High efficiency power conversion circuit having high voltage tolerance

A power conversion circuit, which is configured to operably perform power conversion between a bus voltage at a bus node and a first voltage at a first node;

• the power conversion circuit comprising:
• a bus switch, which is coupled between the bus node and a second node, wherein the second node has a second voltage;
• a plurality of conversion switches coupled, with at least one conversion capacitor, to the first node and the second node, wherein in a power conversion mode, the bus switch is turned ON, and t the plurality of the conversion switches are configured to operably switch the at least one conversion capacitor and periodically, thereby power conversion between the second voltage and the first voltage via a switched capacitor power conversion method is performed;
• and
• a clamp circuit which includes a plurality of sub-clamp circuits, wherein the respective plurality of sub-clamp circuits are configured to operably clamp respective drain-gate voltages of respective corresponding switches of a group of switches, so that respective drain-gate voltages of the respective corresponding switches of the group of switches do not exceed respective a drain-gate clamp voltage, wherein the group of switches include the bus switch and at least one of the plurality of the conversion switches, so that when the bus node is applied with a bus maximum rating voltage, respective drain-source voltages of the bus switch and the respective corresponding plurality of conversion switches are smaller than a corresponding breakdown voltage;
• wherein the bus maximum rating voltage is higher than the respective breakdown voltage of the bus switch and the respective corresponding plurality of conversion switches.