A power supply circuit, comprising: n capacitors, m power branches, and a control chip, wherein the n capacitors are connected in series to a power source that supplies power to the power supply circuit, each of the power branches is connected in parallel to at least one of the n capacitors, the m power branches comprise at least one first-type power branch and at least one second-type power branch, the first-type power branch comprises a pre-boost topology structure and an open-loop topology structure connected in series to the pre-boost topology structure, the second-type power branch comprises a closed-loop topology structure, and n and m are integers greater than or equal to 2; wherein: the pre-boost topology structure comprises a first switching transistor and a second switching transistor, and the pre-boost topology structure comprises a straight-through state and a closed-loop state, wherein the straight-through state is a state in which the first switching transistor is closed and the second switching transistor is open so that an output voltage of the pre-boost topology structure is equal to an input voltage of the pre-boost topology structure, and the closed-loop state is a state in which duty cycles of the first switching transistor and the second switching transistor change with the output voltage of the pre-boost topology structure; and the control chip is connected to the pre-boost topology structure, and is configured to control, based on an output voltage of the power source, the pre-boost topology structure to switch between the straight-through state and the closed-loop state, so that the pre-boost topology structure pre-adjusts the output voltage of the power source and outputs a voltage that falls within a voltage range required by the open-loop topology structure; wherein the control chip is further configured to: when the output voltage of the power source is higher than a preset voltage, control the pre-boost topology structure to be in the straight-through state; and when the output voltage of the power source is lower than the preset voltage, control the pre-boost topology structure to be in the closed-loop state; wherein when the closed-loop topology structure is a topology structure that switches between an open-loop state and a closed-loop state, the control chip is further configured to: when the output voltage of the power source is higher than the preset voltage, control the topology structure that switches between the open-loop state and the closed-loop state to be in the closed-loop state; and when the output voltage of the power source is lower than the preset voltage, control the topology structure that switches between the open-loop state and the closed-loop state to be in the open-loop state. the pre-boost topology structure comprises a first switching transistor and a second switching transistor, and the pre-boost topology structure comprises a straight-through state and a closed-loop state, wherein the straight-through state is a state in which the first switching transistor is closed and the second switching transistor is open so that an output voltage of the pre-boost topology structure is equal to an input voltage of the pre-boost topology structure, and the closed-loop state is a state in which duty cycles of the first switching transistor and the second switching transistor change with the output voltage of the pre-boost topology structure; and the control chip is connected to the pre-boost topology structure, and is configured to control, based on an output voltage of the power source, the pre-boost topology structure to switch between the straight-through state and the closed-loop state, so that the pre-boost topology structure pre-adjusts the output voltage of the power source and outputs a voltage that falls within a voltage range required by the open-loop topology structure; wherein the control chip is further configured to: when the output voltage of the power source is higher than a preset voltage, control the pre-boost topology structure to be in the straight-through state; and when the output voltage of the power source is lower than the preset voltage, control the pre-boost topology structure to be in the closed-loop state; wherein when the closed-loop topology structure is a topology structure that switches between an open-loop state and a closed-loop state, the control chip is further configured to: when the output voltage of the power source is higher than the preset voltage, control the topology structure that switches between the open-loop state and the closed-loop state to be in the closed-loop state; and when the output voltage of the power source is lower than the preset voltage, control the topology structure that switches between the open-loop state and the closed-loop state to be in the open-loop state.