpose of connecting the UVP pin to a 10k resistor. Can it be left floated in your design?

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi, Wesley,

Excuse me, do you have a feedback on this?

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

Thanks for your tracking.

1. I think your analysis is a little bit confused. Because the signal has been disconnected before the 632 in the input of the FM chip. 

2. Besides that, if i left floated the UVP pin, the DRV632 will be shutdown and my system can't work normal.

Best regards,
Wesley Huang

Hi, Wesley,

Yes, I think we require some clarification. Do you mean that there's no signal at the DRV632 input? What is the power supplies state during this disconnection event?

Regarding the UVP pin, what are the expected Vuvp and hysteresis values that you expect? See details on section 9.3.7 ( https://www.ti.com/lit/ds/symlink/drv632.pdf#page=10 ).

Best regards,
Luis Fernando Rodríguez S.

Hi, Wesley,

Excuse me, do you have a feedback on this? 

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi, Wesley,

I'm closing this e2e thread due to the inactivity.

However, please feel free to post your questions or comments about this case. We will be glad to help you.

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

Thanks for your tracking.

1.Sorry for the delay because of the business trip.

2.  Yes, There's no signal at the DRV632 input when the disconnected case happened. The PVDD and UVP is normal after I tested the Waveform of these two PIN when the disconnected case happened.

3 .  I think the difference of the frequency of the charge pump between the AD22650 and DRV632 cause this issue.The frequency of the modulated signal in FM chip is set by the sofawre, so the difference of the frequenct of the charge pump will create the different EMI which effect the modulated signal in FM chip. Do you thinki it is reasonable？

Best regards,
Wesley Huang

refer to the newest reply

Hi, Wesley,

This is an interesting theory. Do you have a way to test your application with a different FM frequency? The DRV632 works with a frequency range of 200KHz to 400KHz.

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

Thanks for your tracking.

1.After I adapeted the FM frequency, the issue has been improved a little but still existed. Do you have other ways to verify the cause as I analysis?

2. If the cause is like my analysis, is there any other way to solve it expect adapting the FM frequency?

Best regards,
Wesley Huang

Hi, Wesley,

Based on the problem, it seems that the issue is associated to the FM device and not to the DRV632. We can provide support for the DRV632, but it seems that it is working correctly. It is not having output since it is not receiving an input signal.

Is your FM device a TI device? If so, our experts can help you in order to analyze the issue on this device.

Best regards,
Luis Fernando Rodríguez S.

Hi, Wesley,

Do you have any update on this?

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

Thanks for your tracking.

I'm doing experiments to verify some problems, and then upload them to you for analysis.

Best regards,
Wesley Huang

Thank you, Wesley,

We will wait for your feedback.

Have a good day!

Best regards,
Luis Fernando Rodríguez S.

Hi, Luis,

Thanks for your tracking.

You have given me the direction of analysis and I will handle the rest.

Best regards,
Wesley Huang