IRSM836-084MA

11

February 9, 2016

Fault Reporting and Programmable Fault Clear Timer

The IRSM836-084MA provides an integrated fault reporting output and an adjustable fault clear timer.

There are two situations that would cause the IRSM836-084MA to report a fault via the FLT pin. The first is an

under-voltage condition of VCC and the second is when the ITRIP pin recognizes a fault.

The fault clear timer provides a means of automatically re-enabling the module operation a preset amount

of time after the fault condition has disappeared. When a fault condition occurs, the fault diagnostic output (FLT)

stays in the low state until the fault condition has been removed and the fault clear timer expires; once the fault

clear timer expires, the voltage on the FLT pin will return to the logic-high voltage. Figure 4a is a block-level

diagram that focuses on the fault diagnostic and fault clear timer functionality of the driver chip within the module.

The fault clear timer is defined with a simple resistor-capacitor (RC) network on the RCin pin, as shown in Figure

4b.

Figure 5 is a timing diagram showing the states of the FLT and RCin pins during both normal operation and

under a fault condition. Under normal operation, both FLT and RCin are in high impedance (open drain) states.

VSS

– C

and the fault clear timer begins

– that is, C

Figure 4a: Block diagram showing internal

functioning of fault diagnostic and fault clear timer

Figure 4b: Programming the fault clear timer

HIN (x3)

RCIN

EN

ITRIP

FLT

VRx

LIN (x3)

IRSM836-084MA