powerSTEP01 integration failure

[shilchenbach]

Hello powerSTEP01 Experts,

 

we did a re-design of our powerSTEP01 driver PCB. Unfortunately, we created a problem in the new electronic, which causes the powerSTEP01 not working anymore and after weeks of test and research, we can't find the reason for this. So, we hope someone can give any advice to locate problem. The device is behaving like follows:

•  After a power reset, the first drive command causes a current pulse of 3A at 4V von OUTA and the motor stalls.
•  After this, the voltage level on OUTA1 and OUTA2 remains GND. On OUTB1 we have 1V.
•  The STALL_A, STALL_B and OCD bits remain set to 1 (no error)
•  It seems like the powerSTEP01 is trying to move the motor, not knowing that OUTA isn't working.
•  We have several new electronics behaving like this.

Did anyone observe this behavior before? What can be the reason for this?

 

Thank's in advance,

Stephan

[Peter BENSCH]

This behaviour usually points to a hardware issue in the output stage or current-sense path, rather than a software problem. Please check:

• OUTA1/OUTA2 for a short to GND
• Sense resistor value and Kelvin routing
• Motor wiring and coil continuity
• Decoupling capacitors and power grounding
• Whether the status bits are interpreted correctly
• Possibly latched overcurrent protection

Additionally, the question arises: what did you change in the redesign?

Regards
/Peter

[shilchenbach]

Hello Peter,

thank you for the support.

In the re-design we added the sense-resistor for optional current-mode driving. But I already shortcut the sense-resistors, cut the sense-inputs and wired them to ground. There is no short to ground at the OUTA/B signals.

In the re-design we changed the foot-print for better soldering, but the rest is identically.

Best Regards,

Stephan

 

[shilchenbach]

Hello,

ich checked 6 of our new powerSTEP01 circuit boards show the same failure. Only OUTA1 remains on GND level after a speed command. I can measure all 4 reverse-bias diodes with 0.53V from GND to the outputs. When the device is in High-Z, all outputs show 24V. Which condition can cause only OUTA1 to fail?

Best Regards,

Stephan