Patent ID: 7808757
Filing Date: 2010-10-05
Classification: H02H

Abstract:
1. Power supply apparatus with overload protection comprising: switch means responsive to an input signal for switching between an ON-state for supplying current from a source of power to a load and an OFF-state for interrupting the supply of current to the load; and protection means responsive to an overload condition to switch said switch means to said OFF-state; wherein said protection means is responsive to a first overload condition during an initial phase of a predetermined duration after said switch means switches to said ON-state so as to switch said switch means back to said OFF-state and maintain said switch means in said OFF-state, and is subsequently responsive to a second overload condition if said first overload condition is not detected during said initial phase so as to switch said switch means to said OFF-state and subsequently switch said switch means back to said ON-state after an interval of time; wherein said protection means is again responsive to said first overload condition during a further phase of a predetermined duration when said switch means switches back to said ON-state after said interval of time so as to switch said switch means back to said OFF-state and maintain said switch means in said OFF-state, said further phase having a shorter duration than said initial phase.