A power supply circuit , comprising: a primary rectifier unit , configured to perform rectification on input alternating current to output a first voltage having a periodically changing voltage value and the waveform of the first voltage is a pulsating waveform; a modulation unit , configured to modulate the first voltage to generate a second voltage; a transformer , configured to generate a third voltage based on the second voltage; a secondary rectifier and filtering unit , configured to perform rectification and filtering on the third voltage to generate an output current of the power supply circuit ; a current feedback unit , configured to receive the output current, and to send a feedback signal to the modulation unit when a current value of the output current reaches a preset current limit value, wherein the modulation unit is configured to perform modulating the first voltage to generate the second voltage according to the feedback signal, to limit the current value of the output current below the current limit value; and a control unit , configured to determine a voltage of the alternating current, to set the current limit value of the current feedback unit as a first current value when the voltage of the alternating current is of a first type, and to set the current limit value of the current feedback unit as a second current value when the voltage of the alternating current is of a second type, in which an amplitude of the voltage of the first type is greater than that of the voltage of the second type, and the first current value is greater than the second current value, wherein the power supply circuit does not comprise a liquid electrolytic capacitor at the primary side. a primary rectifier unit , configured to perform rectification on input alternating current to output a first voltage having a periodically changing voltage value and the waveform of the first voltage is a pulsating waveform; a modulation unit , configured to modulate the first voltage to generate a second voltage; a transformer , configured to generate a third voltage based on the second voltage; a secondary rectifier and filtering unit , configured to perform rectification and filtering on the third voltage to generate an output current of the power supply circuit ; a current feedback unit , configured to receive the output current, and to send a feedback signal to the modulation unit when a current value of the output current reaches a preset current limit value, wherein the modulation unit is configured to perform modulating the first voltage to generate the second voltage according to the feedback signal, to limit the current value of the output current below the current limit value; and a control unit , configured to determine a voltage of the alternating current, to set the current limit value of the current feedback unit as a first current value when the voltage of the alternating current is of a first type, and to set the current limit value of the current feedback unit as a second current value when the voltage of the alternating current is of a second type, in which an amplitude of the voltage of the first type is greater than that of the voltage of the second type, and the first current value is greater than the second current value, wherein the power supply circuit does not comprise a liquid electrolytic capacitor at the primary side. <EOS>