The first classification of loss of ground when using a Texas Instruments high-side switch is the loss of the local device ground. In this condition, other components of the overall system may have maintained a valid ground reference; however the ground that is referenced by the TI high-side switch has been lost. Figure 1-1 illustrates this condition.

The second classification of a loss of ground fault when designing with a TI high-side switch is the loss of ground of the entire module. As high-side switches generally power off board loads, this can be a loss of ground of the entire module or board such as an electronic control unit (ECU). Figure 1-2 illustrates this condition.

For both loss of local device ground and loss of global module ground, TI high-side switches will have built-in protection mechanisms to disable output and prevent damage. In this automatic shutoff condition, the device turns off the output to protect the downstream load. Once the ground reference is reestablished, the device returns to normal operation and the output follows the relevant signal on the IN pin.