Patent ID: 7379484

Claim:
A laser diode control circuit loop, comprising: a reference circuit with a programmable reference current, generated by a current source switch unit, a first endpoint of said reference circuit providing a first voltage and a second endpoint of said reference circuit providing a second voltage, according as said reference current passing through said first endpoint and said second endpoint; a voltage regulator connected to said current source switch unit for providing a reference voltage according as said reference current; a first high speed switch unit connected with said current source switch unit and said voltage regulator; a second high speed switch unit with said first endpoint and said second endpoint, connected to a first resistor within a fifth endpoint; wherein another end of said first resistor is connected to ground, said fifth endpoint generates a fifth endpoint voltage, and the current of said fifth endpoint is as said reference current; an emitter follower connected with said voltage regulator and said first endpoint for receiving said reference voltage to provide said first voltage and provide a corresponding second voltage within said second endpoint; and a driving circuit, a third endpoint thereof connected to said first endpoint of said reference circuit, a fourth endpoint thereof connected to said second endpoint of said reference circuit, an output end thereof providing a driving voltage and an output current to drive said laser diode.