Projection device and power conversion device

A power conversion device, comprising:

• a transformer, comprising a primary side input terminal, a secondary side output terminal, and an auxiliary output terminal, wherein the primary side input terminal is configured to receive a DC voltage, the transformer transforms the DC voltage to output a first voltage via the auxiliary output terminal and a second voltage via the secondary side output terminal, and the second voltage is greater than the first voltage;
• a first switch element, coupled between the transformer and a ground terminal;
• a control circuit, coupled to a control terminal of the first switch element;
• and
• a feedback module, coupled to the secondary side output terminal, the auxiliary output terminal, and the control circuit, wherein the feedback module is configured to receive a mode control signal, and to generate a feedback signal according to the first voltage output from the auxiliary output terminal and the second voltage output from the secondary side output terminal,
• wherein, in response to the mode control signal corresponding to a first mode, the feedback signal changes according to the first voltage;
• and
• in response to the mode control signal corresponding to a second mode, the feedback signal changes according to the second voltage;
• wherein the control circuit receives the feedback signal from the feedback module, a conductive state of the first switch element is switched according to the feedback signal, and a feedback voltage is generated to the primary side input terminal according to the feedback signal.