Hello,
I am working on a project with DRV11873.
I made my own DRV11873 board to test the IC.
In the movie below you can see 2 soldered boards - it's like the evaluation board of DRV119873, but split into 2 boards:
- left board - it's a part of timer555 and it's PWM generation (it was my first board which worked very well, but suddenly it died, so I created new board with only DRV11873 part)
- right board - it's a part of DRV11873 recommended in it's datasheet
The video shows the problem:
Don't care about left board - it works just fine, I checked it's PWM generation (by changing potentiometer output it generates 0 to ~5V signal).
The problem is somewhere with right board - the DRV11873 part. As you can see it has a motor connected to it. The motor is alive and working. It's a 12V motor from an old HDD.
Electrical schematic:
It's basically almost the same as it is in DRV11873Eval Board datasheet but without PWM generation part.
Can you, after watching the schematic and the video, tell me what's wrong with the whole structure of connections?
What I already did:
- made a voltage regulator board (with L7812) and powered the driver - I thought it's something with the power part, but nothing changed,
- few times changed the filter capacitors (C4, C5 in my scheme) to bigger capacitors - no change,
- even changed C4,C5 to non-SMD capacitors (because I thought that it's something with their structure [X5R, X7R, Y5V..] [I read about SMD capacitors capacity dependance over changing voltage - that's why] - nothing changed.
What I measured:
- 12V does go to IC,
- 5V does go out IC (LED proves it),
- ALL connections are good,
- non-connected PWMIN pin to PWM source has ~5V over it - when connected it gets voltage from PWM,
- between CPP and CPN there's ~12V,
- VCP has ~18V,
- every motor pin (MOTA, MOTB, MOTC, MOTCOM) has ~3,5V when the motor does not move (changing when moving),
- Motor "moves" like on the video every ~3 secs.
Any ideas?
