A power management device comprising a power management processing unit and a separate safety unit; the power management processing unit comprising: an input configured to receive current at an input voltage (VBAT); a plurality of power units (120a-e) each configured to supply current from the input at a respective output (125a-e), and a main sequencer configured to implement a power-up sequence in which the plurality of power units (120a-e) are powered-up to supply said respective current in a predetermined sequence stored in the main sequencer; the safety unit comprising: a plurality of voltage monitors (155a-e) each configured to monitor the output voltage of a respective one of the power units (120a-e); a power-good unit, configured to provide a power-good output signal (PGOOD) indicative of normal operation of the power management device; wherein the safety unit further comprises a safety sequencer, distinct from the main sequencer and configured to store sequence data; and wherein the safety unit further comprises a safety processing unit, configured to use the sequence data stored in the safety sequencer to monitor the plurality of power units (120a-e) during the power-up sequence by means of the respective voltage monitors (155a-e), wherein the safety unit further comprises a fail-state unit configured to provide an output (FSOB) indicative of a fail-state of the power management device, and wherein the safety processing unit is further configured to provide the output (FSOB) to at least one of the power-good unit and the fail-state unit in response to the monitoring. a power management processing unit and a separate safety unit; the power management processing unit comprising: an input configured to receive current at an input voltage (VBAT); a plurality of power units (120a-e) each configured to supply current from the input at a respective output (125a-e), and a main sequencer configured to implement a power-up sequence in which the plurality of power units (120a-e) are powered-up to supply said respective current in a predetermined sequence stored in the main sequencer; an input configured to receive current at an input voltage (VBAT); a plurality of power units (120a-e) each configured to supply current from the input at a respective output (125a-e), and a main sequencer configured to implement a power-up sequence in which the plurality of power units (120a-e) are powered-up to supply said respective current in a predetermined sequence stored in the main sequencer; the safety unit comprising: a plurality of voltage monitors (155a-e) each configured to monitor the output voltage of a respective one of the power units (120a-e); a power-good unit, configured to provide a power-good output signal (PGOOD) indicative of normal operation of the power management device; a plurality of voltage monitors (155a-e) each configured to monitor the output voltage of a respective one of the power units (120a-e); a power-good unit, configured to provide a power-good output signal (PGOOD) indicative of normal operation of the power management device; wherein the safety unit further comprises a safety sequencer, distinct from the main sequencer and configured to store sequence data; and wherein the safety unit further comprises a safety processing unit, configured to use the sequence data stored in the safety sequencer to monitor the plurality of power units (120a-e) during the power-up sequence by means of the respective voltage monitors (155a-e), wherein the safety unit further comprises a fail-state unit configured to provide an output (FSOB) indicative of a fail-state of the power management device, and wherein the safety processing unit is further configured to provide the output (FSOB) to at least one of the power-good unit and the fail-state unit in response to the monitoring.