188.8.131.52 Current Limited Load Switches
The TPS65218D0 provides three current limited load switches with individual inputs, outputs, and enable control. Each switch provides the following control and diagnostic features:
- The ON/OFF state of the switch is controlled by the corresponding LSx_EN bit in the ENABLE register.
- LS1 can be controlled by the sequencer or through I2C communication.
- LS2 and LS3 can ONLY be controlled through I2C communication. The sequencer has no control over LS2 and LS3.
- Each switch has an active discharge function, disabled by default, and enabled through the LSxDCHRG bit. When enabled, the switch output is discharged to ground whenever the switch is disabled.
- When the PFI input drops below the power-fail threshold (the power-fail comparator trips), the load switches are automatically disabled to shed system load. This function must be individually enabled for each switch through the corresponding LSxnPFO bit. The switches do not turn back on automatically as the system voltage recovers, and must be manually re-enabled.
- An interrupt (LSx_I) issues whenever a load switch actively limits the output current, such as when the output load exceeds the current limit value. The switch remains ON and provides current to the load according to the current-limit setting.
- All three load switches have local overtemperature sensors which disable the corresponding switch if the power dissipation and junction temperature exceeds safe operating value. The switch automatically recovers once the temperature drops below the OTS threshold value minus hysteresis. The LSx_F (fault) interrupt bit is set while the switch is held OFF by the OTS function.