Patent ID: 7403215

Claim:
A method of controlling current sources in a laser driver comprising: providing a laser source; providing at least one bias current source coupled to said laser source; providing at least two switched current sources, each independently controllable to be switchably coupled to said laser source; providing a laser power control signal that corresponds to a desired laser output power for each of said at least two switched current sources; defining an output power error measure based upon an error between a measured laser output power and said desired laser output power for each of said at least two switched current sources; characterizing a control system in which said output power error measures combine to change a magnitude of each of said at least two switched current sources and said at least one bias current source such that said output power error measures converge over time; sampling laser output power for each of said at least two switched current sources during a non-printing portion of a scan operation; and adjusting said magnitudes of said at least two switched current sources and said at least one bias current source based upon said characterized control system and said sampled laser output power for each of said at least two switched current sources.