A switching power device comprising: a normally-ON transistor having a source terminal and a gate terminal ; a normally-OFF transistor , having a source terminal or drain terminal connected to the source terminal of the normally-ON transistor ; a driver connected to the gate terminal of the normally-ON transistor and arranged to drive the gate terminal of the normally-ON transistor to perform switching of the normally-ON transistor ; a switching transistor connected between the source terminal of the normally-ON transistor and a common connection of the driver ; a sequencer ; wherein the switching transistor is turned off upon system turn on; and wherein the sequencer is configured to, after a predetermined time from system turn on: turn on the switching transistor so as to connect the source terminal of the normally-ON transistor to the common connection of the driver ; turn on the normally-OFF transistor so as to connect the source terminal of the normally-ON transistor to the drain or source terminal respectively of the normally-OFF transistor ; and permit insertion of pulse-width modulation signals for switching the switching power device. a normally-ON transistor having a source terminal and a gate terminal ; a normally-OFF transistor , having a source terminal or drain terminal connected to the source terminal of the normally-ON transistor ; a driver connected to the gate terminal of the normally-ON transistor and arranged to drive the gate terminal of the normally-ON transistor to perform switching of the normally-ON transistor ; a switching transistor connected between the source terminal of the normally-ON transistor and a common connection of the driver ; a sequencer ; wherein the switching transistor is turned off upon system turn on; and wherein the sequencer is configured to, after a predetermined time from system turn on: turn on the switching transistor so as to connect the source terminal of the normally-ON transistor to the common connection of the driver ; turn on the normally-OFF transistor so as to connect the source terminal of the normally-ON transistor to the drain or source terminal respectively of the normally-OFF transistor ; and permit insertion of pulse-width modulation signals for switching the switching power device. wherein the switching transistor is turned off upon system turn on; and wherein the sequencer is configured to, after a predetermined time from system turn on: turn on the switching transistor so as to connect the source terminal of the normally-ON transistor to the common connection of the driver ; turn on the normally-OFF transistor so as to connect the source terminal of the normally-ON transistor to the drain or source terminal respectively of the normally-OFF transistor ; and permit insertion of pulse-width modulation signals for switching the switching power device. turn on the switching transistor so as to connect the source terminal of the normally-ON transistor to the common connection of the driver ; turn on the normally-OFF transistor so as to connect the source terminal of the normally-ON transistor to the drain or source terminal respectively of the normally-OFF transistor ; and permit insertion of pulse-width modulation signals for switching the switching power device. <EOS>