A voltage converting apparatus comprising: a plurality of output channels (120, 130) configured to provide a plurality of output voltages; a main energy transfer circuit comprising an inductor and configured to transfer, through the inductor, energy of an input power supply to a target output channel among the output channels (120, 130); an auxiliary energy transfer circuit (140, 150) connected to one of the output channels (120, 130), wherein the apparatus further comprises additional auxiliary energy transfer circuits respectively connected to remaining ones of the output channels so that the apparatus comprises a plurality of auxiliary energy transfer circuits respectively connected to the plurality of output channels in a one-to-one correspondence; a plurality of auxiliary energy controllers (160, 170), wherein each auxiliary energy controller (160, 170) of the plurality of auxiliary energy controllers (160, 170) is configured to control a respective auxiliary energy transfer circuit to transfer a respective amount of energy needed by a respective output channel to the respective output channel, wherein the main energy transfer circuit is further configured to determine, based on an amount of energy to be transferred to the output channels (120, 130) connected to the auxiliary energy transfer circuits (140, 150), the target output channel to which energy of the input power supply is to be transferred through the inductor, wherein each of the auxiliary energy transfer circuits (140, 150) is configured to transfer energy to the output channel connected to the respective auxiliary energy transfer circuit (140, 150) without using the inductor, and wherein each of the auxiliary energy transfer circuits (140, 150) comprises a current source configured to supply a current to the output channel connected to the respective auxiliary energy transfer circuit (140, 150), or comprises a variable resistor, in which case the respective auxiliary energy controller (160, 170) is configured to control an amount of a current to be transferred to the output channel (120, 130) connected to the respective auxiliary energy transfer circuit (140, 150) by adjusting a resistance value of the variable resistor, wherein the plurality of auxiliary energy controllers (160, 170) are further configured to respectively estimate respective output errors of the output channels based on the respective outputs of the output channels; an output error summer configured to calculate a sum of the estimated respective output errors of the output channels; and an inductor control signal generator configured to control a switch to adjust the amount of power supplied from the input power supply to the inductor based on the sum of the estimated respective output errors. a plurality of output channels (120, 130) configured to provide a plurality of output voltages; a main energy transfer circuit comprising an inductor and configured to transfer, through the inductor, energy of an input power supply to a target output channel among the output channels (120, 130); an auxiliary energy transfer circuit (140, 150) connected to one of the output channels (120, 130), wherein the apparatus further comprises additional auxiliary energy transfer circuits respectively connected to remaining ones of the output channels so that the apparatus comprises a plurality of auxiliary energy transfer circuits respectively connected to the plurality of output channels in a one-to-one correspondence; a plurality of auxiliary energy controllers (160, 170), wherein each auxiliary energy controller (160, 170) of the plurality of auxiliary energy controllers (160, 170) is configured to control a respective auxiliary energy transfer circuit to transfer a respective amount of energy needed by a respective output channel to the respective output channel, wherein the main energy transfer circuit is further configured to determine, based on an amount of energy to be transferred to the output channels (120, 130) connected to the auxiliary energy transfer circuits (140, 150), the target output channel to which energy of the input power supply is to be transferred through the inductor, wherein each of the auxiliary energy transfer circuits (140, 150) is configured to transfer energy to the output channel connected to the respective auxiliary energy transfer circuit (140, 150) without using the inductor, and wherein each of the auxiliary energy transfer circuits (140, 150) comprises a current source configured to supply a current to the output channel connected to the respective auxiliary energy transfer circuit (140, 150), or comprises a variable resistor, in which case the respective auxiliary energy controller (160, 170) is configured to control an amount of a current to be transferred to the output channel (120, 130) connected to the respective auxiliary energy transfer circuit (140, 150) by adjusting a resistance value of the variable resistor, wherein the plurality of auxiliary energy controllers (160, 170) are further configured to respectively estimate respective output errors of the output channels based on the respective outputs of the output channels; an output error summer configured to calculate a sum of the estimated respective output errors of the output channels; and an inductor control signal generator configured to control a switch to adjust the amount of power supplied from the input power supply to the inductor based on the sum of the estimated respective output errors.