3.2.3 Shutdown Circuitry

On the baseboard, this circuitry is implemented but inhibited by default (R131 is not populated).

The SHDN signal, output of the shutdown controller, signals the shutdown request to the power supply. This output signal is supplied by VDDBU that is present in Backup mode.

The shutdown controller manages the main power supply and is connected to the ENABLE input pin of the DC/DC converter providing the main power supplies of the system.

Figure 3-9. Shutdown Controller