Datasheet

TMC2590 DATASHEET (V1.0 / 2019-FEB-22) 47
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12.3 Temperature Sensors
The driver integrates a four-level temperature sensor (100°C pre-warning, 120°C overtemperature
release and selectable 136°C / 150°C thermal shutdown) for diagnostics and for protection of the IC
and MOSFETs as well as for adjacent components against excess heat. Choose the overtemperature
level to safely cover error conditions like missing heat convection. Heat is mainly generated by the
power MOSFETs, and, at increased voltage, by the internal voltage regulators. For many applications,
already the overtemperature pre-warning will indicate an abnormal operation situation and can be
used to initiate user warning or power reduction measures like motor current reduction. The thermal
shutdown is just an emergency measure and temperature rising to the shutdown level should be
prevented by design.
Hint
After triggering the overtemperature sensor (ot flag), the driver remains switched off until the system
temperature falls below the overtemperature release level (120°C) to avoid continuous heating to the
shutdown level. Cool down typically needs a few 100ms to 1 second.
The high-side P-channel gate drivers have a temperature dependency which can be compensated to
some extent by increasing the gate driver current when the warning temperature threshold is
reached. The chip automatically corrects for the temperature dependency above the warning
temperature when the temperature-compensated modes of SLPH is used. In these modes, the gate
driver current is increased by one step when the temperature warning threshold is reached.
12.4 Undervoltage Detection
The undervoltage detector monitors both the internal logic supply voltage and the supply voltage. It
prevents operation of the chip when the MOSFETs cannot be guaranteed to operate properly because
the gate drive voltage is too low. It also initializes the chip at power up.
In undervoltage conditions, the logic control block becomes reset and the driver is disabled. All
MOSFETs are switched off. All internal registers are reset to zero. Software should additionally monitor
the supply voltage to detect an undervoltage condition. If software cannot measure the supply
voltage, an undervoltage condition can be detected by reading out the SE current value. Following a
reset due to undervoltage occurs, the CS parameter is cleared, which is reflected in an SE status of 0
in the read response.
Status
Description
Range
Comment
OTPW
Overtemperature warning. This bit indicates
whether the warning threshold is reached.
Software can react to this setting by reducing
current.
0 / 1
1: temperature
prewarning level
reached
OT
Overtemperature shutdown. This bit indicates
whether the shutdown threshold has been
reached and the driver has been disabled.
0 / 1
1: driver shut down
due to over-
temperature
OTSENS
Program overtemperature threshold to a reduced
level in order to give better protection for the
external power stage and other components. The
driver re-enables when the temperature falls
below 120°C.
0 / 1
0: 150°C
1: 136°C
Status
Description
Range
Comment
EN_PFD
Set this bit to allow operation with a 5V only
supply. This bit additionally controls resonance
dampening of the motor.
0 / 1
Undervoltage level
0: <7V
1: <4.5V