Embodiments of this application provide a voltage conversion circuit, a control method, a DC/DC converter and a device. The voltage conversion circuit includes a failure isolation module, a soft start module, and a voltage conversion module. The voltage conversion module includes an output filter capacitor. Both a first terminal of the failure isolation module and a first terminal of the soft start module are connected to a positive electrode of a first battery, both a second terminal of the failure isolation module and a second terminal of the soft start module are connected to a first terminal of the output filter capacitor, and a second terminal of the output filter capacitor is connected to a negative electrode of the first battery. The soft start module is configured to connect the first battery and the output filter capacitor, so that the first battery charges the output filter capacitor.