Power supply selector and power supply selection method

A power supply selector, comprising:

• a first selection module, configured to receive multiple candidate power supplies and select a power supply from the multiple candidate power supplies as an internal power supply;
• a control module, coupled to the first selection module and configured to receive the multiple candidate power supplies, use the internal power supply as a power supply, and compare voltages of the multiple candidate power supplies to generate a control signal of each candidate power supply in the multiple candidate power supplies;
• a second selection module, coupled to the control module and configured to receive the multiple candidate power supplies, and select a power supply for output from the multiple candidate power supplies under control of the control signal of each candidate power supply;
• a voltage shift module, the second selection module coupled to the control module through the voltage shift module, and the voltage shift module is configured to obtain the power supply for output fed back by the second selection module as a power supply of the voltage shift module, and shift a high voltage level of the control signal of each candidate power supply to a voltage of the power supply for output;
• and
• a drive module, configured to obtain the control signal of each candidate power supply output by the voltage shift module, improve driving capability of the output control signal of each candidate power supply, and output the control signal of each candidate power supply with improved driving capability to the second selection module.