Voltage sequencing circuit for powering-up sensitive electrical components

A device comprising:

• an electrical system that includes a plurality of circuits designed to be powered from different electrical power sources;
• and
• a voltage sequencer coupled to the electrical system and supplying power to the plurality of circuits in the electrical system, the voltage sequencer including:
• a plurality of power regulators for supplying the power to the plurality of circuits in the electrical system,
• a power monitor connected to outputs of the plurality of power regulators, the power monitor detecting failures in the power supplied by the power regulators, and
• decision logic connected to the plurality of power regulators and to outputs of the power monitor, the decision logic performing a power-up sequence of the electrical system by sequentially enabling the plurality of power regulators and verifying, based on the outputs from the power monitor, that an enabled one of the power regulators is producing stable output power before enabling a next one of the plurality of power regulators.

A method for powering-up an electrical system to receive power from a plurality of different power sources, comprising:

• (a) enabling a first one of the plurality of power sources to source power to the electrical system;
• (b) waiting a predetermined period for the power from the first power source to settle;
• (c) beginning to monitor an output of the first power source for a failure in the sourced power;
• repeating (a), (b) and (c) for each additional power source in the plurality of power sources;
• and
• disabling all of the enabled ones of the plurality of power sources when any of the monitored power sources fail.