ISO8200B datasheet(25/33 Pages) STMICROELECTRONICS

25 / 33 page

ISO8200B

Power section

Doc ID 023802 Rev 1

25/33

7.2

Thermal protection

The device is protected against overheating due to overload conditions. During the driving

period, if the output is overloaded, the device suffers two different thermal stresses, the

former related to the junction, and the latter related to the case.

The two faults have different trigger thresholds: the junction protection threshold is higher

than the case protection one; generally the first protection that is activated in thermal stress

conditions is the junction thermal shutdown. The output is turned off when the temperature

is higher than the related threshold and turned back on when it goes below the reset

threshold. This behavior continues until the fault on the output is present.

If the thermal protection is active and the temperature of the package increases over the

fixed case protection threshold, the case protection is activated and the output is switched

off and back on when the junction temperature of each channel in fault and case

temperature are below the respective reset thresholds.

Figure 17 shows the thermal protection behavior, while Figure 18 reports typical

temperature trends and output vs. input state.

Figure 17.

Thermal protection flowchart

Input IN(i) HIGH

Output (i) ON

Fault(i) Off

TJ(i) >TJSD

TC >TCSD

TC >TCR

Output (i) OFF

Fault(i) ON

TJR >TJ(i)

AM14995v1

ISO8200B Datasheet(PDF) 25 Page - STMicroelectronics