Patent ID: 8022737

Claim:
A delay circuit for receiving an input signal from a signal source, the delay circuit comprising: a delay unit capable of being configured in a first mode and a second mode; a switch unit for receiving a voltage from a power supply and selectively transmitting the voltage to the delay unit according to the input signal; and a generator being coupled to the power supply; wherein in the first mode, the input signal is in a first logic level, the switch unit is turned on according to the input signal, thus the delay unit is charged up by the voltage from the power supply to generate a first electrical signal, the generator is used for generating a first output signal according to the first electrical signal, the first output signal is equivalent to the first logic level input signal that is delayed for a first predetermined time period; wherein in the second mode, the input signal is in a second logic level different from the first logic level, the switch unit is cut off according to the input signal, thus the delay unit is discharged to generate a second electrical signal, the generator is used for generating a second output signal according to the second electrical signal, the second output signal is equivalent to the second logic level input signal that is delayed for a second predetermined time period.