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Hello,
I am trying to get a haptic feedback either using LRA motor with DRV2605, or using piezo with DRV2605/DRV2700 (based on application report SLOA255).
When using just LRA, the haptic feedback is barely noticeable. However, when the LRA is driven directly from a power supply, the feedback is strong.
When using the DRV2700 with a signal from DRV2605, there is no feedback can be felt. I also notice that the FB pin does not output 1.3V. Thus my PVDD signal is around 10V instead of 65V.
Attached is the schematics of the haptic driver circuit. The selection between Piezo or LRA is done using J1 and J2 jumpers.
LRA motor - 1020-15-003-001 (www.digikey.ca/.../j2rmtd)
Piezo - Z63000Z2910Z 1Z 2 (www.digikey.ca/.../j2rm8v)
I am looking for any possible recommendation.
Thank you.
Regards,
Leon
Hello Ivan,
Thank you for your prompt reply.
For some reason, I thought that the motor is LRA type. I will update the registers and will test it as ERM motor.
Regarding DRV2700 I have a few questions:
Regards,
Leon
Hello Ivan,
I wanted to update you regarding the motor test. After changing the registers to drive the ERM motor, the performance of the motor immediately improved. We will continue playing with registers to get the best results.
I understand your point regarding REXT on the DRV2700 circuit. I will replace the resistor and will update you on the results.
Thank you again for continuing support.
Regards
Leon
Hello Ivan,
Sorry for the delay in responding.
As mentioned in the above post DRV2605 works properly for us.
However, the DRV2700 still does not perform. I replaced REXT resistor to 10k. Unfortunately, it did not improve the performance. As soon as the EN pin is asserted high, the supply voltage drops from 5V to around 3.5V - 4V (board-dependent). Any suggestions? Troubleshooting steps?
Thank you.
Regards,
Leon
Hi Ivan,
All capacitors that are used for DRV2700 are 100nF, X7R, 20%, 50V (CGA2B3X7R1H104M050BD). I realize that C13 is below expected 68V boost voltage, but speaking with cap manufacturers, at 23 deg C, the capacitors can take significantly higher voltage than rated.
Anyway, if you believe that this might be an issue, please let me know and I will try to find a capacitor with a higher voltage rating.
Regards,
Leon
Ivan,
I replaced the C13 cap to 08051C104K4T2A (100V, X7R, 10% 0805). The only issue is that it is 0805, so I had to do some adjustment was required on the board. However, the connections are solid.
The input DRV2605 stage is disconnected by removing jumpers on J1 and J2. All other devices (except the microcontroller) are disabled by using their respective EN pins.
After powering the circuit the results did not change. The same results are observed.
Unfortunately, it would be extremely hard to power the DRV2700 from a separate power supply. It would require trace cutting, component lifting, and wire-up steps. I am not sure if that would be a good test.
Regards,
Leon
Hi Ivan,
Attached is the screenshot of SW pin during operation. Please note at this stage the DRV2700 is only powered and enabled. No piezo connected and no input provided.
The circuit is powered DC power supply and its limit is maxed (3A).
I did try a few other boards before I contact forum. Unfortunately, I see sort of the same issues.
When DRV2700 is powered and enabled, it is significantly affecting the supply rail (in some boards the supply drops to 4V and other to 3V). Please see the attached power circuit as well.
Hello Ivan,
I really apologize for long reply time. I was urgently dragged to a different project and I had to leave this project completely. I changed the 10uH inductor (IHLP2020BZER100M01) to 15uH inductor (IHLP2020CZER150M01). There is no change in performance.
Any recommendations?
Regards,
Leon