Soft start control method based on DC/DC circuit, circuit thereof, controller, and onboard device

The invention relates to the field of onboard power circuits and in particular to a soft start control method based on a DC/DC circuit, a circuit thereof, a controller, and an onboard device. The softstart control method based on the DC/DC circuit is used for a DC/DC soft start control circuit. The DC/DC circuit soft start control method includes: instructing a switch circuit to operate in an offstate to disconnect a circuit through which a high-voltage power supply charges a bus capacitor; and controlling the operating state of a voltage conversion circuit such that the power of an active load reversely charges the bus capacitor through the voltage conversion circuit. Thus, the voltage of the bus capacitor is charged to the voltage of the high-voltage power supply, thereby reducing a difference between the DC voltage and the bus capacitor voltage at the moment when the high-voltage power supply is connected, achieving a purpose of suppressing the startup inrush current and realizingthe soft start of the DC/D