The TPS2342 contains main supply power control, auxiliary supply power control, power FETs for 12-V, -12-V and auxiliary 3.3-V supplies, VIO control, and digital control of slots. Each TPS2342 contains supply control and switching for two slots. The TPS2342 supports both serial and direct communication to the slots. The main power control circuits start with all supplies off and all outputs are held off until all power supplies to the TPS2342 are valid. When power is requested via the serial interface or by direct control, the control circuit applies constant current to the gates of the power FETs, allowing each FET to ramp load voltage linearly. Each supply can be programmed for a desired ramp rate by selecting the appropriate gate capacitor. The power control circuits monitor load current and latch off that slot if the load current exceeds a programmed maximum value. Once the 12-V, the 5-V, and the 3.3-V FETs are fully enhanced, the load voltage is monitored. If the load voltage drops out of specification after these FETs are fully enhanced, the slot latches off. |