US Patent 7978983 Optical triggered self-timed clock generation

A self-timed clock circuit and method of generating a self-timed clock circuit. The circuit includes means for charging a circuit node in response to an external reset signal; means for discharging the circuit node in response to a trigger signal generated by a photodiode; means for generating a first signal indicating a logic level of the circuit node; means for generating and delaying a second signal indicating the logic state of the circuit node; means for combining the first and second signals to generate a recharge signal; and means for recharging the circuit node in response to the recharge signal.