v dd and v ss and the voltage v dd the voltage v 2 is higher than the voltage v ss in principle for example the voltage v 2 can be in the range between the average of the voltages v dd and v ss and the voltage v ss the falling edge trigger circuit 301 triggers a pulse signal p f with a predetermined period on the node s f according to the input signal d in more particularly the falling edge trigger circuit 301 triggers a pulse signal with the predetermined period p f on the node s f when the input signal d in in the transient status that the voltage of the input signal d in falls from the high voltage to the low voltage falling edges the pulse signal p f is transmitted to the control end c of the switch sw 1 when the switch sw 1 does not receive the pulse signal p f the first end 1 of the switch sw 1 is not coupled to the second end 2 of the switch sw 1 that is the voltage source v 1 does not transmit the voltage v 1 to the output end of the output circuit 300 and thus the output signal d out is not affected when the switch sw 1 receives the pulse signal p f the first end 1 of the switch sw 1 is coupled to the second end 2 of the switch sw 1 that is the voltage source v 1 transmits the voltage v 1 to the output end of the output.