Patent ID: 6972606

Claim:
A delay circuit for providing an output signal according to an input signal so that when the level of the input signal changes from a first input level to a second input level, the level of the output signal changes from a first output level to a second output level after a predetermined delay time, the delay circuit comprising: a voltage generator for providing a reference voltage when the input signal changes from the first input level to the second input level; a current generator for providing a charging current when the input signal changes from the first input level to the second input level; a feedback control module comprising a control end and two transmit ends, the control end for receiving a charging voltage, and the feedback control module able to transmit the charging current from the current generator between the two transmit ends, and the feedback control module changing the proportion between a cross voltage of the two transmit ends and the current flowing between the two transmit ends; a storage unit electrically connected to the current generator and the control end of the feedback control module for receiving the charging current from the feedback control module and thereby generating the charging voltage; and an amplifier having two input ends electrically connected to the storage unit and the voltage generator in order to receive respectively the charging voltage and the reference voltage, the amplifier able to change the level of the output signal from the first output level to the second output level when the relationship between the reference voltage and the charging voltage changes.