Datasheet

TMC2590 DATASHEET (V1.0 / 2019-FEB-22) 46
www.trinamic.com
As the low-side short detection includes the sense resistor, it is sensitive to the actual sense resistor
and provides a good precision of overcurrent detection. This way, it will safely cover most overcurrent
conditions.
Hint
Once a short condition is safely detected, the corresponding driver bridge (A or B) becomes switched
off, and the s2ga or s2gb flag, respectively s2vsa or s2vsb becomes set.
To restart the motor, disable and re-enable the driver.
Attention
Short protection cannot protect the system and the power stages for all possible short events, as a
short event is rather undefined and a complex network of external components may be involved.
Therefore, short circuits should basically be avoided.
12.2 Open-Load Detection
Interrupted cables are a common cause for systems failing, e.g. when connectors are not firmly
plugged. The TMC2590 detects open load conditions by checking, if it can reach the desired motor coil
current. This way, also undervoltage conditions, high motor velocity settings or short and
overtemperature conditions may cause triggering of the open load flag, and inform the user, that
motor torque may suffer. In motor stand still, open load cannot be measured, as the coils might
eventually have zero current.
Hint
Open load detection is provided for system debugging. Open load detection does not necessarily
indicate a malfunction of the driver.
In order to safely detect an interrupted coil connection, read out the open load flags at low or
nominal motor velocity operation, only. However, the ola and olb flags have just informative
character and do not cause any action of the driver. False indication may result with full- or halfstep
operation. Use microstepping for a safe result.
The open-load detection status is indicated by two bits:
Status flag
Description
Range
Comment
SHORTA
The SHORT bits identify a short condition on coil
A or coil B persisting for multiple chopper cycles.
The bits are cleared when the MOSFETs are
disabled.
Detailed warning for high-side or low-side FETs
is available in S2VSA and S2VSB (low-side short
detector) and S2GA and S2GB (high-side short
detector)
0 / 1
0: No short detected
1: Short detected
SHORTB
S2VSA
S2VSB
S2GA
S2GB
Status flag
Description
Range
Comment
OLA
These bits indicate an open-load condition on
coil A and coil B. The flags become set, if no
chopper event has happened during the last
period with constant coil polarity. The flag is not
updated with too low actual coil current below
1/16 of maximum setting. It is a pure indicator.
No action is taken depending on these flags.
0 / 1
0: No open-load
detected
1: Open-load
detected
OLB