Manualshelf

Data Sheet

ManualsBrandsPololu ManualsStepper Motor ControllersPololu TB67S249FTG Stepper Motor Driver Carrier (1.7 A continuous)
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TB67S279FTG, TB67S289FTG, TB67S249FTG Application Note
2018-03-07
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Preliminary
11.6. Error detection function
This IC incorporates a thermal shutdown circuit (TSD) and an over current protection (ISD),
which are unique error detections to power ICs, in addition to a general UVLO function. Each
function is described below.
11.6.1. Thermal shutdown circuit (TSD)
When the junction temperature of the IC reaches a preset specified value, the internal detection
circuit operates to turn off the output block. The dead band time is provided to avoid a false
detection, which is caused by switching and so on. While TSD is activated, the operation of the IC
is in the standby mode continuously. To release this function, apply the power supply again or
configure the standby mode by DMODE0, DMODE, and DMODE pins. TSD function is activated
when the IC is overheated irregularly. Therefore, do not use the TSD function often.
11.6.1.1. Dead band time of thermal shutdown circuit
This IC has a system clock (f
OSCS
= 6.4 MHz (typ.)) to count up a dead band time for the error
detection. Thermal shutdown circuit can avoid a false detection by configuring the dead band time,
which is counted by the system clock.
tTSD = 5 μs (typ.)
11.6.2. Over current protection (ISD)
When the motor output current exceeds a specified value, over current protection circuit, which is
implemented in the output block, operates to turn off the output block. The dead band time is
provided to avoid a false detection, which is caused by switching and so on. While ISD is activated,
the operation of the IC is in the standby mode continuously. To release this function, apply the
power supply again or configure the standby mode by DMODE0, DMODE1, and DMODE2 pins.
11.6.2.1. Dead band time of over current protection
This IC has a system clock (f
OSCS
=6.4 MHz (typ.)) to count up the dead band time for the error
detection. Over current protection can avoid a false detection by configuring the dead band time,
which is counted by the system clock.
tISD = 1.25 μs (typ.)