Auxiliary recharge

A charging circuit for supplying charge to a charge store for providing power to a switching controller of a switch mode power converter (SMPC), the SMPC comprising:

• an inductive component having a winding coupled to receive power from an input to said SMPC;
• a switching circuit comprising first and second switching transistors, said first transistor coupled in series between said winding and said second transistor and to receive a winding current wherein said winding current is a current derived from said winding;
• a switching controller to control switching of said second transistor;
• and
• a charge store coupled to provide power to said switching controller, the charging circuit comprising:
• a current diversion circuit to conduct a said winding current from the first transistor to said charge store;
• and
• said second transistor arranged to controllably decouple a reference voltage line from said current diversion circuit to allow said winding current to flow through said current diversion circuit to said charge store.

A charging circuit for supplying charge to a charge store for providing power to a switching controller of a switch mode power converter (SMPC), the SMPC having:

• an inductive component having a winding coupled to receive power from an input to said SMPC;
• a switching circuit comprising first and second switching transistors, said first transistor coupled in series between said winding and said second transistor;
• a switching controller to control switching of said second transistor;
• and
• a charge store to provide power to said switching controller,
• the charging circuit comprising:
• means for conducting current from said winding through said first transistor;
• and
• means for diverting said current through a conduction path to said charge store.