The invention discloses a power supply circuit, a terminal, and a
voltage output method. The power supply circuit includes a power supply
input output circuit and a
feedback control circuit; the power supply
input output circuit includes a power supply input module, a power supply output module, a feedback comparison module, and a grounding module; the power supply output module is connected to a power receiving device; one end of the
feedback control circuit is connected to the power supply output module, and the other end of the
feedback control circuit is connected to the feedback comparison module; the feedback
control circuit is used for inputting the corresponding feedback
voltage to the feedback comparison module according to the output
voltage of the power supply output module; the feedback voltage and the output voltage meet at least one preset calculation formula, the feedback comparison module compares the feedback voltage and the preset reference voltage, and when the comparison result is different, the power supply output module adjusts the output voltage till the feedback voltage is identical to the reference voltage. According to the invention, the feedback
control circuit is improved so as to achieve output of voltages at different levels, and the feedback
control circuit is simple in design, is easy to achieve, can avoid an additional power supply
input output circuit, and can save the cost.