One embodiment of the present application discloses a control circuit comprising a driving circuit which comprises a voltage adjusting circuit, a first transistor and a second transistor. The first transistor comprises: a first terminal; a second terminal; and a control terminal, for receiving a bias voltage generated from at least operating voltage of the control circuit. The second transistor comprises: a first terminal, coupled to a second terminal of the first transistor; a second terminal, for receiving a first predetermined voltage; and a control terminal, for receiving the control voltage. A control system comprising the control circuit is also disclosed.