SECTION 16
FAULT PROTECTION
The IM481H is internally protected against over temperature, and over current.
The over temperature set point is between 60 and 70 °C. Care should be taken when
choosing and installing a heat sink so that there is a good thermal conduction, otherwise
hot spots may occur in the IM481H which will reduce the operating thermal range.
The over current protection consists of PHASE to PHASE, and +V to PHASE.
If an output driver in the IM481H detects an over temperature condition it will shut down
but will not activate the fault output. Once the temperature drops to a safe operating
temperature, the IM481H will resume operation.
If an over current fault is detected by the IM481H, the outputs will be disabled and cannot
be re-enabled without resetting the driver or by cycling power. At the same time the active
high FAULT output (pin 19) is enabled.
The FAULT IN input (pin 6) can be used to force a fault condition. When pulled low the
signal is latched and the outputs will be disabled. The fault condition can only be cleared
by cycling power or resetting the driver.
SECTION 17
THERMAL REQUIREMENTS
The IM481H may require heat sinking to maintain a safe operating temperature. Care
should be taken when mounting the IM481H to a heat sink with an electrically conductive
surface that an isolating thermal pad is used.
NOTE:
The watts dissipated by the IM481H can be calculated as follows:
Watts Dissipated = ( 0.6 x ( Peak per Phase Output Current )2 )
EXAMPLE: Peak per Phase Output Current = 1.4 amps
Watts Dissipated = 1.18
20
WARNING ! Rear mounting surface of driver contains
different voltages and must be kept isolated when attached
to a conductive surface !
An optional thermal pad ( Part # TI-481 ) and heat sink ( Part # H-481 ) is available
for the IM481H