Abstract: A board includes a functional module, and further includes n switch modules, where first ends of the n switch modules are connected to the functional module, and second ends of the n switch modules are connected to n main power interface units respectively, where n is an integer greater than or equal to 2; and a power supply selecting module connected to control ends of the n switch modules, where the power supply selecting module is configured to detect residual power of the n main power interface units, select, from main power interface units with residual power greater than or equal to rated power of the board, a main power interface unit with lowest residual power as a power supply interface unit, and control a switch module connected to the power supply interface unit to be switched on.

Abstract: A voltage adjustment method, and a voltage pre-regulator power supply circuit and system, that implements highly-efficient output of a power supply in a quasi straight-through state and increases voltage output precision of a circuit. The voltage adjustment method includes receiving a to-be-adjusted voltage through a positive wire input end and a negative wire input end; changing, in a control mode in which a connection time is fixed and a disconnection time is adjusted, a duty cycle for the to-be-adjusted voltage to obtain a primary adjusted voltage; and changing, in a control mode in which a disconnection time is fixed and a connection time is adjusted, a duty cycle for the primary adjusted voltage to obtain an output voltage. The present disclosure is applied to a non-isolated direct-current quasi straight-through pre-regulator power supply.

Abstract: A board includes a functional module, and further includes n switch modules, where first ends of the n switch modules are connected to the functional module, and second ends of the n switch modules are connected to n main power interface units respectively, where n is an integer greater than or equal to 2; and a power supply selecting module connected to control ends of the n switch modules, where the power supply selecting module is configured to detect residual power of the n main power interface units, select, from main power interface units with residual power greater than or equal to rated power of the board, a main power interface unit with lowest residual power as a power supply interface unit, and control a switch module connected to the power supply interface unit to be switched on.

Abstract: A voltage adjustment method, and a voltage pre-regulator power supply circuit and system, that implements highly-efficient output of a power supply in a quasi straight-through state and increases voltage output precision of a circuit. The voltage adjustment method includes receiving a to-be-adjusted voltage through a positive wire input end and a negative wire input end; changing, in a control mode in which a connection time is fixed and a disconnection time is adjusted, a duty cycle for the to-be-adjusted voltage to obtain a primary adjusted voltage; and changing, in a control mode in which a disconnection time is fixed and a connection time is adjusted, a duty cycle for the primary adjusted voltage to obtain an output voltage. The present disclosure is applied to a non-isolated direct-current quasi straight-through pre-regulator power supply.