Datasheet
Application Note 13 2015-02-11
Revision 1.0
ISO2H823V2.5 Evaluation Board
Board Manual
Functional Description
The thermal hysteresis is reset during inactive mode. Therefore when switching to the active mode the power
transistor is first switched on if the junction temperature is below 150°C.
Current Sense and Limitation
To achieve an excellent accuracy for the current limitation and current referred diagnostic (OCLx) an external
reference resistor is used. The nominal resistor value is 6.81 kΩ , the tolerance should be within 2% to meet an
overall current limit tolerance from 0.73 A to 1.3 A.
To offer open load diagnostics in active mode, a part of the power transistor is driven down when the drain-source-
voltage drops below a certain limit (low load condition). The voltage drop across the remaining part is used to
evaluate an open load diagnostic.
Diagnostic Functions
For each of the output stages 5 different types of diagnostics are available.
Table 3 specifies the diagnostics.
Some of the diagnostics are available only in active mode, others only in inactive mode. The diagnostics OLIx,
OLAx, SCVx can be prolonged within the complementary mode. Overtemperature in inactive mode is not reported
(set to zero).
Table 3 Diagnostic
Item Diagnostic Type Inactive Mode Active Mode
OTx Overtemperature no yes (OTx Active)
OLIx Open Load/Wire Break, “inactive” yes no
OLAx Open Load/Wire Break, “active” no yes
OCLx Current Sense,
Overload Detection
no yes
SCVx Short Circuit to V
BB
yes not distinguishable from OLAx