In many automotive modules, the high-side switch
must provide diagnostic information about the downstream load. More complex loads
require high accuracy sensing. A few examples follow:
- LED Lighting: In many architectures, the
Body Control Module must be compatible with both incandescent bulbs and also LED
modules. The bulb can be relatively simple to diagnose. However, the LED module
consumes less current and also can include multiple LED strings in parallel. The
same BCM is used in both cases, so the high-side switch must be able to
accurately diagnose both load types.
- Solenoid Protection: Often solenoids are
precisely controlled by low-side switches. However, in a fault event, the
low-side switch cannot disconnect the solenoid from the power supply. Use a
high-side switch to continuously monitor several solenoids. If the system
current becomes higher than expected, the high-side switch can disable the
module.