TDA4VM-Q1: Reverse current measurement ways

Vyom,

I'm not sure I completely understand your theory here. Can you please give more specifics about your setup and what led you to the theory about reverse current? 

Are you saying that there is electrical damage occurring to your 964 IC? Or something else in the system is getting damaged? 

What kind of test are you doing on this system when the damage occurs? Hot plugging cameras? Hot unplugging cameras? Other?

Best Regards,

Casey 

Dear Casey,

Thanks for the response!

The reason for suspecting the reverse current is due to following observations

- The TDA4VM setup with deserializer in vehicle was working from few days and last tested on Friday, and then suddenly the same setup stopped working      yesterday(this kind of behavior was observed earlier while using 4-camera in-vehicle testing)

- I have an extension board to connect power supply, where LED's shows that the L and N Reverse and N Open, I am sharing the video of the same

Just to confirm the same through other methods, I would like to know how we can measure this reverse current?

Observation could be wrong but our deserializer's are not working and we need to find the cause.

Few observations more 

- Over heating of the deserializer ( just within few minutes of use)

- Slow loading of the sensor initialization logs

This issue I have already reported 2 months back, please find the query for your reference  https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1339361/tda4vm-q1-application-logs-loading-slowly-and-camera-is-not-started

Thanks and Regards,

Vyom Mishra

Vyom,

I still don't understand what you mean about reverse current. This board doesn't have the capability to back feed the 12V power supply. In fact there is a Schottky diode on the input rail to prevent backfeed to the power supply:

Have you tried plugging the kit into a different power supply? Looks like the one you are using may be broken. 

What kind of test are you doing on this system when the damage occurs? Hot plugging cameras? Hot unplugging cameras? Other?

How are you concluding that the deserializer is overheating? Do you have a thermal image of the board to share? I think more likely may be that there is something shorted in the PoC network connections or one of the PoC LDOs is damaged. Have you checked to see if you are getting the expected output voltages from VFEED_LDO1 and VFEED_LDO2?

Best Regards,

Casey 

Dear Casey,

Thanks for the detailed information shared!

Have you tried plugging the kit into a different power supply? Looks like the one you are using may be broken. 

We have used multiple extension boards and observed the same, this extension board might not be accurate but created suspection.

What kind of test are you doing on this system when the damage occurs? Hot plugging cameras? Hot unplugging cameras? Other?

We have vehicle setup with 4-camera's , we were using DES UB964 board 1 and it stopped sending camera feed to EVM. Then connected another new DES UB964 and the same setup was working. The non-working DES UB964 got heated very badly with no reason.

How are you concluding that the deserializer is overheating? Do you have a thermal image of the board to share?

Physical observation while touching with hands compared to the working DES, I am not aware about creating the thermal image of the board, please let me know how I can generate and share to you?

 I think more likely may be that there is something shorted in the PoC network connections or one of the PoC LDOs is damaged. Have you checked to see if you are getting the expected output voltages from VFEED_LDO1 and VFEED_LDO2?

I will check this and let you know

Thanks and Regards,

Vyom Mishra