Other Parts Discussed in Thread: TPS54040, DRV8312
Hi,
Have been using the DRV83053 for a while; I've had successes with it, failures too. The board what I am using is my own, but is very similar to the BOOSTXL-DRV8305.
I've posted a picture of the board in this thread.
I am attaching the schematic here:
Previously, it was not quite evident what caused the failures, but recently I've been able to identify a bit more as to what's probably happening. Maybe the issue could be sorted out with some help and hence the post.
After fixing the issue as in my previous post. outlined here:
the board has been functioning and has been running quite well, even with motor being braked physically. It looked quite pretty.
Some days back
DRV8305 latest failure situation - Situation log
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* Motor got stuck due to a mechanical fault, while running.
* SMPS tripped and shut down likely due to OCP
* Smell of cashews being roasted.
* Switched off Power
* Switched ON after a few minutes, SMPS powered ON. Motor does not run.
* No 3.3V LDO output on the DRV8305 - have a Green LED with 330 ohms connected to the LDO output. Likely draws about 10mA. The LED is not lit.
* Checking and looking deeper,
- no visible burns/cracks:
- Initial checks showed L1 (a 0.47Ohms resistor is connected in that position) went open
- Looking deeper, C21, C22 (47nF) capacitors are shorted internally
- Looking further, R5 100ohms resistor is open
- C4 appears to be shorted internally.
- MOSFET's appear okay, checking with a meter.
* Removed C21, C22 (47nF) capacitors
- C21 is really shorted internally
- C22 appears okay, checked with a LCR meter, shows 47nF
- Checking impedance between DRV8305 Pins 43 & 42, it appears they are shorted internally.
- Checking impedance between DRV8305 Pins 39 & 40, it appears they are shorted internally.
- Removed C4 (2.2uF) capacitor, it appears okay, LCR meter shows 2.2uF
- Checking impedance between DRV8305 Pins 38 & 41, it appears they are shorted internally.
So, it appears that the DRV8305 is dead too, without diving any further deep.
What could cause the charge pump capacitors to fail thus. This has been the standard way the failures has been happening each and every time. Once the bootstrap capacitor fails, likely the DRV8305 also fails. Thus the resistor too. This one problem is holding me back from proceeding on this project, for a while. Sigh!
I wonder what could be causing this issue ? Anything that could be changed in the design to avoid this issue over and over again ? (I have tried looking into each and everything that I could read about it, but cant seem to find what I am missing)
HELP! HELP! Can someone please help ?
Thanks,
Manu