DRV110: DRV110 Audible Ring

Hi Michael,

I will look into this issue and ty to replicate in the lab. Please give me 24 hours and I will reach out when I know more. 

Best,

David

Hi Michael,

Does the ringing still occur when the load is driven at lower frequencies?

Best,

David

I will try this later today. I thought that might not have been idea since a lower PWM would bring it more into the audible range. I'll shoot for 16kHz as a test. 

Hi Michael,

I would also suggest checking to see if the current slew rate has changed when replacing the op amp and FET. Sometimes low frequency component can be heard if slew rate is too slow. 

Best,

David

I took some scope captures of the Gate and voltage across the FET. Looks like it's not switching at a fixed 20kHz but rater 36kHz and 13kHz. The gate doesn't fully saturate but it does get past the point where the FET is fully "turned on". I don't believe it's due to the FET switching too slow or fast the rise time I measured and calculated is ~500nS, which seems reasonable. 

I also swapped the FET out for the same as the previous rev and still the ringing persist. 

Scope Capture Purple Voltage across the FET Yellow is the Gate Voltage. Bottom right shows the frequency of the cursors. 

No Luck reducing the freq to 16kHz using a 249kOhm Rosc resistor. 

Hi Michael,

I will use one of our EVMs in the lab tomorrow to try and duplicate this issue. I will reach within 24 hours with what I find. 

Best,

David

Thanks David. Let me know if you need any thing from my side (scope captures, different value components to try...) to help root cause this. 

Hi Michael,

I was not able to reproduce the issue. I saw some ringing on the output voltage pin, which is from the FET switching but nothing significant on the current. 

Using the EVM I matched all the conditions you mentioned for the inputs. My input voltage was 24 V. 

The 52VDC is exceeding the abs max for this part. Does this issue still occur when the input voltage is reduced. 

Another difference from the above schematic is the SENSE pin capacitance, could you try changing this to 100pF?

I would also suggest purchasing the DRV110EVM to speed up the testing and try different configurations. 

DRV110EVM Evaluation board | TI.com

Best,

David

Hi Michael,

Thanks for the update, this is good to know.

If this is not suitable for your design, and you need any alternate device recommendations please check out some of our newer solenoid drivers:

DRV8803 data sheet, product information and support | TI.com 

DRV8844 data sheet, product information and support | TI.com

DRV8952 data sheet, product information and support | TI.com

Best,

David

Thanks I will take a look