A power supply circuit, comprising: a voltage convertor circuit, configured to convert an input voltage into an output voltage, the voltage convertor circuit having a primary side and a secondary side, the primary side having at least one switch unit configured to control the primary side to selectively feed the input voltage in accordance with a controlling signal (SN2, SN1), the secondary side having at least two rectifying diodes (D80, D81) configured to rectify voltage coupled from the primary side; a controller, configured to generate the controlling signal (SN2, SN1) to control the switch unit; and a voltage generator, configured to be coupled to the primary side, configured to generate a voltage, and configured to provide the voltage to a power supply terminal (Vdd) of the controller, when none of the at least two rectifying diodes (D80, D81) being in an open fail state, the voltage provided to the controller being an operating voltage of the controller, and the controller is configured to generate the controlling signal (SN2, SN1) by being provided with the operating voltage; when one of the at least two rectifying diodes (D80, D81) being in the open fail state, the voltage provided to the controller being a shutdown voltage, and the controller is configured to stop generating the controlling signal (SN2, SN1) by being provided with the shutdown voltage, wherein the voltage generator comprises: an auxiliary winding (T31-b), arranged on the primary side, and arranged between a first node and a second node, the auxiliary winding (T31-b) couples to a primary winding (T31-a) of the primary side of the voltage convertor circuit; a first diode, arranged in a first branch connecting the first node and the power supply terminal (Vdd) of the controller; a second diode, arranged in a second branch connecting the first node and the power supply terminal (Vdd) of the controller; and a Zener diode, arranged in the second branch, the operating voltage is provided through the first branch, the shutdown voltage is provided through the second branch. a voltage convertor circuit, configured to convert an input voltage into an output voltage, the voltage convertor circuit having a primary side and a secondary side, the primary side having at least one switch unit configured to control the primary side to selectively feed the input voltage in accordance with a controlling signal (SN2, SN1), the secondary side having at least two rectifying diodes (D80, D81) configured to rectify voltage coupled from the primary side; a controller, configured to generate the controlling signal (SN2, SN1) to control the switch unit; and a voltage generator, configured to be coupled to the primary side, configured to generate a voltage, and configured to provide the voltage to a power supply terminal (Vdd) of the controller, when none of the at least two rectifying diodes (D80, D81) being in an open fail state, the voltage provided to the controller being an operating voltage of the controller, and the controller is configured to generate the controlling signal (SN2, SN1) by being provided with the operating voltage; when one of the at least two rectifying diodes (D80, D81) being in the open fail state, the voltage provided to the controller being a shutdown voltage, and the controller is configured to stop generating the controlling signal (SN2, SN1) by being provided with the shutdown voltage, wherein the voltage generator comprises: an auxiliary winding (T31-b), arranged on the primary side, and arranged between a first node and a second node, the auxiliary winding (T31-b) couples to a primary winding (T31-a) of the primary side of the voltage convertor circuit; a first diode, arranged in a first branch connecting the first node and the power supply terminal (Vdd) of the controller; a second diode, arranged in a second branch connecting the first node and the power supply terminal (Vdd) of the controller; and a Zener diode, arranged in the second branch, the operating voltage is provided through the first branch, the shutdown voltage is provided through the second branch. an auxiliary winding (T31-b), arranged on the primary side, and arranged between a first node and a second node, the auxiliary winding (T31-b) couples to a primary winding (T31-a) of the primary side of the voltage convertor circuit; a first diode, arranged in a first branch connecting the first node and the power supply terminal (Vdd) of the controller; a second diode, arranged in a second branch connecting the first node and the power supply terminal (Vdd) of the controller; and a Zener diode, arranged in the second branch, the operating voltage is provided through the first branch, the shutdown voltage is provided through the second branch.