Patent ID: 8217664

Claim:
An apparatus for generating a time delayed event, comprising: a first time measurement unit comprising: a first constant current source; a first current steering switch coupled to the first constant current source; a first capacitor coupled to the first current steering switch, the first capacitor having a known value of capacitance, wherein a first voltage on the first capacitor increases substantially linearly in time when the first current steering switch couples the first constant current source to the first capacitor; a first circuit for controlling the first current steering switch, wherein the first current steering switch couples the first capacitor to the first constant current source when the first circuit detects a start of an event; a second time measurement unit comprising: a second constant current source; a second current steering switch coupled to the second constant current source; a second capacitor coupled to the second current steering switch, the second capacitor having a known value of capacitance, wherein a second voltage on the second capacitor increases substantially linearly in time when the second current steering switch couples the second constant current source to the second capacitor; a second circuit for controlling the second current steering switch, wherein the second current steering switch couples the second capacitor to the second constant current source when the second circuit detects an end of the event; a first analog comparator having a positive input for receiving the first voltage and a negative input for receiving a first reference voltage; and a second analog comparator having a negative input for receiving the second voltage and a positive input for receiving a second reference voltage; wherein a start of a delayed event occurs when the first voltage is equal to or greater than the first reference voltage, and an end of the delayed event occurs when the second voltage is equal to or greater than the second reference voltage.