An adjuster includes a power transfer circuit, a negative feedback circuit, a constant current source circuit and a control circuit. Two inputs of an error amplifier in the negative feedback circuit receive a reference voltage and a feedback voltage corresponding to an output signal of the adjuster respectively, and the error amplifier is configured to output a first voltage signal when the feedback voltage is less than the reference voltage, and output a second voltage signal when the feedback voltage is greater than the reference voltage, during the starting process of the adjuster. The control circuit is configured to control the negative feedback circuit to be turned off and the constant current source circuit to be turned on, and control the constant current source circuit to be turned off and the negative circuit to be turned on according to the second voltage signal.