A step-up apparatus comprising a step-up circuit, the step-up circuit comprising: an inductor, connectable to a first terminal of a power supply; N switch components (T1, T2,..., Tn), wherein the N switch components are connected in series, a first terminal of the first switch component of the N switch components is connectable to the first terminal of the power supply through the inductor, a second terminal of an N th switch component is connectable to a second terminal of the power supply, N > 1; N-1 flying capacitors (C1 C2,..., Cn-1) and N flyback diodes (D1, D2,..., Dn), wherein a first terminal of the ith flying capacitor is connected to a first terminal of the first switch component through first i flyback diodes, and a second terminal of the ith flying capacitor is connected to a second terminal of the ith switch component and wherein during normal operation of the step-up circuit, a voltage withstood by the i th flying capacitor is a sum of voltages withstood by the first i switch components, wherein i is a positive integer less than N; and wherein a voltage withstood by an i th flyback diode of the N flyback diodes is the same as that withstood by an i th switch component of the N switch components; and the step-up circuit further comprises a pre-charge unit, and the step-up apparatus is configured to control the pre-charge unit to charge the N-1 flying capacitors before the step-up circuit outputs a voltage, so that the voltage across the i th flying capacitor is the sum of the voltages withstood by the first i switch components of the N switch components during normal operation; characterized in that: K switch components of the N switch components have withstand voltage specifications different from each other, voltages withstood by the K switch components during normal operation are different from each other, both N and K are positive integers, and K ≤ N, the step-up apparatus is configured to control the N switch components (T1, T2,..., Tn) to be on or off, so that the step-up circuit outputs a voltage, wherein the step-up apparatus is configured to control an on or off time of each of the N switch components, to control the voltages withstood by the K switch components during normal operation to be different from each other, so that a voltage actually withstood by each switch component is close to a withstand voltage specification to a maximum extent, thereby improving the system efficiency of the step-up circuit. an inductor, connectable to a first terminal of a power supply; N switch components (T1, T2,..., Tn), wherein the N switch components are connected in series, a first terminal of the first switch component of the N switch components is connectable to the first terminal of the power supply through the inductor, a second terminal of an N th switch component is connectable to a second terminal of the power supply, N > 1; N-1 flying capacitors (C1 C2,..., Cn-1) and N flyback diodes (D1, D2,..., Dn), wherein a first terminal of the ith flying capacitor is connected to a first terminal of the first switch component through first i flyback diodes, and a second terminal of the ith flying capacitor is connected to a second terminal of the ith switch component and wherein during normal operation of the step-up circuit, a voltage withstood by the i th flying capacitor is a sum of voltages withstood by the first i switch components, wherein i is a positive integer less than N; and wherein a voltage withstood by an i th flyback diode of the N flyback diodes is the same as that withstood by an i th switch component of the N switch components; and the step-up circuit further comprises a pre-charge unit, and the step-up apparatus is configured to control the pre-charge unit to charge the N-1 flying capacitors before the step-up circuit outputs a voltage, so that the voltage across the i th flying capacitor is the sum of the voltages withstood by the first i switch components of the N switch components during normal operation; characterized in that: K switch components of the N switch components have withstand voltage specifications different from each other, voltages withstood by the K switch components during normal operation are different from each other, both N and K are positive integers, and K ≤ N, the step-up apparatus is configured to control the N switch components (T1, T2,..., Tn) to be on or off, so that the step-up circuit outputs a voltage, wherein the step-up apparatus is configured to control an on or off time of each of the N switch components, to control the voltages withstood by the K switch components during normal operation to be different from each other, so that a voltage actually withstood by each switch component is close to a withstand voltage specification to a maximum extent, thereby improving the system efficiency of the step-up circuit. K switch components of the N switch components have withstand voltage specifications different from each other, voltages withstood by the K switch components during normal operation are different from each other, both N and K are positive integers, and K ≤ N, the step-up apparatus is configured to control the N switch components (T1, T2,..., Tn) to be on or off, so that the step-up circuit outputs a voltage, wherein the step-up apparatus is configured to control an on or off time of each of the N switch components, to control the voltages withstood by the K switch components during normal operation to be different from each other, so that a voltage actually withstood by each switch component is close to a withstand voltage specification to a maximum extent, thereby improving the system efficiency of the step-up circuit.